tag:theconversation.com,2011:/id/topics/zoonoses-4864/articlesZoonoses – The Conversation2024-03-07T18:17:29Ztag:theconversation.com,2011:article/2234812024-03-07T18:17:29Z2024-03-07T18:17:29ZMany owners allow their dogs to lick their faces, but it could be unhealthy – and even fatal<figure><img src="https://images.theconversation.com/files/580085/original/file-20240306-20-4atcf6.jpg?ixlib=rb-1.1.0&rect=13%2C20%2C4653%2C3085&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/boy-his-dog-pomeranian-cup-ice-1142817122">RanQuick/Shutterstock</a></span></figcaption></figure><p>Any dog owners reading this will know the joy of getting home and being greeted with utter delight by their pet – tail wagging wildly before enthusiastic but face-drenching licks. While some owners will push their pooches away playfully to discourage face licking, others positively revel in their dog’s affection and may even offer up pursed lips for a canine kiss. </p>
<p>It’s a heartwarming scene. But think of what that doggy companion has been licking throughout the day. Their food and water, their paws, their toys and chews – and maybe their bottom and genitals. Do those cute kisses seem a little less appealing now? </p>
<p>Not matter what pets have licked, many owners are so taken with their dogs that they’re willing to overlook the potential hygiene issues. </p>
<p>And licking is important for dogs. It’s an instinctive canine behaviour. When dogs repeatedly lick their mouths, it can be a <a href="https://www.sciencedirect.com/science/article/abs/pii/S0168159196011318">subtle sign of stress</a> or fear, especially when combined with ears back and a tense expression. In fact, observing lip licking frequency is a way to gauge dogs’ welfare during <a href="https://www.sciencedirect.com/science/article/abs/pii/S1558787814000070">training sessions</a> and when <a href="https://www.sciencedirect.com/science/article/pii/S0031938407002582?via%3Dihub">kept in kennels</a>. </p>
<p>Dogs also use lip licking as a <a href="https://doi.org/10.1016/j.beproc.2017.11.006">behavioural response</a> to humans’ emotional states. Evidence suggests that <a href="https://theconversation.com/woof-dogs-really-can-tell-how-their-owners-are-feeling-new-study-shows-53075">dogs are empathetic</a>. They can recognise emotions in both humans and other dogs using visual and audio cues. A study showed that dogs lick their lips more frequently when looking at <a href="https://doi.org/10.1016/j.beproc.2017.11.006">angry human faces</a>.</p>
<p>For dogs, then, lip licking is a natural instinct – and that applies to relationships with their humans, too. For anyone living with a dog, being licked is a common event, and many dogs will try to lick the faces and mouths of their humans. <a href="https://www.mdpi.com/1660-4601/17/12/4300">Almost half</a> of canine owners report being licked on their face by their dog. But, given the penchant that many dogs have for consuming items owners might not find appetising (quick <a href="https://theconversation.com/explaining-coprophagy-why-do-dogs-eat-their-own-poo-91273">poo snack</a>, anyone?) is it hygienic, or even safe, to let your dog lick your face? </p>
<h2>What hides within</h2>
<p>Owners usually love their dogs, and <a href="https://www.tandfonline.com/doi/abs/10.1080/13607863.2019.1633620">dogs’ companionship</a> and affection can do wonders for their owners’ wellbeing and <a href="https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2022.903647/full">mental health</a>. But there’s no doubt that, for some humans, canine saliva might do more harm than good. </p>
<p>For people <a href="https://www.cdc.gov/healthypets/specific-groups/high-risk/organ-transplant-patients.html">who are immunocompromised</a>, have open wounds, or a dog who likes to supplement their meals with a spot of coprophagia (poop eating), then it’s best to avoid those face licks. </p>
<p>Dogs’ mouths can harbour a <a href="https://www.cmaj.ca/content/187/10/736.short">range of microorganisms</a> that are usually low risk for humans. However, in rare cases, <a href="https://www.who.int/news-room/fact-sheets/detail/zoonoses">zoonoses</a> (infectious diseases passed on between species) can be transmitted from dogs to humans by bites, licks and scratches.</p>
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<p>Most of the time, humans who come into contact with dog saliva do not become ill. In fact, many people manage to live alongside their pets, licks and all, without encountering any health issues. </p>
<p>However, there are rare cases where people have become seriously ill following contact with dog saliva. For example, <em>Capnocytophaga canimorsus</em>, a bacteria found in the mouths of <a href="https://theconversation.com/how-deadly-is-your-dogs-saliva-62074">up to three quarters</a> of otherwise healthy dogs and cats, has caused <a href="https://casereports.bmj.com/content/2016/bcr-2016-215450">life-threatening sepsis</a>.</p>
<p>Other microbes such as <em>Pasteurella multocida</em> can be spread by contact with dog saliva, potentially resulting in serious outcomes <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(19)30953-5/abstract">including meningitis</a>. </p>
<p>People considered to be at high risk from <a href="https://doi.org/10.1128/cmr.00024-13">zoonotic infections</a> are the immunocompromised, very young children, older adults and pregnant women. </p>
<p>If you fall into one of these groups, then it’s in your interest to dodge dog licks. Additional measures should also be implemented for at risk dog owners. Keep surfaces clean, minimise contamination of household items and maintain scrupulous household hygiene at all times, especially after contact with animals.</p>
<p>Antibiotic resistance is recognised as a major <a href="https://www.unep.org/topics/chemicals-and-pollution-action/pollution-and-health/antimicrobial-resistance-global-threat">global health challenge</a>. Canine saliva can be a potential <a href="https://www.mdpi.com/2079-6382/11/11/1490">source of bacteria</a> carrying antibiotic resistant genes. These bacteria are capable of colonising humans after <a href="https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.621597/full">exposure to dog saliva</a>. </p>
<p>However, in 2023 <a href="https://www.the-microbiologist.com/news/multi-drug-resistant-organisms-can-be-transmitted-between-healthy-dogs-and-cats-and-their-hospitalised-owners/761.article">a German study</a> of 2,800 hospital patients and their companion animals verified “that the sharing of multidrug-resistant organisms between companion animals and their owners is possible”, but the study only identified a handful of cases. The researches therefore <a href="https://www.theguardian.com/society/2023/mar/19/dogs-and-cats-could-be-passing-on-drug-resistant-bugs-to-owners-study-finds">concluded that</a> “cat or dog ownership isn’t an important risk factor for multidrug-resistant organism colonisation in hospital patients.” </p>
<p>It is possible, then, that being licked by your dog could contribute to the spread of antibiotic resistance – but it isn’t likely.</p>
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<h2>Doctor dog</h2>
<p>Despite potential threats to health, can dog licks be beneficial? </p>
<p>Records suggest that in the past, <a href="https://ethnobiomed.biomedcentral.com/articles/10.1186/s13002-017-0175-6">animal saliva</a> has been used for wound healing, with some dogs specially trained to <a href="https://www.sciencedirect.com/science/article/abs/pii/014067369290480Q">lick open wounds</a>. However, there is no research to suggest that allowing animal companions to lick wounds will help them to heal. Allowing animals to lick open wounds, in fact, could put an owner at increased <a href="https://www.liebertpub.com/doi/abs/10.1089/vbz.2019.2558">risk of infection</a>.</p>
<p>The relationship between humans and their dogs can confer other potentially healing benefits. <a href="https://www.bacp.co.uk/about-therapy/types-of-therapy/animal-assisted-therapy/#:%7E:text=Animal%2Dassisted%20therapy%20can%20help,struggling%20with%20anxiety%20or%20depression.">Animal-assisted therapy</a> helps people with a range of issues, such as anxiety, eating disorders and trauma. Cuddling and stroking dogs, for example, <a href="https://www.hopkinsmedicine.org/health/wellness-and-prevention/the-friend-who-keeps-you-young#:%7E:text=The%20cortisol%2Dlowering%20and%20oxytocin,%E2%80%9CIt's%20relaxing%20and%20transcendental.%E2%80%9D">can help patients</a> to feel calmer and lower blood pressure and heart rate. </p>
<p>Dog owners tend to benefit from their pets through increased <a href="https://www.sciencedirect.com/science/article/abs/pii/S1469029216300048">physical activity and social connections</a>, as well as companionship and improved mental health. Licking, however, is not essential to the close bond between human and canine.</p>
<p>Within reason, for most people, letting your dog lick you is probably safe. With good management, healthcare (for you and your dog) and excellent hygiene, the risks of an occasional lick are likely to be minimal. But it’s a good idea to enforce the “not on the mouth” rule, for everyone’s safety.</p><img src="https://counter.theconversation.com/content/223481/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jacqueline Boyd is affiliated with The Kennel Club (UK) through membership, as Chair of the Activities Health and Welfare Subgroup and member of the Dog Health Group. Jacqueline is a full member of the Association of Pet Dog Trainers (APDT #01583) and she also writes, consults and coaches on canine matters on an independent basis, in addition to her academic affiliation at Nottingham Trent University</span></em></p>Dogs may be a human’s best friend but there are limits – is face licking one of them?Jacqueline Boyd, Senior Lecturer in Animal Science, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2234702024-02-21T13:17:46Z2024-02-21T13:17:46ZWhat is Alaskapox? A microbiologist explains the recently discovered virus that just claimed its first fatality<figure><img src="https://images.theconversation.com/files/575275/original/file-20240211-16-m5e8r4.jpg?ixlib=rb-1.1.0&rect=29%2C32%2C993%2C617&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Red-backed voles may be harboring Alaskapox.</span> <span class="attribution"><a class="source" href="https://ecuador.inaturalist.org/">iNaturalist Ecuador</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span></figcaption></figure><p><em>Alaskapox, a virus in the same family as smallpox, cowpox and mpox, <a href="https://abcnews.go.com/Health/wireStory/alaskapox-recent-death-brings-attention-virus-small-animals-107207953">claimed its first fatality</a> in January 2024 when an elderly Alaskan man died of the illness.</em></p>
<p><em>The virus, which was discovered in 2015, had previously resulted in only relatively mild illnesses in the six other people infected by it. So why did the Alaskan man die?</em></p>
<p><em>Raúl Rivas González, a microbiologist at the University of Salamanca in Spain, explains what we know about Alaskapox, what happened to the man in Alaska, and the threat posed by the thousands of similar viruses out there.</em></p>
<h2>What’s the origin of Alaskapox?</h2>
<p>Alaskapox is an orthopox virus <a href="https://doi.org/10.1093%2Fcid%2Fcix219">discovered in 2015</a> in the Fairbanks area of Alaska. </p>
<p>Until the most recent case, there were only six known human infections, which all involved mild illnesses consisting of a localized rash and the swelling of lymph nodes. </p>
<h2>How did the man in Alaska die?</h2>
<p>In mid-September 2023, the man was living on the Kenai Peninsula, south of the city of Anchorage, Alaska, and <a href="https://abcnews.go.com/Health/wireStory/alaskapox-recent-death-brings-attention-virus-small-animals-107207953">undergoing drug treatment for cancer</a>, and so had a suppressed immune system. He noticed a tender red papule – a type of skin lesion – in his right armpit.</p>
<p>Understandably, he was scared and decided to go to the doctor immediately. Over the next six weeks, he made several visits to the primary care center and the local emergency department for clinical evaluation of the lesion.</p>
<p>The case was confusing and the possible infection difficult to identify. He did not respond to antibiotic treatment. A needle biopsy revealed no evidence of malignancy or bacterial infection. The health care providers were puzzled. </p>
<p>After the situation worsened, the man was hospitalized in Anchorage. Eventually, doctors performed an extensive battery of tests and sent a sample to the Centers for Disease Control and Prevention, which determined he had <a href="http://www.doi.org/10.3390/v11080708">Alaskapox</a>.</p>
<p>He was immediately given treatment for the virus, but it was too late and he died at the end of January. Officials <a href="https://epi.alaska.gov/bulletins/docs/b2024_02.pdf">confirmed the cause of death</a> was Alaskapox in February.</p>
<h2>Where do viruses like Alaskapox come from?</h2>
<p>Currently, more than <a href="https://doi.org/10.1128%2Fjcm.00337-22">10,000 species of viruses</a> have been recognized by the International Committee on Taxonomy of Viruses. We know that about 270 of them can infect people. </p>
<p>Some of these viruses have been known for centuries, such as polio and smallpox, while others like Alaskapox have only recently emerged. In fact, viruses constitute about <a href="https://doi.org/10.1098%2Frstb.2011.0354">two-thirds of all new human pathogens</a>. These new viruses differ widely in their risk to human health, ranging from the rare and mild illness caused by the Menangle virus to the <a href="https://covid.cdc.gov/covid-data-tracker/#datatracker-home">devastating public health impact</a> of the virus that causes COVID-19. </p>
<p>Of the viruses known to infect humans, about 80% are naturally occurring in nonhuman hosts, primarily <a href="https://doi.org/10.1016%2Fj.scitotenv.2020.142372">in mammals and birds</a> and, to a lesser extent, in arthropods and other wildlife. </p>
<p>Infectious agents transmitted from animals to humans are estimated to constitute about 60% of known human pathogens and up to <a href="https://doi.org/10.1073/pnas.1919176117">75% of emerging human pathogens</a>. Unfortunately, there is insufficient knowledge about wild animals that may harbor thousands of unknown virus species that could be human pathogens. </p>
<p>The evidence so far indicates that the Alaskapox virus is present in several species of <a href="https://doi.org/10.1093%2Fcid%2Fcix219">small mammals</a>, most notably shrews and the red-backed vole. In other words, Alaskapox is a new example of an infectious disease that can make the leap from animals to humans, a process known as zoonosis. Although available data suggests that the public health impact of Alaskapox virus is limited, it is likely widespread in small mammal populations in Alaska, and other infections in people may not have been diagnosed. </p>
<p>At present, no person-to-person transmission of Alaskapox has been documented. However, because some types of orthopoxviruses can be transmitted by direct contact with skin lesions, it is recommended that people with wounds that are suspected to be caused by Alaskapox keep the affected area covered with a bandage.</p>
<h2>What other orthopoxviruses pose a risk?</h2>
<p>In addition to Alaskapox virus, some other orthopoxviruses have recently been recognized, such as Akhmeta virus and/or Abatino virus, that highlight the possibility of unknown members of this genus with <a href="https://doi.org/10.1056%2FNEJMoa1407647">zoonotic potential</a>. </p>
<p>Other orthopoxviruses with zoonotic potential, such as mpox virus and cowpox virus, are increasingly being reported as a cause of human disease. In fact, the ongoing mpox outbreak that started in May 2022 has resulted in more than <a href="https://www.cdc.gov/poxvirus/mpox/response/2022/index.html">93,000 cases and 177 deaths</a>. This situation may have been facilitated by the discontinuation of routine vaccination against the eradicated human smallpox, as this vaccine gave rise to <a href="https://doi.org/10.1038/s41392-023-01574-6">some degree of population immunity</a> against other orthopoxviruses.</p>
<p>In addition to the above, there are many other orthopoxviruses that infect mammals. Examples are the ectromelia virus that causes mousepox, camelpox, raccoonpox, gerbilpox and skunkpox or some sublineages of vaccinia virus such as rabbitpox and buffalopox. </p>
<p>Poxviruses infect a broad spectrum of hosts, including insects, birds, reptiles and mammals. The wide host range, the wide geographical distribution and the constant global emergence of zoonotic viruses, including new orthopoxviruses, pose a global health threat that requires close monitoring and appropriate preventive measures. </p>
<p>In this situation, I believe the most prudent course of action is to urgently adopt a <a href="https://www.cdc.gov/onehealth/basics/index.html">One Health approach</a> that recognizes that the health of humans, animals, plants and the wider environment are interconnected, and accept that we cannot address human health without also addressing animal and environmental health.</p><img src="https://counter.theconversation.com/content/223470/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Raúl Rivas González does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Alaskapox was discovered in 2015 and has generally only caused mild illness – until now.Raúl Rivas González, Catedrático de Microbiología. Miembro de la Sociedad Española de Microbiología., Universidad de SalamancaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2122032023-09-14T10:41:46Z2023-09-14T10:41:46ZFrance launches bird vaccination scheme, amid fears of a repeat of H5N1 outbreaks<figure><img src="https://images.theconversation.com/files/548173/original/file-20230913-15-o3wxi9.jpg?ixlib=rb-1.1.0&rect=0%2C12%2C1200%2C855&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Vaccination of poultry in Hong Kong. </span> <span class="attribution"><span class="source">F. Keck</span>, <span class="license">Fourni par l'auteur</span></span></figcaption></figure><p>Of all the recently emerging and potentially pandemic viruses, the highly pathogenic avian influenza (HPAI) virus H5N1 is one of the fiercest. <a href="https://academic.oup.com/cid/article/34/Supplement_2/S58/459477">First detected in Hong Kong in 1997</a>, it spread to the rest of the world with a mortality rate of 60% when transmitted from birds to humans. The World Health Organization has declared in August 2023 that <a href="https://www.who.int/fr/emergencies/disease-outbreak-news/item/2023-DON461">878 cases and 458 deaths were recorded since 1997</a>. </p>
<p>The past two years have seen a new strain of the virus circulate among wild birds and domestic poultry in Europe and the Americas, <a href="https://www.ecdc.europa.eu/en/publications-data/avian-influenza-overview-april-june-2023">with high avian mortality</a>. So far, humans appear to have been spared, with five cases recorded since early 2023. International health authorities are however keeping a close eye on mutations of the virus and prescribing strict measures to control its spread.</p>
<p>But French health authorities are also not standing idle, green-lighting avian flu vaccination in the country for the first time and introducing innovative monitoring schemes. The country’s agricultural sector is in no mood to take risks, after the last outbreak of H5N1 in 2022 resulted in the slaughter of <a href="https://www.lemonde.fr/en/france/article/2022/12/24/the-french-government-postpones-bird-flu-vaccination-deadline-to-fall-2023_6008920_7.html">21 million birds in France</a> at an estimated cost of 1.5 billion euros. At the time, health services who came to “depopulate” buildings were so overwhelmed by the scale of the task that many farmers had to euthanise their poultry themselves, sometimes with no other means than cutting off ventilation in the buildings. These culls undermined not only the viability of the poultry industry, but also animal-welfare standards and farmers’ morale.</p>
<h2>Disparities between large and small farms</h2>
<p>French health authorities imposed containment and hygiene measures (respectively referred to as “sheltering” and “biosecurity”) on poultry farms to protect them from the risk of transmission of avian flu by wild birds. As highlighted in <a href="https://www.assemblee-nationale.fr/dyn/16/organes/commissions-permanentes/affaires-economiques/missions-de-la-commission/mi-grippeaviaire">a report by the French National Assembly</a>, these measures have had a significant negative impact on small-scale free-range poultry farms, as large-scale industrial operations were more easily able to integrate the costs. </p>
<p>The Confédération Paysanne, France’s progressive farmers’ union, negotiated with the health authorities for measures adapted to <a href="https://www.confederationpaysanne.fr/mc_nos_positions.php?mc=956">small-scale outdoor farming</a>. Both the Assembly’s rapporteurs and the farmers’ unions point out that genetic diversity on small farms can provide a form of immunity against emerging viruses. This is not the case with closed farms, where biosecurity measures can accentuate the vulnerability of poultry, which are genetically standardised and weakened by the use of antibiotics.</p>
<h2>France introduces avian vaccination</h2>
<p>After the massive slaughters of spring 2022, poultry farmers have asked health authorities to make avian flu vaccination accessible. Until recently, European regulation prohibited such vaccination, as it makes it impossible to know whether exported poultry are virus free, but <a href="https://eur-lex.europa.eu/legal-content/FR/TXT/?uri=uriserv%3AOJ.L_.2023.052.01.0001.01.FRA&toc=OJ%3AL%3A2023%3A052%3ATOC">this ban was lifted</a> this year. In Asia, countries such as China and Vietnam with high levels of domestic poultry consumption vaccinate their flocks against bird flu, while those with high exports, such as Thailand, do not. In France, 40% of the value produced by the poultry sector comes from exports, even though half the poultry meat consumed is imported. Only birds raised in French zoos are vaccinated.</p>
<p>The French National Agency for Health Safety, Anses, has tried experiments on the vaccination of ducks that <a href="https://www.anses.fr/fr/system/files/SABA2022SA0165.pdf">carry avian flu viruses asymptomatically</a>. These experiments were first made on small farms in southwest France, then in animal houses at a laboratory in Brittany. The results were deemed sufficiently positive for the Ministry of Agriculture to announce a vaccination campaign for farmed ducks in autumn 2023, allowing for a <a href="https://agriculture.gouv.fr/experimentation-de-vaccination-des-canards-mulards-en-elevage-contre-un-virus-iahp">manufacturing time of 6 to 8 months</a>.</p>
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<img alt="Chickens being transported by bicycle in Suzhou, China" src="https://images.theconversation.com/files/532939/original/file-20230620-21-e74oss.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/532939/original/file-20230620-21-e74oss.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532939/original/file-20230620-21-e74oss.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532939/original/file-20230620-21-e74oss.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532939/original/file-20230620-21-e74oss.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532939/original/file-20230620-21-e74oss.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532939/original/file-20230620-21-e74oss.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Chickens being transported by bicycle in Suzhou, China, in 2009. High poultry consumption in Asia has encouraged the use of vaccination in the wake of avian flu epidemics.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Bicyclette_et_poulets_%28Suzhou,_Chine%29.jpg">Gérald Tapp/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The technical difficulty of vaccinating poultry lies in their short lifespan compared to other farm animals (around 60 days) and the fact that two doses are required for the vaccine to be effective. Farmers point out that the first dose can be injected at birth (as is the case for vaccination against <a href="https://www.gov.scot/publications/newcastle-disease/">Newcastle disease</a>), but pharmaceutical laboratories estimate that 75% of the cost of vaccination is due to vaccine handling and post-vaccination follow-up. Vaccination cannot be carried out on a large scale in France because of the diversity of avian species and viral strains. </p>
<p>Anses has issued the following recommendations:</p>
<ul>
<li><p>Vaccination of ducks as a preventive and experimental measure.</p></li>
<li><p>Vaccination of poultry in the event of an outbreak of H5N1 as an emergency measure.</p></li>
<li><p>When a bird flu outbreak is detected in a vaccinated areas, only the affected farm should be culled, not those nearby.</p></li>
</ul>
<p>Experts point out that vaccination will not enable health authorities to avoid other sanitary measures, such as surveillance of virus strains in normal times and <a href="https://www.science.org/content/article/wrestling-bird-flu-europe-considers-once-taboo-vaccines">culling of poultry in emergencies</a>. Vaccination mishaps risks of releasing strains of H5N1, which can mutate and amplify in the ecological niche opened up by the destruction of other strains.</p>
<h2>Sentinel chickens</h2>
<p>The DIVA (Differentiating Infected from Vaccinated Animals) system is prescribed by health authorities to distinguish between viruses introduced by vaccination and those that herald a new outbreak of infection. This system may be inspired by measures adopted in Hong Kong, where unvaccinated chickens are placed at farm entrances to act as sentinels. The Chinese term <em>shaobingji</em> refers to these chickens are “soldiers” who <a href="https://limn.it/articles/hong-kong-as-a-sentinel-post/">sound the alarm on the presence of the virus</a>.</p>
<p>Nevertheless, vaccination offers farmers the hope of <a href="https://hal.science/hal-01207044/file/C30Larrere.pdf">reestablishing a “domestic contract”</a> with their poultry, between the daily anguish of finding a sick bird and the desolation of having to slaughter an entire “batch”. The terms of the bird flu debate – between containment and vaccination – seem to replay the one that took place around Covid-19 three years earlier, as if human and avian populations were subject to the same “biopolitics” consisting, in Michel Foucault’s words, of <a href="https://journals.openedition.org/lhomme/29305">“making populations live and letting them die”</a>. </p>
<p>When animals are vaccinated, they cease to be perceived as commodities that can be slaughtered in the event of a defect. Instead, they once again become living beings who are cared for because of the risk to their species and ours.</p>
<h2>Wildfowl and domestic poultry</h2>
<p>The experts’ insistence on the need to continue monitoring wild birds and domestic poultry also shows that vaccination, while it may lighten the moral burden on poultry farmers, in no way solves the ecological problems posed by export-oriented industrial farming. </p>
<p>Against a backdrop of climate change, which is also affecting wild birds’ migratory trajectories, poultry farmers can play the role of sentinels by reporting cases of sick birds found in their fields. The <a href="https://www.ofb.gouv.fr/ce-quil-faut-savoir-sur-linfluenza-aviaire">French Office for Biodiversity</a> and the <a href="https://www.lpo.fr/la-lpo-en-actions/agir-pour-la-faune-en-detresse/faq-grippe-aviaire">League for the Protection of Birds</a> have pointed out that the number of wild birds carrying bird flu has increased to such an extent that wildlife specialists will be unable to count them.</p>
<p>Experts are not yet talking about vaccinating wild birds against influenza, something that would be technically impossible and morally dubious. However, bird flu has not only forced health authorities to innovate in prevention and containment strategies, but has also blurred the divide that has long separated livestock management and wildlife surveillance.</p>
<hr>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/310261/original/file-20200115-134768-1tax26b.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/310261/original/file-20200115-134768-1tax26b.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=158&fit=crop&dpr=1 600w, https://images.theconversation.com/files/310261/original/file-20200115-134768-1tax26b.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=158&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/310261/original/file-20200115-134768-1tax26b.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=158&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/310261/original/file-20200115-134768-1tax26b.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=198&fit=crop&dpr=1 754w, https://images.theconversation.com/files/310261/original/file-20200115-134768-1tax26b.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=198&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/310261/original/file-20200115-134768-1tax26b.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=198&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>Created in 2007 to help accelerate and share scientific knowledge on key societal issues, the AXA Research Fund has supported nearly 700 projects around the world conducted by researchers in 38 countries. To learn more, visit the site of the AXA Research Fund or follow on Twitter @AXAResearchFund.</em></p><img src="https://counter.theconversation.com/content/212203/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Frédéric Keck has received funding from the Axa Research Fund, the Agence nationale de la recherche, DIM One Health and the Canadian Institute for Advanced Rese</span></em></p>Vaccination against bird flu offers farmers hope, rather than being caught between the anguish of finding a sick bird and the desolation of having to slaughter their entire flock.Frédéric Keck, Anthropologie, EHESS, CNRS, Laboratoire d'anthropologie sociale, Collège de France, Auteurs historiques The Conversation FranceLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2124942023-09-08T09:13:31Z2023-09-08T09:13:31ZCOVID mutates rapidly in white-tailed deer, but here’s why we don’t need to worry – for now<figure><img src="https://images.theconversation.com/files/546708/original/file-20230906-22-m3sydi.jpg?ixlib=rb-1.1.0&rect=0%2C519%2C5585%2C3203&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/white-tail-deer-odocoileus-virginianus-young-1359728207">Michael Tatman/Shutterstock</a></span></figcaption></figure><p>At some point during the pandemic, Sars-CoV-2, the virus that causes COVID, spread from humans to white-tailed deer in the US. </p>
<p>In 2021, scientists revealed that <a href="https://www.pnas.org/doi/10.1073/pnas.2114828118">40% of white-tailed deer</a> sampled in Michigan, Pennsylvania, Illinois and New York state had COVID antibodies.</p>
<p>Surveillance of these deer continues, and a <a href="https://www.nature.com/articles/s41467-023-40706-y">new study</a> by researchers at Ohio State University found that the virus is still spreading among the animals – and back to humans. And it is evolving rapidly.</p>
<p>The researchers looked at the prevalence of COVID in a small sample of white-tailed deer in north-eastern Ohio. The samples were taken between November 2021 and March 2022. From 1,522 nasal swabs, 163 tested positive for alpha and delta variants of COVID. The researchers also found that the virus had spread many times from humans to deer and from deer to humans (known as “spillover”). </p>
<p>Coronaviruses are covered in spikes and it is these spikes that latch on to our cells to gain entry and begin replicating. The particular part of our cells that the spikes latch on to is called the ACE2 receptor. This receptor is similar in deer and humans, and coronaviruses have lost little time in exploiting this.</p>
<p>Human contact with deer is common in parts of the US, where many millions of white-tailed deer live as wild, urbanised or farmed animals. In these habitats, deer may be exposed to human waste. They can carry bacteria with similar antimicrobial resistance patterns to local humans.</p>
<figure class="align-center ">
<img alt="A graphic depicting a coronavirus" src="https://images.theconversation.com/files/546490/original/file-20230905-19-lsat4h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546490/original/file-20230905-19-lsat4h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=346&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546490/original/file-20230905-19-lsat4h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=346&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546490/original/file-20230905-19-lsat4h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=346&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546490/original/file-20230905-19-lsat4h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=435&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546490/original/file-20230905-19-lsat4h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=435&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546490/original/file-20230905-19-lsat4h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=435&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">A coronavirus with its distinctive spikes.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/coronavirus-covid19-under-microscope-3d-illustration-1643947495">Andrii Vodolazhskyi/Shutterstock</a></span>
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<p>The Ohio researchers found that COVID multiplied and spread in deer over several months, causing no obvious illness or deaths in the animals. Migrating deer – males in particular – spread the virus as they moved across the county. </p>
<p>It is not known if other potential hosts such as skunks, squirrels or rodents contracted the virus too, but spread from deer back to humans was seen. How this exchange happened, though, is unclear. </p>
<p>Deer sampled on Staten Island, New York, over the same period showed evidence of spillover infection from humans by another COVID variant, omicron. Viral exchanges between communities and their deer are happening often.</p>
<h2>Mutating three times faster in deer than in humans</h2>
<p>By measuring changes in the COVID genomes in the deer using a new statistical method, the researchers in Ohio estimated that the rate of COVID mutation was three times greater than in humans. The types of genetic changes were not the same as those in human COVID. The mutations appeared to be adaptive responses that might have increased viral spread in its new deer hosts. </p>
<p>COVID showed early increases in its diversity in humans, too, which was perhaps more rapid in the first years after 2019.</p>
<p>Crucially, the spill-back of virus from deer to humans has not caused new human outbreaks that are making doctors lose sleep. Evolutionary changes in COVID in deer populations have not resulted in a virus that can evade our antibodies. So there is no current public health risk linked to this increased mutation rate.</p>
<p>As with humans, some deer are “<a href="https://theconversation.com/what-is-a-super-spreader-an-infectious-disease-expert-explains-130756">super-spreaders</a>”. Social network analysis shows this process in deer’s use of scraping sites, where males leave their scents to set up breeding groups. Human-made feeding or bait stations (for hunting) exacerbate the rate of viral spread, too. </p>
