tag:theconversation.com,2011:/fr/topics/bird-flu-14773/articlesBird flu – The Conversation2024-03-11T17:18:48Ztag:theconversation.com,2011:article/2223062024-03-11T17:18:48Z2024-03-11T17:18:48ZThe next pandemic? It’s already here for Earth’s wildlife<p>I am a conservation biologist who studies emerging infectious diseases. When people ask me what I think the next pandemic will be I often say that we are in the midst of one – it’s just afflicting a great many species more than ours.</p>
<p>I am referring to the highly pathogenic strain of avian influenza H5N1 (HPAI H5N1), otherwise known as bird flu, which has killed millions of birds and unknown numbers of mammals, particularly during the past three years. </p>
<p>This is the strain that emerged in domestic geese in China in 1997 and quickly jumped to humans in south-east Asia with a mortality rate of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1634780/">around 40-50%</a>. My research group <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1634780/">encountered the virus</a> when it killed a mammal, an endangered <a href="https://svw.vn/owstons-civet/">Owston’s palm civet</a>, in a captive breeding programme in Cuc Phuong National Park Vietnam in 2005.</p>
<p>How these animals caught bird flu was never confirmed. Their diet is mainly earthworms, so they had not been infected by eating diseased poultry like many captive tigers in the region.</p>
<p>This discovery prompted us to collate all confirmed reports of fatal infection with bird flu to assess just how broad a threat to wildlife this virus might pose.</p>
<p>This is how a newly discovered virus in Chinese poultry came to threaten so much of the world’s biodiversity.</p>
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<img alt="A person in white overalls operates a forklift carrying dead turkeys." src="https://images.theconversation.com/files/580987/original/file-20240311-22-gzginr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580987/original/file-20240311-22-gzginr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580987/original/file-20240311-22-gzginr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580987/original/file-20240311-22-gzginr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580987/original/file-20240311-22-gzginr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580987/original/file-20240311-22-gzginr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580987/original/file-20240311-22-gzginr.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">
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<span class="caption">H5N1 originated on a Chinese poultry farm in 1997.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/western-negev-israel-march-18-2006-111241157">ChameleonsEye/Shutterstock</a></span>
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<h2>The first signs</h2>
<p>Until December 2005, most confirmed infections had been found in a few zoos and rescue centres in Thailand and Cambodia. Our analysis in 2006 showed that nearly half (48%) of all the different groups of birds (known to taxonomists as “orders”) contained a species in which a fatal infection of bird flu had been reported. These 13 orders comprised 84% of all bird species. </p>
<p>We reasoned 20 years ago that the strains of H5N1 circulating were probably highly pathogenic to all bird orders. We also showed that the list of confirmed infected species included those that were globally threatened and that important habitats, such as Vietnam’s Mekong delta, lay close to reported poultry outbreaks.</p>
<p>Mammals known to be susceptible to bird flu during the early 2000s included primates, rodents, pigs and rabbits. Large carnivores such as Bengal tigers and clouded leopards were reported to have been killed, as well as domestic cats.</p>
<p>Our 2006 paper showed the ease with which this virus crossed species barriers and suggested it might one day produce a pandemic-scale threat to global biodiversity.</p>
<p>Unfortunately, our warnings were correct.</p>
<h2>A roving sickness</h2>
<p>Two decades on, bird flu is killing species from <a href="https://www.theguardian.com/environment/2024/jan/02/polar-bear-dies-from-bird-flu-age-of-extinction">the high Arctic</a> to <a href="https://www.cidrap.umn.edu/avian-influenza-bird-flu/avian-flu-reaches-antarcticas-mainland">mainland Antarctica</a>.</p>
<p>In the past couple of years, bird flu has spread rapidly across Europe and infiltrated North and South America, killing millions of poultry and a variety of bird and mammal species. <a href="https://wwwnc.cdc.gov/eid/article/30/3/23-1098_article">A recent paper</a> found that 26 countries have reported at least 48 mammal species that have died from the virus since 2020, when the latest increase in reported infections started.</p>
<p>Not even the ocean is safe. Since 2020, 13 species of aquatic mammal have succumbed, including American sea lions, porpoises and dolphins, often dying in their thousands in South America. A wide range of scavenging and predatory mammals that live on land are now also confirmed to be susceptible, including mountain lions, lynx, brown, black and polar bears.</p>
<p>The UK alone has <a href="https://www.rspb.org.uk/birds-and-wildlife/seabird-surveys-project-report">lost over 75%</a> of its great skuas and seen a 25% decline in northern gannets. Recent declines in sandwich terns (35%) and common terns (42%) were also <a href="https://maryannsteggles.com/wp-content/uploads/2024/02/Bird-flu-causing-%E2%80%98catastrophic-fall-in-UK-seabird-numbers-conservationists-warn-Bird-flu-The-G.pdf">largely driven by the virus</a>. </p>
<p>Scientists haven’t managed to <a href="https://wwwnc.cdc.gov/eid/article/30/3/23-1098_article">completely sequence</a> the virus in all affected species. Research and continuous surveillance could tell us how adaptable it ultimately becomes, and whether it can jump to even more species. We know it can already infect humans – one or more genetic mutations may make it more infectious.</p>
<h2>At the crossroads</h2>
<p>Between January 1 2003 and December 21 2023, 882 cases of human infection with the H5N1 virus were reported from 23 countries, of which <a href="https://cdn.who.int/media/docs/default-source/influenza/human-animal-interface-risk-assessments/influenza-at-the-human-animal-interface-summary-and-assessment--from-4-october-to-1-november-2023.pdf?sfvrsn=6c67e7df_2&download=true">461 (52%) were fatal</a>.</p>
<p>Of these fatal cases, more than half were in Vietnam, China, Cambodia and Laos. Poultry-to-human infections were first recorded in Cambodia in December 2003. Intermittent cases were reported until 2014, followed by a gap until 2023, yielding 41 deaths from 64 cases. The subtype of H5N1 virus responsible has been detected in poultry in Cambodia since 2014. In the early 2000s, the H5N1 virus circulating had a high human mortality rate, so it is worrying that we are now starting to see people dying after contact with poultry again.</p>
<p>It’s not just H5 subtypes of bird flu that concern humans. The H10N1 virus was originally isolated from wild birds in South Korea, but has also been reported in samples from China and Mongolia. </p>
<p><a href="https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1256090/full">Recent research</a> found that these particular virus subtypes may be able to jump to humans after they were found to be pathogenic in laboratory mice and ferrets. The first person who was confirmed to be infected with H10N5 <a href="https://www.who.int/emergencies/disease-outbreak-news/item/2024-DON504">died</a> in China on January 27 2024, but this patient was also suffering from seasonal flu (H3N2). They had been exposed to live poultry which also tested positive for H10N5.</p>
<p>Species already threatened with extinction are among those which have died due to bird flu in the past three years. The first deaths from the virus in mainland Antarctica have just been <a href="https://www.cidrap.umn.edu/avian-influenza-bird-flu/avian-flu-reaches-antarcticas-mainland">confirmed in skuas</a>, highlighting a looming threat to penguin colonies whose eggs and chicks skuas prey on. Humboldt penguins have already been <a href="https://www.nytimes.com/2023/08/30/science/birds-flu-antarctica.html">killed by the virus</a> in Chile.</p>
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<img alt="A colony of king penguins." src="https://images.theconversation.com/files/580982/original/file-20240311-26-mmf7j5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580982/original/file-20240311-26-mmf7j5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580982/original/file-20240311-26-mmf7j5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580982/original/file-20240311-26-mmf7j5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580982/original/file-20240311-26-mmf7j5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580982/original/file-20240311-26-mmf7j5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580982/original/file-20240311-26-mmf7j5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&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">Remote penguin colonies are already threatened by climate change.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/king-penguin-colony-103683413">AndreAnita/Shutterstock</a></span>
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<p>How can we stem this tsunami of H5N1 and other avian influenzas? Completely overhaul poultry production on a global scale. Make farms self-sufficient in rearing eggs and chicks instead of exporting them internationally. The trend towards megafarms containing over a million birds must be stopped in its tracks. </p>
<p>To prevent the worst outcomes for this virus, we must revisit its primary source: the incubator of intensive poultry farms.</p>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?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">
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<p class="fine-print"><em><span>Diana Bell 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>Bird flu is decimating species already threatened by climate change and habitat loss.Diana Bell, Professor of Conservation Biology, University of East AngliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2206032024-01-15T17:11:42Z2024-01-15T17:11:42ZFirst polar bear to die of bird flu – what are the implications?<p>Climate change is a threat to polar bear’s survival. Now they have a new deadly challenge facing them: bird flu. It was <a href="https://www.cbsnews.com/news/bird-flu-kills-polar-bear-first-time/">recently confirmed</a> that a polar bear from northern Alaska has died from the disease. </p>
<p>The current strain of H5N1 influenza has affected a <a href="https://www.nature.scot/doc/naturescot-scientific-advisory-committee-sub-group-avian-influenza-report-h5n1-outbreak-wild-birds">far wider range of species</a> than any previously recorded strain. This has included <a href="https://www.gov.uk/government/publications/bird-flu-avian-influenza-findings-in-non-avian-wildlife">several mammal species</a>, such as foxes, otters, mink, sea lions and seals (including, for the first time, <a href="https://www.itv.com/news/2024-01-11/bird-flu-found-in-antarctic-seals-could-pose-threat-to-fragile-ecosystem">seals in Antarctica</a>). Cases have been detected in humans, too.</p>
<p>However, while some cases in mammals have been associated with large numbers of animal deaths, the few cases in humans have, so far, shown only mild symptoms or have been <a href="https://ukhsa.blog.gov.uk/2023/06/06/ukhsas-asymptomatic-avian-influenza-surveillance-programme/">asymptomatic</a>. So, why are there such differences between species, and what are the implications of this polar bear’s death for the wider polar bear population, as well as other large mammals and humans?</p>
<p>Influenza viruses are highly adaptable. Their relatively simple genetic code not only changes at random via mutation in the same way as truly living organisms, but also via <a href="https://doi.org/10.1371%2Fjournal.ppat.1004902">reassortment</a>. This is where closely related viruses that infect the same host cell exchange genetic material to produce novel genomes. This can lead to greater adaptation for invasion, survival and replication within that host species.</p>
<p>This is probably how the current H5N1 strain has come to affect such a variety of bird species, with devastating effects for some populations. </p>
<p>Normally, large numbers of deaths associated with a disease are considered to be caused by the spread of a disease between individuals within the population. However, very specific <a href="https://www.nature.com/articles/s41579-023-00943-w">genetic changes</a> are needed for avian influenza viruses to become adapted to mammalian hosts. </p>
<p>These changes have not yet been detected in the current strain of H5N1. Although individual-to-individual transmission cannot be ruled out for some mammalian species that have been affected by H5N1, neither can vertical transmission – the transfer of the virus via consumption.</p>
<p>If we look at the <a href="https://www.gov.uk/government/publications/bird-flu-avian-influenza-findings-in-non-avian-wildlife">list of mammals</a> that have been infected by the current H5N1 strain, we see carnivores – and particularly those that are known to scavenge. </p>
<p>Very large numbers of some seabird species have died rapidly with H5N1. The likelihood of a seal or a polar bear finding and eating at least one infected bird carcass at an arctic colony suffering an outbreak seems quite high. </p>
<p>It is easy to imagine a pod of seals finding a colony of seabirds suffering an outbreak of H5N1 and gorging on carcasses. Under these circumstances, each seal would probably ingest and inhale massive viral loads. Those massive viral loads may have overrun the seals’ immune systems, leading to rapid infection and death without infection being passed between seals. </p>
<p>Whether the polar bear encountered large numbers of dead seabirds, one or more seals that had become infected after eating dead seabirds or some other source of virus remains unknown. The answer may be uncovered via testing of the virus and comparison with viruses found in species that occupy the same landscape. This approach is being used to <a href="https://science.vla.gov.uk/fluglobalnet/publications/flumap-update-oct23.html">track the spread</a> of H5N1 between wild animals and poultry in the UK.</p>
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<img alt="An elephant seal in South George." src="https://images.theconversation.com/files/569199/original/file-20240114-23-g758ql.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/569199/original/file-20240114-23-g758ql.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/569199/original/file-20240114-23-g758ql.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/569199/original/file-20240114-23-g758ql.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/569199/original/file-20240114-23-g758ql.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/569199/original/file-20240114-23-g758ql.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/569199/original/file-20240114-23-g758ql.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">Bird flu was recently detected in elephant and fur seals in South Georgia.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/elephant-seal-on-beach-south-georgia-781207378">Zaruba Ondrej/Shutterstock</a></span>
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<h2>More to find out</h2>
<p>Much of this remains hypothetical – for now. The consequences of the polar bear’s death for the species’ populations and for other large mammals cannot be predicted with a high degree of certainty. But if genetic testing reveals that the polar bear’s H5N1 remains poorly adapted to mammalian hosts, we might expect few other cases in polar bears. </p>
<p>Any further cases might also be closely associated with outbreaks of H5N1 in a nearby seabird colony. It also seems likely that the list of affected mammals and their geographical distribution should continue to grow, but relatively slowly. This list is likely to continue to include only carnivores – and scavengers in particular. </p>
<p>On the other hand, because influenza viruses are highly adaptable, ongoing surveillance of the H5N1 strain remains critically important. This will prepare us in case a new variant emerges that is adapted to mammalian hosts, potentially including humans. </p>
<p>The consequences of H5N1 for populations of some seabirds have been devastating. The consequences of failure to respond appropriately to a mammal-adapted H5N1 could be severe for polar bears – and for us.</p><img src="https://counter.theconversation.com/content/220603/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alastair Ward receives funding from the BBSRC to investigate the ongoing H5N1 outbreak as part of the Flu:TrailMAP consortium. </span></em></p>Avian influenza has killed a polar bear and may have infected other bears.Alastair Ward, Associate Professor of Biodiversity and Ecosystem Management, University of LeedsLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2167382023-12-22T00:08:48Z2023-12-22T00:08:48ZAvian influenza has killed millions of seabirds around the world: Antarctica could be next<p>Antarctica is often imagined as the last untouched wilderness. Unfortunately, <a href="https://www.woah.org/en/disease/avian-influenza/">avian influenza</a> (“bird flu”) is encroaching on the icy continent. The virus has already reached the <a href="https://maps.app.goo.gl/QvLgto7pq8ggDALd6">sub-Antarctic islands</a> between the Antarctic Peninsula and South America. It’s only a matter of time before it reaches the Antarctic continent. </p>