<p>White-tailed deer could be referred to as a new reservoir of COVID viruses. Animal reservoirs encompass a continuous process of viral division and change. Hosts impose selective pressures on viruses that influence the rate at which a virus’s genome changes. For example, influenza A evolves more rapidly in populations of birds or pigs than in people. </p>
<p>Probably, the lifespan of an infected animal, metabolic processes within its cells, immune actions, damage to viral RNA from host enzymes or other pathogens all force viral mutation. Whatever the reasons, these observations from Ohio raise the possibility that in those millions of white-tailed deer, COVID viruses might develop into a new strain or variant capable of spreading significant illness to humans.</p>
<p>Blood tests of <a href="https://onlinelibrary.wiley.com/doi/10.1111/tbed.14534">UK deer in 2020-21</a> found no evidence of COVID in these animals. This could be because British deer species have distinctive ecological niches and COVID susceptibilities. But it is clear that this sort of ongoing surveillance provides valuable intelligence.</p><img src="https://counter.theconversation.com/content/212494/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>COVID has spread many times from humans to white-tailed deer and back again.Colin Michie, Deputy Lead, School of Medicine, University of Central LancashireIain Richards, Senior Lecturer, Animal Life, University of Central LancashireLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2108982023-09-04T20:05:24Z2023-09-04T20:05:24ZIs it okay to kiss your pet? The risk of animal-borne diseases is small, but real<figure><img src="https://images.theconversation.com/files/545229/original/file-20230829-19-r94gri.jpg?ixlib=rb-1.1.0&rect=0%2C314%2C4886%2C3197&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Our relationship with pets has changed drastically in recent decades. Pet ownership is at an all-time high, with <a href="https://animalmedicinesaustralia.org.au/media-release/more-than-two-thirds-of-australian-households-now-own-a-pet/">a recent survey</a> finding 69% of Australian households have at least one pet. We spend an estimated A$33 billion every year on caring for our fur babies.</p>
<p>While owning a pet is linked to numerous <a href="https://www.onehealth.org/blog/10-mental-physical-health-benefits-of-having-pets">mental and physical health benefits</a>, our pets can also harbour infectious diseases that can sometimes be passed on to us. For most people, the risk is low.</p>
<p>But some, such as pregnant people and those with weakened immune systems, are at <a href="https://www.cdc.gov/healthypets/specific-groups/high-risk/index.html">greater risk</a> of getting sick from animals. So, it’s important to know the risks and take necessary precautions to prevent infections.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-what-bugs-can-you-catch-from-your-pets-40954">Health Check: what bugs can you catch from your pets?</a>
</strong>
</em>
</p>
<hr>
<h2>What diseases can pets carry?</h2>
<p>Infectious diseases that move from animals to humans are called zoonotic diseases or <a href="https://www.cdc.gov/onehealth/basics/zoonotic-diseases.html">zoonoses</a>. More than <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3668296/#B18">70 pathogens</a> of companion animals are known to be transmissible to people.</p>
<p>Sometimes, a pet that has a zoonotic pathogen may look sick. But often there may be no visible symptoms, making it easier for you to catch it, because you don’t suspect your pet of harbouring germs.</p>
<p>Zoonoses can be transmitted directly from pets to humans, such as through contact with saliva, bodily fluids and faeces, or indirectly, such as through contact with contaminated bedding, soil, food or water. </p>
<p>Studies suggest <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4500695/">the prevalence of pet-associated zoonoses is low</a>. However, the true number of infections is likely <a href="https://www.mdpi.com/1660-4601/17/11/3789">underestimated</a> since many zoonoses are not “<a href="https://www.healthdirect.gov.au/notification-of-illness-and-disease">notifiable</a>”, or may have multiple exposure pathways or generic symptoms. </p>
<p>Dogs and cats are major reservoirs of zoonotic infections (meaning the pathogens naturally live in their population) caused by viruses, bacteria, fungi and parasites. <a href="https://www.who.int/data/gho/data/themes/topics/rabies">In endemic regions in Africa and Asia</a>, dogs are the main source of rabies which is transmitted through saliva. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-the-rabies-virus-28654">Explainer: the rabies virus</a>
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<p>Dogs also commonly carry <em>Capnocytophaga</em> bacteria <a href="https://www.cdc.gov/capnocytophaga/index.html">in their mouths and saliva</a>, which can be transmitted to people through close contact or bites. The vast majority of people won’t get sick, but these bacteria can occasionally cause infections in people with weakened immune systems, <a href="https://www.cdc.gov/capnocytophaga/signs-symptoms/index.html">resulting</a> in severe illness and sometimes death. Just last week, such a death <a href="https://thewest.com.au/news/wa/tracy-ridout-perth-mum-dies-11-days-after-rare-bacterial-infection-from-minor-dog-bite-c-11748887">was reported in Western Australia</a>.</p>
<p>Cat-associated zoonoses include a number of illnesses spread by the faecal-oral route, such as giardiasis, campylobacteriosis, salmonellosis and toxoplasmosis. This means it’s especially important to wash your hands or use gloves whenever handling your cat’s litter tray.</p>
<p>Cats can also sometimes transmit infections through bites and scratches, including the aptly named <a href="https://www.cdc.gov/healthypets/diseases/cat-scratch.html#:%7E:text=Cat%20scratch%20disease%20(CSD)%20is,the%20surface%20of%20the%20skin.">cat scratch disease</a>, which is caused by the bacterium <em>Bartonella henselae</em>.</p>
<p>Both dogs and cats are also reservoirs for <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10122942/">methicillin-resistant bacterium <em>Staphylococcus aureus</em></a> (MRSA), with close contact with pets identified as an important risk factor for zoonotic transmission.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/545415/original/file-20230829-27-mpgatg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A woman with curly hair being licked in the face by a Staffordshire terrier" src="https://images.theconversation.com/files/545415/original/file-20230829-27-mpgatg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/545415/original/file-20230829-27-mpgatg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/545415/original/file-20230829-27-mpgatg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/545415/original/file-20230829-27-mpgatg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/545415/original/file-20230829-27-mpgatg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/545415/original/file-20230829-27-mpgatg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/545415/original/file-20230829-27-mpgatg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Dog saliva hosts a bacterium that can cause serious illness and even death in some people.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/girl-kissing-dog-breed-staffordshire-terrier-200987354">Shutterstock</a></span>
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<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/cats-carry-diseases-that-can-be-deadly-to-humans-and-its-costing-australia-6-billion-every-year-147910">Cats carry diseases that can be deadly to humans, and it's costing Australia $6 billion every year</a>
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<h2>Birds, turtles and fish can also transmit disease</h2>
<p>But it’s not just dogs and cats that can spread diseases to humans. Pet birds can occasionally transmit <a href="https://www.cdc.gov/pneumonia/atypical/psittacosis/">psittacosis</a>, a bacterial infection which causes pneumonia. Contact with <a href="https://www.fda.gov/animal-veterinary/animal-health-literacy/pet-turtles-source-germs">pet turtles</a> has been linked to <em>Salmonella</em> infections in humans, particularly in young children. Even pet fish have been linked to a <a href="https://www.cdc.gov/healthypets/pets/fish.html">range of bacterial infections</a> in humans, including vibriosis, mycobacteriosis and salmonellosis.</p>
<p>Close contact with animals – and some behaviours in particular – increase the risk of zoonotic transmission. <a href="https://pubmed.ncbi.nlm.nih.gov/19398275/">A study from the Netherlands</a> found half of owners allowed pets to lick their faces, and 18% allowed dogs to share their bed. (Sharing a bed increases the duration of exposure to pathogens carried by pets.) The same study found 45% of cat owners allowed their cat to jump onto the kitchen sink.</p>
<p>Kissing pets has also been linked to occasional zoonotic infections in pet owners. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3298380/">In one case</a>, a woman in Japan developed meningitis due to <em>Pasteurella multicoda</em> infection, after regularly kissing her dog’s face. These bacteria are often found in the oral cavities of dogs and cats.</p>
<p>Young children are also more likely to engage in behaviours which increase their risk of <a href="https://www.cdc.gov/healthypets/specific-groups/high-risk/children.html?CDC_AA_refVal=https%3A%2F%2Fwww.cdc.gov%2Fhealthypets%2Fspecific-groups%2Fchildren.html">getting sick</a> from animal-borne diseases – such as putting their hands in their mouth after touching pets. Children are also less likely to wash their hands properly after handling pets.</p>
<p>Although anybody who comes into contact with a zoonotic pathogen via their pet can become sick, certain people are more likely to suffer from serious illness. These people include the young, old, pregnant and immunosuppressed.</p>
<p>For example, while most people infected with the toxoplasmosis parasite will experience only mild illness, it can be life-threatening or <a href="https://www.nhs.uk/common-health-questions/pregnancy/what-are-the-risks-of-toxoplasmosis-during-pregnancy/">cause birth defects in foetuses</a>. </p>
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<a href="https://images.theconversation.com/files/546103/original/file-20230904-27-lzhdw9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A little blonde girl lying on the floor kissing a large blonde dog" src="https://images.theconversation.com/files/546103/original/file-20230904-27-lzhdw9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546103/original/file-20230904-27-lzhdw9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546103/original/file-20230904-27-lzhdw9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546103/original/file-20230904-27-lzhdw9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546103/original/file-20230904-27-lzhdw9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546103/original/file-20230904-27-lzhdw9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546103/original/file-20230904-27-lzhdw9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Young children under 5 years old are more at risk of zoonotic diseases, and also more likely to engage in behaviours that increase their chances of catching something from their pet.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<h2>What should I do if I’m worried about catching a disease from my pet?</h2>
<p>There are a number of good hygiene and pet husbandry practices that can reduce your risk of becoming sick. These include:</p>
<ul>
<li>washing your hands after playing with your pet and after handling their bedding, toys, or cleaning up faeces</li>
<li>not allowing your pets to lick your face or open wounds</li>
<li>supervising young children when they are playing with pets and when washing their hands after playing with pets</li>
<li>wearing gloves when changing litter trays or cleaning aquariums</li>
<li>wetting bird cage surfaces when cleaning to minimise aerosols</li>
<li>keeping pets out of the kitchen (especially cats who can jump onto food preparation surfaces) </li>
<li>keeping up to date with preventative veterinary care, including vaccinations and worm and tick treatments </li>
<li>seeking veterinary care if you think your pet is unwell.</li>
</ul>
<p>It is especially important for those who are at a higher risk of illness to take precautions to reduce their exposure to zoonotic pathogens. And if you’re thinking about getting a pet, ask your vet which type of animal would best suit your personal circumstances.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/one-in-three-people-are-infected-with-toxoplasma-parasite-and-the-clue-could-be-in-our-eyes-182418">One in three people are infected with _Toxoplasma_ parasite – and the clue could be in our eyes</a>
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<img src="https://counter.theconversation.com/content/210898/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Animals, including the ones that live in our homes, can carry all kinds of illnesses. Most of the time it’s not a problem, but here’s what you should do to avoid getting sick.Sarah McLean, Lecturer in environmental health, Swinburne University of TechnologyEnzo Palombo, Professor of Microbiology, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2047932023-05-03T20:18:18Z2023-05-03T20:18:18ZMigrating birds could bring lethal avian flu to Australia’s vulnerable birds<figure><img src="https://images.theconversation.com/files/524010/original/file-20230503-598-6p3lw4.jpg?ixlib=rb-1.1.0&rect=133%2C76%2C1675%2C1341&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>In 2021, avian influenza evolved into a new form – a new and remarkably lethal variant <a href="https://www.cdc.gov/flu/avianflu/timeline/avian-timeline-2020s.htm">first found</a> in Europe. </p>
<p>Bird flu is usually most dangerous to birds kept in close quarters, such as chicken farms. But as it spread around the world, the highly pathogenic HPAI A(H5N1) variant began killing millions and millions of wild birds too.</p>
<p>Seabird colonies in the UK <a href="https://www.theguardian.com/environment/2022/jul/20/avian-flu-h5n1-wreaks-devastation-seabirds-aoe">have been</a> decimated. The virus can kill up to half of the birds it infects. It has also spread into sea lions and seals. </p>
<p>Luckily, it doesn’t spread easily in humans. More than 50 million birds have <a href="https://www.gov.uk/government/publications/highly-pathogenic-avian-influenza-in-great-britain-evaluation-and-future-actions/highly-pathogenic-avian-influenza-in-great-britain-evaluation-and-future-actions">already been culled</a> over 37 countries in a bid to slow the spread. </p>
<p>Australia’s birds have so far dodged this bullet. Our isolation has kept us safe for now. Antarctica’s birds have stayed safe too. But if this variant makes it here in the lungs of a migratory shorebird, our unique birds will be at extreme risk. Black swans, for instance, are <a href="https://theconversation.com/australias-iconic-black-swans-have-a-worrying-immune-system-deficiency-new-genome-study-finds-198159">especially vulnerable</a> to all types of avian flu. </p>
<p>The federal government <a href="https://www.agriculture.gov.au/biosecurity-trade/pests-diseases-weeds/animal/avian-influenza">will boost</a> surveillance measures when large flocks of migratory birds begin arriving later this year. It’s unlikely to be enough, as we enter a time of high risk from September onwards. </p>
<h2>Could it really get here?</h2>
<p>Yes. </p>
<p>Surveillance of Australia’s vast coastlines is all but impossible. Instead, the government is likely to focus on the major wetlands and shallow inlets which attract migratory birds. </p>
<p>Every year, around eight million birds take the <a href="http://www.eaaflyway.net/">East Asian-Australasian Flyway</a> – a route stretching from the Arctic Circle down through east and south-east Asia to Australia and New Zealand. </p>
<p>Is the H5N1 flu lethal enough to be self-limiting? Not necessarily. A bird could get a mild dose and still be infectious when it arrives. That means there’s a good chance this variant could arrive. It would only take one infectious shorebird to trigger outbreaks. </p>
<p>If it gets here, the virus would decimate poultry farms and wild birds, just as it has overseas. In densely populated farms, it <a href="https://theconversation.com/amp/avian-influenza-how-bird-flu-affects-domestic-and-wild-flocks-and-why-a-one-health-approach-matters-182497?gclid=Cj0KCQjw6cKiBhD5ARIsAKXUdyYH4aJm6oykUQptABxji5W1BXlT1ePoiG7L4-DNOA-ScfK2pnZRd1gaAhUBEALw_wcB">can kill</a> 90-100% of all birds. </p>
<p>It could pose an extinction threat to iconic birds such as black swans, which have an <a href="https://theconversation.com/australias-iconic-black-swans-have-a-worrying-immune-system-deficiency-new-genome-study-finds-198159">immune deficiency</a> making them particularly at risk. Flocking birds like rainbow lorikeets and corellas would also be at extra risk of catching the virus. </p>
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<a href="https://images.theconversation.com/files/524013/original/file-20230503-16-99q8j2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="black swan" src="https://images.theconversation.com/files/524013/original/file-20230503-16-99q8j2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524013/original/file-20230503-16-99q8j2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524013/original/file-20230503-16-99q8j2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524013/original/file-20230503-16-99q8j2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524013/original/file-20230503-16-99q8j2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524013/original/file-20230503-16-99q8j2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524013/original/file-20230503-16-99q8j2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Black swans are particularly vulnerable to this virus.</span>
<span class="attribution"><span class="source">Mitchell Luo/Unsplash</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>Federal Agriculture Minister Murray Watt has dismissed the idea Australia is unprepared. </p>
<p><a href="https://www.theguardian.com/australia-news/2023/may/01/australia-wild-birds-deadly-form-of-avian-flu-influenza-hpai-subtype-h5">He said</a> his government had been “closely monitoring the global HPAI situation” and had boosted early warning efforts. </p>
<p>But what we don’t have is an action plan for what happens if the virus does arrive, as seems likely. </p>
<p>Responses like the <a href="https://theconversation.com/hear-me-out-we-could-use-the-varroa-mite-to-wipe-out-feral-honey-bees-and-help-australias-environment-185959">mass destruction</a> of beehives after the devastating varroa mite arrived are unlikely to work for a virus. A tailored vaccine could help domestic birds, but it would be all but impossible to administer to wild birds. </p>
<p>Over time, birds with natural resistance would survive and breed populations back up. But endangered species or those particularly vulnerable would find it much harder to bounce back. </p>
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Read more:
<a href="https://theconversation.com/australias-iconic-black-swans-have-a-worrying-immune-system-deficiency-new-genome-study-finds-198159">Australia's iconic black swans have a worrying immune system deficiency, new genome study finds</a>
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<h2>Haven’t our birds survived bird flu before?</h2>
<p>Yes, but not quite like this one. </p>
<p>In 2020, three egg producers in Victoria <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8401172/">had an outbreak</a> of another highly pathogenic influenza variant, H7N7. To stop it spreading, authorities culled all birds in the farms.</p>
<p>This variant emerged when low pathogenic viruses carried by local wild birds evolved into a deadlier form. While authorities stopped its spread on poultry farms, they could do nothing about the wild reservoir of the virus. </p>
<p>If H7N7 is still around, it could pose even more problems. When two different influenza virus subtypes infect the same host cell, their genetic material can mix to create a new virus, which could be milder – or more severe.</p>
<p>Australian scientists have researched the impact of <a href="https://royalsocietypublishing.org/doi/epdf/10.1098/rspb.2022.2237">low pathogenic avian influenza</a> on many bird families, which gives some insight into how highly pathogenic avian influenza may spread in Australia. For instance, arid areas would likely be better protected from the virus, which does not like dry conditions. </p>
<p>But can we act in time? We know what to do when there’s an outbreak in domesticated birds. But if the virus gets into wild birds and takes off, we have no plan. </p>
<p>Rapid monitoring and surveillance of wildlife pathogens is a major gap in Australia’s biosecurity framework – and one we should fill. </p>
<h2>We must prepare</h2>
<p>COVID from bats or <a href="https://www.theatlantic.com/science/archive/2023/03/covid-origins-research-raccoon-dogs-wuhan-market-lab-leak/673390/">raccoon dogs</a>. Ebola <a href="https://www.science.org/content/article/bat-species-may-be-source-ebola-epidemic-killed-more-11000-people-west-africa">from bats</a>. Avian flu from birds. As we back nature into a corner, we can find ourselves more exposed to the viruses wild animals carry. </p>
<p>So far, the HPAI H5N1 strain is only known to have jumped into humans a <a href="https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON445">handful of times</a>. </p>
<p>That’s lucky. Around 800 people have contracted one of the variants of bird flu since 2003. Of these, more than half died. That’s a similar death rate to many of the birds dying of the avian flu elsewhere in the world. The main protection we have at present is the fact avian flu finds it hard to infect us in the first place. </p>
<p>To save our birds – and potentially, ourselves – we need a better way to detect and track viral outbreaks in wildlife, particularly those which could jump across into humans. </p>
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<strong>
Read more:
<a href="https://theconversation.com/what-is-spillover-bird-flu-outbreak-underscores-need-for-early-detection-to-prevent-the-next-big-pandemic-200494">What is spillover? Bird flu outbreak underscores need for early detection to prevent the next big pandemic</a>
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<img src="https://counter.theconversation.com/content/204793/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Parwinder Kaur does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>From September onwards, migratory birds will arrive on Australian shores. If one is carrying the lethal bird flu, it could devastate our birdlifeParwinder Kaur, Associate Professor | Director, DNA Zoo Australia, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2039592023-04-18T15:38:49Z2023-04-18T15:38:49ZHow to be sushi smart: tips on avoiding anisakis disease<figure><img src="https://images.theconversation.com/files/521270/original/file-20230417-16-akyh66.jpg?ixlib=rb-1.1.0&rect=0%2C25%2C1756%2C1014&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Nematode larvae belonging to the genus _Anisakis_ can cause the disease anisakiasis, a threat to human health.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/es/image-photo/living-anisakis-worm-just-found-on-1142197133">Shutterstock / WH_Pics</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>From sushi and sashimi (Japan) to poke bowls (Hawaii) and ceviche (Peru), consumption of raw or undercooked fish and other seafood is becoming increasingly popular. Appealing as such dishes can be, they can also increase the risk of exposure to fish-borne parasites. </p>
<p>It’s not a matter to take lightly. Every year, almost one in ten people fall ill from eating contaminated food. The World Health Organisation estimates that some <a href="https://www.sciencedirect.com/science/article/pii/S0020751905002766">56 million cases</a> of parasitic infections associated with the consumption of fish products occur annually.</p>
<h2>Tiny but troublesome stowaways</h2>
<p>Among the fish-borne parasites that can affect humans, there are three major groups of parasitic worms, also known as <em>helminths</em>: flatworms, spiny-headed worms (acanthocephalans) and ciliated worms (nematodes).</p>
<p>Diagnoses of infection with Opisthorchis, a family of flatworms, are the most common, but they occur mainly in <a href="https://pubmed.ncbi.nlm.nih.gov/33158552/">East and Southeast Asia</a>. Of more global concern are those caused by some nematodes of the family Anisakidae, particularly species of the genera <em>Anisakis</em>, <em>Pseudoterranova</em> and <em>Contracaecum</em>. As a consequence, they’re the focus of much of the world’s medical and economic concern.</p>
<p>The parasitic disease <a href="https://www.cdc.gov/parasites/anisakiasis/index.html">anisakiasis</a>, caused by nematode larvae belonging to the genus <em>Anisakis</em>, is considered the main threat to human health. Every year and on all continents, countless cases are diagnosed in humans, in part because the rise in consumption of foods such as sushi and sashimi. In Japan alone, where it is traditional to eat raw fish and seafood dishes, more than <a href="https://pubmed.ncbi.nlm.nih.gov/33025215/">7,000 cases of anisakiasis occur annually</a>.</p>
<h2>From marine mammals to human stomachs</h2>
<p>Today, anisakiasis is not only an emerging global human health problem, but it is also an economic concern, due to the potential negative effects on consumer confidence and trade associated with infected fish products.</p>
<p>So how can this troublesome disease be avoided? The answer lies in understanding the parasites’ life cycle.</p>
<p>The genus <em>Anisakis</em> comprises nine species, three of which (<em>Anisakis simplex</em>, <em>Anisakis pegreffii</em> and <em>Anisakis physeteris</em>) have been confirmed as zoonotic pathogens. These nematodes infect a wide range of marine organisms; fish and cephalopods serve as intermediate hosts, while dolphins, whales, seals and other marine mammals are the <a href="https://www.nature.com/articles/s41598-022-17710-1">final hosts</a>.</p>
<p>Adult worms are found in the mucous membrane that lines the stomachs of marine mammals. The parasite’s eggs are expelled along with the animal’s faeces and hatch in seawater. There, krill – small crustaceans that form the basis of the ocean food chain – eat them and become infected with larval stages of the nematodes. When the krill are in turn eaten by fish or squid, another stage of larvae infects the predators’ guts and become embedded on the surface of their organs and eventually in their muscles.</p>
<p>And that’s where we humans come in. When we consume fish, squid, octopus or other seafood containing <a href="https://www.cdc.gov/parasites/anisakiasis/biology.html">third-stage <em>Anisakis</em> larvae</a> that’s raw or undercooked, we can become accidental hosts to <em>Anisakis</em> larvae. Once ingested, they settle in our stomach and sometimes the small intestine.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/518175/original/file-20230329-14-yedtuz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/518175/original/file-20230329-14-yedtuz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/518175/original/file-20230329-14-yedtuz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/518175/original/file-20230329-14-yedtuz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/518175/original/file-20230329-14-yedtuz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/518175/original/file-20230329-14-yedtuz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/518175/original/file-20230329-14-yedtuz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/518175/original/file-20230329-14-yedtuz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="attribution"><a class="source" href="https://www.shutterstock.com/es/image-photo/parasites-under-microscope-woman-suffering-helminthiasis-2223896623">New Africa/Shutterstock</a></span>
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<h2>Stomach pain and worse</h2>
<p>While the parasite cannot reproduce in humans, it can survive for a short period of time and cause anisakiasis, which can range from mild to severe depending on the person infected. The most typical symptoms of gastric anisakiasis include abdominal pain, nausea and vomiting within hours of ingesting the larvae. Other symptoms can include <a href="https://pubmed.ncbi.nlm.nih.gov/25039016/">allergic reactions</a> and even <a href="https://www.mayoclinic.org/diseases-conditions/anaphylaxis/symptoms-causes/syc-20351468">anaphylactic shock</a>. Infection of the small intestine is less common, but when it occurs it can result in an inflammatory mass and symptoms similar to <a href="https://www.niddk.nih.gov/health-information/digestive-diseases/crohns-disease">Crohn’s disease</a>, which develops one to two weeks later.</p>
<p>Some workers in the fishing industry as well as cooks and other professionals who regularly deal with fish may suffer from occupational allergic anisakiasis. Here, ingestion of the parasite’s larvae is not necessary for the disease to occur – those affected become <a href="https://pubmed.ncbi.nlm.nih.gov/28429304/">sensitive to <em>Anisakis</em> proteins</a> that come into contact with the skin or respiratory tract.</p>
<p>Thankfully, the overall prognosis for anisakiasis is generally positive. Most infections are self-limiting and usually resolve spontaneously after several weeks. Person-to-person transmission is effectively impossible.</p>
<h2>Ceviche, sashimi and even pickled anchovies</h2>
<p>More than 90% of anisakiasis cases worldwide are reported in Japan, and most of the remaining 10% in countries such as Spain, Italy, the United States (Hawaii), the Netherlands and Germany. These are regions where we traditionally eat raw or undercooked fish dishes such as sushi and sashimi, ceviche and carpaccio, <a href="https://www.sciencedirect.com/science/article/pii/S0034528823000607">pickled or pickled anchovies</a>, Hawaiian-style <a href="https://en.wikipedia.org/wiki/Lomi-lomi_salmon">salmon lomi-lomi</a> and salted herring. The species that are <a href="https://www.sciencedirect.com/science/article/pii/S0078323422000446">most frequently parasitised</a> include salmon, tuna, squid, cod, hake, mackerel, mackerel, horse mackerel, blue whiting, sardines and anchovies.</p>
<p>How can anisakiasis be prevented? Preventive measures are essential to control and minimise the disease. While the worms can resist pickling and smoking, semi-preserves such as anchovies and traditionally salted dried fish such as cod or mojamas involve processes that kill the parasite. The best approach is to use a traditional cooking technique such as cooking, frying, baking or grilling. The <a href="https://www.aesan.gob.es/AECOSAN/web/seguridad_alimentaria/subdetalle/anisakis.htm">Spanish Agency for Food Safety and Nutrition</a> reports that when the cooking temperature of a seafood reaches or exceeds 60°C (140 Fahrenheit) for at least one minute, the parasite is killed.</p>
<p>While such methods aren’t an option for fans of sushi, sashimi, and ceviche, freezing is. When seafood is subjected to -20°C for seven days or -35°C for more than 15 hours, the <a href="https://pubmed.ncbi.nlm.nih.gov/32247867/">larvae are destroyed</a>. If you’re not sure that your freezer can go that low, it’s prudent to buy frozen fish. Indeed, to increase consumer food safety, in some countries, commercially prepared sushi is frozen before being sold.</p>
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<a href="https://images.theconversation.com/files/521606/original/file-20230418-24-ei0c1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/521606/original/file-20230418-24-ei0c1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521606/original/file-20230418-24-ei0c1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=150&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521606/original/file-20230418-24-ei0c1n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=150&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521606/original/file-20230418-24-ei0c1n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=150&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521606/original/file-20230418-24-ei0c1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=189&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521606/original/file-20230418-24-ei0c1n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=189&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521606/original/file-20230418-24-ei0c1n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=189&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Left: A coiled anisakid worm (<em>Pseudoterranova decipiens</em>) in a fillet of cod. Center: The head end of <em>Pseudoterranova decipiens</em>. Right: A <em>Pseudoterranova decipiens</em> recovered from a human patient.</span>
<span class="attribution"><a class="source" href="https://www.cdc.gov/parasites/anisakiasis/index.html">DPDx/CDC</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p><a href="https://food.ec.europa.eu/system/files/2016-10/biosafety_fh_eu_food_establishments-20111214_scfcah_guidance_parasites_en.pdf">European legislation</a> requires that seafood not be offered for sale with visible parasites. To avoid anisakiasis, it’s advisable to buy clean and gutted fish and to visually inspect them – even fish fillets merit examination. </p>
<p>There are a few exceptions from the freezing requirement. Oysters, mussels, clams, and other molluscs; fish from inland waters (rivers, lakes, marshes…) and freshwater fish farms (trout and carp, for example). Farm-raised fish may also be safe, providing that they were reared from embryos obtained in captivity, fed with feed without zoonotic parasites, and kept in a parasite-free environment.</p>
<p>While there’s much to be aware of, it’s better than suffering the consequences of inattention or inaction. With the correct steps and a measure of precaution, it’s possible to enjoy seafood in a safe and responsible way.</p><img src="https://counter.theconversation.com/content/203959/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Raúl Rivas González ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>Raw seafood dishes such as sushi, poke bowls and ceviche are increasingly popular, but can harbour fish-borne parasites. What’s the best way to protect ourselves?Raúl Rivas González, Miembro de la Sociedad Española de Microbiología. Catedrático de Microbiología, Universidad de SalamancaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2016322023-03-27T18:54:30Z2023-03-27T18:54:30ZBird flu FAQ: What is avian influenza? How is it transmitted to humans? What are the symptoms? Are there effective treatments and vaccines? Will H5N1 become the next viral pandemic?<figure><img src="https://images.theconversation.com/files/517749/original/file-20230327-346-q2ntym.jpg?ixlib=rb-1.1.0&rect=9%2C320%2C3283%2C2241&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Avian influenza ('bird flu') is a highly transmissible and usually mild disease that affects wild birds such as geese, swans, seagulls, shorebirds, and also domestic birds such as chickens and turkeys.