<p>So far avian influenza has been detected in several seabird species on <a href="https://www.bas.ac.uk/media-post/first-confirmed-cases-of-avian-influenza-in-the-antarctic-region/">South Georgia Island</a> and the <a href="https://falklands.gov.fk/agriculture/avian-influenza">Falkland (Malvinas) Islands</a>. These birds are known to travel to Antarctica. Researchers also suspect avian influenza caused mass deaths of southern elephant seals. </p>
<p>The arrival of avian influenza in Antarctica could have potentially catastrophic consequences for the wildlife, decimating large populations. </p>
<p>Antarctic avian influenza outbreaks may also disrupt tourism and research activities during the busy summer season. So what can we do during this challenging time? </p>
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Read more:
<a href="https://theconversation.com/migrating-birds-could-bring-lethal-avian-flu-to-australias-vulnerable-birds-204793">Migrating birds could bring lethal avian flu to Australia's vulnerable birds</a>
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<h2>The bird flu pandemic</h2>
<p>We are in the midst of a “panzootic” – a large-scale pandemic of <a href="https://www.woah.org/en/disease/avian-influenza/">avian influenza</a>, which is occurring across the world and has affected more than 200 species of wild birds.</p>
<p>While this strain of avian influenza (H5N1) <a href="https://www.nature.com/articles/s41586-023-06631-2">is an old foe</a>, the genetics and epidemiology of the virus have shifted. Once mostly found in poultry, it is now infecting large numbers of wild birds. Migrating birds have <a href="https://www.nature.com/articles/s41559-023-02182-x">spread the virus</a> with substantial outbreaks now occurring in Europe, Asia, Africa, North America and South America. </p>
<p>Avian influenza has devastated seabird populations around the world, including a 70% reduction of <a href="https://onlinelibrary.wiley.com/doi/10.1111/ibi.13275">northern gannets</a> on Bass Rock in the United Kingdom. Many birds are diseased, with signs including loss of coordination, watery eyes, head twisting, breathing distress or lethargy. </p>
<p>Beyond birds, this virus may have killed more than <a href="https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4611782">30,000 South American sea lions</a> and over <a href="https://www.lanacion.com.ar/sociedad/puerto-madryn-murieron-mas-de-200-crias-de-elefantes-marinos-en-las-ultimas-dos-semanas-nid27102023/">2,500 southern elephant seal</a> pups in South America. In South Georgia mass deaths have been observed in <a href="https://www.bas.ac.uk/media-post/additional-cases-of-avian-flu-hpai-confirmed-on-south-georgia/">elephant seal pups</a> but the virus was not detected in samples sent for laboratory tests.</p>
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Read more:
<a href="https://theconversation.com/invasive-species-are-threatening-antarcticas-fragile-ecosystems-as-human-activity-grows-and-the-world-warms-172058">Invasive species are threatening Antarctica's fragile ecosystems as human activity grows and the world warms</a>
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<h2>Bird flu moving further south</h2>
<p>The first detection of avian influenza near Antarctica occurred in early October on Bird Island, <a href="https://www.bas.ac.uk/media-post/additional-cases-of-avian-flu-hpai-confirmed-on-south-georgia/">South Georgia</a>, in brown skuas (seabirds similar to large gulls). </p>
<p>A case on the Falkland (Malvinas) Islands was confirmed a few weeks later in another seabird species, the southern fulmar. </p>
<p>Genetic analysis revealed the virus entered these regions on <a href="https://www.biorxiv.org/content/10.1101/2023.11.23.568045v1">two separate occasions</a>.</p>
<p>Skuas and kelp gulls were highlighted as species <a href="https://www.scar.org/library/science-4/life-sciences/antarctic-wildlife-health-network-awhn/5973-risk-assessment-avian-influenza/file/">most likely to spread the virus to the Antarctic continent</a> in a recent risk assessment, as they travel into the region from South America. They are also highly susceptible to avian influenza, with related species in the <a href="https://www.nature.scot/avian-flu-causes-another-challenging-summer-seabirds#:%7E:text=Pink%2Dfooted%20geese%2C%20herring%20gulls,breeding%20population%20of%20great%20skua">Northern Hemisphere suffering losses of more than 60%</a>. </p>
<h2>What does this mean for Antarctica?</h2>
<p>The Antarctic Peninsula, with its <a href="https://www.scar.org/research-features/climate-expansion-ice-free-habitat/">ice-free areas</a>, is an important breeding ground for many key Antarctic species. </p>
<p>Critically, those species – and others, including the iconic Emperor penguin – live in <a href="https://www.bas.ac.uk/about/antarctica/wildlife/penguins/">dense colonies</a> and are not found elsewhere in the world, making them particularly vulnerable to disease outbreaks.</p>
<p>Outbreaks on the Antarctic Peninsula will also be extremely disruptive to the tourism industry. More than <a href="https://iaato.org/information-resources/data-statistics/">104,000 people</a> visited as tourists in the 2022–23 season. People visit to see wildlife, make a continental landing, and enjoy the scenery.</p>
<p>Once avian influenza is confirmed at a particular location, sites will be <a href="https://iaato.org/iaato-2022-23-biosecurity-protocols-regarding-avian-influenza/">closed to tourists</a>. This will lead to a different experience for visitors, with land-based wildlife encounters pivoting to cruise-based activities. </p>
<h2>What are we doing?</h2>
<p>The <a href="https://www.scar.org/science/awhn/">Antarctic Wildlife Health Network</a> of the Scientific Committee on Antarctic Research has developed recommendations for the research and tourism communities. </p>
<p>These recommendations include information around biosecurity, testing and reporting of cases. The network’s <a href="https://scar.org/library-data/avian-flu">database</a> collates information on suspected and confirmed cases of the H5N1 avian influenza strain in the Antarctic region. This is central to rapid data sharing.</p>
<p>During the 2022–23 season, a <a href="https://www.biorxiv.org/content/10.1101/2023.10.24.563692v1.full.pdf">small number of researchers</a> tested suspected cases and conducted surveys, which excluded the presence of avian influenza. </p>
<p>This year, through the generosity of industry partners, we will dramatically expand this effort. The network will conduct surveys across the Antarctic and sub-Antarctic to monitor the presence and impact of the virus on wildlife. </p>
<p>Safety and biosecurity measures have been boosted across the <a href="https://www.comnap.aq/heightened-risk-of-hpai-in-antarctica">scientific community</a> and <a href="https://iaato.org/wp-content/uploads/2020/04/IAATO_Don_t_Pack_a_Pest.EN_190070.pdf">tourism industry</a> to reduce the risk of people spreading the virus. This should ensure essential scientific research and tourism activities can continue safely. </p>
<p>New measures now in place include:</p>
<ul>
<li>disinfection of boots and outer clothing</li>
<li>wearing of N95 masks, protective glasses and gloves when working with wildlife</li>
<li>restrictions on access to infected sites.</li>
</ul>
<p>Tourism can play an important role in detecting and monitoring the spread of the virus, alerting authorities to new cases in locations not visited by scientists. </p>
<p>The International Association of Antarctica Tour Operators is on high alert. Extra training for <a href="https://iaato.org/polar-stakeholders-response-to-avian-influenza-as-2023-24-antarctic-season-begins/">field staff</a> will help them identify wildlife illness quickly. </p>
<h2>Antarctica is connected</h2>
<p>Many threats to Antarctica – including climate change, pollution, and pathogens – originate elsewhere. Climate change is expected to <a href="https://www.who.int/europe/news/item/01-07-2022-new-report-highlights-the-impact-of-changes-in-environment-on-one-health#:%7E:text=Climate%20change%20and%20rising%20temperatures,of%20both%20pathogens%20and%20vectors.">increase the spread of infectious diseases in wildlife</a> and Antarctica is not immune.</p>
<p>Disease surveillance and information sharing between all those active in the far south are vital to help minimise the impacts of avian influenza and future disease threats. </p>
<p>The avian influenza example highlights the connectivity of our world, and why we need to care for the planet at home in order to protect the far south. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/ancient-pathogens-released-from-melting-ice-could-wreak-havoc-on-the-world-new-analysis-reveals-209795">Ancient pathogens released from melting ice could wreak havoc on the world, new analysis reveals</a>
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</em>
</p>
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<img src="https://counter.theconversation.com/content/216738/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hanne E F Nielsen receives funding from the Australian Research Council, Linkage partner organisation Intrepid Travel, the Dutch Research Council, and the Australian Antarctic Division. Hurtigruten Australia provides in-kind support for fieldwork.</span></em></p><p class="fine-print"><em><span>Michelle Wille has an honorary appointment with the WHO Collaborating Centre for Reference and Research on Influenza. </span></em></p><p class="fine-print"><em><span>Meagan Dewar 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>A deadly strain of bird flu is circulating in animals. So far the virus has been detected in seabirds on islands near Antarctica. What does this mean for wildlife, tourism and research?Hanne E F Nielsen, Senior lecturer, University of TasmaniaMeagan Dewar, Lecturer in the School of Science, Psychology and Sport, Federation University AustraliaMichelle Wille, Senior research fellow, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2145142023-12-21T16:16:30Z2023-12-21T16:16:30ZVaccinating livestock against common diseases is a form of direct climate action<figure><img src="https://images.theconversation.com/files/566576/original/file-20231219-19-ke5un.jpg?ixlib=rb-1.1.0&rect=643%2C11%2C2724%2C2109&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/veterinarian-protective-rubber-gloves-inoculates-cow-2324670827">PERO studio/Shutterstock</a></span></figcaption></figure><p>Animal diseases have a devastating impact on livestock production. In 2022, for example, <a href="https://www.who.int/news/item/12-07-2023-ongoing-avian-influenza-outbreaks-in-animals-pose-risk-to-humans">131 million</a> domestic poultry died or were culled as a result of <a href="https://www.cdc.gov/flu/avianflu/index.htm#:%7E:text=Avian%20influenza%20or%20bird%20flu,other%20bird%20and%20animal%20species.">avian influenza</a> (also called “bird flu”).</p>
<p>Yet the cost of livestock disease goes beyond a shortage of turkeys for the holiday season. Every animal that is lost to a preventable disease is also associated with greenhouse gas emissions that the planet cannot afford.</p>
<p>Animal diseases reduce the productivity of a farm. This is because livestock grow at a slower pace, are unable to reach target weights or fail to reproduce. Diseases may also drastically increase the rate at which livestock die. </p>
<p>Diseases with high mortality levels, such as <a href="https://www.daera-ni.gov.uk/articles/classical-swine-fever#:%7E:text=Classical%20Swine%20Fever%20is%20a,no%20impact%20on%20human%20health.">classical swine fever</a> or avian influenza, mean farmers need to use more resources and raise additional animals to maintain food production. This will cause the generation of more greenhouse gas emissions.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-uk-urgently-needs-to-cut-its-methane-emissions-by-2030-cows-and-sheep-hold-the-key-to-success-185621">The UK urgently needs to cut its methane emissions by 2030: cows and sheep hold the key to success</a>
</strong>
</em>
</p>
<hr>
<p>However, controlling common animal diseases effectively through tools like vaccination proves to be a sustainable way of tackling climate change. According to <a href="https://onehealthoutlook.biomedcentral.com/articles/10.1186/s42522-023-00089-y">new research</a> that was carried out by one of us (Jude Capper), controlling <a href="https://www.cdc.gov/flu/avianflu/influenza-a-virus-subtypes.htm">“high pathogenicity” avian influenza</a> – a virus that can cause severe disease and death in infected poultry – with vaccines would reduce greenhouse gas emissions by almost 16% per kilogram of meat without having to resort to culling.</p>
<figure class="align-center ">
<img alt="A vet removing the carcasses of chickens on a farm that have died from bird flu." src="https://images.theconversation.com/files/566579/original/file-20231219-23-1jike7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566579/original/file-20231219-23-1jike7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566579/original/file-20231219-23-1jike7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566579/original/file-20231219-23-1jike7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566579/original/file-20231219-23-1jike7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566579/original/file-20231219-23-1jike7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566579/original/file-20231219-23-1jike7.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">Bird flu caused the death of 131 million domestic poultry in 2022.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/veterinarian-takes-carcasses-chickens-on-farm-2153618663">Pordee_Aomboon/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Reducing emissions</h2>
<p>Using vaccines to prevent disease also supports better food security and livelihoods. <a href="https://www.msdvetmanual.com/generalized-conditions/porcine-reproductive-and-respiratory-syndrome/porcine-reproductive-and-respiratory-syndrome">Porcine reproductive and respiratory syndrome</a> is endemic in countries including the US, China and Vietnam. The virus does not always kill infected pigs, but it limits output from swine farms as it affects reproduction and growth. In affected herds, up to 19% of sows fail to produce piglets and 75% of young pigs die before weaning.</p>
<p>Every 100,000 sows spared from porcine reproductive and respiratory syndrome would prevent more than 420,000 tonnes of greenhouse gas emissions. This is equivalent to removing more than 230,000 cars from the road, and means greenhouse gas emissions per kilogram of pork would fall by 22.5%. </p>
<p>Similarly, eliminating <a href="https://www.woah.org/en/disease/foot-and-mouth-disease/#:%7E:text=FMD%20is%20characterised%20by%20fever,leaves%20them%20weakened%20and%20debilitated.">foot and mouth disease</a> where it is endemic (many low- and middle-income countries in Africa and Asia) would cut emissions by more than 10% per kilogram of product. Foot and mouth disease is highly contagious and led to a <a href="https://www.bbc.co.uk/news/magazine-35581830">crisis</a> for UK agriculture when it hit in 2001. The disease is a major cause of reduced production around the globe, despite not always killing livestock.</p>
<figure class="align-center ">
<img alt="Traffic on a motorway surrounded by heavy smog." src="https://images.theconversation.com/files/566584/original/file-20231219-15-d54tpf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566584/original/file-20231219-15-d54tpf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566584/original/file-20231219-15-d54tpf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566584/original/file-20231219-15-d54tpf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566584/original/file-20231219-15-d54tpf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566584/original/file-20231219-15-d54tpf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566584/original/file-20231219-15-d54tpf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Vaccinating 100,000 sows against porcine reproductive and respiratory syndrome could reduce emissions by an amount comparable to that produced by 230,000 cars.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/beijing-china-december-25-2015-traffic-355127348">testing/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Controlling outbreaks</h2>
<p>More than <a href="https://www.sciencedirect.com/science/article/pii/S0305750X15002703">80% of farms</a> in low-income countries are smallholder or backyard operations. This type of farm generates more greenhouse gas emissions per unit of meat, milk and eggs than commercial farms because of lower productivity. </p>
<p>Farms in these countries are reservoirs of disease. This means the threat of a global outbreak – and the associated implications for greenhouse gas emissions – is never zero. These reservoirs occur because of a lack of disease surveillance, infrastructure, trained personnel and available medicines to detect, record and control livestock diseases.</p>
<p>Nevertheless, controlling endemic livestock diseases through vaccination reduces the risk of outbreaks across species and regional borders. By controlling <a href="https://www.woah.org/en/disease/avian-infectious-bronchitis/">avian bronchitis</a> (a highly contagious respiratory disease mainly in chickens) where it is endemic among backyard poultry, we can reduce emissions by more than 11% while also limiting the risk of an outbreak. </p>