</span> <span class="attribution"><span class="source">(CDC and NIAID)</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/bird-flu-faq--what-is-avian-influenza-how-is-it-transmitted-to-humans-what-are-the-symptoms-are-there-effective-treatments-and-vaccines-will-h5n1-become-the-next-viral-pandemic" width="100%" height="400"></iframe>
<p>Avian influenza (“bird flu”) is a highly contagious viral infection that affects wild and domestic birds worldwide. It has recently gained notoriety for its devastating impact on the commercial poultry sector and as an <a href="https://www.gavi.org/vaccineswork/five-things-know-about-whether-h5n1-bird-flu-outbreak-could-turn-pandemic?gclid=EAIaIQobChMItpTYmv76_QIVxsiUCR14wADYEAAYASAAEgJi4PD_BwE">emerging human public health threat</a>. </p>
<h2>What are avian influenza viruses?</h2>
<p>Influenza viruses belong to the Orthomyxovirus family and are grouped into four species <a href="https://ncbiinsights.ncbi.nlm.nih.gov/2023/02/21/influenza-virus-ncbi-taxonomy/">designated by the letters A (Alpha), B (Beta), C (Gamma) and D (Delta</a>). Almost all influenza infections in humans are caused by influenza A and B viruses. </p>
<p>Influenza A viruses have been <a href="https://doi.org/10.1111%2Firv.12412">named avian (bird), swine (pig), equine (horse), canine (dog), chiropteran (bat) and human</a>, based on their natural reservoir (the organism where they are most commonly found). </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/517396/original/file-20230324-24-5vkuoi.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="diagram of influenza heirarchy" src="https://images.theconversation.com/files/517396/original/file-20230324-24-5vkuoi.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517396/original/file-20230324-24-5vkuoi.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=426&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517396/original/file-20230324-24-5vkuoi.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=426&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517396/original/file-20230324-24-5vkuoi.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=426&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517396/original/file-20230324-24-5vkuoi.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=535&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517396/original/file-20230324-24-5vkuoi.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=535&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517396/original/file-20230324-24-5vkuoi.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=535&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Influenza species and host-specific forms of Influenza A.</span>
<span class="attribution"><span class="source">(Sameer Elsayed)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Avian influenza and other Influenza A viruses are categorized into subtypes according to the composition of their hemagglutinin (H) and neuraminidase (N) surface proteins. <a href="https://doi.org/10.3201%2Feid2410.ET2410">There are 18 known H types (H1 to H18) and 11 known N types (N1 to N11)</a>. The combination of an H type and an N type defines a specific influenza virus subtype (for example, H5N1). </p>
<h2>What do we know about avian influenza?</h2>
<p>Avian influenza (“bird flu”) was <a href="https://doi.org/10.5822%2F978-1-61091-466-6_7">first described in the late 1800s</a>. It’s a highly transmissible and <a href="https://doi.org/10.3390%2Fpathogens10050630">usually mild disease of wild birds such as geese, swans, seagulls, shorebirds, and also domestic birds such as chickens and turkeys</a>. It is <a href="https://doi.org/10.1080%2F22221751.2022.2155072">usually caused by influenza A viruses with an H5 or H7 hemaglutinin type</a>, for example, H5N1 or H7N9. </p>
<figure class="align-center ">
<img alt="White chickens outdoors on grass" src="https://images.theconversation.com/files/517337/original/file-20230324-24-qz4ve3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517337/original/file-20230324-24-qz4ve3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=297&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517337/original/file-20230324-24-qz4ve3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=297&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517337/original/file-20230324-24-qz4ve3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=297&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517337/original/file-20230324-24-qz4ve3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=373&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517337/original/file-20230324-24-qz4ve3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=373&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517337/original/file-20230324-24-qz4ve3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=373&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">In Canada and the U.S., outbreaks of H5N1 influenza in domestic and wild birds have been reported in most regions.</span>
<span class="attribution"><span class="source">Wikimedia Commons/Woodly Wonderwords</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>While many forms of these viruses are minimally virulent — meaning they cause mild disease — some are highly virulent, meaning that they cause more serious disease. <a href="https://doi.org/10.1080%2F22221751.2022.2155072">Millions of poultry deaths in Asia, Europe, the Americas and Australia</a> have been <a href="https://www.paho.org/en/documents/epidemiological-alert-outbreaks-avian-influenza-caused-influenza-ah5n1-region-americas">attributed to highly virulent forms of H5N1, H5N8, H7N7 and H7N9, with H5N1 accounting for the vast majority of cases</a>. </p>
<p>In Canada and the U.S., outbreaks of H5N1 influenza in domestic and wild birds <a href="https://www.paho.org/en/documents/epidemiological-alert-outbreaks-avian-influenza-caused-influenza-ah5n1-region-americas">have been reported in most regions</a>. </p>
<h2>How is avian influenza transmitted to humans?</h2>
<figure class="align-right ">
<img alt="a roast chicken on a wooden board" src="https://images.theconversation.com/files/517570/original/file-20230327-24-35bjxm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/517570/original/file-20230327-24-35bjxm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517570/original/file-20230327-24-35bjxm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517570/original/file-20230327-24-35bjxm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517570/original/file-20230327-24-35bjxm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517570/original/file-20230327-24-35bjxm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517570/original/file-20230327-24-35bjxm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Bird flu cannot be transmitted by eating cooked poultry products.</span>
<span class="attribution"><span class="source">(Unsplash/Tofan Teodor)</span></span>
</figcaption>
</figure>
<p>Avian influenza viruses are not easily transmitted from birds to humans or to other animals. <a href="https://doi.org/10.1093%2Fbmb%2Fldz036">Humans are accidental hosts — meaning that the virus does not typically circulate among people</a>. Humans may acquire the virus after <a href="https://doi.org/10.1007%2F978-94-024-0908-6_10">inhaling birds’ respiratory droplets or exposure of their mucus membranes to bird feces, saliva or contaminated surfaces</a>. </p>
<p>Bird flu cannot be transmitted by eating cooked poultry products. Always follow <a href="https://www.canada.ca/en/health-canada/services/meat-poultry-fish-seafood-safety/poultry-safety.html">food safety guidelines</a> for cooking and for handling raw poultry.</p>
<p><a href="https://doi.org/10.1371/journal.ppat.1011135">Recently discovered mutations in the neuraminidase (N) gene</a> of H5N1 viruses isolated from humans appear to promote bird-to-human transmission. Fortunately, <a href="https://doi.org/10.3201%2Feid2105.141756">human-to-human transmission is extremely rare</a>.</p>
<h2>When was avian influenza first reported in humans?</h2>
<p>The <a href="https://doi.org/10.1007%2F82_2012_254">first human cases of avian influenza were reported in 1997 by public health authorities in Hong Kong</a>. These infections were linked to poultry infected with a highly virulent H5N1 subtype. Of the 18 affected individuals, six <a href="https://doi.org/10.1007%2F82_2012_254">(33 per cent) succumbed to their illness</a>. </p>
<p>Since then, avian influenza has been responsible for <a href="https://doi.org/10.1080%2F22221751.2022.2155072">at least 2,600 infections and over 1,000 deaths</a> in humans worldwide. In the majority of human cases, <a href="https://doi.org/10.1080%2F22221751.2022.2155072">infection was acquired following exposure to live poultry</a> rather than wild birds.</p>
<p>Human infections due to avian influenza viruses have primarily been caused by subtypes H5N1, H5N6, H7N7 and H7N9. All but two of the documented human fatalities to date have <a href="https://doi.org/10.1080%2F22221751.2022.2155072">occurred in low-to-middle-income countries</a>, likely as a consequence of the total case burden and lack of access to antiviral drugs. </p>
<h2>What are the signs and symptoms of avian influenza in humans? How is it diagnosed?</h2>
<p><a href="https://www.who.int/news-room/fact-sheets/detail/influenza-(avian-and-other-zoonotic)?gclid=EAIaIQobChMIhdC4osP0_QIVsRR9Ch29oA3PEAAYAiAAEgJXU_D_BwE">Early symptoms of avian influenza in humans are similar to those caused by seasonal influenza viruses</a> such as H3N2 and H1N1. Typical symptoms include fevers, chills, muscle aches, cough, sore throat, shortness of breath, headache and fatigue. </p>
<p><a href="https://doi.org/10.1007%2F978-94-017-7363-8_3">Infections caused by highly virulent forms of H5N1 or H7N9 subtypes may follow a more severe course of illness</a> characterized by internal bleeding, multi-organ failure and a high mortality rate.</p>
<p>The combination of an influenza-like illness and a recent history of exposure to live poultry should raise suspicion for avian influenza. The diagnosis is confirmed by detection of viral RNA in nasopharyngeal specimens using tests for specific subtypes. </p>
<h2>What treatments are available for avian influenza?</h2>
<p>Antiviral drugs belonging to the <a href="https://doi.org/10.7883/yoken.JJID.2021.751">neuraminidase inhibitor (such as oseltamivir) and endonuclease inhibitor classes (for example, baloxivir) appear to be highly effective against most avian influenza subtypes, including H5N1 and H7N9</a>. However, <a href="https://doi.org/10.1016%2Fj.antiviral.2020.104886">antiviral resistance</a> has been well documented and represents a threat to the potency of these agents in the face of constant viral evolution. </p>
<h2>Is there a human vaccine against avian influenza?</h2>
<figure class="align-center ">
<img alt="Person in a blue T-shirt being given an injection in the upper arm" src="https://images.theconversation.com/files/517331/original/file-20230324-26-qz4ve3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517331/original/file-20230324-26-qz4ve3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517331/original/file-20230324-26-qz4ve3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517331/original/file-20230324-26-qz4ve3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517331/original/file-20230324-26-qz4ve3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517331/original/file-20230324-26-qz4ve3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517331/original/file-20230324-26-qz4ve3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Human vaccines against avian flu have been developed and approved, but current stockpiles are unlikely to meet demand if there is a surge in human infections.</span>
<span class="attribution"><span class="source">Wikimedia/U.S. Marine Corps/Jackeline Perez Rivera</span></span>
</figcaption>
</figure>
<p>Licensed vaccines exist to protect humans against avian influenza, although they are not commercially available. </p>
<p><a href="https://www.news.sanofi.us/press-releases?item=137063">In 2007, the U.S. Food and Drug Administration (FDA) approved an H5N1 vaccine</a> for adults ages 18 and older. These vaccines form part of the U.S. government’s <a href="https://aspr.hhs.gov/SNS/Pages/Sustaining-the-Stockpile.aspx">Strategic National Stockpile (SNS)</a> of medicines for deployment in the event of a public health emergency. <a href="https://www.fda.gov/vaccines-blood-biologics/safety-availability-biologics/influenza-h5n1-virus-monovalent-vaccine-adjuvanted-manufactured-id-biomedical-corporation-questions">In 2013, the FDA approved a second H5N1 vaccine</a> that is also part of the SNS. </p>
<p><a href="https://www.ema.europa.eu/en/medicines/human/EPAR/pandemic-influenza-vaccine-h5n1-astrazeneca-previously-pandemic-influenza-vaccine-h5n1-medimmune">Similar vaccines are licensed in other jurisdictions</a>. All of these vaccines were shown to be safe and effective at the time of approval.</p>
<p>In contrast, <a href="https://doi.org/10.12688%2Fgatesopenres.13171.1">H5N1 vaccines for use in animals are commercially available</a>. Vaccination of poultry has been widely adopted in <a href="https://doi.org/10.12688%2Fgatesopenres.13171.1">China and other low-to-middle income countries</a>. The <a href="https://thehill.com/homenews/administration/3887075-white-house-weighs-mass-poultry-vaccination-amid-bird-flu-outbreak/">U.S.</a> and <a href="https://doi.org/10.1126/science.adc9644">Europe</a> are gearing up for a massive poultry vaccination campaign to curtail the spread of bird flu. </p>
<h2>How else can I protect myself against avian influenza?</h2>
<p>Avoiding direct contact with live poultry is perhaps the single most effective measure to prevent development of avian influenza. If exposure to potentially infected birds cannot be avoided, personal protective gear including gloves, gowns, face masks and eye shields should be worn. Hands should be thoroughly washed with soap and water after all potential exposures. <a href="https://doi.org/10.1128/mSphere.00474-19">Alcohol-based hand sanitizers are less effective at inactivating influenza viruses compared to handwashing</a>. </p>
<h2>Are bird feeders safe to use?</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/517569/original/file-20230327-28-56ojl8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517569/original/file-20230327-28-56ojl8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517569/original/file-20230327-28-56ojl8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517569/original/file-20230327-28-56ojl8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517569/original/file-20230327-28-56ojl8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517569/original/file-20230327-28-56ojl8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517569/original/file-20230327-28-56ojl8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">There are divergent opinions on the potential role of bird feeders in spreading the disease.</span>
<span class="attribution"><span class="source">(Unsplash/Grayson Smith)</span></span>
</figcaption>
</figure>
<p>Although there is currently a negligible risk of developing avian influenza following wild bird exposure, there are divergent opinions on the role of bird feeders in potentially spreading the disease. </p>
<p>The <a href="https://spca.bc.ca/news/bc-spca-asks-public-to-remove-bird-feeders-due-to-avian-influenza-outbreak/">British Columbia Society for the Prevention of Cruelty to Animals</a> recommends temporarily abandoning the practice of using backyard bird feeders. In contrast, the <a href="https://ask.usda.gov/s/article/Should-bird-feeders-be-taken-down-to-prevent-the-spread-of-diseases-such-as-bird-flu">U.S. Department of Agriculture</a> does not recommend against their use unless poultry are being farmed in the area. </p>
<h2>Is avian influenza the next viral pandemic?</h2>
<p>There is no way to predict if avian influenza will evolve into a pandemic affecting humans. Mitigation strategies to prevent cross-species transmission include large-scale pre-emptive vaccination of domestic birds and culling of infected flocks. </p>
<p>Of major concern is the potential for novel avian influenza subtypes to emerge through antigenic shift. This phenomenon involves reassortment of hemaglutinin and neuraminidase genes when a single host is infected with more than one viral subtype. As such, avian influenza is a <a href="https://www.gavi.org/vaccineswork/next-pandemic/h5n1-and-h7n9-influenza">prime contender as a pandemic viral disease</a> of animals and humans alike. </p>
<p>Current stockpiles of avian influenza vaccines for human use <a href="https://www.cbc.ca/news/health/bird-flu-vaccine-human-1.6784487">will likely be inadequate to meet societal needs</a> should there be a surge in human infections over time.</p><img src="https://counter.theconversation.com/content/201632/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sameer Elsayed does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Avian influenza — commonly known as ‘bird flu’ — is infecting domestic and wild birds in Canada and around the world.Sameer Elsayed, Professor of Medicine, Pathology & Laboratory Medicine, and Epidemiology & Biostatistics, Western UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2011622023-03-08T00:54:10Z2023-03-08T00:54:10ZFirst the floods, then the diseases – why NZ should brace for outbreaks of spillover infections from animals<figure><img src="https://images.theconversation.com/files/513839/original/file-20230306-2723-ijhs9p.jpg?ixlib=rb-1.1.0&rect=0%2C226%2C7955%2C4109&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Phil Yeo/Getty Images</span></span></figcaption></figure><p>When Cyclone Gabrielle hit New Zealand in February, it left a trail of destruction across the North Island. At least 11 people died, and more than <a href="https://www.stuff.co.nz/national/politics/131249421/more-than-10000-people-displaced-in-wake-of-cyclone--where-will-we-house-them">10,000 were displaced</a>. Bridges were washed out (<a href="https://www.nzherald.co.nz/nz/cyclone-gabrielle-bailey-bridges-could-be-two-to-three-months-away-for-hawkes-bay/SDWPA5BKBJADVKDKPG2VCSEARU/">35 in the Hastings district alone</a>), roads closed and <a href="https://theconversation.com/cyclone-gabrielle-broke-vital-communication-links-when-people-needed-them-most-what-happened-and-how-do-we-fix-it-200711">communications cut</a>. </p>
<p>With potable water and wastewater systems damaged and land covered in silt, there is another consequence that may yet appear – diseases, or more specifically, <a href="https://www.who.int/news-room/fact-sheets/detail/zoonoses">zoonoses</a> that spread between animals and people. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1628967574326382592"}"></div></p>
<p>Floods and their aftermath are a time of higher risk for disease spread. While we do not have much data specific to New Zealand, due partly to the difficulty of diagnosing and reporting diseases during times of crisis, we can use information from overseas to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3609207/">predict which diseases may flare up after floods</a>.</p>
<h2>First, the tummy bugs</h2>
<p>The first group of diseases for which we expect to see a rise in case numbers soon after floods is gastroenteritis caused by water-borne pathogens. GPs in Auckland are reporting an <a href="https://www.stuff.co.nz/national/politics/local-democracy-reporting/300812782/rise-in-cases-of-bacterial-disease-leptospirosis-could-be-linked-to-flooding">increase in cases</a> since the Auckland anniversary weekend floods. </p>
<p>Many pathogens survive in the gastrointestinal tract of animals and are released in their feces. Rain and floods facilitate their transmission by providing an environment through which they sometimes enter the food chain or water supply. </p>
<p>In 2016, Hawke’s Bay experienced a <a href="https://www.sciencedirect.com/science/article/abs/pii/S016344532030445X">campylobacteriosis outbreak</a> transmitted through the urban water supply that affected more than 6,000 people. The outbreak occurred just after heavy rain, which likely caused water contaminated with sheep feces to enter a bore. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/floods-create-health-risks-what-to-look-out-for-and-how-to-avoid-them-181718">Floods create health risks: what to look out for and how to avoid them</a>
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<p>Salmonellosis cases are also likely to rise during summer floods, aided by <a href="https://www.ehinz.ac.nz/assets/Factsheets/Released_2022/Gastrointestinal-diseases-climate-change_2022.pdf">higher temperatures</a>. The risk is particularly high as cases in dairy cattle have been <a href="https://nzva.org.nz/news/s-bovismorbificans/">steadily increasing</a> during the past eight years. </p>
<p>Local branches of Te Whatu Ora Health New Zealand in affected areas have been proactive in communicating these risks and <a href="https://www.northlanddhb.org.nz/news-and-publications/public-health-warnings/15-feb-2023-public-health-advisory/">prevention measures</a>, including the importance of wearing protective gear during the cleanup.</p>
<h2>Then, leptospirosis</h2>
<p>About a week to a month after floods, rodent-born disease outbreaks can start to appear. </p>
<p>Floods disturb the habitat of rodents, including rats, and they can be attracted to food waste around people’s homes. This was regularly observed after floods in <a href="https://www.abc.net.au/news/2022-04-04/qld-pest-controllers-report-spike-in-rats-snakes-after-floods/100958648">Queensland last year</a> and in <a href="https://www.stuff.co.nz/national/131278164/rats-swarm-redstickered-west-auckland-neighbourhood-after-floods">Auckland earlier this year</a>. </p>
<p>In New Zealand, our main concern is the bacterial disease leptospirosis. Brown rats carry one of the variants, livestock several others, and, once the bacteria are shed in the animals’ urine, they can <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0227055">survive in water and soil for several days</a>. This ability to survive in flood water means the risk of infection is increased for all variants, including those traditionally associated with ruminants and pigs. </p>
<p>Auckland has reported an <a href="https://www.nzherald.co.nz/nz/auckland-floods-rise-in-cases-of-bacterial-disease-leptospirosis-could-be-linked-to-flooding/XMMHXNLRCBE5VMOKJPISYCONK4/">increase in leptospirosis cases in February</a>, likely linked with the floods at the end of January. Hawke’s Bay was already a <a href="https://www.mdpi.com/2076-0817/9/10/841">known leptospirosis hotspot</a> that could worsen. </p>
<figure class="align-center ">
<img alt="Public health advice on how to prevent catching leptospirosis from infected animals." src="https://images.theconversation.com/files/513832/original/file-20230306-2225-zztl6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513832/original/file-20230306-2225-zztl6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513832/original/file-20230306-2225-zztl6s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513832/original/file-20230306-2225-zztl6s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513832/original/file-20230306-2225-zztl6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513832/original/file-20230306-2225-zztl6s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513832/original/file-20230306-2225-zztl6s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Public health advice on how to prevent catching leptospirosis from infected animals.</span>
<span class="attribution"><span class="source">Te Whatu Ora ‐ Te Matau a Māui Hawke’s Bay</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
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<p>The clinical signs of leptospirosis can vary a lot and it is important people seek medical attention when they feel unwell as it can be treated with antibiotics. People can get infected through contact with urine or a contaminated environment, via the mouth or nose or uncovered skin cuts. </p>
<p><a href="https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2016.21.17.30211">Leptospirosis outbreaks in dogs</a> can also happen. While they are rarely a source of infection for people in New Zealand, dogs can act as sentinels. The New Zealand Veterinary Association (<a href="https://nzva.org.nz/">NZVA</a>) provides <a href="https://nzva.org.nz/flood/companion-animals/">advice to owners of companion animals</a>.</p>
<h2>Finally, the mosquitoes</h2>
<p>New Zealand is likely (at least for now) safe from the final group of diseases emerging after floods: vector-borne diseases. </p>
<p>We don’t have the disease-carrying insects or viruses known to cause outbreaks, but our Fijian neighbours and many other countries often report <a href="https://www.spc.int/updates/news/2023/02/mosquito-borne-diseases-become-climate-reality-in-warming-pacific">dengue outbreaks</a> after floods. </p>
<p>Climate change is making it easier for both the insect carriers and viruses to establish in New Zealand, so we should not <a href="https://www.ehinz.ac.nz/indicators/border-health/mosquito-borne-disease-in-new-zealand">ignore this as a potential future threat</a>.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-mozzie-proof-your-property-after-a-flood-and-cut-your-risk-of-mosquito-borne-disease-178299">How to mozzie-proof your property after a flood and cut your risk of mosquito-borne disease</a>
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<h2>How to protect ourselves</h2>
<p>Vaccination, early detection and treatment of livestock, which act as a reservoir for many of the pathogens above, are effective ways of protecting humans. </p>
<p>Cattle can be vaccinated against three variants of bacteria causing leptospirosis and four types of <em>Salmonella</em>. But vaccination does not cover all the strains and is more difficult in the current situation when fencing has been destroyed and some communities can only access veterinary medicine by helicopter. </p>
<p>The use of personal protective equipment and good hand hygiene for any outdoor activity that involves contact with animals or flood water and soil is the best way to prevent diseases. Rodent control, including rapid disposal of food waste, is also more important than ever.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/58-of-human-infectious-diseases-can-be-worsened-by-climate-change-we-scoured-77-000-studies-to-map-the-pathways-188256">58% of human infectious diseases can be worsened by climate change – we scoured 77,000 studies to map the pathways</a>
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<p>It is important people seek medical care rapidly, both for themselves and their animals when they are unwell. This is how they can access appropriate treatment, but also how surveillance can happen, so New Zealand starts learning its own lessons on health risks associated with floods. </p>
<p>Our cities, population structures, farming systems and wildlife species are different from overseas, so having local data is crucial. This will help during the next heavy rain and floods – and there is no doubt there will be many more.</p>
<hr>
<p><em>We would like to acknowledge the contribution by Masood Sujau.</em></p><img src="https://counter.theconversation.com/content/201162/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Emilie Vallee receives funding from The Wellcome Trust for the project CliZod - Digital Technology Development Award in Climate Sensitive Infectious Disease Modelling number 226044/Z/22/Z. She works at the Tāwharau Ora School of Veterinary Science at Massey University. </span></em></p><p class="fine-print"><em><span>Barry Borman, Deborah Read, and Masako Wada do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Floods are often followed by waves of diseases because pathogens shed by animals can survive in flood waters for days, raising the risk of infection for humans.Emilie Vallee, Senior Lecturer in Veterinary Epidemiology, Massey UniversityBarry Borman, Professor, Massey UniversityDeborah Read, Associate professor, Massey UniversityMasako Wada, Research Officer in Veterinary Epidemiology, Massey UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1946342022-11-16T19:02:51Z2022-11-16T19:02:51ZTo stop new viruses jumping across to humans, we must protect and restore bat habitat. Here’s why<figure><img src="https://images.theconversation.com/files/495554/original/file-20221116-21-drd21f.jpg?ixlib=rb-1.1.0&rect=40%2C28%2C3803%2C2224&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Grey headed flying fox (Pteropus poliocephalus)</span> <span class="attribution"><span class="source">Vivien Jones</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Bats have lived with coronaviruses for millennia. Details are still hazy about how one of these viruses evolved into SARS-CoV-2, which causes COVID in humans. Did it go directly from bats to humans or via another animal species? When? And why? If we can’t answer these questions for this now-infamous virus, we have little hope of preventing the next pandemic.</p>
<p>Some bat species are <a href="https://theconversation.com/bats-are-hosts-to-a-range-of-viruses-but-dont-get-sick-why-139056">hosts for other viruses</a> lethal to humans, from rabies to <a href="https://www.who.int/news-room/fact-sheets/detail/nipah-virus">Nipah</a> to <a href="https://www.who.int/health-topics/hendra-virus-disease#tab=tab_1">Hendra</a>. But their supercharged immune systems allow them to co-exist with these viruses without appearing sick. </p>
<p>So what can we do to prevent these viruses emerging in the first place? We found one surprisingly simple answer in our <a href="https://www.nature.com/articles/s41586-022-05506-2">new research</a> on flying foxes in Australia: protect and restore native bat habitat to boost natural protection.</p>
<p>When we destroy native forests, we force nectar-eating flying foxes into survival mode. They shift from primarily nomadic animals following eucalypt flowering and forming large roosts to less mobile animals living in a large number of small roosts near agricultural land where they may come in contact with horses. </p>
<p>Hendra virus is carried by bats and can spill over to horses. It doesn’t often spread from horses to humans, but when it does, it’s <a href="https://www.health.nsw.gov.au/Infectious/controlguideline/Pages/hendra-case-summary.aspx">extremely dangerous</a>. Two-thirds of Hendra cases in horses have occurred in heavily cleared areas of northern New South Wales and south-east Queensland. That’s not a coincidence. </p>
<p>Now we know how habitat destruction and spillover are linked, we can act. Protecting the eucalyptus species flying foxes rely on will reduce the risk of the virus spreading to horses and then humans. The data we gathered also makes it possible to predict times of heightened Hendra virus risk – up to two years in advance. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/495553/original/file-20221116-17-txxcra.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="grey headed flying fox in flight" src="https://images.theconversation.com/files/495553/original/file-20221116-17-txxcra.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/495553/original/file-20221116-17-txxcra.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/495553/original/file-20221116-17-txxcra.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/495553/original/file-20221116-17-txxcra.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/495553/original/file-20221116-17-txxcra.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/495553/original/file-20221116-17-txxcra.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/495553/original/file-20221116-17-txxcra.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Grey headed flying foxes prefer to roost in huge groups, feeding on eucalypt nectar. But if there are no eucalypts, they look for food in rural and suburban areas.</span>
<span class="attribution"><span class="source">Vivien Jones</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>What did we find out?</h2>
<p>Many Australians are fond of flying foxes. Our largest flying mammal is often seen framed against summer night skies in cities. </p>
<p>These nectar-loving bats play a vital ecosystem role in pollinating Australia’s native trees. (Pollination in Australia isn’t limited to bees – flies, moths, birds and bats do it as well). Over winter, they rely on nectar from a few tree species such as forest red gums (<em>Eucalyptus tereticornis</em>) found mostly in southeast Queensland and northeast NSW. Unfortunately, most of this habitat has been cleared for agriculture or towns. </p>
<p>Flying foxes are typically nomadic, flying vast distances across the landscape. When eucalypts burst into flower in specific areas, these bats will descend on the abundant food and congregate in lively roosts, often over 100,000 strong. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/its-wrong-to-blame-bats-for-the-coronavirus-epidemic-134300">It's wrong to blame bats for the coronavirus epidemic</a>
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</em>
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<p>But Australia is a harsh land. During the severe droughts brought by El Niño, eucalyptus trees may stop producing nectar. To survive, flying foxes must change their behaviour. Gone are the large roosts. Instead, bats spread in many directions, seeking other food sources, like introduced fruits. This response typically only lasts a few weeks. When eucalypt flowering resumes, the bats come back to again feed in native forests. </p>
<p>But what happens if there are not enough forests to come back to? </p>
<p>Between 1996 and 2020, we found large winter roosts of nomadic bats in southeast Queensland became increasingly rare. Instead, flying foxes were forming small roosts in rural areas they would normally have ignored and feeding on introduced plants like privet, camphor laurel and citrus fruit. This has brought them into closer contact with horses.</p>
<p>In related research <a href="https://doi.org/10.1111/ele.14007">published last month</a>, we found the smaller roosts forming in these rural areas also had higher detection rates of Hendra virus – especially in winters after a climate-driven nectar shortage. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/495507/original/file-20221115-10481-529eus.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="flying fox" src="https://images.theconversation.com/files/495507/original/file-20221115-10481-529eus.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/495507/original/file-20221115-10481-529eus.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=408&fit=crop&dpr=1 600w, https://images.theconversation.com/files/495507/original/file-20221115-10481-529eus.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=408&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/495507/original/file-20221115-10481-529eus.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=408&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/495507/original/file-20221115-10481-529eus.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=513&fit=crop&dpr=1 754w, https://images.theconversation.com/files/495507/original/file-20221115-10481-529eus.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=513&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/495507/original/file-20221115-10481-529eus.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=513&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Flying foxes are social, intelligent – and play a key role in pollinating native trees.</span>