<p>Outbreaks can undermine global trade, production and food security. <a href="https://www.nature.com/articles/s43016-020-0057-2">Economic analysis</a> of an <a href="https://www.woah.org/en/disease/african-swine-fever/">African swine fever</a> outbreak in China found that low pork supply would increase global pork prices by between 17% and 85%. The findings also suggest that unmet demand would have significant consequences for the affordability of other meats.</p>
<p>Vaccination also helps to address the threat of antimicrobial resistance, which poses a major threat to human health around the world. Research estimates that antimicrobial resistance was associated with <a href="https://linkinghub.elsevier.com/retrieve/pii/S0140673621027240">around 5 million deaths</a> globally in 2019.</p>
<figure class="align-center ">
<img alt="Free range chicken on a poultry farm." src="https://images.theconversation.com/files/566582/original/file-20231219-17-zf7ff9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566582/original/file-20231219-17-zf7ff9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566582/original/file-20231219-17-zf7ff9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566582/original/file-20231219-17-zf7ff9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566582/original/file-20231219-17-zf7ff9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566582/original/file-20231219-17-zf7ff9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566582/original/file-20231219-17-zf7ff9.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">Most farms in low-income countries are smallholder or backyard operations.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/free-range-chicken-on-traditional-poultry-527302717">goodbishop/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Moving towards sustainability</h2>
<p>Our food system is responsible for <a href="https://www.nature.com/articles/s43016-021-00225-9">one-third</a> of global greenhouse gas emissions. Improving animal health would thus make a significant contribution to meeting the IPCC’s challenge of <a href="https://www.ipcc.ch/2022/04/04/ipcc-ar6-wgiii-pressrelease/">halving emissions</a> by 2030.</p>
<p>At the same time, it would minimise the broader environmental impact of farming through <a href="https://www.fao.org/documents/card/en/c/cc0431en/">efficiency gains</a>. This is particularly crucial in low-income countries where the inability to control or treat livestock diseases has greater consequences for malnutrition, poverty and human health.</p>
<p>Sustainable food production balances three components: environmental responsibility, economic viability and social acceptability. Using vaccines to reduce livestock disease around the globe is one of the few innovations that improves all three – benefiting animals, people and the planet.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?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"></span>
</figcaption>
</figure>
<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
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<p class="fine-print"><em><span>In the past, Jude Capper has consulted to MSD Animal Health, Elanco Animal Health and Zoetis Inc; and has also consulted to the British Cattle Veterinary Association. Professor Capper's research cited within this article was funded by HealthforAnimals. She is the Treasurer for the National Beef Association in the UK.</span></em></p><p class="fine-print"><em><span>Professor Barrett is a veterinary surgeon working for Bristol Veterinary School, University of Bristol, as Professor of Bovine Medicine, Production and Reproduction. He has received funding from industry, charity and research council funding bodies throughout his career. He is also a Past-President of the British Cattle Veterinary Association and the European College of Bovine Health Management. </span></em></p>Vaccinating livestock against common disease not only improves animal welfare, it’s good for the planet too.Jude Capper, Professor of Sustainable Beef and Sheep Production, Harper Adams UniversityDavid Barrett, Professor of Bovine Medicine, Production and Reproduction, University of BristolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2166492023-11-02T14:20:44Z2023-11-02T14:20:44ZBird flu could be eradicated by editing the genes of chickens - our study shows how<p>Recent advances in gene editing technology could potentially be used to create disease-resistant animals. This could curtail the spread of avian influenza, commonly known as bird flu. </p>
<p>In a recent <a href="https://www.nature.com/articles/s41467-023-41476-3">gene editing</a> study, my colleagues and I showcased the potential of gene editing to protect chickens from the threat of bird flu. This disease is caused by an ever-evolving virus that gets around numerous <a href="https://www.daera-ni.gov.uk/articles/biosecurity#:%7E:text=Biosecurity%20is%20the%20prevention%20of,quality%20of%20a%20food%20product.">biosecurity</a> measures such as good hygiene, restricting bird movements, surveillance through appropriate testing, and selective elimination of infected birds.</p>
<p>A gene editing breakthrough would stem the huge economic losses currently suffered as a result of bird flu outbreaks. It would also be a significant step in controlling a disease that can cause serious sickness and death in humans.</p>
<h2>Why managing bird flu matters</h2>
<p>Outbreaks of bird flu around the world cost <a href="https://www.nature.com/articles/d41586-022-03322-2">billions of dollars</a> in losses. The United States Department of Agriculture reported that up to <a href="https://www.reuters.com/business/healthcare-pharmaceuticals/avian-flu-outbreak-wipes-out-5054-mln-us-birds-record-2022-11-24/">50 million birds</a> died from bird flu in 2022. Recently, the South African Poultry Association said more than <a href="https://www.thepoultrysite.com/news/2023/10/avian-influenza-forces-south-africa-to-cull-2-5-million-broilers">7 million</a> chickens were destroyed after outbreaks were detected in the first half of 2023.</p>
<p>Beyond the economic implications, bird flu outbreaks also pose a risk to <a href="https://www.who.int/news/item/12-07-%202023-ongoing-avian-influenza-outbreaks-in-animals-pose-risk-to-humans">human health</a>.</p>
<p>Prior to the COVID-19 pandemic, bird flu was considered a possible trigger for a devastating human pandemic. This prompted international surveillance led by the <a href="https://www.woah.org/en/home/">World Organisation for Animal Health</a>, the <a href="https://www.who.int/">World Health Organization</a> and the <a href="https://www.fao.org/home/en">Food and Agricultural Organisation of the United Nations</a>.</p>
<p>The fear is well-founded as the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3291411/#:%7E:text=Three%20worldwide%20(pandemic)%20outbreaks%20of,and%20Hong%20Kong%20influenza%2C%20respectively.">three flu pandemics</a> of the 20th century – including the <a href="https://www.cdc.gov/flu/avianflu/timeline/avian-timeline-1880-1959.htm">1918 flu pandemic</a> that
claimed tens of millions of lives – originated from birds.</p>
<h2>Vaccinations can only do so much</h2>
<p>Vaccination is a primary method for preventing bird flu outbreaks in chickens. </p>
<p>However, the effectiveness of vaccines is limited because the bird flu virus rapidly evolves. This makes existing vaccines less effective over time. Also, there are multiple strains of the bird flu virus but a vaccine is effective against a specific strain only. </p>
<p>It’s necessary to match a <a href="https://doi.org/10.2903/j.efsa.2023.8271">vaccine</a> with the prevailing strain causing an outbreak. Using vaccines may also involve substantial costs and practical hurdles of distribution.</p>
<h2>Gene editing to improve animal welfare</h2>
<p>In contrast to vaccinations, gene editing targets a protein or proteins within chickens that are vital for all strains of bird flu, effectively stopping the virus in its tracks.</p>
<p>Gene editing refers to the process of making a precise change in a specific gene in an animal to introduce <a href="https://genomebiology.biomedcentral.com/articles/10.1186/s13059-018-1583-1">traits</a> such as resistance to a particular disease, increased productivity and characteristics that enhance animal welfare. </p>
<p>A beneficial genetic change introduced into an animal using gene editing may already occur naturally in another animal. </p>
<p>For example, gene editing was used to make dairy cattle hornless by introducing into them a <a href="https://www.nature.com/articles/nbt.3560">genetic change</a> found in naturally hornless cattle. This is important as many dairy cattle have horns, resulting in the painful practice of <a href="https://www.sciencedirect.com/science/article/abs/pii/S1090023304000486">dehorning</a> calves to reduce the risk of injury to the animal and the farmer.</p>