<span class="attribution"><span class="source">Vivien Jones</span>, <span class="license">Author provided</span></span>
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</figure>
<h2>An early warning system for Hendra virus</h2>
<p>Our models confirmed strong El Niño events caused nectar shortages for flying foxes, splintering their large nomadic populations into many small populations in urban and agricultural areas. </p>
<p>Importantly, the models showed a strong link between food shortages and clusters of Hendra virus spillovers from these new roosts in the following year. </p>
<p>This means by tracking drought conditions and food shortages for flying foxes, we can get crucial early warning of riskier times for Hendra virus – up to two years in advance. </p>
<p>Biosecurity, veterinary health and human health authorities could use this information to warn horse owners of the risk. Horse owners can then ensure their horses are protected with the vaccine. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/495559/original/file-20221116-20-hv7kdm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Flying fox asleep" src="https://images.theconversation.com/files/495559/original/file-20221116-20-hv7kdm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/495559/original/file-20221116-20-hv7kdm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/495559/original/file-20221116-20-hv7kdm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/495559/original/file-20221116-20-hv7kdm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/495559/original/file-20221116-20-hv7kdm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/495559/original/file-20221116-20-hv7kdm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/495559/original/file-20221116-20-hv7kdm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Habitat destruction makes winter flowering and nectar production unreliable, and means congregations of flying foxes in large roosts are increasingly rare.</span>
<span class="attribution"><span class="source">Pat Jones</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>How can we stop the virus jumping species?</h2>
<p>Conservationists have long pointed out human health depends on a healthy environment. This is a very clear example. We found Hendra virus never jumped from flying foxes to horses when there was abundant winter nectar. </p>
<p>Protecting and restoring bat habitat and replanting key tree species well away from horse paddocks will boost bat health – and keep us safer. </p>
<p>Flying foxes leave roosts in cities or rural areas when there are abundant flowering gums elsewhere. It doesn’t take too long – trees planted today could start drawing bats within a decade. </p>
<p>SARS-CoV-2 won’t be the last bat virus to jump species and upend the world. As experts plan ways to better respond to next pandemic and work on <a href="https://www.nature.com/articles/s41541-021-00284-w">human vaccines</a> built on the <a href="https://www.csiro.au/en/research/animals/livestock/hendra">equine Hendra vaccines</a>, we can help too. </p>
<p>How? By restoring and protecting the natural barriers which for so long kept us safe from bat-borne viruses. It is far better to prevent viruses from spilling over in the first place than to scramble to stop a possible pandemic once it’s begun. </p>
<p>Planting trees can help stop dangerous new viruses reaching us. It really is as simple as that. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/bats-are-hosts-to-a-range-of-viruses-but-dont-get-sick-why-139056">Bats are hosts to a range of viruses but don't get sick – why?</a>
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</p>
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<img src="https://counter.theconversation.com/content/194634/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alison Peel has received funding from Australian Research Council (DE190100710), the US National Science Foundation (DEB1716698) and the US Defense Advanced Research Projects Agency (D18AC00031). She is a member of the Wildlife Health Australia Bat Health Focus Group and the Human Animal Spillover and Emerging Diseases Scanning (HASEDS) working group.</span></em></p><p class="fine-print"><em><span>Peggy Eby has received funding from the US National Science Foundation (DEB1716698) and the US Defense Advanced Research Projects Agency (D18AC00031). </span></em></p><p class="fine-print"><em><span>Raina Plowright has received funding from the US National Science Foundation (DEB1716698), the US Defense Advanced Research Projects Agency (D18AC00031) and the U.S. National Institute of Food and Agriculture (1015891)</span></em></p>Bats host many viruses dangerous to humans. But it’s only when their habitats are destroyed that we’re at risk.Alison Peel, Senior Research Fellow in Wildlife Disease Ecology, Griffith UniversityPeggy Eby, Adjunct Senior Lecturer, Centre for Ecosystem Science, UNSW SydneyRaina Plowright, Professor, Cornell UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1896222022-09-05T20:04:33Z2022-09-05T20:04:33Z5 virus families that could cause the next pandemic, according to the experts<p>The CSIRO has delivered a comprehensive <a href="https://www.csiro.au/pandemic">report</a> on how we should prepare for future pandemics. </p>
<p>The report identifies six key science and technology areas such as faster development of vaccines and onshore vaccine manufacturing to ensure supply, new antivirals and ways of using the medicines we already have, better ways of diagnosing cases early, genome analysis, and data sharing. </p>
<p>It also recommends we learn more about viruses and their hosts across the five most concerning virus families. These causes of disease could fuel the next pandemic. </p>
<p>We asked leading experts about the diseases they can cause and why authorities should prepare well:</p>
<h2>1. Coronaviridae</h2>
<p><strong><em>COVID-19, Middle East respiratory syndrome (MERS), severe acquired respiratory syndrome (SARS)</em></strong></p>
<p>The first human <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7204879/">Coronaviruses</a> (229E and OC43) were found in 1965 and 1967 respectively. They were low-grade pathogens causing only mild cold-like symptoms and gastroenteritis. Initial understanding of this family came from study of related strains that commonly infect livestock or laboratory mice that also caused non-fatal disease. The <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3358201/">HKU-1 strain in 1995</a> again did not demonstrate an ability to generate high levels of disease. As such, coronaviridae were not considered a major concern until severe acquired respiratory syndrome (<a href="https://www.who.int/health-topics/severe-acute-respiratory-syndrome#tab=tab_1">SARS-1</a>) first appeared in 2002 in China.</p>
<p>Coronaviridae have a <a href="https://www.nature.com/articles/s41467-021-22785-x">very long RNA genome</a>, coding up to 30 viral proteins. Only four or five genes make infectious virus particles, but many others support diseases from this family by modifying immune responses. The viruses in this family mutate at a steady low rate, selecting changes in the outer spike to allow virus entry into new host cells.</p>
<p>Coronaviridae viruses are widespread in many ecological niches and common in bat species that make up <a href="https://www.si.edu/spotlight/bats/batfacts">20% of all mammals</a>. Mutations spread in their roosts can spillover into other mammals, such as the <a href="https://link.springer.com/article/10.1007/s11259-020-09781-0">civet cat</a>, then into humans. </p>
<p>Coronaviridae <a href="https://www.cdc.gov/coronavirus/2019-ncov/variants/genomic-surveillance.html">genome surveillance</a> shows an array of previously unknown virus strains circulating in different ecological niches. Climate change threatens intersections of these viral transmission networks. Furthermore, pandemic human spread of SARS-CoV-2 (the virus that causes COVID) has now seeded new transmissions back into other species, such as mink, cats, dogs and white-tailed deer. </p>
<p>Ongoing viral evolution in new animal hosts and also in immune-compromised <a href="https://www.bmj.com/content/376/bmj-2021-069807">HIV patients in under-resourced settings</a>, presents an ongoing source of new variants of concern.</p>
<p><strong>– Damian Purcell</strong></p>
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Read more:
<a href="https://theconversation.com/long-covid-how-researchers-are-zeroing-in-on-the-self-targeted-immune-attacks-that-may-lurk-behind-it-169911">Long COVID: How researchers are zeroing in on the self-targeted immune attacks that may lurk behind it</a>
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<h2>2. Flaviviridae</h2>
<p><strong><em>Dengue fever, Japanese encephalitis, Zika, West Nile fever</em></strong></p>
<p>The flaviviridae family causes several diseases, including dengue, Japanese encephalitis, Zika, West Nile disease and others. These diseases are often not life-threatening, causing fever, sometimes with rash or painful joints. A small proportion of those infected get severe or complicated infection. Japanese encephalitis can cause inflammation of the brain, and Zika virus can cause birth defects.</p>
<p>While all these viruses may be spread by mosquito bites, when it comes to each individual virus, not all mosquitoes bring equal risk. There are <a href="https://www.cdc.gov/zika/prevention/transmission-methods.html#:%7E:text=Zika%20virus%20is%20transmitted%20to,spread%20dengue%20and%20chikungunya%20viruses.">key mosquito species</a> involved in transmission cycles of dengue and Zika virus, such as <em>Aedes aegypti</em> and <em>Aedes albopictus</em>, that may be found in close to where people live. These mosquitoes are found in water-holding containers (such as potted plant saucers, rainwater tanks), water-filled plants, and tree holes. They also like to bite people.</p>
<p>The mosquitoes that spread these viruses are not currently widespread in Australia; they’re generally limited to central and far north Queensland. They are routinely detected through biosecurity surveillance at Australia’s major <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8005993/">airports and seaports</a>. With a rapid return to international travel, movement of people and their belongings may become an ever-increasing pathway of introduction of the diseases and mosquitoes back into Australia.</p>
<p>Different mosquitoes are involved in the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7000427/">transmission</a> of West Nile virus and Japanese encephalitis. These mosquitoes are more likely to be found in wetlands and bushland areas than backyards. They bite people but they also like to <a href="https://theconversation.com/how-australian-wildlife-spread-and-suppress-ross-river-virus-107267">bite the animals</a> most likely to be carrying these viruses. </p>
<p>The <a href="https://theconversation.com/japanese-encephalitis-virus-has-been-detected-in-australian-pigs-can-mozzies-now-spread-it-to-humans-178017">emergence of Japanese encephalitis</a>, a virus spread by mosquitoes between waterbirds, pigs, and people, is a perfect example. Extensive rains and flooding that provide idea conditions for mosquitoes and these animals create a “perfect storm” for disease emergence. </p>
<p><strong>– Cameron Webb & Andrew van den Hurk</strong></p>
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Read more:
<a href="https://theconversation.com/japanese-encephalitis-virus-has-been-detected-in-australian-pigs-can-mozzies-now-spread-it-to-humans-178017">Japanese encephalitis virus has been detected in Australian pigs. Can mozzies now spread it to humans?</a>
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<h2>3. Orthomyxoviridae</h2>
<p><strong><em>Influenza</em></strong></p>
<p>Before COVID-19, influenza was the infection most <a href="https://www.health.gov.au/resources/publications/australian-health-management-plan-for-pandemic-influenza-ahmppi">well-known</a> for causing pandemics.</p>
<p>Influenza virus is subdivided into types (A, B, and rarely C and D). Influenza A is further classified into subtypes based on haemagglutinin (H) and neuraminidase (N) protein variants on the surface of the virus. Currently, the most common influenza strains in humans are A/H1N1 and A/H3N2.</p>
<p><a href="https://www.who.int/news-room/spotlight/influenza-are-we-ready/zoonotic-influenza">Zoonotic infection</a> occurs when influenza strains that primarily affect animals “spill over” to humans. </p>
<p>Major changes in the influenza virus usually result from <a href="https://www.nejm.org/doi/full/10.1056/NEJMp0904572">new combinations</a> of influenza viruses that affect birds, pigs and humans. New strains have the potential to cause pandemics as there is little pre-existing immunity.</p>
<p>Since the beginning of the 20th century, there have been four influenza <a href="https://www.cdc.gov/flu/pandemic-resources/basics/past-pandemics.html">pandemics</a>, in 1918, 1957, 1968, and 2009. In between pandemics, seasonal influenza circulates throughout the world. </p>
<p>Although influenza is not as infectious as many other respiratory infections, the very short incubation period of around 1.4 days means outbreaks can spread quickly.</p>
<p>Vaccines are available to prevent influenza, but are only <a href="https://pubmed.ncbi.nlm.nih.gov/31903487/">partially</a> protective. Antiviral treatments are available, including oseltamivir, zanamivir, peramivir and baloxavir. Oseltamivir <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(14)62449-1/fulltext">decreases</a> the duration of illness by around 24 hours if started early, but whether it reduces the risk of severe influenza and its complications is <a href="https://www.thelancet.com/journals/lanres/article/PIIS2213-2600%2814%2970041-4/fulltext">controversial</a>.</p>
<p><strong>– Allen Cheng</strong> </p>
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Read more:
<a href="https://theconversation.com/my-year-as-victorias-deputy-chief-health-officer-on-the-pandemic-press-conferences-and-our-covid-future-166164">My year as Victoria's deputy chief health officer: on the pandemic, press conferences and our COVID future</a>
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<h2>4. Paramyxoviridae</h2>
<p><strong><em>Nipah virus, Hendra virus</em></strong></p>
<p>Paramyxoviridae are a large group of viruses that affect humans and animals. The most well known are measles and mumps, as well as parainfluenza virus (a common cause of <a href="https://www.rch.org.au/kidsinfo/fact_sheets/Croup/">croup</a> in children). </p>
<p>Globally, <a href="https://www.who.int/news-room/fact-sheets/detail/measles">measles</a> is a dangerous disease for young children, particularly those who are malnourished. Vaccines are highly effective with the measles vaccine alone <a href="https://www.who.int/news/item/12-11-2015-measles-vaccination-has-saved-an-estimated-17-1-million-lives-since-2000">estimated</a> to have saved 17 million lives between 2000 and 2014.</p>
<p>One group of paramyxoviruses is of particular importance for pandemic planning – henipaviruses. This includes Hendra virus, Nipah virus and the new <a href="https://theconversation.com/what-is-this-new-langya-virus-do-we-need-to-be-worried-188577">Langya virus</a> (as well as the fictional MEV-1 in the film <a href="https://www.reuters.com/article/idUS57323549020110913">Contagion</a>). These are all zoonoses (diseases that spill over from animals to humans)</p>
<p>Hendra virus was first <a href="https://onlinelibrary.wiley.com/doi/abs/10.5694/j.1326-5377.1995.tb126050.x">discovered</a> in Queensland in 1994, when it caused the deaths of 14 horses and their horse trainer. Infected flying foxes have since spread the virus to horses in Queensland and northern New South Wales. There have been seven <a href="https://www.outbreak.gov.au/for-vets-and-scientists/hendra-virus">reported</a> human cases of Hendra virus in Australia, including four deaths.</p>
<p>Nipah virus is more <a href="https://www.who.int/news-room/fact-sheets/detail/nipah-virus">significant</a> globally. Infection may be mild, but some people develop encephalitis (inflammation of the brain). Outbreaks frequently occur in Bangladesh, where the first <a href="https://pubmed.ncbi.nlm.nih.gov/10781618/">outbreak</a> was reported in 1998. Significantly, Nipah virus appears to be able to be <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6547369/">transmitted</a> from person-to-person though close contact.</p>
<p><strong>– Allen Cheng</strong></p>
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Read more:
<a href="https://theconversation.com/what-is-this-new-langya-virus-do-we-need-to-be-worried-188577">What is this new Langya virus? Do we need to be worried?</a>
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<h2>5. Togaviridae (alphaviruses)</h2>
<p><strong><em>Chikungunya fever, Ross River fever, Eastern equine encephalitis, Western equine encephalitis, Venezuelan equine encephalitis</em></strong></p>
<p>The most common disease symptoms caused by infection with alphaviruses like chikungunya and Ross River viruses are fever, rash and painful joints.</p>
<p>Like some flaviviruses, <a href="https://www.who.int/news-room/fact-sheets/detail/chikungunya">chikungunya virus</a> is thought to be only spread by <em>Aedes aegypti</em> mosquitoes in Australia. This limits risks, for now, to central and far north Queensland. </p>
<p>Many different mosquitoes play a role in transmission of alphaviruses, including dozens of mosquito species suspected as playing a role in the spread of <a href="http://conditions.health.qld.gov.au/HealthCondition/condition/14/217/120/ross-river-virus">Ross River fever</a>. Many of these mosquitoes <a href="https://theconversation.com/how-can-the-bite-of-a-backyard-mozzie-in-australia-make-you-sick-171601">are commonly found across Australia</a>. </p>
<p>But what role may these local mosquitoes play should diseases such as eastern equine encephalitis or western equine encephalitis make their way to Australia? Given the capacity of our home-grown mosquitoes to spread other alphaviruses, it is reasonable to assume they would be effective at transmitting these as well. That’s why the CSIRO report <a href="https://www.csiro.au/pandemic">notes</a> future pandemic preparation should work alongside Australia’s established biosecurity measures. </p>
<p><strong>– Cameron Webb & Andrew van den Hurk</strong></p>
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Read more:
<a href="https://theconversation.com/how-can-the-bite-of-a-backyard-mozzie-in-australia-make-you-sick-171601">How can the bite of a backyard mozzie in Australia make you sick?</a>
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<img src="https://counter.theconversation.com/content/189622/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Allen Cheng receives funding from the Australian National Health and Medical Research Council and the Australian government for research, including in influenza. He is Chair of the Advisory Committee for Vaccines and a member of the Australian Technical Advisory Group on Immunisation. </span></em></p><p class="fine-print"><em><span>Andrew van den Hurk has received funding from local, state and federal agencies to study the ecology of mosquito-borne pathogens, and their surveillance and control. He is an employee of the Department of Health, Queensland Government.</span></em></p><p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p><p class="fine-print"><em><span>Damian Purcell consults for Moderna on mRNA vaccine education and receives funding from the National Health and Medical Research Council, and the Victorian Government grants. He is Past Presidents' advisor for the Australasian Virology Society, and Committee member of the RNA Network of Australia.</span></em></p>Authorities have been warned about five virus families that could cause future pandemics. Here are snapshots of the diseases each can cause and why we should be worried.Allen Cheng, Professor in Infectious Diseases Epidemiology, Monash UniversityAndrew van den Hurk, Medical Entomologist, The University of QueenslandCameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of SydneyDamian Purcell, Professor of virology and theme leader for viral infectious diseases, The Peter Doherty Institute for Infection and ImmunityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1879232022-08-15T20:03:13Z2022-08-15T20:03:13ZOne Health: why we need to combine disease surveillance and climate modelling to preempt future pandemics<figure><img src="https://images.theconversation.com/files/479066/original/file-20220815-59190-imfieg.jpg?ixlib=rb-1.1.0&rect=51%2C0%2C3738%2C2601&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Yang Jianzheng/VCG via Getty Images</span></span></figcaption></figure><p>Within less than three years, the World Health Organization (WHO) has declared two public health emergencies of international concern: COVID-19 in February 2020 and monkeypox in July 2022. </p>
<p>At the same time, extreme weather events are being reported continuously across the world and are expected to become <a href="https://www.carbonbrief.org/explainer-what-the-new-ipcc-report-says-about-extreme-weather-and-climate-change/">more frequent and intense</a>. </p>
<p>These are not separate issues. We will have a better chance of suppressing infectious diseases only if we adopt what the WHO calls a <a href="https://www.who.int/health-topics/one-health#tab=tab_1">One Health approach</a> and integrate predictive modelling and surveillance used in both infectious disease control and climate change. </p>
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<p>Public health experts have relied on <a href="https://sphweb.bumc.bu.edu/otlt/MPH-Modules/EP/EP713_Surveillance/EP713_Surveillance2.html">disease surveillance systems</a> to track emerging diseases since the 19th century. Their methods have become increasingly sophisticated, including <a href="https://www.who.int/initiatives/genomic-surveillance-strategy">genomic surveillance</a> to track how <a href="https://nextstrain.org/">pathogens evolve</a>. </p>
<p>But as long as these surveillance systems depend on diseases that have already emerged, they remain behind the curve and we risk “<a href="https://www.nature.com/articles/s41591-022-01918-9">sleepwalking</a>” into the next pandemic.</p>
<p>Given the impacts of a changing climate on ecosystems, any surveillance of new disease outbreaks must include humans, animals and planetary changes.</p>
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Read more:
<a href="https://theconversation.com/one-health-a-crucial-approach-to-preventing-and-preparing-for-future-pandemics-173637">One Health: A crucial approach to preventing and preparing for future pandemics</a>
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<h2>New and re-emerging pathogens</h2>
<p>COVID-19 will continue to evolve into new variants despite high vaccination rates in some countries and the availability of antiviral treatments. At the same time, new diseases will continue to emerge.</p>
<p>In the first week of August, more than <a href="https://www.cdc.gov/poxvirus/monkeypox/response/2022/world-map.html">25,000 cases of monkeypox</a> were registered worldwide and new reports of deaths continue to emerge. Ghana has declared an <a href="https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON402">outbreak of Marnburg virus disease</a> in July and Mozambique reported its <a href="https://news.un.org/en/story/2022/05/1118502">first case of polio in 30 years</a> in May. </p>
<p>Polio has now also been detected in <a href="https://www.nytimes.com/2022/08/12/nyregion/polio-nyc-sewage.html">wastewater samples in New York</a> and public health authorities in other wealthy countries are racing to head off the re-emergence of a virus that had been almost eliminated. </p>
<p>While the latter is most likely due to a global drop in vaccinations, health experts are warning that new pathogens, particularly those that jump between animals and humans, will <a href="https://www.science.org/content/article/animal-melting-pot-created-climate-change-could-lead-new-disease-outbreaks">become more frequent</a> as habitats change in a warming world.</p>
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Read more:
<a href="https://theconversation.com/nz-children-face-a-perfect-storm-of-dangerous-diseases-as-immunisation-rates-fall-188157">NZ children face a ‘perfect storm’ of dangerous diseases as immunisation rates fall</a>
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<p>Health scientists refer to diseases such as COVID-19 and monkeypox as zoonoses – pathogens known to be transmitted from animals to humans. Close contact between humans and wild animals is increasing as forests are destroyed to make way for agriculture and trade in exotic animals continues. </p>
<p>At the same time, the thawing of permafrost is releasing <a href="https://www.bbc.com/future/article/20190612-the-poisons-released-by-melting-arctic-ice">microbes hidden beneath the ice</a>. Taken together, there is an ever <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7423499/">growing risk of new pathogens</a>. </p>
<h2>The link between human, animal and environmental health</h2>
<p>Global climate models are increasingly sophisticated at projecting how climate change will affect <a href="https://climate.mit.edu/explainers/climate-models">Earth systems</a> and ecosystems. There are efforts to “connect the dots” by integrating human and animal health and the “sickness of the planet”, as described by the late Norwegian physician Per Fugelli in his <a href="https://www.jstor.org/stable/pdf/45354498.pdf">1994 essay</a>, In Search of a Global Social Medicine. </p>
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<p>Incremental steps in integrating disease and planetary surveillance are under way. In 2008, the WHO, the Food and Agriculture Organization (<a href="https://www.fao.org/home/en">FAO</a>), the World Organisation for Animal Health (<a href="https://www.woah.org/en/home/">WOAH</a>) and other organisations jointly drafted a framework for how <a href="https://www.preventionweb.net/publication/contributing-one-world-one-health-strategic-framework-reducing-risks-infectious">best to diminish the risk</a> and minimise the global impact of pandemics. </p>
<p>In 2014, a <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(14)60409-8/fulltext">manifesto</a> published in the Lancet called for an urgent transformation in our values, based on the recognition of our “interdependence and interconnectedness of the risks we face”. </p>
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Read more:
<a href="https://theconversation.com/most-laws-ignore-human-wildlife-conflict-this-makes-us-vulnerable-to-pandemics-135191">Most laws ignore ‘human-wildlife conflict’. This makes us vulnerable to pandemics</a>
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<p>In 2021, the One Health high level expert panel adopted a <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1010537">definition</a> of an integrated, unifying approach that aims to balance and optimise the health of people, animals and ecosystems. </p>
<p>A <a href="https://africacdc.org/programme/surveillance-disease-intelligence/one-health/">One Health approach</a> to disease surveillance is now used by the African Centers for Disease Control and the global network to address antimicrobial resistance. In 2019, the UN’s interagency coordinating group on <a href="https://amr.tghn.org/resources/one-health/">antimicrobial resistance</a> recognised that microbes that infect animals and humans share the same ecosystems and their prevention therefore requires a coordinated approach.</p>
<p>These are relatively recent initiatives in our effort to understand and track past, present and future outbreaks. There may be a long way to go in integrating disciplines, but the answer to predicting and preempting future outbreaks and pandemics lies in a One Health approach.</p><img src="https://counter.theconversation.com/content/187923/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Arindam Basu does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>If surveillance focuses only on diseases that have already emerged, we’ll remain behind the curve. Better prediction of future pandemics will need to integrate animal, planetary and human health.Arindam Basu, Associate Professor, Epidemiology and Environmental Health, University of CanterburyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1881632022-08-14T20:04:15Z2022-08-14T20:04:15ZThe COVID lab leak theory is dead. Here’s how we know the virus came from a Wuhan market<p>My colleagues and I published the most <a href="https://www.science.org/doi/full/10.1126/science.abp8715">detailed</a> <a href="https://www.science.org/doi/10.1126/science.abp8337">studies</a> of the earliest events in the COVID-19 pandemic last month in the journal Science.</p>
<p>Together, these papers paint a coherent evidence-based picture of what took place in the city of Wuhan during the latter part of 2019.</p>
<p>The take-home message is the COVID pandemic probably did begin where the first cases were detected – at the Huanan Seafood Wholesale Market. </p>
<p>At the same time this lays to rest the idea that the virus escaped from a laboratory.</p>
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<h2>Huanan market was the pandemic epicentre</h2>
<p>An analysis of the geographic locations of the earliest known COVID cases – dating to December 2019 – revealed a strong clustering around the Huanan market. This was true not only for people who worked at or visited the market, but also for those who had no links to it.</p>
<p>Although there will be many missing cases, there’s no evidence of widespread sampling bias: the first COVID cases were not identified simply because they were linked to the Huanan market.</p>
<p>The Huanan market was the pandemic epicentre. From its origin there, the SARS-CoV-2 virus rapidly spread to other locations in Wuhan in early 2020 and then to the rest of the world.</p>
<p>The Huanan market is an indoor space about the size of two soccer fields. The word “seafood” in its name leaves a misleading impression of its function. When I visited the market in 2014, a variety of live wildlife was for sale including raccoon dogs and muskrats.</p>
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<img alt="Dark image of the closed Huanan Seafood Wholesale Market, January 2020" src="https://images.theconversation.com/files/478649/original/file-20220811-20-wdm2i8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/478649/original/file-20220811-20-wdm2i8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/478649/original/file-20220811-20-wdm2i8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/478649/original/file-20220811-20-wdm2i8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/478649/original/file-20220811-20-wdm2i8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/478649/original/file-20220811-20-wdm2i8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/478649/original/file-20220811-20-wdm2i8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Chinese authorities closed the Huanan market on the first day of 2020.</span>
<span class="attribution"><span class="source">Getty Images</span></span>
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<p>At the time I suggested to my Chinese colleagues that we sample these market animals for viruses. Instead, they set up a virological surveillance study at the nearby Wuhan Central Hospital, which later cared for many of the earliest COVID patients.</p>
<p>Wildlife were also on sale in the Huanan market in 2019. After the Chinese authorities closed the market on January 1 2020, investigative teams swabbed surfaces, door handles, drains, frozen animals and so on.</p>
<p>Most of the samples that later tested positive for SARS-CoV-2 were from the south-western corner of the market. The wildlife I saw for sale on my visit in 2014 were in the south-western corner.</p>
<p>This establishes a simple and plausible pathway for the virus to jump from animals to humans.</p>
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<strong>
Read more:
<a href="https://theconversation.com/how-do-viruses-mutate-and-jump-species-and-why-are-spillovers-becoming-more-common-134656">How do viruses mutate and jump species? And why are 'spillovers' becoming more common?</a>
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<h2>Animal spillover</h2>
<p>SARS-CoV-2 has evolved into an array of lineages, some familiar to us as the “variants of concern” (what we call Delta, Omicron and so on). The first split in the SARS-CoV-2 family tree – between the “A” and “B” lineages – occurred very early in the pandemic. Both lineages have an epicentre at the market and both were detected there.</p>
<p>Further analyses suggest the A and B lineages were the products of separate jumps from animals. This simply means there was a pool of infected animals in the Huanan market, fuelling multiple exposure events.</p>
<p>Reconstructing the history of mutations in the SARS-CoV-2 genome sequence through time showed the B lineage was the first to jump to humans. It was followed, perhaps a few weeks later, by the A lineage. </p>
<p>All these events are estimated to have occurred no earlier than late October 2019. Claims that the virus was spreading before this date can be dismissed.</p>
<figure class="align-center ">
<img alt="A team of people doing disinfecting work at the Huanan Wholesale Seafood Market, March 2020" src="https://images.theconversation.com/files/478648/original/file-20220811-617-wdm2i8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/478648/original/file-20220811-617-wdm2i8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=374&fit=crop&dpr=1 600w, https://images.theconversation.com/files/478648/original/file-20220811-617-wdm2i8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=374&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/478648/original/file-20220811-617-wdm2i8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=374&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/478648/original/file-20220811-617-wdm2i8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=470&fit=crop&dpr=1 754w, https://images.theconversation.com/files/478648/original/file-20220811-617-wdm2i8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=470&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/478648/original/file-20220811-617-wdm2i8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=470&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A team of people working on disinfecting the Huanan Wholesale Seafood Market, March 2020.</span>
<span class="attribution"><span class="source">China News Service/Getty Images</span></span>
</figcaption>
</figure>
<p>What’s missing, of course, is that we don’t yet know exactly which animals were involved in the transfer of SARS-CoV-2 to humans. Live wildlife were removed from the Huanan market before the investigative team entered, increasing public safety but hampering origin hunting. </p>
<p>The opportunity to find the direct animal host has probably passed. As the virus likely rapidly spread through its animal reservoir, it’s overly optimistic to think it would still be circulating in these animals today.</p>
<p>The absence of a definitive animal source has been taken as tacit support for counter claims that SARS-CoV-2 in fact “leaked” from a scientific laboratory – the Wuhan Institute of Virology.</p>
<h2>Death knell for the lab leak theory</h2>
<p>The lab leak theory rests on an unfortunate coincidence: that SARS-CoV-2 emerged in a city with a laboratory that works on bat coronaviruses.</p>