<p>It’s important not to confuse gene editing with genetic modification, which entails transferring a gene from one species to another. This distinction is necessary for regulatory purposes, especially as the older genetic modification technology has faced <a href="https://www.sciencedirect.com/science/article/abs/pii/S0956713522003863?via%3Dihub">stringent regulations</a> in many countries, hampering its development.</p>
<p>To produce the gene-edited chickens in our study, we used the powerful molecular scissors known as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4975809/#:%7E:text=Go%20to%3A-,Overview%20of%20CRISPR%2FCas9,genome%20(see%20figure%201).">CRISPR/Cas9</a> to make a single gene edit. We targeted the <a href="https://www.ncbi.nlm.nih.gov/gene/8125">ANP32A</a> protein in chickens. </p>
<p>Compared to normal chickens hatched simultaneously, these gene-edited chickens reached maturity without any discernible adverse consequences on their health and wellbeing.</p>
<p>To test their resistance, we exposed the gene-edited chickens to a low dose of the bird flu virus. Remarkably, 9 out of 10 of these birds displayed complete resistance, and no transmission occurred to other chickens. </p>
<p>Taking a more ambitious step, we inoculated the gene-edited chickens
with a high, unnatural dose of the virus – 1,000 times the low dose. This time, 5 out of the 10 inoculated gene-edited chickens became infected. </p>
<p>We also found that the bird flu virus was capable of adapting to use the edited ANP32A protein, as well as two related proteins – <a href="https://www.ncbi.nlm.nih.gov/gene/10541">ANP32B</a> and <a href="https://www.ncbi.nlm.nih.gov/gene/81611">ANP32E</a>. But we demonstrated through experiments in cells that simultaneously editing all three proteins could completely suppress the virus. </p>
<h2>What’s next?</h2>
<p>Ongoing research aims to identify the specific combination of gene edits needed to create the next generation of gene-edited chickens, providing complete and permanent protection against bird flu.</p>
<p>Gene editing should be regarded as an essential tool for preventing and controlling deadly animal diseases. </p>
<p><a href="https://www.nature.com/articles/s41538-019-0035-y">Supportive government regulations</a> will be required to promote the development of gene editing aimed at enhancing animal health and welfare. </p>
<p>The potential for disease resistant animals to protect global food security and public health is a compelling reason to pursue this innovative path in biotechnology.</p><img src="https://counter.theconversation.com/content/216649/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alewo Idoko-Akoh was supported in the highlighted study by funding from the UK Research & Innovation's BBSRC </span></em></p>The three flu pandemics of the 20th century originated from birds, making it critical to fight bird flu. Breakthroughs in gene-editing chickens show promise for eliminating the disease in the future.Alewo Idoko-Akoh, Research associate, University of BristolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2156672023-10-19T11:57:12Z2023-10-19T11:57:12ZBird flu in South Africa: expert explains what’s behind the chicken crisis and what must be done about it<p><em>An outbreak of <a href="https://www.woah.org/en/disease/avian-influenza/">avian flu</a> – a highly contagious viral infection that affects wild birds as well as poultry – <a href="https://www.nicd.ac.za/avian-influenza-outbreak/">has hit poultry farms in South Africa</a>. Two different strains are causing outbreaks in the country – A(H5N1) and influenza A(H7N6). A specialist in poultry health, Shahn Bisschop, answers some questions put to him by The Conversation Africa.</em></p>
<h2>What strain has broken out in South Africa?</h2>
<p>The outbreak caused by a highly pathogenic (HPAI) strain of H7N6 avian influenza is causing the most concern at present. The strain was <a href="https://www.news24.com/fin24/companies/bird-flu-super-infectious-sa-strain-emerges-in-mpumalanga-20230627">first confirmed in chickens</a> near Delmas north of Johannesburg at the beginning of June 2023.</p>
<p>This virus is a novel mutation of a strain which originated from wild birds at or near the location of the original outbreak. </p>
<p>The strain is well-adapted to chickens – it infects them easily and replicates effectively in them, in preference to other avian species – and spreads very easily between birds and farms. An <a href="https://sapa.jshiny.com/jdata/sapa/outbreaklanding/">estimated</a> 10 million have become infected while 6 million died from the H7N6. A further 1.7 million died from H5N1 earlier in the year.</p>
<p>The conventional control measures (collectively known as biosecurity) have been less effective than usual in limiting the spread of the disease. The main measures taken on poultry farms include strictly limiting human and vehicle movement. People entering farms will typically take further measures to limit disease transmission such as showering, changing clothes and disinfecting footwear when moving between different parts of the farm. </p>
<p>Because wild birds are associated with the spread of avian flu, measures are taken to ensure they are completely excluded from all chicken sheds. </p>
<h2>What’s new this time?</h2>
<p>For at least the past nine years, HPAI H5 viruses of the 2.3.4.4 clade <a href="https://www.nature.com/articles/s41421-023-00571-x">have been spread across the globe</a> principally by wild bird migrations and infect a range of avian and mammalian species. The first recorded cases caused by viruses belonging to this clade were reported in South Africa in 2017. A second outbreak occurred in 2020. It was anticipated that the next outbreak would probably also be caused by these viruses and indeed the first reported cases of HPAI in 2023 in the coastal regions were associated with H5 strains.</p>
<p>Local experts are working on the theory that the present outbreak of H7N6 HPAI <a href="https://www.cdc.gov/flu/avianflu/avian-in-birds.htm">was created</a> when a low pathogenicity AI (LPAI) virus circulating without causing disease in wild birds underwent a mutation to become an HPAI strain adapted to causing serious disease in chickens. This mutation occurred locally. </p>
<p>Mutation from LPAI to HPAI has been described in poultry in various parts of the world but was considered less likely than the return of the H5 clade 2.3.4.4 viruses previously encountered.</p>
<h2>What’s in place and what’s missing</h2>
<p>Avian influenza is a “controlled disease”. That means it’s placed under strict government control with the aim of eradication as quickly as possible when outbreaks are detected. All outbreaks on farms are immediately reported to the state veterinary service, which takes responsibility for the disease. </p>
<p>The protocol for HPAI control is that all affected farms are placed under strict quarantine and all surviving birds are destroyed and disposed of as quickly as possible in order to limit the further spread of the disease.</p>
<p>But there are weaknesses in the system. </p>
<p>The biggest is that the state veterinary services don’t have sufficient resources to manage the outbreaks effectively.</p>
<p>Secondly, because the state doesn’t compensate farmers for their losses, they have difficulty getting farmers to comply with orders to cull. This has meant that outbreaks have spread out of control. Infected birds have been moved off infected farms for sale – taking the disease with them.</p>
<p>Farmers in the EU and US are compensated when culling happens. This used to be the case in South Africa but no longer happens.</p>
<p>As a result, South Africa has struggled to contain HPAI outbreaks. In<a href="https://www.nicd.ac.za/wp-content/uploads/2017/06/NICD-Avian-influenza-FAQ_final1-1.pdf"> 2017</a> and <a href="https://rr-africa.woah.org/en/immediate-notifications-in-africa/">2020/21</a> the outbreaks gradually slowed and eventually stopped. </p>
<p>HPAI outbreaks tend to be seasonal. In Europe, they occur principally in winter months. In South Africa, there is a similar but less clear trend to more cases in the winter and fewer in summer. This may be related to reduced viral survival in hotter summer weather.</p>
<h2>Are there new approaches to consider?</h2>
<p>New and innovative thinking is needed to deal with the reality on the ground in South Africa.</p>
<p>One possible solution is the introduction of appropriate vaccines. This would reduce the losses associated with outbreaks and would slow the spread of the disease between farms. Like all vaccines, they can’t prevent birds from becoming infected but they can manage the level of infection and spread. But they can’t eradicate the disease. </p>