<p>Some of these bat coronaviruses are closely related to SARS-CoV-2. But not close enough to be direct ancestors.</p>
<p>Sadly, the focus on the Wuhan Institute of Virology has distracted us from a far more important connection: that, like SARS-CoV-1 (which emerged in late 2002) before it, there’s a direct link between a coronavirus outbreak and a live animal market.</p>
<p>Consider the odds that a virus that leaked from a lab was first detected at the very place where you would expect it to emerge if it in fact had a natural animal origin – vanishingly low. And these odds drop further as we need to link both the A and B lineages to the market.</p>
<p>Was the market just the location of a super-spreading event? Nothing says so. It wasn’t a crowded location in the bustling and globally connected metropolis of Wuhan. It’s not even close to being the busiest market or shopping mall in the city.</p>
<p>For the lab leak theory to be true, SARS-CoV-2 must have been present in the Wuhan Institute of Virology before the pandemic started. This would convince me. </p>
<p>But the inconvenient truth is there’s not a single piece of data suggesting this. There’s no evidence for a genome sequence or isolate of a precursor virus at the Wuhan Institute of Virology. Not from gene sequence databases, scientific publications, annual reports, student theses, social media, or emails. </p>
<p>Even the intelligence community has found nothing. Nothing. And there was no reason to keep any work on a SARS-CoV-2 ancestor secret before the pandemic.</p>
<p>To assign the origin of SARS-CoV-2 to the Wuhan Institute of Virology requires a set of increasingly implausible “what if?” scenarios. These eventually lead to preposterous suggestions of clandestine bioweapon research.</p>
<p>The lab leak theory stands as an unfalsifiable allegation. If an investigation of the lab found no evidence of a leak, the scientists involved would simply be accused of hiding the relevant material. If not a conspiracy theory, it’s a theory requiring a conspiracy.</p>
<p>It provides a convenient vehicle for calls to limit, if not ban outright, gain-of-function research in which viruses with greatly different properties are created in labs. Whether or not SARS-CoV-2 originated in this manner is incidental.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-want-to-know-where-covid-came-from-but-its-too-soon-to-expect-miracles-172155">We want to know where COVID came from. But it’s too soon to expect miracles</a>
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<h2>Wounds that may never be healed</h2>
<p>The acrid stench of xenophobia lingers over much of this discussion. Fervent dismissals by the Chinese scientists of anything untoward are blithely cast as lies.</p>
<p>Yet during this crucial period these same scientists were going to international conferences and welcoming visitors. Do we honestly believe they would have such a pathological disdain for the consequences of their actions?</p>
<p>The debate over the origins of COVID has opened wounds that may never be healed. It has armed a distrust in science and fuelled divisive political opinion. Individual scientists have been assigned the sins of their governments. </p>
<p>The incessant blame game and finger pointing has reduced the chances of finding viral origins even further. History won’t judge this period kindly.</p>
<p>Global collaboration is the bedrock of effective pandemic prevention, but we’re in danger of destroying rather than building relationships. We may even be less prepared for a pandemic than in 2019. Despite political barriers and a salivating media, the evidence for a natural animal origin for SARS-CoV-2 has increased over the past two years. To deny it puts us all at risk.</p><img src="https://counter.theconversation.com/content/188163/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Edward C Holmes receives funding from the Australian Research Council and the National Health and Medical Research Council. He has received consultancy fees from Pfizer Australia and has held honorary appointments (for which he has received no renumeration and performed no duties) at the China CDC in Beijing and the Shanghai Public Health Clinical Center (Fudan University)</span></em></p>For the lab leak theory to be true, SARS-CoV-2 must have been present in the Wuhan Institute of Virology before the pandemic started. But there’s not a single piece of data suggesting this.Edward C Holmes, ARC Australian Laureate Fellow and Professor, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1864862022-08-05T03:42:36Z2022-08-05T03:42:36ZShould we be worried about our pet cats and dogs getting COVID?<figure><img src="https://images.theconversation.com/files/477533/original/file-20220804-9397-c9swv9.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4000%2C2664&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>The SARS-CoV-2 virus, which causes COVID, originated from bats and then, probably after passing through <a href="https://www.contagionlive.com/view/who-china-report-covid-19-passed-bats-humans-animal">an intermediary host</a>, gained the ability to infect humans.</p>
<p>Many new viruses that <a href="https://www.washingtonpost.com/science/2020/04/03/coronavirus-wildlife-environment/">emerge in this way</a>, like SARS-CoV-2, maintain the ability to infect <a href="https://www.cdc.gov/onehealth/basics/zoonotic-diseases.html">both animals and humans</a>.</p>
<p>It’s well documented the SARS-CoV-2 virus infects <a href="https://www.cdc.gov/coronavirus/2019-ncov/daily-life-coping/animals.html">a number of different animals</a>. Cases of COVID have been recorded in animals as different as hamsters, ferrets, lions, tigers, mink and non-human primates.</p>
<p>However the question that concerns many of us in our cosy domesticated worlds, is what sort of threat does the virus pose to cats and dogs, the animals we have the closest relationship with?</p>
<h2>Can cats and dogs get COVID?</h2>
<p>Yes, cats and dogs can get COVID.</p>
<p>Both cats and dogs have been found to have been infected with the virus. A <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0250853">number</a> <a href="https://www.frontiersin.org/articles/10.3389/fvets.2021.779341/full">of studies</a> that involved the testing of domestic pets have confirmed the presence of these infections.</p>
<p>One of the more interesting suggestions from a pre-print study (one that is yet to be reviewed by other scientists), is that cats and dogs were <a href="https://www.biorxiv.org/content/10.1101/2022.04.13.488132v1.full.pdf/">less susceptible to the BA.1 Omicron variant</a> compared to previous variants.</p>
<p>It was speculated the mutations in this variant which we know made it more transmissible in humans may have made it less able to bind to cellular receptors in cats and dogs.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/understanding-how-animals-become-infected-with-covid-19-can-help-control-the-pandemic-173978">Understanding how animals become infected with COVID-19 can help control the pandemic</a>
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<h2>Who gives it to whom?</h2>
<p>Although it’s theoretically possible for COVID to be transmitted in any direction – that is, from humans to cats and dogs, from cats and dogs to humans, and from these pets to each other – the current belief is the virus is primarily transmitted <a href="https://www.cdc.gov/coronavirus/2019-ncov/daily-life-coping/animals.html">from humans to these pets</a>.</p>
<p>There are a number of possible explanations for why transmission generally occurs in this direction.</p>
<p>However, the most likely explanation is that these animals, when infected, generate <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9155877/">much lower viral loads</a> than humans and they may shed the virus for only a short time, which makes them less likely to transmit the virus onwards.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1546585579814518786"}"></div></p>
<h2>How common is it in pets?</h2>
<p>The question of how common COVID is in animals generally, and in domestic pets, is one being actively explored.</p>
<p>In terms of how common it is in cats and dogs, there are methodological challenges to answering this question in large studies. Try taking a nasal swab from your cat and see how this works out!</p>
<p>Despite the practical obstacles, a study published in June suggests these infections may be <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9155877/">more common than initially thought</a>. The researchers studied the blood samples of 59 dogs and 48 cats in Ontario, Canada, which lived with people who’d tested positive to COVID.</p>
<p>They found 52% of the cats, and 41% of the dogs, had antibodies targeted to SARS-CoV-2, suggesting they’d been previously infected with the coronavirus. Cats were more likely than dogs to have contracted COVID in this study, but the authors note there’s a lot of variability in the studies looking into the prevalence of infection in animals.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/deer-mink-and-hyenas-have-caught-covid-19-animal-virologists-explain-how-to-find-the-coronavirus-in-animals-and-why-humans-need-to-worry-176666">Deer, mink and hyenas have caught COVID-19 – animal virologists explain how to find the coronavirus in animals and why humans need to worry</a>
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<hr>
<h2>How severe is it in pets?</h2>
<p>When a cat or dog gets COVID symptoms, they get pretty much <a href="https://www.ctvnews.ca/health/coronavirus/people-with-covid-19-can-infect-and-sicken-cats-and-dogs-by-cuddling-them-study-1.5963625">the same symptoms as humans</a>. </p>
<p>They generally don’t feel well and the symptoms they experience include coughing and sneezing, lethargy and loss of appetite.</p>
<p>But the good news is, available data suggests most of the time infection results in either no symptoms or very mild disease. And the duration of their symptoms, if they get them, <a href="https://www.cidrap.umn.edu/news-perspective/2021/07/dog-cat-owners-covid-19-often-pass-it-pets">may be very short</a>.</p>
<p>Although it’s possible for a pet to get more severe symptoms, this seems to be uncommon.</p>
<h2>So what should we make of this?</h2>
<p>The strong message from what we know so far is that we humans pose much more of a threat to our cats and dogs than they pose to us when it comes to COVID.</p>
<p>Therefore, if you get infected it’s probably sensible to limit contact with your pets, particularly while you’re at your most infectious. Just like you probably do anyway, you should treat your pet as you would any other member of your family when you’re ill and do everything you can to reduce the likelihood of infecting them. </p>
<p>Trying to get your pet to wear a mask, however, is definitely a step too far…</p>
<p>The good news is that even if you were to give your pet COVID, chances are they will either get no symptoms or only mild symptoms. And even if they do experience more severe illness, the evidence suggests they will bounce back quickly.</p>
<p>Of course, if you do suspect your pet has COVID and you are unsure about what to do, you should seek professional advice.</p><img src="https://counter.theconversation.com/content/186486/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hassan Vally does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Data suggests most of the time infection results in either no symptoms or very mild disease for cats and dogs. And the duration of their symptoms, if they get them, may be very short.Hassan Vally, Associate Professor, Epidemiology, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1840852022-06-06T19:40:43Z2022-06-06T19:40:43ZMonkeypox: ‘This is an entirely new spread of the disease’<figure><img src="https://images.theconversation.com/files/467198/original/file-20220606-20-5nho1v.png?ixlib=rb-1.1.0&rect=0%2C8%2C2901%2C1770&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Electron micrograph of monkeypox virus particles isolated in 2003 in the United States from human samples (left, mature, oval viruses; right, immature, round viruses).</span> <span class="attribution"><a class="source" href="https://phil.cdc.gov/Details.aspx?pid=22664">Cynthia S. Goldsmith, Russell Regner / CDC / AP</a></span></figcaption></figure><p><em>One thousand confirmed cases of monkeypox, a disease originating in Africa, have been recorded since early May across at least 30 non-endemic countries such as the United Kingdom, Spain, Portugal, France, the United States, Australia, United Arab Emirates and Israel. But what is this virus? Who is affected? And should we be worried about the recent surge in cases? In a bid to answer such questions, we caught up with Camille Besombes, a medical doctor specialist in infectious diseases, who has been involved for the past three years in <a href="https://research.pasteur.fr/fr/project/afripox/">Afripox</a>, a project that aims to gain a better understanding of the virus in its endemic region. She is currently conducting PhD research within the unit headed by the project’s coordinator, Arnaud Fontanet, a leading medical epidemiologist and emerging infectious disease specialist at the Pasteur Institute.</em></p>
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<p><strong>The Conversation: What exactly is the monkeypox virus?</strong></p>
<p><strong>Camille Besombes:</strong> Monkeypox is a virus belonging to the genus Orthopoxvirus, a family that also includes smallpox. Like smallpox, it is a large DNA virus with a particular appetite for skin tissue. However, smallpox only affected humans, which meant that we were able to eradicate it through worldwide mass vaccination, whereas monkeypox is carried by an animal viral reservoir. And despite its name, the natural reservoir is not actually monkeys.</p>
<p>The term “monkeypox” was coined when the virus was first identified in captive primates (in Denmark back in 1958), but in nature, the virus is most often found in squirrels and other rodents. In 1970, the first human case of monkeypox was documented in a nine-month-old child in the Democratic Republic of the Congo, amid increasing efforts in the campaign to eradicate smallpox.</p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/35148313/">There are two strains of monkeypox that we know of</a>. The type that affects Nigeria, Liberia, Sierra Leone, and Côte d’Ivoire is the so-called West African strain, with a case-fatality rate between 1 to 3%. This is the one that was detected in the recent cases in Europe. The second is the “Congo Basin” strain, which circulates in the Democratic Republic of the Congo (DRC), the Republic of the Congo, the Central African Republic (CAR), and Gabon. Both strains are now circulating in Cameroon: recently, cases of infections implying the West African strain – imported from Nigeria – have been reported. Associated with more severe clinical forms, the Congo Basin strain has a case-fatality rate of around 10%.</p>
<p>We must also keep in mind that these figures are taken from countries where medical care is somewhat lacking, particularly in more remote regions. As for Europe, several patients are currently in hospital with the disease, but no death and no severe form of it have been detected on the continent.</p>
<p><strong>TC: What are the symptoms of this disease?</strong></p>
<p><strong>CB:</strong> Following a relatively long incubation (usually lasting around 6 to 13 days, and up to 21 days), it presents its first onset symptoms during a two-day period known as the “prodromal” phase. These symptoms may include high fever, headaches, swollen lymph nodes (which are a sign that distinguishes it from smallpox), muscle pain, and fatigue. It is at this stage that patients are considered to be contagious.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/464537/original/file-20220520-18-ynskxc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo of monkeypox lesions" src="https://images.theconversation.com/files/464537/original/file-20220520-18-ynskxc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/464537/original/file-20220520-18-ynskxc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464537/original/file-20220520-18-ynskxc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464537/original/file-20220520-18-ynskxc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464537/original/file-20220520-18-ynskxc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464537/original/file-20220520-18-ynskxc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464537/original/file-20220520-18-ynskxc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Monkeypox causes lesions that gradually spread over the infected person’s body.</span>
<span class="attribution"><span class="source">Jean-Marc Zokoé</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<p>Next, the patient develops a rash, <a href="https://www.cdc.gov/poxvirus/monkeypox/symptoms.html">usually starting on the face</a> and gradually spreading over the rest of the body. This rash causes pain and intense itching due to the inflammation that occurs around the skin lesions. In the West African strain, these lesions can be initially rather infrequent and discreet, and may therefore go unnoticed. The disease typically lasts two to four weeks and tends to go away spontaneously in the majority of cases.</p>
<p>The main complications of monkeypox include dehydration due to water loss from numerous and more widespread lesions, secondary bacterial infection of the lesions, sepsis, and corneal or other ocular lesions that may lead to vision loss. On top of these, cases of encephalitis (<em>ed. note: “inflammation of the brain”</em>) have also been documented, most notably in a <a href="https://pubmed.ncbi.nlm.nih.gov/15499541/">child during the 2003 US outbreak</a>.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/464538/original/file-20220520-18-ig02wa.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt=" Photo of an infant covered with lesions due to monkeypox virus " src="https://images.theconversation.com/files/464538/original/file-20220520-18-ig02wa.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/464538/original/file-20220520-18-ig02wa.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464538/original/file-20220520-18-ig02wa.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464538/original/file-20220520-18-ig02wa.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464538/original/file-20220520-18-ig02wa.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464538/original/file-20220520-18-ig02wa.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464538/original/file-20220520-18-ig02wa.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Children are more at risk of developing more severe forms of the disease.</span>
<span class="attribution"><span class="source">Jean-Marc Zokoé</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<p>Children who have been infected with monkeypox are more likely to experience complications and therefore have a higher fatality rate than adults. It is also assumed that immunocompromised individuals (particularly those who are HIV-positive) have a higher risk of developing a severe form of the disease, but there is not enough data yet to know this for certain. During the 2017-18 Nigerian outbreak, <a href="https://pubmed.ncbi.nlm.nih.gov/31285143/">four out of seven people who died from the disease were HIV-positive</a>. Pregnant women could also be affected by less moderate forms and we noted instances of mother-to-child transmission.</p>
<p>Treatment of the disease is largely symptom-based and involves methods like disinfecting the lesions, administering antibiotics in cases of secondary infection, and rehydration. Research is currently being conducted into whether certain antiviral molecules (such as <a href="https://www.ema.europa.eu/en/medicines/human/EPAR/tecovirimat-siga">tecovirimat</a> could be effective against monkeypox, but the results are not yet conclusive.</p>
<p><strong>TC: Is this the first time that the virus has spread outside of the African continent? How many cases have been recorded so far, and where?</strong></p>
<p><strong>CB:</strong> No, it isn’t the first time. Although the Congo Basin strain has never travelled beyond Africa, the West African strain managed to reach the United States in 2003 by way of imported animals that had been infected. More recently, however, a number of countries have reported several cases brought in by humans.</p>
<p>Back in 2003, <a href="https://www.cdc.gov/poxvirus/monkeypox/outbreak/us-outbreaks.html">number of individuals in the United States</a> caught the virus from infected prairie dogs purchased from pet shops where the animals had been in contact with monkeypox-carrying Gambian pouched rats (<em>Cricetomys gambianus</em>) imported from Ghana. A total of 47 suspected cases of human infection were recorded, all the result of zoonotic (i.e., animal-to-human) transmission. There were no instances of interhuman transmission. At the time, the US authorities were concerned that the virus might take over a reservoir of local species, but this did not happen.</p>
<p>Then, in September 2017, a more severe outbreak occurred in Nigeria, which had not experienced any monkeypox epidemic in the preceding 39 years. This particular epidemic is still ongoing, sustained by sporadic, regular transmissions that are both zoonotic and interhuman. To date, at least 500 suspected cases have been declared (215 of which have been confirmed). Reassuringly, albeit regrettably, only 8 deaths have been documented in the past 5 years.</p>
<p>However, the Nigerian epidemic had marked a major change in monkeypox epidemiology and should have acted as a warning to us. Whereas the virus had tended to thrive in forest regions with little connection, in 2017, it hit the country’s more urban areas and at a larger scale. This is how it managed to spread more easily beyond the continent, with cases popping up in 2018 <a href="https://pubmed.ncbi.nlm.nih.gov/32880628/">in Singapore, Israel, and England, brought back by travellers returning from Nigeria</a>.</p>
<p>In the case of England, a local human-to-human transmission occurred when a British healthcare worker <a href="https://jglobalbiosecurity.com/article/10.31646/gbio.22/">became infected while cleaning a patient’s bed</a>. There was no endemic viral circulation at the time, but more infections emerged in 2021, again linked to travellers coming back from Nigeria and occurring both in the UK and in the United States (where two cases were recorded).</p>
<p>In the UK in 2018, scientists also studied the risk of emergence of an endemic animal reservoir. Species such as the common squirrel (<em>Sciurus vulgaris</em>) and domestic mouse (<em>Mus musculus</em>) were thought to be particularly prone to the virus, while other rodents (voles, dormice, other mice) or still hedgehogs were also considered <a href="https://www.gov.uk/government/publications/hairs-risk-assessment-monkeypox/qualitative-assessment-of-the-risk-to-the-uk-human-population-of-monkeypox-infection-in-a-canine-feline-mustelid-lagomorph-or-rodent-uk-pet">as potential reservoirs</a>.</p>
<p><strong>TC: What is different about the current context?</strong></p>
<p><strong>CB:</strong> <a href="https://www.bmj.com/content/377/bmj.o1274">The situation</a> is <a href="https://www.nature.com/articles/d41586-022-01421-8">very different</a> this time around. We know that the first case of the current epidemic, recorded on 7 May in the UK, was that of an individual travelling back from Nigeria. However, several other UK cases have since been confirmed that are apparently unrelated to one another or to this 7th May case. No instance of foreign travel (to African countries) associated with the infections has yet been proven and the direct chains of transmission have not been identified, suggesting the existence of several chains of transmission and a local circulation of the virus.</p>
<p>As of 6th June, 1,000 cases had been detected in at least 30 different countries, worldwide, with the largest number of cases located in the United Kingdom (<a href="https://www.gov.uk/government/news/monkeypox-cases-confirmed-in-england-latest-updates">287 confirmed</a>), Spain (189 confirmed), Portugal (143 confirmed). French authorities have reported 51 confirmed cases. For now, all of the recorded infections outside of Africa have been mild. Only a few patients have been hospitalised and no death or vital threat has been reported. A non-negligible proportion of cases were reported among HIV+ patients.</p>
<iframe src="https://ourworldindata.org/explorers/monkeypox?tab=map&facet=none&hideControls=true&Metric=Confirmed+cases&Frequency=Cumulative&Shown+by=Date+of+confirmation&country=~OWID_WRL" loading="lazy" style="width: 100%; height: 600px; border: 0px none;" width="100%" height="400"></iframe>
<p>That said, these local circulations of the disease are unprecedented. Another new aspect is that the cases have almost exclusively been reported among young males, primarily among homosexual men (<a href="https://www.gov.uk/government/news/ukhsa-latest-findings-into-monkeypox-outbreak">in the UK, the authorities emphasised that “currently most cases have been in men who are gay, bisexual or have sex with men”</a>). Only six suspected and confirmed women were declared in Spain, Czech Republic, Italy, the United States and United Arab Emirates. These last two women were not linked to the European cluster following mass gathering events, but returned from Western Africa, suggesting something is up with the Nigerian epidemic that is exporting the virus.</p>
<p><strong>TC: Why is this new? What are the usual channels of infection?</strong></p>
<p><strong>CB:</strong> Monkeypox epidemics most often arise from animal-to-human transmission, although the exact details of how they occur are unclear and it has not yet been possible to isolate the same viral strain in animals and in humans. It may come from direct contact with a living animal when hunting or eating bush meat.</p>
<p>One thing we have noticed from our research in the CAR is that the outbreaks tend to be seasonal. This would suggest a link with certain seasonal activities like the harvesting of edible caterpillars, which involves individuals entering the forest, where they would be more exposed to local wildlife.</p>
<p>Even though scientists have been tracking the viral reservoir since the 1970s, it has, as of yet, only rarely been isolated in wild animals. The first instance was in <a href="https://pubmed.ncbi.nlm.nih.gov/2867342/">1985 in the DRC</a> and involved a species known as a Thomas’s rope squirrel (<em>Funisciurus anerythrus</em>), thought to be the reservoir of the virus. The next was that of a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4036778/">sooty mangabey monkey in 1992</a> (<em>Cercocebus atys</em>) in Côte d’Ivoire. Then, two decades later, the virus was isolated <a href="https://www.researchsquare.com/article/rs-414280/v1(2021)%20doi:10.21203/rs.3.rs-414280/v1">in a Gambian pouched rat and another rodent species</a> (<em>Stochomys longicaudatus</em>), as well as in another rope squirrel (<em>Funisciurus _bayonii</em>) and a shrew (<em>Corcidura litoralis</em>). As things stand, the prime suspects for the viral reservoir are rodents, including squirrels.</p>
<figure class="align-center ">
<img alt="Image of the squirrel _Funisciurus anerythrus_" src="https://images.theconversation.com/files/464550/original/file-20220520-22-ycsfnc.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/464550/original/file-20220520-22-ycsfnc.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464550/original/file-20220520-22-ycsfnc.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464550/original/file-20220520-22-ycsfnc.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464550/original/file-20220520-22-ycsfnc.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464550/original/file-20220520-22-ycsfnc.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464550/original/file-20220520-22-ycsfnc.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The <em>Funisciurus anerythrus</em> squirrel is the suspected reservoir of the monkeypox virus.</span>
<span class="attribution"><a class="source" href="https://www.naturalista.mx/observations/91613867">cherifikoukomon</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>Interestingly, monkeypox was also <a href="https://pubmed.ncbi.nlm.nih.gov/32341480/">found in chimpanzee feces</a> in Taï National Park, Côte d’Ivoire, during an outbreak among primates, which implies the possibility of environmental contamination.</p>
<p>Aside from zoonotic transmission, there’s also human-to-human transmission, which occurs as a result of direct and prolonged contact with infected individuals through exposure to bodily fluids or contaminated materials (e.g. clothing, bedding, or surfaces). Such infections most often take place within the home.</p>
<p>Transmission through inhalation of respiratory droplets has also been considered, but this point is difficult to ascertain. Generally speaking, infections take place within the family home, where there is closer human proximity and modes of contact are numerous and diverse. Africa has also seen some cases of hospital-acquired infection.</p>
<p>In a detailed case description of the 2017 Nigerian outbreak, a large proportion of individuals suffered genital infections (68%), suggesting for the first time that the virus could be <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0214229">transmitted through close skin-to-skin contact during sex</a>. Our data also shows that the rate of such infections is very high among cases recorded in the CAR.</p>
<p>Close, intimate contact during intercourse may be behind the new increased frequency in interhuman transmission of monkeypox, a virus that is usually thought to present low transmissibility. This theory is supported by the fact that – at the time of writing – the “non-African” cases of recent weeks <a href="https://www.nature.com/articles/d41586-022-01421-8">have mainly affected young men who have sex with men</a> or who identify as homosexual. It should be noted, though, that such transmissions could also occur during heterosexual intercourse.</p>
<p>Italian researchers have recently detected <a href="https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2022.27.22.2200421dNOqOXpB6UZW0!-e5CvHkNDnLULK2likc_KiXJc1imufkf_T4VXcf9ioTyz3ec33AGy6YKlMeS7NWNXGRNl1EH$">significant amount of monkeypox virus in the semen of 3 patients</a>. However, the authors stressed that these findings “cannot be considered definitive evidence of infectivity”. The implications for transmission are not clear either.</p>
<p><strong>TC: Should we be worried about this disease becoming widespread? What can we do to prevent this?</strong></p>
<p><strong>CB:</strong> For now, we can’t say for certain what will happen. The problem is that the chain of transmission of these new cases has yet to be identified. As indicated by the daily evolution of the virus, and due to its relatively long incubation period, there is a real risk that new infections could emerge within the coming days and weeks, whether in countries that are already affected or elsewhere.</p>
<p>Numerous cases in Spain and Europa <a href="https://www.dailymail.co.uk/news/article-10839877/Monkeypox-outbreak-Europes-biggest-100-cases-reported.html">appear to be linked to two festivals, one in Belgium between 4 and 9 May and one</a> that took place in the Canary Islands between 5 and 15 May. The latter was <a href="https://www.dailymail.co.uk/news/article-10839877/Monkeypox-outbreak-Europes-biggest-100-cases-reported.html">attended by 80,000 people</a>, potentially making it a “super-spreading” event.</p>
<p>In order to prevent the spread of the virus, we need to raise awareness among the communities and individuals concerned, and among doctors, so that we can quickly identify each case and trace their contacts. One difficulty facing doctors is that monkeypox lesions resemble those caused by chickenpox and, when they occur on the genitals, they can be mistaken for symptoms of some STIs (like syphilis and herpes). A monkeypox diagnosis can be confirmed by a PCR test and isolation of the virus, but only a few specialist laboratories are equipped for these types of analysis.</p>
<p>Nevertheless, we can find some reassurance in the fact that monkeypox outbreaks resolve spontaneously and relatively quickly. The longest chain of transmission ever identified was carried over <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4880088/">seven generations, meaning that seven humans passed on the disease consecutively before transmission ceased</a>.</p>
<p>It is unclear why spreads simply stop like this. One hypothesis is that, until recently, these outbreaks would occur in small villages within restricted communities where some individuals might have already been immune, so the virus would contaminate only those who had never been in contact with it. But the 2003 epidemic in the United States also ended quickly and without any secondary human-to-human infection.</p>
<p>It remains to be seen where this new outbreak will take us.</p>
<p><strong>TC: Could the smallpox vaccine protect against this virus?</strong></p>
<p><strong>CB:</strong> We know that a natural infection of smallpox offers cross-protection against monkeypox. In the 1980s, it was shown that the smallpox vaccine could also provide cross-protection at a rate of around 85%. However, these estimates were made just a few years after the mass-vaccination campaign to eradicate smallpox. It is now believed that its efficacy is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2168110/">closer to around 63% against severe disease</a>.</p>
<p>Moreover, smallpox vaccination was suspended in the 1980s once the disease was wiped out. Today, only a handful of healthcare professionals are vaccinated (in case of bioterrorist threats, while the virus is stored under high surveillance at a number of laboratories) and the <a href="https://www.mesvaccins.net/web/diseases/29-variole">first generation</a> of the vaccine is no longer used, due to significant side effects.</p>
<p>At present, if ever necessary, the most suitable vaccine for a roll-out would be the “third-generation” version known as Imvamune (or Imvanex or Jynneos). This is an <a href="https://www.sciencedirect.com/topics/immunology-and-microbiology/attenuated-vaccine">attenuated vaccine</a> that can be administered to immunocompromised people, unlike older vaccines. It has already been given to healthcare professionals and contact cases in Israel, Singapore, and the UK, and its effectiveness is <a href="https://pubmed.ncbi.nlm.nih.gov/30445121/">currently being assessed among healthcare professionals in the DRC</a>.</p>
<p>There are also a number of fourth-generation “subunit” vaccines in development. These do not contain the attenuated virus and instead have only fragments of it. They are also being assessed for their effectiveness.</p>
<p>Vaccines can be administered as either a pre-exposure (i.e., before contact with the virus) or a post-exposure treatment. With regards to the latter, US guidelines recommend that it be given preferably within 4 days and up to 14 days after exposure. On 27 May two French individuals received post-exposure vaccination for the first time after a high-risk contact with confirmed cases.</p>
<p><strong>TC: Could we see other variants of monkeypox emerging? Is the genome of the virus currently circulating in Europe identical to the West African strain?</strong></p>
<p><strong>CB:</strong> Monkeypox is a DNA virus, which means that it is less likely to mutate than an RNA virus like SARS-CoV-2.</p>
<p>It is actually quite simple to determine whether we are dealing with a West African or Congo Basin strain. We just need to sequence out short sections of its DNA. But given the large size of the viral genome, it takes time and effort to obtain a complete sequence. We need this complete sequence in order to detect differences in sequences more precisely, which would allow us to identify chains of transmission and find out how cases are linked. However, if our experience with SARS-CoV-2 has taught us anything, it’s that a large-scale global effort can be of great help in moving things along.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/464738/original/file-20220523-16-m4igxt.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Chart showing relationships between different monkeypox strains" src="https://images.theconversation.com/files/464738/original/file-20220523-16-m4igxt.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/464738/original/file-20220523-16-m4igxt.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=502&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464738/original/file-20220523-16-m4igxt.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=502&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464738/original/file-20220523-16-m4igxt.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=502&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464738/original/file-20220523-16-m4igxt.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=631&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464738/original/file-20220523-16-m4igxt.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=631&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464738/original/file-20220523-16-m4igxt.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=631&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Phylogenetic tree depicting the ‘family’ relationships between the different strains of monkeypox virus responsible for outbreaks.</span>
<span class="attribution"><a class="source" href="https://nextstrain.org/monkeypox">Nextrain.org</a></span>
</figcaption>
</figure>
<p>Initial sequencing carried out on samples from a Portuguese and a Belgian patient have shown the genetic proximity of the virus to strains isolated <a href="https://virological.org/t/first-draft-genome-sequence-of-monkeypox-virus-associated-with-the-suspected-multi-country-outbreak-may-2022-confirmed-case-in-portugal/799">in Nigeria and during the previous out-of-African spread of the virus in 2018</a>, with genomes of the ongoing outbreak <a href="https://virological.org/t/belgian-case-of-monkeypox-virus-linked-to-outbreak-in-portugal/801#post_2">being highly similar</a>. This is in favour of a single introduction followed by community spread in Western countries after superspreading events.</p>
<p>More detailed genomic analyses comparing 2022 strains to those of 2018 identified around 40 mutations (fivefold the expected rate of mutations) with a pattern specific of the action of an antiviral enzyme called APOBEC which may reveal the sustained circulation of the virus <a href="https://virological.org/t/initial-observations-about-putative-apobec3-deaminase-editing-driving-short-term-evolution-of-mpxv-since-2017/830">in a new animal intermediate host, or in humans</a>. This observation, possibly indicating a recent increase in viral circulation in Nigeria, matches the documentation of cases in peri-urban areas of Nigeria like Abuja, together with increased frequencies of overseas exportation of cases.</p>
<p>A recent article hypothesises that Nigerian synanthropic rodent populations (<em>i.e., undomesticated rodents that live in close association with people and benefits from their surroundings</em>) <a href="https://www.ijidonline.com/article/S1201-9712(22)00322-8/fulltext">have increased in recent years as</a> a result of land conversion and high urbanisation leading to increased human-rodent contact.</p>
<p>Further sequencing is required to address remaining questions, like genome adaptation toward increased viral transmissibility. But, for the time being, there has been no evidence to suggest this.</p>
<p>In a more exceptional way, what looks like a relapse of the monkeypox disease <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(22)00228-6/fulltext">was reported among one of the 2018 UK patients</a>, with an increased lymphadenopathy, a recurrence of rash and a transient shedding of monkeypox viral DNA following initial complete recovery. This hypothesis requires further study to be exploited.</p>
<p><strong>TC: In 2019, the Institut Pasteur came together with partners in France and the CAR to launch the <a href="https://research.pasteur.fr/fr/project/afripox/">Afripox project</a>, driven by a goal to increase understanding of the monkeypox virus and its spread. What exactly does the project involve?</strong></p>
<p><strong>CB:</strong> Afripox is a cross-disciplinary project that was set up in light of an increasing number of monkeypox outbreaks in the CAR, as reported by Emmanuel Yandoko Nakoune, Director of the Laboratory for Arboviruses, Viral Haemorrhagic Fevers, Emerging Viruses, and Zoonoses at the Institut Pasteur in Bangui, the country’s capital.</p>
<p>In the past few decades, monkeypox outbreaks have been more numerous and frequent in Africa overall, with the disease also expanding into areas where it was not endemic before. Improved medical monitoring and reduced immunity (following the end of smallpox vaccinations in 1980) are likely to have contributed to this figure, but the phenomenon may also reflect a growing viral circulation in a region of the world currently experiencing major ecological disturbances.</p>
<p>Faced with the many uncertainties surrounding the epidemiology of monkeypox, the idea for this project was to rely on the CAR’s existing national medical monitoring system to develop a <a href="https://theconversation.com/le-concept-one-health-doit-simposer-pour-permettre-lanticipation-des-pandemies-139549">One Health</a> approach toward the monkeypox virus, encompassing all its aspects in epidemiology, ecology, zoology, anthropology, and virology.</p>
<p>For instance, through our partnership with researchers from the French National Museum of Natural History, we are attempting to identify its animal reservoir. Meanwhile, along with the <a href="https://sesstim.univ-amu.fr/">SESSTIM</a> team in Marseille, we are exploring the disease’s ecology in order to better understand why it spreads more in forest areas, pinpoint how deforestation affects outbreaks, determine whether or not there is a seasonal aspect, and so on.</p>
<figure class="align-center ">
<img alt="Emmanuel Nakoune and Camille Besombes investigating an outbreak of monkeypox." src="https://images.theconversation.com/files/464556/original/file-20220520-20-wnzq6c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/464556/original/file-20220520-20-wnzq6c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464556/original/file-20220520-20-wnzq6c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464556/original/file-20220520-20-wnzq6c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464556/original/file-20220520-20-wnzq6c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464556/original/file-20220520-20-wnzq6c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464556/original/file-20220520-20-wnzq6c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Emmanuel Nakoune and Camille Besombes investigating an outbreak of monkeypox in Zoméa, Lobaye, CAR.</span>
<span class="attribution"><span class="source">Jean Marc Zokoé</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In the near future, the Afripox project also hopes to use on-the-ground PCR diagnostic tests that are currently being developed by the Emergency Biological Response Unit (“Cibu”) team at the Institut Pasteur in Paris. For now, suspected case samples are analysed in Bangui, but these tests would allow for reduced diagnosis time and quicker implementation of the appropriate measures.</p>
<p>Lastly, the epidemiological and anthropological aspects of the virus are being explored by the teams at the Institut Pasteur Paris (namely, the Emerging Diseases Epidemiology Unit and the Emerging Diseases Anthropology and Ecology Unit), in collaboration with local researchers. Their goal is to precisely determine the risk factors of zoonotic or interhuman transmission and ascertain why monkeypox has been on the rise since the 1980s.</p>
<p>While it is essential to identify the mechanics of this latest human-to-human epidemic of a relatively new format, it is also vital to understand how monkeypox emerges and circulates in its continent of origin.</p>
<p>When Afripox was launched three years ago, few could have imagined that this disease would one day spread beyond the African continent and across the planet. The current epidemic has highlighted once more the importance of investing in scientific research over the long term, so that we can be better prepared for any and all eventualities.</p>
<hr>
<p><em>Translated from the French by Enda Boorman for <a href="http://www.fastforword.fr/en">Fast ForWord</a>.</em></p><img src="https://counter.theconversation.com/content/184085/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Camille Besombes has received funding from the French National Research Agency (ANR).</span></em></p><p class="fine-print"><em><span>Arnaud Fontanet has received funding from the French National Research Agency (ANR), the SCOR Research Foundation and the Institut Pasteur.</span></em></p>This is not the first time that the monkeypox virus has spread beyond Africa, its continent of origin. But the current epidemic is unprecedented for a number of reasons.Camille Besombes, Médecin infectiologue - Epidémiologie - Unité d'épidémiologie des maladies émergentes, Institut PasteurArnaud Fontanet, Médecin, directeur de l’Unité d’épidémiologie des maladies émergentes à l’Institut Pasteur de Paris, professeur de santé publique, Conservatoire national des arts et métiers (CNAM)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1824972022-05-25T20:14:59Z2022-05-25T20:14:59ZAvian influenza: How bird flu affects domestic and wild flocks, and why a One Health approach matters<figure><img src="https://images.theconversation.com/files/465133/original/file-20220524-21-6ngtt3.jpg?ixlib=rb-1.1.0&rect=80%2C4%2C2852%2C1953&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The strain of H5N1 bird flu identified in Canada, the United States and Europe can cause severe disease and high mortality in domestic poultry.</span> <span class="attribution"><span class="source">(AP Photo/Robert F. Bukaty)</span></span></figcaption></figure><p>A strain of avian flu virus is spreading in domestic poultry flocks in Canada, but is not a risk to humans at this point in time.</p>
<p>Avian influenza virus, commonly known as bird flu, is a contagious influenza type A virus that can infect and kill poultry (such as chickens, turkeys, pheasants, quail, domestic ducks, geese and guinea fowl) and wild birds (including migratory birds). </p>
<p>There are at least 16 types of avian influenza virus, which are classified by a combination of two groups of proteins: hemagglutinin or HA, and neuraminidase or NA. This is where the H and N in avian influenza strains come from: they identify specific HA and NA proteins, like the current H5N1 strain causing outbreaks in Europe, the <a href="https://www.ctvnews.ca/health/u-s-reports-its-first-human-case-of-h5-bird-flu-1.5881424">United States</a> and <a href="https://www.ctvnews.ca/health/avian-flu-is-spreading-across-canadian-poultry-farms-here-s-what-you-need-to-know-1.5853215">Canada</a>. </p>
<p>Types of avian influenza virus are further classified as highly pathogenic (HPAI) or low pathogenicity (LPAI). HPAI viruses — including the current strain of H5N1 — <a href="https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/avian-influenza">are extremely infectious, can cause severe disease and high mortality (90-100 per cent) in domesticated poultry</a> and spreads rapidly from flock to flock. </p>
<h2>Avian influenza: Where is it?</h2>
<p>Pathogenicity (the ability to cause disease) is defined in relation to disease severity in domestic poultry. Nonetheless, the reach of avian flu is not limited to this population. H5N1 is spreading in wild bird populations across the globe. <a href="https://www.oie.int/en/document/h5n1-highly-pathogenic-avian-influenza-in-poultry-and-wild-birds-winter-of-2021-2022-with-focus-on-mass-mortality-of-wild-birds-in-uk-and-israel/">Significant outbreaks have been detected in Asia, Africa and Europe since October 2021</a>. </p>
<figure class="align-center ">
<img alt="Red chickens at outdoor feeders" src="https://images.theconversation.com/files/465140/original/file-20220524-24-f7i299.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465140/original/file-20220524-24-f7i299.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465140/original/file-20220524-24-f7i299.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465140/original/file-20220524-24-f7i299.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465140/original/file-20220524-24-f7i299.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465140/original/file-20220524-24-f7i299.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465140/original/file-20220524-24-f7i299.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Domestic poultry can be exposed to avian flu by infected migratory birds.</span>
<span class="attribution"><span class="source">(AP Photo/Steve Helber)</span></span>
</figcaption>
</figure>
<p>H5N1 is of immediate national concern in Canada, as migratory birds flock to our shores. The Eurasian strain of H5N1 was detected in Newfoundland in December 2021, and in hunted wild birds in the eastern U.S. in January 2022. Between December 2021 and May 2022, this virus has been detected in <a href="https://inspection.canada.ca/animal-health/terrestrial-animals/diseases/reportable/avian-influenza/hpai-in-canada/status-of-ongoing-avian-influenza-response-by-prov/eng/1640207916497/1640207916934">eight Canadian provinces</a> and <a href="https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/avian-influenza/hpai-2022">35 U.S. states</a>.</p>
<h2>Avian influenza and animal health</h2>
<p>Wild birds can be infected with highly pathogenic avian influenza and show no signs of illness. They can carry the disease to new areas when migrating, exposing domestic poultry to the virus. </p>
<p>An <a href="https://www.canada.ca/en/environment-climate-change/services/migratory-game-bird-hunting/avian-influenza-wild-birds.html">infected bird may show signs</a> including coughing, gasping for air, head swelling and diarrhea. Because influenza viruses in birds can replicate in tissues beyond the respiratory system, infected birds may also display neurological signs including paralysis and tremor. </p>
<p>Once infected, mortality is nearly unavoidable in some bird species, occurring within 24-72 hours. The first sign of infection may sometimes be mass mortality events.</p>
<p>Ramifications of outbreaks are borne by individual farmers and felt throughout the agricultural sector. Where outbreaks occur, it is often the policy to <a href="https://www.bloomberg.com/news/articles/2022-05-06/bird-flu-outbreak-nears-worst-ever-in-u-s-with-37-million-dead">cull all poultry</a>, whether infected or healthy, to help contain the spread of the virus. This represents <a href="https://www.cbc.ca/news/canada/british-columbia/fraser-valley-avian-flu-1.6462000">heavy economic losses for farmers</a>, which can have a long-lasting impact on their livelihoods and well-being. </p>
<p>Of course, avian influenza virus does not differentiate between farm and field; it may decimate wild bird populations in addition to cultivated flocks, and there have been reports of <a href="https://www.oie.int/en/document/h5n1-highly-pathogenic-avian-influenza-in-poultry-and-wild-birds-winter-of-2021-2022-with-focus-on-mass-mortality-of-wild-birds-in-uk-and-israel/">mass mortality incidents in the United Kingdom and Israel in 2021 and 2022</a>. In addition to disrupting the local ecology, including often delicately calibrated food webs, such outbreaks occur at the detriment of biodiversity.</p>
<h2>Avian influenza virus and environmental health</h2>
<p>The effects of climate change on disease ecology are impossible to ignore. Migratory birds — especially waterfowl — are a <a href="https://www.cdc.gov/flu/avianflu/avian-in-birds.htm">natural reservoir for avian influenza virus</a>. As birds migrate and mingle with other individuals and flocks, viruses “drift” and “shift,” meaning that viral genetic material may change in unexpected ways. </p>
<p>In the context of <a href="http://dx.doi.org/10.20506/rst.27.2.1821">avian flu and climate change</a>, where migration routes and seasons are changing, previously separate migratory bird populations are now encountering one another, increasing the probability that new virus variants will emerge. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/465137/original/file-20220524-11834-snn7an.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Birds in a grassy area with more birds flying overhead" src="https://images.theconversation.com/files/465137/original/file-20220524-11834-snn7an.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465137/original/file-20220524-11834-snn7an.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465137/original/file-20220524-11834-snn7an.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465137/original/file-20220524-11834-snn7an.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465137/original/file-20220524-11834-snn7an.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465137/original/file-20220524-11834-snn7an.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465137/original/file-20220524-11834-snn7an.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Cranes fly at the Hula Lake conservation area in January 2022 in northern Israel, where bird flu has killed thousands of migratory cranes.</span>
<span class="attribution"><span class="source">(AP Photo/Ariel Schalit)</span></span>
</figcaption>
</figure>
<h2>Avian influenza virus and human health</h2>
<p>Several avian influenza subtypes, including the H5 subtype, <a href="https://doi.org/10.3390%2Fpathogens10050630">have been shown to cross species, travelling from birds into mammals — including dogs, cats, swine and humans</a>. It is important to note that these events are infrequent and that <a href="https://www.cdc.gov/flu/avianflu/avian-in-humans.htm">avian influenza virus does not currently pose a health risk to humans</a>. </p>
<p>Although close to <a href="https://www.who.int/emergencies/disease-outbreak-news/item/influenza-a-(h5)---united-kingdom-of-great-britain-and-northern-ireland">880 human infections and over 450 deaths</a> have been attributed to previous strains of H5N1, there have only been two known cases of <a href="https://www.cdc.gov/media/releases/2022/s0428-avian-flu.html">human infection with the current circulating strain</a>. However, there is a concern that, through mutations and genetic exchanges, H5N1 avian influenza virus may gain the ability to transmit from birds to humans and possibly from humans to humans. </p>
<p>Because of avian flu’s potential to spread rapidly throughout an animal population, a robust surveillance program to monitor the evolution and diversity of avian influenza viruses for preventive action is an essential public health measure.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/465141/original/file-20220524-12-1ibzmd.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Many white chickens at a chicken farm" src="https://images.theconversation.com/files/465141/original/file-20220524-12-1ibzmd.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465141/original/file-20220524-12-1ibzmd.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465141/original/file-20220524-12-1ibzmd.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465141/original/file-20220524-12-1ibzmd.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465141/original/file-20220524-12-1ibzmd.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=507&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465141/original/file-20220524-12-1ibzmd.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=507&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465141/original/file-20220524-12-1ibzmd.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=507&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">There is an urgent need for governments to invest in local and global initiatives that focus on the human-animal-environment interface of disease.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Jonathan Hayward</span></span>
</figcaption>
</figure>
<h2>Avian influenza virus and One Health</h2>
<p>Management and control of avian influenza virus requires a <a href="https://www.who.int/news-room/questions-and-answers/item/one-health">One Health approach</a>, which places equal importance on measures that address avian influenza virus from animal, human and environmental health perspectives. </p>
<p>Climate change, human population growth and socio-economic factors have long-lasting impacts on environmental health. A cross-sectoral approach for communication and preparedness responses is needed to co-ordinate surveillance and biosecurity measures that will control outbreaks. A <a href="https://doi.org/10.3390%2Ftropicalmed4020088">One Health approach</a> will help ensure environmental conservation obligations are met and the health of people, livestock and wildlife is protected.</p>
<p>There is an urgent need for governments to invest in local and global initiatives that focus on the <a href="https://www.who.int/news-room/fact-sheets/detail/zoonoses">human-animal-environment interface of disease</a>. One such investment includes funding higher education programs in One Health. These programs will prepare the next generation of Canadians to address societal grand challenges — like pandemic preparedness — with a One Health lens, enabling the formation of teams whose expertise transcends disciplinary boundaries. </p>
<p>Now, more than ever, we need to ensure that both local and global One Health initiatives are developed as a core component of planning preparedness for future pandemics.</p><img src="https://counter.theconversation.com/content/182497/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Shayan Sharif receives funding from Food from Thought, Canadian Poultry Research Council, Egg Farmers of Canada and Saskatchewan Chicken Industry. </span></em></p><p class="fine-print"><em><span>Jeffrey Wichtel is President-Elect of the Deans Council Agriculture, Food and Veterinary Medicine</span></em></p>Avian influenza virus — or bird flu — can infect domestic poultry such as chickens and turkeys, as well as wild birds. The H5N1 strain has been identified in Canada.Shayan Sharif, Professor of Immunology and Associate Dean, Research and Graduate Studies, University of GuelphJeffrey J. Wichtel, Dean, Ontario Veterinary College, University of GuelphLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1828802022-05-17T18:31:53Z2022-05-17T18:31:53ZOn the trail of the origins of Covid-19<figure><img src="https://images.theconversation.com/files/462448/original/file-20220511-14-wmpaxu.jpg?ixlib=rb-1.1.0&rect=0%2C23%2C4000%2C2215&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cave inhabited by bats.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/fr/image-photo/huge-group-bats-waits-patiently-exit-1440955400">Sanatana/Shutterstock</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>As the Covid-19 virus (coronavirus SARS-CoV-2) continues to spread and claim victims worldwide, its <a href="https://www.nature.com/articles/d41586-022-00732-0">origins</a> remain unknown. Each scientific community puts forward its own <a href="https://www.theguardian.com/world/2021/dec/31/why-hunt-for-covid-origins-still-wrapped-in-politics-impasse-china-west">theory</a>, with some suggesting the virus may have leaked out of a <a href="https://theconversation.com/covid-19-why-the-lab-leak-theory-must-be-formally-investigated-161297">laboratory</a>.</p>
<p>Another theory, based on recent studies of the <a href="https://www.science.org/content/article/do-three-new-studies-add-proof-covid-19-s-origin-wuhan-animal-market">Wuhan wet market</a> in China, along with others carried out in <a href="https://www.nature.com/articles/s41467-021-26809-4">Cambodia</a>, <a href="https://www.nature.com/articles/s41586-022-04532-4">Laos, Japan, China, and Thailand</a>, posits that an ancestral virus in rhinolophus bats went on from infecting wild and/or domestic animals to humans. Indeed, in these different studies, several viruses with genetic sequences very similar to SARS-CoV-2 were isolated in these bats.</p>
<h2>A missing link</h2>
<p>Though it has been shown some bat species have hosted these coronaviruses naturally, the wild or domestic animal (or animals) that acted as a bridge between them and humans – the missing link – remains unidentified. Pangolins were first suspected, but now appear to have been collateral victims rather than one of these much-talked-about missing links. A coronavirus genome sequence detected in pangolins was indeed related to that of SARS-CoV-2, but the rest of the genome was <a href="https://link.springer.com/article/10.1007/s10311-020-01151-1">too distant from it genetically</a> to back the hypothesis.</p>
<p>Moreover, the pangolins hosts in which the viruses that were genetically close to SARS-CoV-2 were found had mostly been confiscated at live-animal markets, at the end of the supply chain. As a result, they had been in lengthy contact with other animal species. It is very likely they were infected along this supply chain rather than in their natural environment. <a href="https://theconversation.com/origin-of-the-covid-19-virus-the-trail-of-mink-farming-155989">Mink farms</a> were also suspected of being an intermediate host in China.</p>
<p>Lastly, pangolins and rhinolophus bats do not share the same habitat, making it highly unlikely there was any contact between the two species in which the virus jumped from one to the other. On the other hand, civets and raccoon dogs could be an intermediate source of <a href="https://pubmed.ncbi.nlm.nih.gov/16140765/">SARS-CoV-1</a>). Rodents or primates could also carry pathogens with zoonotic potential, such as hantaviruses – which can cause haemorrhagic fever with renal syndrome – or filoviruses, <a href="https://www.pnas.org/doi/10.1073/pnas.2002324118">which include the Ebola virus</a>. The latter is passed on to humans through wild animals, in particular bats, antelopes, and primates such as chimpanzees and gorillas, then spreads among humans, mainly by direct contact with blood, secretions and other bodily fluids from infected people. The average case fatality rate is around 50%.</p>
<p>In 2013, initial cases of disease from the Ebola virus were detected in <a href="https://pubmed.ncbi.nlm.nih.gov/34424896">West Africa</a>. The rise of these cases led to over 10,000 deaths, mainly in Guinea, Liberia, and Sierra Leone.</p>
<h2>The risky habit of bushmeat-eating</h2>
<p>Activities such as hunting, animal-handling or eating meat from wild animals therefore create the conditions for viruses to spread from animals to humans – a potentially devastating phenomenon called “spillover”.</p>
<p>The <a href="https://www.cirad.fr/en/cirad-news/news/2020/science/covid-19-zoocov-a-new-project-to-prevent-coronavirus-transmission-from-wildlife-to-humans">ZooCov</a> project has sought to define and quantify this risk in Cambodia. For almost two years – and right from the start of the pandemic – it has adopted a <a href="https://www.oie.int/en/what-we-do/global-initiatives/one-health/">“One Health”</a> approach to explore whether – and how – pathogens such as coronaviruses can be passed on to humans from wild animals that are hunted and eaten.</p>
<p>Indeed, in South-East Asia, wild animals are regularly traded, and bushmeat is customarily eaten. This eating habit is often opportunistic. In some communities, it complements a low-protein diet. It can also be frequent and targeted. In Cambodia, 77% of 107 families interviewed in the ZooCov project said they had eaten bushmeat in the <a href="https://www.cirad.fr/en/cirad-news/news/2022/coronavirus-surveillance-a-concrete-example-of-the-one-health-approach-in-action-in-cambodia">past month</a>.</p>
<p>Use for medicinal purposes is also widespread. In Vietnam, an <a href="https://pubmed.ncbi.nlm.nih.gov/35356028/">analysis of records</a> of the Vietnamese authorities confiscating pangolins and related by-products between 2016 and 2020 reported 1,342 live pangolins (6,330 kg), 759 dead pangolins or pangolin carcasses (3,305 kg), and 43,902 kg of pangolin scales.</p>
<p>Yet this consumption also has a cultural and social dimension that is still not properly understood. Among the well-off – and often in big cities – people sometimes eat bushmeat out of a desire for social status, and a belief that eating it endows them with the physical or physiological <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30063-3/fulltext">attributes</a> of the animal. They also sometimes eat bushmeat out of rejection of industrially produced meat, considered unhealthy. Animals are widely reared to meet this demand and the demand for <a href="https://www.who.int/publications/i/item/WHO-2019-nCoV-fur-farming-risk-assessment-2021.1">fur production</a>.</p>
<p>In the Stung Treng and Mondolkiri provinces of Cambodia, where protected forest areas remain, researchers surveyed more than 900 people living on the edge of these forests to determine the structure of the illegal bushmeat trade. Statistical analyses are underway to identify the people most at risk of contact with wildlife thus with such pathogens. We already know those exposed are mostly young middle-class men, and that some communities are more exposed than others. Sociological studies have also helped better grasp today’s context: the legal framework, the profiles of players in the trade, their motives and deterrents in trade and consumption of wild animals, and how the context has changed with each different health crisis (bird flu, Ebola, SARS-CoV-1, etc.).</p>
<h2>Which populations are most at risk?</h2>
<p>These successive crises seem to have scarcely affected the habits of these communities. Beyond regularly eating bushmeat, one fourth of the families surveyed said they still hunted or ensnared wild animals, and 11% claimed to sell bushmeat or wild animals. Furthermore, in the same areas of study, over 2,000 samples taken from wild animals trafficked or eaten for subsistence – bats, rodents, turtles, monkeys, birds, wild pigs, etc. – were analysed. Some of these samples tested positive for coronaviruses and scientists at the Institut Pasteur du Cambodge (IPC) are currently sequencing their genome in a bid to learn more about their origin, evolution, and zoonotic potential. Finally, researchers collected blood samples from over 900 people from the same region to find out whether they had been in contact with a coronavirus or coronaviruses. These analyses are still underway, but what we do know is that these people had not been exposed to SARS-CoV-2 when the survey was conducted.</p>
<p>If the Covid crisis has taught us anything, it is the importance of detecting such emergences early in order to nip the pathogens in the bud. While many questions remain about the way cases emerge, there are just as many questions about the monitoring systems that should be set up to track them. The results of the ZooCov project will be used to develop a system for detecting spillover of zoonotic viruses early, particularly by strengthening the system for monitoring wildlife health that is already in operation in Cambodia, which was set up by the <a href="https://cambodia.wcs.org/Initiatives/Wildlife-Health.aspx">Wildlife Conservation Society</a> (WCS). Other large-scale projects in research and development will help us understand, detect, and prevent these phenomena of emerging cases.</p>
<hr>
<p><em>The authors would like to thank Cambodia’s Ministry of Health, its Ministry of Agriculture, Forestry and Fisheries, and its Ministry of Environment, as well as all the project’s partners: Institut Pasteur du Cambodge (IPC), the Wildlife Conservation Society (WCS), Flora and Fauna International (FFI), Institut de Recherche pour le Développement (IRD), Hong Kong University (HKU), the GREASE network, International Development Enterprise (iDE), the World Wildlife Fund (WWF), Elephant Livelihood Initiative Environment (ELIE), BirdLife International, Jahoo, and World Hope International.</em></p>
<p><em>Translated from the French by Thomas Young for <a href="http://www.fastforword.fr/en">Fast ForWord</a>.</em></p><img src="https://counter.theconversation.com/content/182880/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Véronique Chevalier a reçu des financements de l'Agence Nationale de la Recherche (ANR), la Région Occitanie et la Fondation Pasteur.</span></em></p><p class="fine-print"><em><span>François Roger et Julia Guillebaud ne travaillent pas, ne conseillent pas, ne possèdent pas de parts, ne reçoivent pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'ont déclaré aucune autre affiliation que leur poste universitaire.</span></em></p>Scientists exploring the possibility of an animal origin for Covid-19 are still investigating the missing link between bats and human beings.Véronique Chevalier, Veterinarian epidemiologist, CiradFrançois Roger, Directeur régional Asie du Sud-Est, vétérinaire et épidémiologiste, CiradJulia Guillebaud, Ingénieure de recherche , Institut PasteurLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1816472022-05-10T14:57:51Z2022-05-10T14:57:51ZBanning wild meat is not the solution to reducing future disease outbreaks<figure><img src="https://images.theconversation.com/files/460263/original/file-20220428-4038-33jm5u.jpg?ixlib=rb-1.1.0&rect=18%2C27%2C5988%2C3980&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/tomohon-indonesia-02-19-2020-grilled-1689513163">Happy Auer/Shutterstock</a></span></figcaption></figure><p>There have been widespread calls for a global ban on the sale and consumption of wild meat. Following the spread of COVID in early 2020 (which is thought to have originated in bats), over 200 conservation organisations signed an <a href="https://lioncoalition.org/2020/04/04/open-letter-to-world-health-organisation/">open letter</a> to the World Health Organization, urging a permanent ban on all live wildlife markets and the use of wild animal products in traditional medicine. </p>
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<p>The risk of disease spillover has been used by conservationists to legitimise arguments about the perceived need to <a href="https://www.nationalgeographic.co.uk/environment-and-conservation/2020/05/to-prevent-pandemics-stop-disrespecting-nature">separate humans from “wild” nature</a>. Since the pandemic began, bans on wild animal consumption and trade have been introduced in several countries. Before COVID, bird flu and <a href="https://www.sciencedirect.com/science/article/pii/S027795361730758X">Ebola virus</a> outbreaks also triggered bans on wildlife trade and consumption in northern Vietnam and west Africa, respectively.</p>
<p>By restricting contact between humans and wild animals, such bans should in theory minimise the risk of future disease outbreaks. Yet these restrictions neglect their potential impact on rural and Indigenous groups, who often depend on wild produce, particularly meat, fish and insects, as sources of dietary protein, fat and micronutrients. </p>