<p>But there are limited options in terms of available vaccines. And South Africa would need to ensure that the vaccines registered for use in the country were effective against the local strain. If vaccines are poorly matched to outbreak strains, they won’t be effective.</p>
<p>All of this will take time, even with the best effort of government and industry. </p>
<h2>Does the strain pose a risk to people? What should consumers should be aware of?</h2>
<p>The South African Poultry Association <a href="http://www.poultrydiseases.co.za/750-2/">has made it clear</a> that poultry products are safe for consumption. It has been <a href="https://www.up.ac.za/research-matters/news/post_2991581-up-researchers-weigh-in-on-bird-flu-outbreak">collaborating with the University of Pretoria</a> to make sure poultry products are indeed safe. Together with leading scientists they have sequenced the current field strain of H7 avian influenza virus. In <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10302261/">a recent paper </a> scientists reported that none of the amino acid markers were present that afford the virus the ability to bind to mammalian cells.</p>
<p>This shows that infection of humans with the current virus is highly unlikely.</p><img src="https://counter.theconversation.com/content/215667/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Shahn Bisschop 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>New and innovative thinking is needed to deal with the reality on the ground in South Africa.Shahn Bisschop, Senior lecturer, specialist poultry veterinarian, University of PretoriaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2128502023-09-06T06:10:34Z2023-09-06T06:10:34ZAustralia’s least wanted – 8 alien species and diseases we must keep out of our island home<figure><img src="https://images.theconversation.com/files/546390/original/file-20230905-17-lal73z.jpg?ixlib=rb-1.1.0&rect=48%2C64%2C5343%2C3758&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Solenopsis_invicta1.jpg">Alexander Wild/Wikimedia Commons</a></span></figcaption></figure><p>This week’s landmark report on the impact of <a href="https://www.ipbes.net/ias">invasive alien species</a> revealed costs to the global economy exceeded US$423 billion (A$654 billion) a year in 2019. Costs have at least <a href="https://www.ipbes.net/IASmediarelease#:%7E:text=Approved%20on%20Saturday%20in%20Bonn,%24423%20billion%20annually%20in%202019%2C">quadrupled</a> every decade since 1970 and that trend is set to continue. </p>
<p>Prevention is better than a cure. Stopping pests and diseases arriving and establishing in Australia is not only better for the environment, it’s much <a href="https://cebra.unimelb.edu.au/__data/assets/pdf_file/0020/3535013/CEBRA_Value_Docs_KeyResultSummary_v0.6_Endorsed.pdf">cheaper</a> too. </p>
<p>The biosecurity system is our front line against invasion. Species that pose a significant <a href="https://www.igb.gov.au/sites/default/files/documents/environmental-biosecurity-risk_2.pdf">risk to agriculture</a> have historically received more attention, but we also need to defend our borders against threats to nature. </p>
<p>Here we take a closer look at some pests and diseases we need to keep out at all costs, to protect our biodiversity.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546391/original/file-20230905-15-598vx2.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A graph showing how the cost of managing an invasive alien species gets much larger once it is established." src="https://images.theconversation.com/files/546391/original/file-20230905-15-598vx2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546391/original/file-20230905-15-598vx2.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=374&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546391/original/file-20230905-15-598vx2.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=374&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546391/original/file-20230905-15-598vx2.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=374&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546391/original/file-20230905-15-598vx2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=470&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546391/original/file-20230905-15-598vx2.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=470&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546391/original/file-20230905-15-598vx2.png?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"></a>
<figcaption>
<span class="caption">The invasion curve shows the cost of managing an incursion at various stages. Prevention is much cheaper than dealing with invaders after they arrive, and early eradication is much cheaper than longer-term containment or control.</span>
<span class="attribution"><span class="source">Invasive Species Council</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-true-damage-of-invasive-alien-species-was-just-revealed-in-a-landmark-report-heres-how-we-must-act-211893">The true damage of invasive alien species was just revealed in a landmark report. Here's how we must act</a>
</strong>
</em>
</p>
<hr>
<h2>One of the biggest threats to biodiversity</h2>
<p>Alien species are those deliberately or accidentally introduced to areas where they are not native. If they cause problems, we call them invasive.</p>
<p>Invasive alien species include weeds, feral animals, exotic pests and diseases. </p>
<p>Those that have already arrived have taken a huge toll. Introduced predators were largely responsible for most of <a href="https://www.sciencedirect.com/science/article/pii/S000632071930895X">Australia’s mammal extinctions</a>. And introduced diseases have decimated <a href="https://theconversation.com/we-name-the-26-australian-frogs-at-greatest-risk-of-extinction-by-2040-and-how-to-save-them-166339">our frogs</a>.</p>
<p>Invasive species are pushing <a href="https://www.publish.csiro.au/PC/PC18024">most (82%)</a> of Australia’s 1,914 nationally listed threatened species closer to extinction. </p>
<p>Imagine if those invasive species had been kept out of Australia. Here are eight of the <a href="https://www.agriculture.gov.au/biosecurity-trade/policy/environmental/priority-list">pests and diseases</a> we really need to keep out. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/1-7-million-foxes-300-million-native-animals-killed-every-year-now-we-know-the-damage-foxes-wreak-177832">1.7 million foxes, 300 million native animals killed every year: now we know the damage foxes wreak</a>
</strong>
</em>
</p>
<hr>
<h2>1. Giant African land snail</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546378/original/file-20230905-29-vftj6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A very large brown snail on a hand" src="https://images.theconversation.com/files/546378/original/file-20230905-29-vftj6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546378/original/file-20230905-29-vftj6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546378/original/file-20230905-29-vftj6j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546378/original/file-20230905-29-vftj6j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546378/original/file-20230905-29-vftj6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546378/original/file-20230905-29-vftj6j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546378/original/file-20230905-29-vftj6j.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>
<figcaption>
<span class="caption">A giant African snail in Hong Kong, where it is invasive.</span>
<span class="attribution"><span class="source">Thomas Brown/Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p><a href="https://www.publish.csiro.au/PC/PC18024">Giant African snails</a> have a ferocious appetite. They feed on more than 500 species of plants including agricultural crops and eucalyptus trees. The shells of these giants can be 20cm long and females typically lay 1,200 eggs a year. Adult snails could sneak into shipping containers or machinery and their eggs could be transported in soil or goods. They are now present on Christmas Island. </p>
<h2>2. Avian influenza</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546379/original/file-20230905-23-cno6xu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Faces of two pelicans close up, showing their red gullets." src="https://images.theconversation.com/files/546379/original/file-20230905-23-cno6xu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546379/original/file-20230905-23-cno6xu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546379/original/file-20230905-23-cno6xu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546379/original/file-20230905-23-cno6xu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546379/original/file-20230905-23-cno6xu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546379/original/file-20230905-23-cno6xu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546379/original/file-20230905-23-cno6xu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Thousands of Dalmatian pelicans were killed by highly pathenogenic Avian influenza in Europe in 2022.</span>