<p>Our <a href="https://www.jstor.org/stable/j.ctt19b9jsg">previous work</a> has documented the importance of “wild foods” worldwide. And we continue to find evidence that wild meat plays a critical role in enhancing the diets of Indigenous groups, such as Khasi communities in <a href="https://www.nesfas.in/research/">Meghalaya</a>, northeast India. (To be clear, we’re not in any way promoting the consumption of endangered animals, which is strictly prohibited around the world.)</p>
<figure class="align-center ">
<img alt="Khasi women carrying baskets." src="https://images.theconversation.com/files/460295/original/file-20220428-20-m86ogi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/460295/original/file-20220428-20-m86ogi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/460295/original/file-20220428-20-m86ogi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/460295/original/file-20220428-20-m86ogi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/460295/original/file-20220428-20-m86ogi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/460295/original/file-20220428-20-m86ogi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/460295/original/file-20220428-20-m86ogi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Wild meat is an important source of nutrition for the Khasi people of north-eastern India.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/meghalaya-india-february-8-2016-two-742386562">gregorioa/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Understanding spillover events</h2>
<p>For our <a href="https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(22)00064-X/fulltext">latest review</a>, we extracted evidence on “spillover events” (the transmission of a pathogen from an animal to a human) linked to wild meat consumption and related practices (such as hunting and butchering), from available scientific papers published between 1940 and 2021. We found such evidence to be limited and often of poor quality. </p>
<p>Of course, there are <a href="https://wedocs.unep.org/bitstream/handle/20.500.11822/32060/zoonoses.pdf?sequence=1&isAllowed=y">risks to eating wild meat</a>, but we need to better understand the specific consumption behaviour and practices that give rise to disease so that we can devise more targeted approaches to mitigate future outbreaks.</p>
<p>There is a risk that castigating wild meat harvesting practices in low-income settings fails to recognise the risks of zoonotic diseases (diseases that can be transmitted from animals to humans) associated with western food production and consumption practices. </p>
<p>We found that the highest number of spillover events reported in the scientific papers were from the US, and these were primarily linked to recreational hunting. While there are probably spatial biases in reporting (in some places, diseases may go undiagnosed or be under-reported), elsewhere, <a href="https://www.nature.com/articles/nature06536/">research</a> has suggested that only 3% of emerging infectious diseases from 1940 to 2004 were attributable to wild meat, compared with 17% from conventional agriculture and the food industry. And 31% was linked to changes in land use, including deforestation and habitat fragmentation.</p>
<p>We highlighted specific mechanisms that appeared to heighten spillover risk from wild meat harvesting and consumption, such as involvement in hunting or wild meat preparation, including skinning and butchering. Cooking methods also mattered, with the consumption of raw or undercooked meat often mentioned in reports.</p>
<h2>Towards more targeted policy responses</h2>
<p>Our research suggests the need for more nuanced approaches to protect an increasingly globalised and interconnected world from the potential risks of zoonotic spillover while not stigmatising the consumption practices of communities that rely on wild resources.</p>
<p>Knowing which animals harbour disease, knowing who is most exposed to high-risk animal species, understanding seasonal changes in exposure, and disseminating an understanding of safe and unsafe hunting and cooking practices could be more effective than total bans, and may result in better adoption of protective behaviour. </p>
<p>Simply banning wild meat consumption stigmatises consumers and risks pushing consumption practices underground, where they become harder to understand and regulate. </p>
<p>With the rate of emergence of new diseases accelerating, there is a need for more <a href="https://www.euro.who.int/en/health-topics/health-policy/one-health">inclusive approaches</a>, which balance the vulnerabilities of diverse, local communities and their continued need for wild food sources, with the need to reduce the risk of future spillover associated with eating wild meat.</p><img src="https://counter.theconversation.com/content/181647/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Following the global spread of COVID, there have been widespread calls for blanket bans on the consumption and trade of wild animals. But such bans may have unintended consequences.Charlotte Milbank, PhD Candidate in Geography and Epidemiology, University of CambridgeBhaskar Vira, Professor of Political Economy at the Department of Geography and Fellow of Fitzwilliam College., University of CambridgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1767712022-03-02T14:58:12Z2022-03-02T14:58:12ZWhy we shouldn’t worry about COVID spilling back from animals into human populations<p>Human physiological uniqueness made possible our colonisation of the world. Since our ancestors emerged from the African savanna tens of thousands of years ago, we’ve migrated and established residence in more or less every region on the planet, <a href="https://pubmed.ncbi.nlm.nih.gov/19586946/">regardless</a> of how hot or cold in temperature or high or low in altitude.</p>
<p>This tendency towards dispersal and exploration led some people to think of hominins — humans and our nearest extinct cousins such as the Neanderthals — as <a href="https://pubmed.ncbi.nlm.nih.gov/18046751/">the colonising ape</a>. Our unusual biological and behavioural adaptability — sometimes called plasticity — allows us to adjust to a variety of inhospitable environments.</p>
<p>An analogous story appears to be true of SARS-CoV-2 (the virus that causes COVID), which is now found just about wherever people are. And it’s arguably the same quality — plasticity — that’s enabled this rapid spread and evolutionary success of both humans and disease. We are descendants of the early colonising ape; the variants infecting us are descendants of the colonising virus. And one implication of this line of descent is that variants evolving in other animals are unlikely to pose much of a threat to us.</p>
<p>To understand why, think about how humans have, over the past millennia, adapted to hostile environments. Although we’re just one species — <em>Homo sapiens</em> — there’s tremendous variation in our appearance and to a lesser extent our genetic makeup. Naturalists of the 19th century noticed, for example, that average body size in warm-blooded species tends to increase as average temperature decreases. Modern-day researchers have confirmed that this rule — <a href="https://pubmed.ncbi.nlm.nih.gov/9712477/">known as Bergmann’s rule</a> — applies to some populations of humans.</p>
<p>Other changes are found in people that have lived in high-altitude regions - such as some areas of Tibet - long enough for nature to select traits that promoted survival in this environment. In these regions, the air is dense and consequently there is less oxygen available. And, unlike in low-temperature environments, people can’t just put on thicker layers to better survive: biological changes are necessary. These changes include improved oxygen delivery to the bloodstream and metabolism — and recently researchers have found specific genes that may explain these physiological changes.</p>
<p>Over time, then, it’s clear that humans, like all species, adapted to their surroundings. Unlike other species, however, we didn’t become different species to do so, and our plasticity helps to explain why. According to the evidence, we are generalists. Because of our capacity for learning and our unusual physiologies, we can adapt to most environments on Earth. By contrast, most species are specialists. They are adapted entirely to their specific ecological circumstances. Artificially moving any would probably lead to their extinction.</p>
<h2>Generalist virus</h2>
<p>Analogously, since it began transmitting among people, new SARS-CoV-2 variants appeared that helped the virus to infect humans more effectively. In its earliest detected state, the novel coronavirus infected different animals. We’ve known since mid-2020, for example, that <a href="https://www.cdc.gov/coronavirus/2019-ncov/daily-life-coping/animals.html">cats and dogs</a> are susceptible to infection, as are bats, which — directly or indirectly — people blame for the virus’s ability to infect humans. Yet it’s possible that what we’ve been dealing with all along is a virus that, because of its unusual evolutionary lineage, was, like us, a generalist.</p>
<p>The <a href="https://www.nature.com/articles/s41598-021-91470-2">conditions</a> of the Wuhan live animal and seafood markets in 2019 may have given SARS-CoV-2 the breeding ground to develop this strategy. Millions of creatures living in enclosed spaces on top of one another provide the perfect conditions for a virus — which overall evolve at <a href="https://www.newscientist.com/article/mg24532640-700-the-zombie-world-of-viruses-could-hold-the-key-to-evolution-itself/">astonishingly fast rates</a> — to adapt to these hosts, without ever needing to develop strategies specific to any single one.</p>
<p>The variants we’ve consequently seen emerge among humans — alpha, beta, delta and now omicron — are the same evolutionary steps we’d expect from a novel organism adapting to a new host environment. Regardless of their other qualities, these variants are each more infectious and transmissible than the last. The virus is specialising to us, much as humans have specialised to the many environments we inhabit.</p>
<p>In 2020, a SARS-CoV-2 variant <a href="https://www.nature.com/articles/d41586-020-03218-z">emerged in mink</a>, which marked a step towards specialisation in that species. However, it didn’t pose much of a public health threat to humans. More recently, there has been evidence of <a href="https://www.nytimes.com/2022/03/01/health/coronavirus-variant-deer-ontario.html">zoonosis from Ontario deer</a> – and there are likely to be many more such examples in the future – but these variants are unlikely to outcompete better human-adapted variants such as omicron. Much as people that evolved to live in particular environments, <a href="https://www.sciencedaily.com/releases/2020/10/201021163945.htm">or to have a particular kind of diet</a>, face health threats when their living circumstances drastically change, SARS-CoV-2 variants that evolve in other species won’t be specialised to us.</p>
<p>Omicron, and whatever the next variants are that signify increased specialisation to humans, are likely to be better adapted, and thus fitter when circulating among us. <a href="https://www.newyorker.com/science/elements/did-omicron-come-from-mice">Claims</a> about the threats of animal reservoirs are, therefore, probably unfounded. But we should, of course, continue to be vigilant.</p>
<p>As we enter the third year of the pandemic, it’s critical, perhaps more than ever, that we use the intelligence with which evolution has graced us — and which has been, and continues to be, essential to our survival — to outmanoeuvre the public health threats we face. More and better-specialised variants of SARS-CoV-2 will continue to emerge. And it’s towards these — and novel viral threats that stem from <a href="https://blogs.scientificamerican.com/observations/one-root-cause-of-pandemics-few-people-think-about/">dangerous agricultural practices</a> — that we should look.</p><img src="https://counter.theconversation.com/content/176771/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jonathan R Goodman does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The fear that SARS-CoV-2 will evolve in animals and then spread back to us in a more virulent form is unfounded.Jonathan R Goodman, PhD Candidate, Human Evolutionary Studies, University of CambridgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1752902022-02-27T13:08:39Z2022-02-27T13:08:39ZOrgan transplants from pigs: Medical miracle or pandemic in the making?<figure><img src="https://images.theconversation.com/files/447227/original/file-20220218-3064-xtzvrp.jpg?ixlib=rb-1.1.0&rect=422%2C35%2C4922%2C3332&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Xenotransplantation is the transplanting of cells, tissues or organs from animals to humans. Pre-clinical trials of organ transplant from pigs have addressed some of the technical barriers.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Three out of four <a href="https://www.cdc.gov/onehealth/basics/zoonotic-diseases.html">new diseases are zoonotic</a>, meaning they have evolved to infect new host species. For example, a mutated <a href="https://www.cdc.gov/flu/avianflu/virus-transmission.htm">bird-flu virus</a> may jump from wild birds to free-range domestic poultry and then to humans who are in contact with poultry. Similar pathways have led to infection by the pathogens that cause <a href="https://doi.org/10.1038/nrmicro.2017.45">Ebola, Zika, HIV, Lyme disease and likely COVID-19</a>.</p>
<p>If a new medical technology increased the risk of a new zoonotic pandemic — however marginally — how would society decide the balance of risk and benefit? If you needed new lungs that were only available in another country, would a health prohibition on the transplant in your own country stop you? </p>
<p>New developments in organ transplant technology may have streamlined a pathway for new zoonotic diseases, but the biotechnology innovators and medical research institutes have not engaged the public on the risks. Failing to do so may jeopardize the potential of a promising therapy.</p>
<h2>Xenotransplantation</h2>
<p>Over 4,400 Canadians are waitlisted for the lifesaving transplant of a new kidney, liver or lung. In 2019, <a href="https://www.blood.ca/en/stories/data-offers-hope-patients-waiting-organ-transplant">250 died waiting</a>. In the United States and elsewhere, <a href="https://www.organdonor.gov/learn/organ-donation-statistics">the supply gap is more extreme</a> and high hopes ride on xenotransplantation: the transplanting of cells, tissues or organs from animals. </p>
<p>Pre-clinical trials of organ transplants from pigs have addressed the technical barriers to xenotransplantation, reducing the likelihood of rejection. Last summer, Maryland School of Medicine surgeons reported the 31-day survival of a baboon after receiving a <a href="https://doi.org/10.1111/ajt.16809">lung from a genetically modified pig</a>. </p>
<p>Weeks later, a team at New York University transplanted a kidney from a genetically modified pig into a <a href="https://doi.org/10.1111/xen.12718">brain-dead person</a>. In December 2021, surgeons at Maryland School of Medicine transplanted a genetically modified pig heart into a <a href="https://doi.org/10.1038/d41586-022-00111-9">living 57-year-old man</a>. </p>
<p>All projects were approved under U.S. Food and Drug Administration (FDA) regulations, and corporate funding was supplemented by the U.S. National Institutes of Health. The next step with the FDA is to approve clinical trials. Normalization of xenotransplantation could happen before there is informed public acceptance of the benefits and risks.</p>
<h2>A potential zoonotic pathway</h2>
<p>As a developmental geneticist, it has been exciting to track these advances. The revolution in designer gene editing (known as CRISPR-Cas9) makes this stunning progress possible. <a href="https://doi.org/10.1126/science.aan4187">CRISPR allows molecules on the surface of pig cells to be modified</a> so the human immune system will not trigger tissue rejection.</p>
<figure class="align-center ">
<img alt="Illustration in blue tones of a human torso with respiratory tract and lungs in red" src="https://images.theconversation.com/files/447231/original/file-20220218-13070-hep7im.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/447231/original/file-20220218-13070-hep7im.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=465&fit=crop&dpr=1 600w, https://images.theconversation.com/files/447231/original/file-20220218-13070-hep7im.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=465&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/447231/original/file-20220218-13070-hep7im.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=465&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/447231/original/file-20220218-13070-hep7im.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=585&fit=crop&dpr=1 754w, https://images.theconversation.com/files/447231/original/file-20220218-13070-hep7im.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=585&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/447231/original/file-20220218-13070-hep7im.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=585&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Zoonotic bacteria and viruses enter most readily through the delicate surfaces of the respiratory tract.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>To prevent human transplant recipients from being infected with pig <a href="https://www.genome.gov/genetics-glossary/Retrovirus">retroviruses</a> (viruses that can integrate their genetic material into the host’s cells), the retroviruses hiding in the pig genome have been <a href="https://doi.org/10.1111/xen.12595">removed by CRISPR editing</a>. The risk of transferring a disease directly from a genetically modified donor pig to the human host is negligible.</p>
<p>However, disease-free transplanted pig organs could become infected after transplantation. Zoonotic bacteria and viruses enter hosts most readily through the <a href="https://doi.org/10.1051/vetres:2006062">delicate surfaces of the respiratory tract</a>, as with COVID-19. Living pig cells in a transplanted lung could readily be infected by an inhaled pig virus, including a novel virus from a wild animal host that has evolved to infect pigs. </p>
<p>After entering the human body, a replicating zoonotic virus could generate millions of mutations a day, because their mechanism for gene copying <a href="https://doi.org/10.3390/v13091882">is naturally error prone</a>. A pig virus replicating in a lung transplanted into a human could <a href="https://theconversation.com/how-do-viruses-mutate-and-jump-species-and-why-are-spillovers-becoming-more-common-134656">produce variants</a> that may be capable of recognizing and infecting human cells. Although likely a rare event, it is not impossible that this could trigger a new zoonotic pandemic.</p>
<h2>Risk, fear and polarization</h2>
<p>The scenario described above could evoke risk and fear from a complex new medical technology. It parallels the thinking involved in <a href="https://doi.org/10.1038/s41591-021-01459-7">vaccine hesitancy</a> or the <a href="https://www.scientificamerican.com/article/why-people-oppose-gmos-even-though-science-says-they-are-safe/">distrust of genetically modified foods</a>. Both are well anchored in today’s political culture. In both cases, citizens increasingly demand prior consent and the choice to opt out — despite possible risks to public health. <a href="https://doi.org/10.1038/s41598-022-05498-z">Vaccine hesitancy</a> has increased the death toll from COVID-19 and delayed economic recovery from the pandemic.</p>
<p>In contrast, distrust of the industrialization of food has discouraged introduction of genetically modified foods that <a href="https://doi.org/10.4161/21645698.2014.967570">enhance nutrition or sustain agricultural productivity</a> in a warming climate. Consumers question whether genetically modified organisms (GMOs) exist for public benefit or for corporate profit.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/447229/original/file-20220218-19-vy6cvf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A protester wearing a winter hat with their face covered with a scarf, hold a paper plate that says 'No GMOs on my plate'" src="https://images.theconversation.com/files/447229/original/file-20220218-19-vy6cvf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/447229/original/file-20220218-19-vy6cvf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=798&fit=crop&dpr=1 600w, https://images.theconversation.com/files/447229/original/file-20220218-19-vy6cvf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=798&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/447229/original/file-20220218-19-vy6cvf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=798&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/447229/original/file-20220218-19-vy6cvf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1003&fit=crop&dpr=1 754w, https://images.theconversation.com/files/447229/original/file-20220218-19-vy6cvf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1003&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/447229/original/file-20220218-19-vy6cvf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1003&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Distrust of the industrialization of food has discouraged introduction of GMO foods.</span>
<span class="attribution"><span class="source">(CP PHOTO/Paul Chiasson)</span></span>
</figcaption>
</figure>
<p>Increasingly, health issues such as <a href="https://theconversation.com/politicizing-covid-19-vaccination-efforts-has-fuelled-vaccine-hesitancy-175416">vaccination</a>, vaping or genetic testing generate highly polarized <a href="https://doi.org/10.1093/ntr/ntaa276">platforms for misinformation</a>, debate and political leverage. <a href="https://thedecisionlab.com/insights/society/social-media-and-moral-outrage/">Social media algorithms amplify extreme positions and elicit strong emotional reactions</a> at the <a href="http://dx.doi.org/10.1177/1461444818822813">expense of the middle ground</a>. When communications from the scientific community are reactive, poorly targeted or <a href="https://doi.org/10.1080/02691728.2020.1739778">unintelligible to the average person</a>, the influence of science in the policy process is diminished.</p>
<p>In 2022, progress in xenotransplant technology makes <a href="https://edition.cnn.com/2022/01/15/opinions/pig-heart-transplant-big-deal-reiner/index.html">good news stories</a>. Immense pressure to resolve the growing organ shortage for transplantation may tempt the biotechnology business and public regulators to be insufficiently critical as they seek permission to proceed with clinical studies. They must prepare for the nature and scale of backlash from those tired of experts and mistrustful of corporate motivation and institutional authority. </p>
<p>Concern about zoonosis from transplants was <a href="https://www.nuffieldbioethics.org/publications/xenotransplantation">voiced over twenty years ago</a>, long before CRISPR transformed the field. <a href="https://www.fda.gov/regulatory-information/search-fda-guidance-documents/phs-guideline-infectious-disease-issues-xenotransplantation">Since then</a>, there appear to be no hard facts or even a call for research on zoonotic infection through xenotransplants after transplantation. Bioethicists are <a href="https://www.thehastingscenter.org/xenotransplantation-three-areas-of-concern/">flagging the issue now</a>, but the silence about xenotransplant zoonosis from biotechnology corporations and their affiliated preclinical research institutes leaves an open door to a narrative motivated by skepticism and distrust. It is incumbent on them to lead a public dialogue on managing the risk of novel zoonotic diseases arising from infection after transplantation.</p><img src="https://counter.theconversation.com/content/175290/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>J Roger Jacobs receives funding from the Natural Sciences and Engineering Research Council of Canada.</span></em></p>New developments in organ transplants from animals show promise. However, there has been no public engagement about a potential risk. It may streamline a pathway to humans for new zoonotic diseases.J Roger Jacobs, Professor, Department of Biology, McMaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1721552022-02-24T19:13:17Z2022-02-24T19:13:17ZWe want to know where COVID came from. But it’s too soon to expect miracles<figure><img src="https://images.theconversation.com/files/448203/original/file-20220224-23-1h2z9vg.jpg?ixlib=rb-1.1.0&rect=2%2C1%2C995%2C556&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/sarscov2-coronavirus-virus-which-causes-covid19-1688912314">Shutterstock</a></span></figcaption></figure><p>About two years into the pandemic, we’re still trying to find where and how it all started. Only last week, <a href="https://www.nature.com/articles/s41586-022-04532-4">we heard</a> bats in Laos may hold a clue about the origin of SARS-CoV-2, the virus that causes COVID.</p>
<p>Our interest in viral origins, especially pandemic viruses, is understandable. But we need to remember one key lesson from history. It can take years to pin down their animal source. </p>
<p>Here’s why it’s important to keep trying and – in the case of the origin of SARS-CoV-2 – why it’s too soon to expect miracles.</p>
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Read more:
<a href="https://theconversation.com/i-was-the-australian-doctor-on-the-whos-covid-19-mission-to-china-heres-what-we-found-about-the-origins-of-the-coronavirus-155554">I was the Australian doctor on the WHO's COVID-19 mission to China. Here's what we found about the origins of the coronavirus</a>
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<h2>We can learn from the past</h2>
<p>Emerging infectious diseases like COVID are becoming an <a href="https://theconversation.com/how-do-viruses-mutate-and-jump-species-and-why-are-spillovers-becoming-more-common-134656">increasing problem</a>. Most are zoonotic. In other words, they originate in non-human animals, <a href="https://www.nature.com/articles/nature06536">mainly wildlife</a>. </p>
<p>However, identifying these animal sources and how the viruses entered human populations is difficult. This is a major problem. </p>
<p>If we can identify sources and routes of spillover, then we should be better able to understand the processes driving emergence of new diseases. This means we could better predict when and where spillover is likely to occur in the future. </p>
<p>Understanding the underlying processes would also help us devise strategies to either reduce the risk of wildlife diseases transferring to humans, or to nip spillover in the bud before an epidemic or pandemic occurs.</p>
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Read more:
<a href="https://theconversation.com/how-do-viruses-mutate-and-jump-species-and-why-are-spillovers-becoming-more-common-134656">How do viruses mutate and jump species? And why are 'spillovers' becoming more common?</a>
</strong>
</em>
</p>
<hr>
<h2>This is all very hard, but predictably so</h2>
<p>In the case of SARS-CoV-2, some people say scientists’ inability so far to identify the source wildlife population and to definitely say how the virus entered human populations suggests the virus originated in a laboratory. Yet <a href="https://www.sciencedirect.com/science/article/pii/S0092867421009910">the lab origin theory has been thoroughly debunked</a>.</p>
<p>However, this delay in finding definitive answers is not unusual. For many recently emerged human viruses, the wildlife source (the natural <a href="https://wwwnc.cdc.gov/eid/article/8/12/01-0317_article">reservoir</a>) took years to identify, or is still rather unclear.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1460224993334280192"}"></div></p>
<p>For example, <a href="https://www.hopkinsmedicine.org/ebola/about-the-ebola-virus.html">Ebola</a> has caused devastating outbreaks of deadly haemorrhagic disease in Africa since the 1970s. </p>
<p>Most scientists think <a href="https://www.embopress.org/doi/full/10.15252/emmm.201404792">bats are the reservoir</a>. Yet no one has yet successfully isolated Ebola virus from a wild bat, despite lots of circumstantial evidence.</p>
<h2>How about bats and COVID?</h2>
<p>The <a href="https://www.nature.com/articles/s41586-022-04532-4">closest known animal virus</a> to SARS-CoV-2 occurs in a species of horseshoe bat found throughout China and Southeast Asia. That virus is called RaTG13.</p>
<p>Although RaTG13 and SARS-CoV-2 are <a href="https://www.nature.com/articles/s41586-022-04532-4">96.1% similar</a> in their genetic code overall, this does not necessarily mean the human SARS-CoV-2 came directly from those bats. </p>
<p>In the same way, while <a href="https://bmcgenomics.biomedcentral.com/articles/10.1186/s12864-020-06962-8">chimpanzees are the closest living relatives of humans</a>, we definitely did not descend from chimpanzees, nor did chimpanzees descend from us.</p>
<figure class="align-center ">
<img alt="Chimpanzee mother kissing chimpanzee child" src="https://images.theconversation.com/files/448195/original/file-20220224-23-hgznkx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/448195/original/file-20220224-23-hgznkx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/448195/original/file-20220224-23-hgznkx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/448195/original/file-20220224-23-hgznkx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/448195/original/file-20220224-23-hgznkx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/448195/original/file-20220224-23-hgznkx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/448195/original/file-20220224-23-hgznkx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The DNA of chimpanzees and humans is almost identical. But that doesn’t mean we are directly related.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/female-chimpanzee-baby-on-mangrove-trees-353063024">Shutterstock</a></span>
</figcaption>
</figure>
<p>Genetic similarity between two species tells us they are connected in a “family tree” to a common ancestor. The extent of that similarity gives some information about how long it was since the two species arose from that ancestor. </p>
<p>For SARS-CoV-2 and the bat coronavirus RaTG13, this separation likely occurred <a href="https://www.sciencedirect.com/science/article/pii/S0092867421009910">some decades ago</a>.</p>
<h2>Viral family trees have ‘tangles’</h2>
<p>To make things more complex, some viruses can also acquire genetic changes via <a href="https://www.nature.com/articles/nrmicro2614">recombination</a>. This occurs when two different virus strains or species infect the same cell. They can swap bits of genetic code with each other, producing a “mosaic” virus. This means the “family tree” becomes more like a tangle of brushwood.</p>
<p>So, rather than looking for a single coronavirus as the ancestor of SARS-CoV-2, we need to look at a whole range of related viruses that might co-occur in nature.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1495458547253100548"}"></div></p>
<p>More evidence for this came just last week, in a <a href="https://www.nature.com/articles/s41586-022-04532-4">paper</a> published in the prestigious journal Nature. </p>
<p>It found previously unknown bat viruses in Laos that are not quite as closely related to SARS-CoV-2 as RaTG13 overall. But some of these bat viruses from Laos are more closely related to SARS-CoV-2 than RaTG13 at the particular region that allows the virus to bind to human cells.</p>
<p>This means SARS-CoV-2 likely arose from mixing of different bat coronaviruses in natural bat populations. This is likely how SARS-CoV-2 acquired the genetic sequence that allows it to bind to human cells and infect humans.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-it-will-soon-be-too-late-to-find-out-where-the-covid-19-virus-originated-166743">Why it will soon be too late to find out where the COVID-19 virus originated</a>
</strong>
</em>
</p>
<hr>
<h2>What about pangolins?</h2>
<p>Pangolins are scaly mammals considered a delicacy in parts of Asia and are severely endangered by the wildlife trade. There has been a <a href="https://www.sciencedirect.com/science/article/pii/S0960982220303602">lot of discussion</a> about the possibility pangolins may have been a bridge species that enabled the transfer of this coronavirus from bats to humans.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1494975073316442114"}"></div></p>
<p>These ideas arose because we know some highly pathogenic (disease causing) emerging viruses in humans do indeed have a bridge host. Bats infect them and they, in turn, pass the virus to humans. </p>
<p>For example, we work on <a href="https://theconversation.com/explainer-why-is-hendra-virus-so-dangerous-2083">Hendra virus</a> in Australia, where <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2014.2124">horses act as a bridge host</a>. Flying foxes (a type of bat) infect horses, which in turn, infect humans. </p>
<p>Similarly, <a href="https://www.frontiersin.org/articles/10.3389/fimmu.2020.552909/full">MERS</a> (Middle East respiratory syndrome) is caused by a coronavirus of bats which has passed to camels and then on to humans.</p>
<p>With the new coronaviruses detected in bats in Laos, our understanding of the role of pangolins has changed. It appears both pangolins and humans <a href="https://www.nature.com/articles/s41586-022-04532-4">are infected by</a> coronaviruses derived from bats, but the human virus did not come via pangolins. </p>
<h2>How did a coronavirus get from bats in caves to humans in Wuhan?</h2>
<p>This critical question <a href="https://www.sciencedirect.com/science/article/pii/S0092867421009910">remains a mystery</a>. People go into the caves where these horseshoe bats live, often to collect guano (bat faeces) for fertiliser. But the nearest bat caves are some distance from Wuhan. </p>
<p><a href="https://www.nature.com/articles/s41598-021-91470-2">No bats were sold</a> in the Wuhan wet market that many of the earliest cases were linked to. </p>
<p>However, Wuhan is a major city and transport hub. So an infected person who had been in those caves may well have passed through Wuhan, and visited the wet markets. </p>
<p>SARS-CoV-2 is now known to infect a wide range of other mammals. So it is also possible a bat or a human may have infected another mammal, which then passed through the Wuhan wet market.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/new-preliminary-evidence-suggests-coronavirus-jumped-from-animals-to-humans-multiple-times-168473">New preliminary evidence suggests coronavirus jumped from animals to humans multiple times</a>
</strong>
</em>
</p>
<hr>
<h2>What do we still want to know?</h2>
<p>Lessons learnt from other viruses meant that early on in the SARS-CoV-2 outbreak, we had a solid basis for hypothesising the virus had links to bats and quite possibly arose through a bridging host in the wildlife market. </p>
<p>We still have unanswered questions about the path the virus took from bats to humans. But the more we continue to look in bat populations, the more we find these pieces of SARS-CoV-2 genetic code already exist in nature. </p>
<p>As with other emerging viruses, if we keep looking, we may eventually find all the missing pieces we need to close the case on where SARS-CoV-2 came from. If we’re smart, we’ll use this information to take action to prevent the next pandemic.</p><img src="https://counter.theconversation.com/content/172155/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hamish McCallum receives funding from ARC, and the US agencies NSF, NIH and DARPA.
</span></em></p><p class="fine-print"><em><span>Alison Peel receives funding from ARC, and the US agencies NSF and DARPA. </span></em></p>The delay in finding definitive answers to how novel infectious diseases come about is not unusual. Look at what happened to our search for Ebola virus.Hamish McCallum, Director, Centre for Planetary Health and Food Security, Griffith UniversityAlison Peel, Senior Research Fellow in Wildlife Disease Ecology, Griffith UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1766662022-02-17T13:04:48Z2022-02-17T13:04:48ZDeer, mink and hyenas have caught COVID-19 – animal virologists explain how to find the coronavirus in animals and why humans need to worry<figure><img src="https://images.theconversation.com/files/446830/original/file-20220216-24-gxwvhf.jpg?ixlib=rb-1.1.0&rect=200%2C324%2C3835%2C2635&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">White-tailed deer are one of the few wild species that scientists have found to be infected with the coronavirus – at least so far.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:White-tailed_Deer_(Odocoileus_virginianus)_fawn_(15127378806).jpg#/media/File:White-tailed_Deer_(Odocoileus_virginianus)_fawn_(15127378806).jpg">Andrew C/WikimediaCommons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>In April 2020, tigers and lions at the Bronx Zoo made the news when <a href="https://newsroom.wcs.org/News-Releases/articleType/ArticleView/articleId/14084/Update-Bronx-Zoo-Tigers-and-Lions-Recovering-from-COVID-19.aspx">they came down with COVID-19</a>. In the months following these surprising diagnoses, researchers and veterinarians found SARS-CoV-2, the virus that causes COVID-19, in <a href="https://www.aphis.usda.gov/aphis/dashboards/tableau/sars-dashboard">nearly a dozen other species</a>, both in captivity and in the wild. </p>
<p>How are so many animals catching the coronavirus? And what does this mean for human and animal health? </p>
<p>We are <a href="https://scholar.google.com/citations?user=o1CqidUAAAAJ&hl=en&oi=ao">veterinary</a> <a href="https://scholar.google.com/citations?user=w9u-0VoAAAAJ&hl=en&oi=ao">researchers</a> who <a href="https://scholar.google.com/citations?user=4PsS9YcAAAAJ&hl=en&oi=ao">investigate</a> animal diseases, including zoonotic diseases that can infect both humans and animals. It is important, for both human and animal health, to know what species are susceptible to infection by the coronavirus. Our labs and others across the world have tested domestic, captive and wild animals for the virus, in addition to <a href="https://doi.org/10.1073/pnas.2013102117">conducting experiments</a> to determine which species are susceptible. </p>
<p>The list of <a href="https://www.aphis.usda.gov/aphis/dashboards/tableau/sars-dashboard">infected animals so far</a> includes more than a dozen species. But in reality, infections may be much more widespread, as very few species and individual animals have been tested. This has real implications for human health. Animals can not only spread pathogens like the coronavirus, but also can be a source of new mutations.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/446122/original/file-20220213-25032-e2n4g3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing a number of animals that are susceptible to the coronavirus." src="https://images.theconversation.com/files/446122/original/file-20220213-25032-e2n4g3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446122/original/file-20220213-25032-e2n4g3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=506&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446122/original/file-20220213-25032-e2n4g3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=506&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446122/original/file-20220213-25032-e2n4g3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=506&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446122/original/file-20220213-25032-e2n4g3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=636&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446122/original/file-20220213-25032-e2n4g3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=636&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446122/original/file-20220213-25032-e2n4g3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=636&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">By exposing some animals to the coronavirus experimentally, researchers can understand what species are susceptible and how they react to infection.</span>
<span class="attribution"><a class="source" href="https://app.biorender.com/biorender-templates">Adapted from 'Human body with curved callout' by BioRender.com on Feb. 16, 2022.</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>Which animals have caught the coronavirus?</h2>
<p>As of February 2022, researchers and veterinary diagnostic labs have confirmed that <a href="https://en.wikipedia.org/wiki/List_of_animals_that_can_get_SARS-CoV-2#cite_note-22">31 species</a> are susceptible to SARS-CoV-2. In addition to pets and zoo animals, researchers have found that a number of <a href="https://doi.org/10.1371/journal.ppat.1008903">nonhuman primates</a>, <a href="https://doi.org/10.3389/fmicb.2021.626553">ferrets</a>, <a href="https://doi.org/10.1371/journal.ppat.1009585">deer mice</a>, <a href="https://apnews.com/article/coronavirus-pandemic-science-lifestyle-colorado-health-25411ccf517bb16d2128b4c774b6d6c9">hyenas</a>, <a href="https://dx.doi.org/10.3201%2Feid2708.210180">wood rats, striped skunks and red fox</a> are among the animals that are susceptible to infection by SARS-CoV-2. </p>
<p>White-tailed deer and mink are the only two species of animals that have been found harboring the virus in the wild. Fortunately, <a href="https://www.pnas.org/content/117/42/26382.short">most animals</a> don’t appear to experience clinical disease like humans do, with the exception of <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1010068">mink</a>. However, even animals that don’t appear sick may be able to transmit the virus to each other and, potentially, back to people. Still unanswered are many questions about which animals can contract the virus and what, if anything, that means for people.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/446831/original/file-20220216-27-1xbf8oq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A small, long, dark brown mink standing on the ground." src="https://images.theconversation.com/files/446831/original/file-20220216-27-1xbf8oq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446831/original/file-20220216-27-1xbf8oq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=411&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446831/original/file-20220216-27-1xbf8oq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=411&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446831/original/file-20220216-27-1xbf8oq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=411&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446831/original/file-20220216-27-1xbf8oq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=516&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446831/original/file-20220216-27-1xbf8oq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=516&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446831/original/file-20220216-27-1xbf8oq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=516&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Scientists knew ferrets were susceptible to the first SARS outbreak in 2002, so they tested the closely related mink after reports of sicknesses at mink farms.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:American_Mink.jpg#/media/File:American_Mink.jpg">Patrick Reijnders/WikimediaCommons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>How to look for a virus in animals</h2>
<p>There are three ways to study zoonotic diseases: by looking at pets or captive species like animals in zoos, testing wild animals for the coronavirus or by exposing animals to the virus in a lab.</p>
<p>During early stages of the pandemic, when a few pet owners or zoo caretakers observed animals with breathing problems or coughing, they arranged with veterinarians to get them tested for the coronavirus. The U.S. Department of Agriculture and <a href="https://www.cdc.gov/coronavirus/2019-ncov/daily-life-coping/animals.html">the Centers for Disease Control and Prevention</a> coordinate COVID-19 testing and management in animals. The same process of taking a sample and running it through a PCR machine to test for the coronavirus works just as well for animals as it does for people, though swabbing the nose of a lion – or even a pet cat – requires a bit more training and finesse. Veterinary diagnostic laboratories <a href="https://cvmbs.source.colostate.edu/veterinary-diagnostic-laboratory-to-process-human-covid-19-tests/">like our own</a> run hundreds of thousands of tests for animal diseases each year, so we were able to <a href="https://www.neoteryx.com/microsampling-blog/how-veterinary-diagnostic-labs-are-pivoting-to-support-human-covid-19-testing">easily begin testing for SARS-CoV-2</a>.</p>
<p>Relying on previous research, scientists have been able to make some guesses as to which animals are susceptible and have been testing these hypotheses. Cats, hamsters and ferrets were all infected during the <a href="https://dx.doi.org/10.1016%2FB978-0-12-369408-9.00036-6">first SARS outbreak</a> in 2002, so researchers suspected they would be susceptible to the new coronavirus. Sure enough, research showed that SARS-CoV-2 <a href="https://doi.org/10.1073/pnas.2013102117">readily infected</a> these species in <a href="https://doi.org/10.3389/fmicb.2021.626553">laboratory experiments</a>. Mink are closely related to ferrets, and during the summer and fall of 2020, mink farms across the U.S. became <a href="https://www.cnn.com/2020/10/09/us/mink-covid-outbreak-trnd/index.html">sites of huge outbreaks</a> after people passed the coronavirus to the animals. </p>
<p>Using computer models, scientists were also able to predict that the coronavirus could easily infect some species of deer using <a href="https://doi.org/10.1073/pnas.2010146117">key proteins on their cells</a>. Based on these predictions, researchers began testing white-tailed deer for the coronavirus and <a href="https://www.aphis.usda.gov/animal_health/one_health/downloads/qa-covid-white-tailed-deer-study.pdf">first reported positives</a> in August 2021.</p>
<p>Most recently, on Feb. 7, 2022, researchers published a preprint paper showing that deer on Staten Island, New York, are infected with the <a href="https://doi.org/10.1101/2022.02.04.479189">omicron variant.</a> Since this is the virus infecting most New Yorkers, this provides strong evidence that humans somehow transmitted the virus to deer. How deer in at <a href="https://www.nytimes.com/2022/02/07/health/coronavirus-deer-animals.html">least six states and Canada</a> initially came in contact with SARS-CoV-2 remains a mystery.</p>
<p>Finally, to understand how the coronavirus affects animals, researchers have been conducting carefully controlled exposure experiments. These studies evaluate how infected animals shed the virus, whether they have clinical symptoms, and whether and how much the virus mutates in different species.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/446832/original/file-20220216-15-1at9c8i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Five different colored spherical coronaviruses representing some of the existing variants." src="https://images.theconversation.com/files/446832/original/file-20220216-15-1at9c8i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446832/original/file-20220216-15-1at9c8i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446832/original/file-20220216-15-1at9c8i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446832/original/file-20220216-15-1at9c8i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446832/original/file-20220216-15-1at9c8i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446832/original/file-20220216-15-1at9c8i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446832/original/file-20220216-15-1at9c8i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">When the coronavirus jumps from species to species, the chances of a new variant emerging increase.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/covid-19-omicron-sign-royalty-free-image/1356934479?adppopup=true">Andriy Onufriyenko/Moment via Getty Images</a></span>
</figcaption>
</figure>
<h2>Risks of a species-jumping coronavirus</h2>
<p>The risk of contracting SARS-CoV-2 from an animal is, for most people, far lower than being exposed to it by another human. But if the coronavirus is living and spreading among animals and occasionally jumping back to humans, this process – known as <a href="https://theconversation.com/is-covid-19-infecting-wild-animals-were-testing-species-from-bats-to-seals-to-find-out-151467">spillover and spillback</a> – poses its own threats to public health. </p>
<p>First, infection of animals simply increases the concentration of SARS-CoV-2 in an environment. Second, large populations of animals that can sustain the infection can act as a reservoir for the virus, maintaining it even if the number of infections in humans decreases. This is particularly concerning with deer that live in high numbers in suburban areas and could transmit the virus back to people.</p>
<p>Finally, when SARS-CoV-2 spreads from humans to animals, <a href="https://doi.org/10.1073/pnas.2105253118">our laboratory’s own work</a> indicates that the virus very rapidly accumulates mutations. Viruses adapt to the unique characteristics – body temperature, diet and immune composition – of whatever animal they are living in by mutating. The more species infected, <a href="https://doi.org/10.1073/pnas.2105253118">the more mutations</a> occur. It’s possible that the new variants emerging in people could infect new animal species. Or it’s possible that new variants could initially arise from animals and infect humans. </p>
<p>The story of SARS-CoV-2 in animals isn’t over yet. According to the CDC, six of every 10 human infectious diseases can be spread from animals to people, and around three-quarters of <a href="https://www.cdc.gov/onehealth/basics/zoonotic-diseases.html">new or emerging infectious diseases in people come from animals</a>. Research has shown that investing in the study of zoonotic diseases could <a href="https://www.science.org/doi/10.1126/sciadv.abl4183">vastly reduce the costs of future pandemics</a>, and this type of complex research has <a href="https://doi.org/10.1126/sciadv.abl4183">historically been underfunded</a>. Yet despite this, in 2021, the CDC allocated only <a href="https://www.neha.org/node/61710">$193 million</a> toward the study of emerging zoonotic infectious diseases – less than <a href="https://www.hhs.gov/sites/default/files/fy-2022-budget-in-brief.pdf">a quarter of 1 percent of the CDC’s total budget</a>. </p>
<p>There are still many unknowns about how viruses transfer between humans and animals, how they live and mutate in animal populations and the risks of species-jumping viruses. The more researchers know, the better health officials, governments and scientists can prepare and prevent the next pandemic.</p>
<p>[<em>Research into coronavirus and other news from science</em> <a href="https://memberservices.theconversation.com/newsletters/?nl=science&source=inline-science-corona-research">Subscribe to The Conversation’s new science newsletter</a>.]</p><img src="https://counter.theconversation.com/content/176666/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sue VandeWoude receives funding from the National Science Foundation, National Institutes of Health, Morris Animal Foundation, and EveryCat Health Foundation. </span></em></p><p class="fine-print"><em><span>Angela Bosco-Lauth receives funding from the National Institutes of Health, National Science Foundation, United States Department of Agriculture-APHIS, and Defense Threat Reduction Agency.
</span></em></p><p class="fine-print"><em><span>Christie Mayo receives funding from the United States Department of Agriculture and National Animal Health Laboratory Network</span></em></p>Scientists have been testing captive and wild animals for the coronavirus since the pandemic began. Only a few wild species are known to carry the virus, but many more have been shown to be susceptible.Sue VandeWoude, University Distinguished Professor of Microbiology, Immunology, and Pathology and Director of the One Health Institute, Colorado State UniversityAngela Bosco-Lauth, Assistant Professor of Biomedical Sciences, Colorado State UniversityChristie Mayo, Associate Professor of Microbiology, Immunology and Pathology, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1725202021-11-30T13:58:03Z2021-11-30T13:58:03ZTop Kenyan scientist shares the joys and challenges of creating life-saving vaccines<figure><img src="https://images.theconversation.com/files/433911/original/file-20211125-19-14ew8e4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Rift Valley Fever virus, 3D illustration.
</span> <span class="attribution"><span class="source">Kateryna Kon/Shutterstock</span></span></figcaption></figure><p><em>Professor George Warimwe should be a household name in Kenya. He’s a leading scientist who has created a life-saving vaccine against Rift Valley Fever. He is also leading policy-changing work on Yellow Fever vaccines. Warimwe has now been awarded the <a href="https://royalsociety.org/grants-schemes-awards/awards/africa-prize/">Royal Society Africa Prize</a> for his work on vaccine development and capacity building in Africa. Moina Spooner, from The Conversation Africa, spoke to Warimwe about his life as a vaccinologist.</em></p>
<h2>What types of vaccines have you helped to create?</h2>
<p>I have a slight bias towards diseases that affect both humans and animals, so-called zoonotic diseases. This is for a few reasons. </p>
<p>Growing up, animals were very important to my family life. We used to keep livestock, and we had a prized bull. The bull had to be sold to generate enough money for me to go to university – my education depended on that animal. The importance that animals have in people’s lives sparked my interest and I went on to study veterinary medicine. </p>
<p>I also became interested in zoonotic diseases because humans share many infectious diseases with animals. Roughly <a href="https://royalsocietypublishing.org/doi/10.1098/rstb.2001.0888">[60%]</a> of all human infections are acquired from animals. And of all emerging infectious diseases, over <a href="https://royalsocietypublishing.org/doi/10.1098/rstb.2001.0888">70%</a> are from animals or involve transmission between humans and animals. </p>
<p>For me, taking account of what happens in both humans and animals is really important to understand how to control diseases in both. And so I try to develop vaccines for both. </p>
<h2>Is there a vaccine that you’re particularly proud of?</h2>
<p>When I decided to go into vaccinology (creating vaccines) I identified Rift Valley Fever as the first disease I wanted to work on. This is because it’s a disease that was <a href="https://onlinelibrary.wiley.com/doi/10.1002/path.1700340418">first identified</a> in Kenya in 1930 and affects both humans and livestock (sheep, goats, cattle and camels). </p>
<p>Rift Valley Fever is highly deadly. Over <a href="https://onlinelibrary.wiley.com/doi/10.1002/path.1700340418">90%</a> of young animals die from infection. The disease can be transmitted to humans. People who work or live with these animals can catch it from them and people can also catch it from mosquitoes. It can cause severe illness in humans, and <a href="https://www.who.int/news-room/fact-sheets/detail/rift-valley-fever">over 30%</a> of those with severe illness die. </p>
<p>So, Rift Valley Fever has major implications for human and animal health. And because it’s the same virus that causes disease in humans and livestock, it’s possible to develop a single vaccine that you can use across humans and animals. We can exploit the knowledge of how immunity develops in animals to develop effective vaccines for humans and vice versa. </p>
<p>We knew that immunity to the disease is conferred by antibodies that bind to glycoproteins on the surface of the virus. To develop a vaccine we inserted the gene encoding these glycoproteins into a vaccine vector (a ‘vehicle’ to deliver the information into cells) called ChAdOx1. This ChAdOx1 vector has been used to make other vaccines, including the Oxford AstraZeneca COVID-19 vaccine. </p>
<p>When you administer the vaccine to a human or an animal, it gets into the body’s cells and directs the cells to make large amounts of the vaccine antigen (Rift Valley Fever glycoproteins) without viral replication. The body responds to this by making antibodies that can block a Rift Valley Fever virus from infecting you. </p>
<p>In our previous studies we showed that the vaccine – ChAdOx1 RVF – was safe and <a href="https://www.nature.com/articles/srep20617">highly protective</a> in multiple livestock species (sheep, goats, cattle) in Kenya. We’ve now started evaluating the same vaccine in humans. It’s in Phase 1 clinical trials at Oxford University with no safety concerns to date. </p>
<p>This has been a massive achievement, and will likely address the unmet need for a licensed human vaccine; so I’m most proud of it. </p>
<h2>What considerations and concerns do you have when developing vaccines?</h2>
<p>There are lots of <a href="https://www.who.int/docs/default-source/blue-print/call-for-comments/tpp-rift-valley-fever-vaccines-draft3-0pc.pdf?sfvrsn=f2f3b314_2">things to think about</a>. For instance, what immune response are you aiming to generate with the vaccine? Do you have the appropriate technology to generate the immune response? And if you do, will you be able to produce lots of the vaccine? How will it be stored? We’ve seen this with the COVID-19 pandemic. There are vaccines that can be stored at fridge temperature, and there are those that need ultra-cold storage (minus 80°C). There are vaccines that only need one dose, whereas others need several. We have to consider the logistics around this. </p>
<p>You also need to think of the target population of the vaccine. Will it be for adults or children? This is obviously dependent on the distribution of the disease that you are trying to make a vaccine for. For instance, if making a vaccine for use in children you need to think of how it would be deployed and whether it will need to be co-administered with other childhood vaccines. </p>
<p>An understanding of the nature of the immune response and clinical manifestations of the disease is also necessary, so that you know whether the vaccine provides protection or not.</p>
<p>These are things you have to think of very early on that play into the final cost of the product and the ease of implementing the vaccine programme. It’s like a checklist that you have to form at the start. And you try to address potential challenges – such as new variants – very early on and think of solutions. </p>
<p>Then you can start making your vaccine with a clear plan of how you will evaluate its safety, ability to generate an immune response, ability to provide protection, and a clear pathway for its licensing and eventual use.</p>
<h2>What can be done to help improve vaccine development?</h2>
<p>I have been incredibly fortunate to have excellent mentorship from global leaders in vaccinology. Added to this is the excellent research environment at the KEMRI-Wellcome Trust Research Programme in Kenya where I have been able to progress my research with input from many colleagues with diverse scientific expertise spanning immunology, social science, economics and policy. </p>
<p>There is lots of talent in Africa, enough to match and solve the current health challenges in the continent. To harness this we need to create a supportive research environment and associated infrastructure, provide mentorship and back this up with sustained funding opportunities. National governments in Africa have a critical role in addressing this through, among other things, funding research. </p>
<p>We also need to improve how much vaccine is produced in Africa. As a continent we produce <a href="https://www.nature.com/articles/d41586-021-01048-1">less than 1%</a> of vaccines needed; we import the rest. This has left the continent vulnerable to external forces. There is hope though. The Partnership for African Vaccine Manufacturing is developing plans to increase local production with an <a href="https://africacdc.org/news-item/african-union-and-africa-cdc-launches-partnerships-for-african-vaccine-manufacturing-pavm-framework-to-achieve-it-and-signs-2-mous/">“ambition to manufacture 60% of Africa’s routine immunisation needs on the continent by 2040”</a> while strengthening other components of the vaccine ecosystem. </p>
<p>Long-term investment in the talent in Africa will be a key success factor for our ambitions in addressing the major health challenges we face today and others that are currently brewing.</p>
<p><em>You can view Professor Warimwe’s Africa Prize 2021 lecture <a href="https://www.youtube.com/watch?v=xXkNZ2OMOJQ">here</a>.</em></p><img src="https://counter.theconversation.com/content/172520/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>George Warimwe receives funding from the Wellcome Trust, UK Dept of Health & Social Care and the European and Developing Countries Clinical Trials Partnership (EDCTP). </span></em></p>Manufacturing is just one part of the vaccine ecosystem. It’s the health system that delivers vaccines and people must be willing to take them.George Warimwe, Group Leader, KEMRI-Wellcome Trust Research Programme, Kenya; Associate Professor, Centre for Tropical Medicine & Global Health, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1712682021-11-08T13:13:12Z2021-11-08T13:13:12ZWhite-tailed deer found to be huge reservoir of coronavirus infection<p>New research from the US has shown that white-tailed deer are being infected with SARS-CoV-2, the virus that causes COVID-19 in humans. Antibodies were found in <a href="https://www.pnas.org/content/118/47/e2114828118">40% of deer</a> that were tested from January to March 2021 across Michigan, Pennsylvania, Illinois and New York state. <a href="https://www.biorxiv.org/content/10.1101/2021.10.31.466677v1">A second unpublished study</a> has detected the virus in 80% of deer sampled in Iowa between November 2020 and January 2021.</p>
<p>Such high levels of infection led the researchers to conclude that deer are actively transmitting the virus to one another. The scientists also identified different SARS-CoV-2 variants, suggesting there have been many human-to-deer infections.</p>
<p>The large numbers of white-tailed deer in North America and the fact that they often live close to people provide several opportunities for the disease to move between the two species. This can include wildlife management operations, field research, recreation, tourism and hunting. In fact, hunters are likely to be one of the most obvious sources of potential reinfection as they regularly handle dead animals. It has also been suggested that water sources contaminated with SARS-CoV-2 might provide a <a href="https://www.sciencedirect.com/science/article/pii/S0048969720328758">pathway for transmission</a>, although this has yet to be proved.</p>
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<img alt="Woman close to a white-tailed deer." src="https://images.theconversation.com/files/430777/original/file-20211108-17-160m6er.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/430777/original/file-20211108-17-160m6er.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/430777/original/file-20211108-17-160m6er.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/430777/original/file-20211108-17-160m6er.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/430777/original/file-20211108-17-160m6er.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/430777/original/file-20211108-17-160m6er.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/430777/original/file-20211108-17-160m6er.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">There are many ways the virus could have spread from humans to deer.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/deer-bambi-zoo-cage-woman-kiss-1942137493">Volodymyr TVERDOKHLIB/Shutterstock</a></span>
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<p>Human-to-deer and deer-to-deer transmission are believed to be driving the rapid spread of the disease within white-tailed deer populations across the US. This is particularly apparent during the early months of 2021 when COVID infections were spiking in the human population. Previous studies have shown that SARS-CoV-2 can be passed from humans to domestic and captive animals including <a href="https://www.nature.com/articles/s41467-020-20097-0">cats, dogs</a>, zoo animals and, most notably, <a href="https://www.theguardian.com/environment/2021/feb/18/mink-farms-a-continuing-covid-risk-to-humans-and-wildlife-warn-eu-experts">farmed mink</a>. But, until now, the disease had not been shown to spread in wildlife species.</p>
<p>White-tailed deer are the most abundant large mammal in North America with a range extending from <a href="https://www.fs.fed.us/database/feis/animals/mammal/odvi/all.html#SocialBehavior">Canada to South America</a>. The US population alone is estimated to number <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.8084">30 million animals</a>. They are a social species that live in family groups of two to 12 individuals that can thrive in a range of habitats, including <a href="https://www.bloomberg.com/news/articles/2017-08-07/the-deer-of-suburbia-aren-t-going-anywhere">urban parks and woodland</a>. </p>
<p>These aspects of their ecology and behaviour have made them a species of particular concern when it comes to the spread of diseases, including <a href="https://www.frontiersin.org/articles/10.3389/fvets.2018.00301/full">bovine tuberculosis</a> and <a href="https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/ecy.1538?casa_token=65F1BWPlfGYAAAAA:U91bDPEr9Bu3fgFHMK31BY695WleH_UZuFgFQ5es6VCco35xdNZHcv35K5OlzKDmQnxD4__DqrSiA-Q">chronic wasting disease</a>. These pathogens have already led to considerable effects on the health of wild and domestic animal populations around the globe.</p>
<p>The findings from these latest studies have raised concerns that white-tailed deer could be a reservoir of SARS-CoV-2. Not only could this readily infect large numbers of animals, but also, more worryingly, it could spill back to humans.</p>
<p>This type of infection cycle was documented in workers on <a href="https://www.science.org/doi/10.1126/science.abe5901">infected mink farms</a>, which ultimately led to the Danish government euthanising their entire captive population of <a href="https://www.bbc.co.uk/news/world-europe-54818615">17 million animals</a>. It is important to underline that there is currently no evidence of SARS-CoV-2 transmission from white-tailed deer to humans. Initial experimental work has also suggests that infected deer tend not to have symptoms. Still, disease transmission in wildlife populations has considerable implications for <a href="https://www.nature.com/articles/d41586-021-00531-z">human and animal health</a>.</p>
<h2>Potential source of new variants</h2>
<p>There is the possibility that viral mutation in a reservoir host, such as white-tailed deer, could lead to new variants of the disease. These variants may lead to greater infection rates, increased virulence (severity of symptoms) and prove more effective at evading the human immune system. Likewise, any reinfection from wildlife reservoirs could also complicate our long-term efforts to fight and suppress the disease.</p>
<p>Influenza, which jumps readily between birds, humans and other mammals (particularly pigs), presented similar problems. These multiple reservoirs of disease can lead to new strains emerging that humans have lower immunity against, as was the case with <a href="https://www.bloomberg.com/news/articles/2021-06-02/how-flu-s-mutations-threaten-birds-pigs-and-humans-quicktake">swine flu in 2009</a>.</p>
<p>It is important to note that there are limitations to these studies, both in terms of the methods used and the limited geographical range of investigation. The most recent and unpublished study used the latest genetic approaches to reliably detect SARS-CoV-2 in tissue samples but focused only <a href="https://www.biorxiv.org/content/10.1101/2021.10.31.466677v1">on deer in Iowa</a>. Whereas the antibody tests in the first study were conducted across four states but only show that the animal has been <a href="https://www.pnas.org/content/118/47/e2114828118">exposed to the virus</a>. Yet the combined findings have highlighted that transmission of SARS-CoV-2 is likely to be widespread in white-tailed deer.</p>
<p>There is a great deal that we still need to learn about the developing situation with COVID and deer. The most important topics to focus on include understanding how the virus is being transmitted from humans to deer and determining the risk of spillover back into the human population. Research is urgently needed to assess the risk that this potential reservoir of SARS-CoV-2 presents to humans, as well as the possible spread of the virus to other wildlife species that deer interact with, such as predators and scavengers.</p><img src="https://counter.theconversation.com/content/171268/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>In a sample of white-tailed deer, 80% were found to have an active COVID infection.Graeme Shannon, Lecturer in Zoology, Bangor UniversityAmy Gresham, PhD Student, Behavioural Ecology, Bangor UniversityOwain Barton, PhD Student, Ecology, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1684732021-09-23T20:05:52Z2021-09-23T20:05:52ZNew preliminary evidence suggests coronavirus jumped from animals to humans multiple times<p>The origin of the SARS-CoV-2 virus, which has caused the COVID-19 pandemic, has been hotly debated.</p>
<p>This debate has caused substantial difficulties in the Australia-China relationship, with a call by Foreign Minister <a href="https://www.abc.net.au/news/2020-04-19/payne-calls-for-inquiry-china-handling-of-coronavirus-covid-19/12162968">Marise Payne for another inquiry into its origin</a> being considered by China as a hostile act.</p>
<p>What’s not in doubt is the <a href="https://www.nature.com/articles/s41591-020-0820-9">closest relatives of the virus are found in bats</a>. How, where and when the virus spilled over into humans is the contentious issue. </p>
<p>One widely supported hypothesis is the spillover occurred in the “wet markets” of Wuhan, where many species of wildlife from across China are held in crowded conditions.</p>
<p>However, there’s no evidence the species of bats in which the closest relatives of SARS-CoV-2 are found were sold through the Wuhan wet markets at any time in the <a href="https://www.nature.com/articles/s41598-021-91470-2">two years before the pandemic</a>. This hypothesis requires the existence of a “bridge host”, another species that becomes infected via spillover from the original bat hosts, and then passes the virus onto humans.</p>
<p>Bridge hosts are well-known in many emerging human diseases. For example, Hendra virus, which my group studies, has flying foxes as its reservoir. Hendra spills over to horses <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2014.2124">with some frequency</a>. Horses then amplify the virus as a bridge host and can infect humans.</p>
<p>Fortunately, this is extremely rare, with only <a href="https://www.health.nsw.gov.au/Infectious/controlguideline/Pages/hendra-case-summary.aspx">seven known cases</a>. Tragically, four of those people died. Hendra has never been known to spread directly from flying foxes to humans.</p>
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<a href="https://theconversation.com/i-was-the-australian-doctor-on-the-whos-covid-19-mission-to-china-heres-what-we-found-about-the-origins-of-the-coronavirus-155554">I was the Australian doctor on the WHO's COVID-19 mission to China. Here's what we found about the origins of the coronavirus</a>
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<h2>More evidence a lab leak is very unlikely</h2>
<p>A second, much more <a href="https://theconversation.com/the-covid-19-lab-leak-hypothesis-is-plausible-because-accidents-happen-i-should-know-162430">contentious hypothesis</a> is the origin of the pandemic was the result of a “lab leak”. </p>
<p>Wuhan has one of the most sophisticated virological laboratories in China, and the laboratory does work on bat viruses. The suggestion is the virus may have inadvertently been released into the general community via one of the workers. No direct evidence supports this hypothesis.</p>
<p>A new pre-print study, <a href="https://virological.org/t/evidence-against-the-veracity-of-sars-cov-2-genomes-intermediate-between-lineages-a-and-b/754">released online this month</a>, provides <a href="https://www.nature.com/articles/d41586-021-02519-1">strong evidence</a> to support the “natural spillover” hypothesis, with results that are hard to reconcile with the “lab leak” hypothesis.</p>
<p>The study is yet to be peer reviewed. But it’s based on a detailed examination of the genetic sequences of two early lineages obtained from people infected in late 2019 and early 2020. </p>
<p>For convenience, these two lineages are called A and B. The two lineages differ by just two nucleotides (letters in the genetic code) at two different key sites in the genetic sequence.</p>
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<p>If there was a single lab escape event, the separation into lineages A and B must have happened after the lab escape. We would therefore expect to see a substantial number of intermediate lineages, with the lineage A nucleotide at one site, and the lineage B nucleotide at the other site.</p>
<p>However, if almost all of the genetic sequences obtained from humans are “pure” lineage A or pure lineage B, this suggests there were at least two different spillover events, either directly from bats or via bridge hosts. </p>
<p>And the evolution of the two lineages occurred before humans were infected.</p>
<p>The researchers downloaded all complete genetic sequences for SARS-CoV-2 that had been lodged in a widely used genomic database. Of these sequences, 369 were lineage A, 1,297 were lineage B and just 38 were intermediates. </p>
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Read more:
<a href="https://theconversation.com/why-it-will-soon-be-too-late-to-find-out-where-the-covid-19-virus-originated-166743">Why it will soon be too late to find out where the COVID-19 virus originated</a>
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<p>Genetic sequencing isn’t perfect. Close examination of the 38 intermediates strongly suggested they were more likely to be sequencing errors of pure lineage A or lineage B than to be true intermediates.</p>
<p>The genetic evidence, therefore, suggests very strongly there have been at least two separate spillover events into human populations, one being from lineage A and another being from lineage B.</p>
<h2>Did a human bring SARS-CoV-2 to the wet markets?</h2>
<p>The data don’t tell us there have been only two spillover events — there may have been more. Nor do they tell us whether these spillovers happened directly from bats, or whether some or all happened via an intermediate bridge host.</p>
<p>A Nature news article suggests this evidence <a href="https://www.nature.com/articles/d41586-021-02519-1">points to the spillover having happened via the wildlife trade</a>, but I think this is taking it a step too far. </p>
<p>While some of the wildlife species sold through the Wuhan wet market can indeed become infected with SARS-CoV-2 (for example <a href="https://wwwnc.cdc.gov/eid/article/26/12/20-3733_article">raccoon dogs</a> and <a href="https://www.sciencedirect.com/science/article/pii/S1473309920309129?via%3Dihub">mink</a>), there’s no evidence any sold through the market were infected.</p>
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<p>Many of the earliest human viral sequences (all lineage B) were recovered from the Wuhan seafood market, but wet markets and abattoirs are well-known to be places where the SARS-CoV-2 virus spreads very well from human to human.</p>
<p>So, it may have been a human who brought the virus to the Wuhan seafood market, rather than a species of wildlife.</p>
<p>One thing we do know is this pandemic originated through a human coming in contact with another species infected with the virus.</p>
<p>It’s unknown whether this was a bat or a bridge host, and whether this contact occurred in a wildlife market, or in a bat cave, or somewhere else entirely different.</p>
<p>Nevertheless, as humans encroach more and more on the habitats of wild animals and as wild animals are brought more frequently into close contact with humans, we can expect further spillovers and pandemics to occur.</p>
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Read more:
<a href="https://theconversation.com/how-do-viruses-mutate-and-jump-species-and-why-are-spillovers-becoming-more-common-134656">How do viruses mutate and jump species? And why are 'spillovers' becoming more common?</a>
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<p class="fine-print"><em><span>Hamish McCallum receives funding from the Australian Reserch Council and from the US agencies NSF, NIH and DARPA</span></em></p>It’s more evidence a lab leak is very unlikely.Hamish McCallum, Director, Centre for Planetary Health and Food Security, Griffith UniversityLicensed as Creative Commons – attribution, no derivatives.