<span class="attribution"><span class="source">Birger Strahl/Unsplash</span></span>
</figcaption>
</figure>
<p><a href="https://www.agriculture.gov.au/biosecurity-trade/pests-diseases-weeds/animal/avian-influenza#what-is-avian-influenza">Avian influenza</a> or bird-flu is a viral disease found in birds. Some strains can kill farmed poultry and <a href="https://wildlifehealthaustralia.com.au/Portals/0/Documents/FactSheets/Avian/Avian_Influenza_in_Wild_Birds_in_Australia.pdf">susceptible wild birds</a>. Such highly pathogenic strains are thought to have killed millions of wild birds globally in the past few years. The virus can also jump across to mammals, recently knocking off <a href="https://www.nhm.ac.uk/discover/news/2023/march/bird-flu-kills-thousands-south-american-sea-lions-outbreak-continues.html">3,500 sea lions Peru</a>.</p>
<p>Migratory birds could bring the virus here but it could also be carried in imported birds and poultry products, including contaminated eggs, feathers, poultry feed and equipment. Our biosecurity system is responsible for <a href="https://wildlifehealthaustralia.com.au/ProgramsProjects/WildBirdSurveillance.aspx">surveillance</a> and early detection, preparedness and management to protect our vulnerable wildlife. In California, preparation includes <a href="https://www.aphis.usda.gov/aphis/newsroom/stakeholder-info/SA_By_Date/SA-2023/ca-condor-hpai">vaccinating</a> endangered condors.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/migrating-birds-could-bring-lethal-avian-flu-to-australias-vulnerable-birds-204793">Migrating birds could bring lethal avian flu to Australia's vulnerable birds</a>
</strong>
</em>
</p>
<hr>
<h2>3. New tramp ants</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546383/original/file-20230905-17-non40r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close up of an ant's head" src="https://images.theconversation.com/files/546383/original/file-20230905-17-non40r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546383/original/file-20230905-17-non40r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=426&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546383/original/file-20230905-17-non40r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=426&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546383/original/file-20230905-17-non40r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=426&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546383/original/file-20230905-17-non40r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=535&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546383/original/file-20230905-17-non40r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=535&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546383/original/file-20230905-17-non40r.jpg?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">A red imported fire ant in the US.</span>
<span class="attribution"><span class="source">Alexander Wild/Wikimedia Commons</span></span>
</figcaption>
</figure>
<p>We’re already battling some species of <a href="https://www.dcceew.gov.au/environment/invasive-species/insects-and-other-invertebrates/tramp-ants#:%7E:text=Key%20threatening%20processes&text=Loss%20of%20biodiversity%20and%20ecosystem,%2C%20Solenopsis%20invicta%20(fire%20ant)">tramp ants</a>, but there’s more where that came from - there are at least 16 different species. So far six species including <a href="https://www.outbreak.gov.au/current-outbreaks/red-imported-fire-ant">red imported fire ants</a> have been detected, with efforts underway to contain or eradicate them at their incursion points. On Christmas Island, another tramp ant species (<a href="https://www.dcceew.gov.au/sites/default/files/env/resources/898583db-b929-491a-8448-73fb652bca66/files/brochure-detail-crazy-ant-control-options.pdf">yellow crazy ants</a>) formed “super colonies”, killing every animal in their path, including tens of millions of the island’s iconic red and robber crabs. Ants are easily transported to new areas in dirt, plants and cargo. Tramp ants threaten Australian ecosystems, agriculture and human health. </p>
<h2>4. Bat white nose syndrome</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546385/original/file-20230905-21-y5cwgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A small bat hanging from a cave roof with a white face" src="https://images.theconversation.com/files/546385/original/file-20230905-21-y5cwgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546385/original/file-20230905-21-y5cwgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546385/original/file-20230905-21-y5cwgk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546385/original/file-20230905-21-y5cwgk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546385/original/file-20230905-21-y5cwgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546385/original/file-20230905-21-y5cwgk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546385/original/file-20230905-21-y5cwgk.jpg?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"></a>
<figcaption>
<span class="caption">A little brown bat displaying white nose syndrome in the US.</span>
<span class="attribution"><span class="source">Moriarty Marvin/USFWS/WikimediaCommons</span></span>
</figcaption>
</figure>
<p><a href="https://www.agriculture.gov.au/biosecurity-trade/pests-diseases-weeds/animal/white-nose-syndrome#:%7E:text=Australia%20is%20free%20of%20WNS,causing%20fungus%20could%20enter%20Australia.">White nose syndrome</a> is a bat disease caused by a fungus. In less than 20 years it has killed more than five million bats across North America, causing local extinctions and reducing the beneficial services performed by bats such as eating harmful insects. The fungus could be introduced to Australian caves on the shoes, clothing and equipment of people who had previously visited caves in Europe or North America. </p>
<h2>5. Crayfish plague</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546386/original/file-20230905-23-6joum6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A small crayfish in an aquarium" src="https://images.theconversation.com/files/546386/original/file-20230905-23-6joum6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546386/original/file-20230905-23-6joum6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546386/original/file-20230905-23-6joum6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546386/original/file-20230905-23-6joum6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546386/original/file-20230905-23-6joum6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546386/original/file-20230905-23-6joum6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546386/original/file-20230905-23-6joum6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dwarf Cajun crayfish can be carriers of crayfish plague.</span>
<span class="attribution"><span class="source">Chris Lukhaup/USDA-FS/Wikimedia Commons</span></span>
</figcaption>
</figure>
<p>A highly infectious fungal disease, <a href="https://www.agriculture.gov.au/sites/default/files/sitecollectiondocuments/animal/ahl/ANZSDP-Crayfish-plague.pdf">crayfish plague</a> is the main cause of crayfish declines across Europe. It has the potential to devastate Australian freshwater crayfish populations. North American crayfish can be carriers of the disease and the illegal trade of crayfish, such as the dwarf Cajun crayfish for aquariums, also threatens to introduce the disease. </p>
<h2>6. New myrtle rust strains</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546387/original/file-20230905-25-j3j5if.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Leaves covered in a yellow powdery bloom." src="https://images.theconversation.com/files/546387/original/file-20230905-25-j3j5if.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546387/original/file-20230905-25-j3j5if.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546387/original/file-20230905-25-j3j5if.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546387/original/file-20230905-25-j3j5if.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546387/original/file-20230905-25-j3j5if.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546387/original/file-20230905-25-j3j5if.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546387/original/file-20230905-25-j3j5if.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">The plant disease myrtle rust killing native rose apple leaves in Hawaii.</span>
<span class="attribution"><span class="source">Pest Plants and Animals/Wikimedia Commons</span></span>
</figcaption>
</figure>
<p>When a strain of myrtle rust arrived in Australia in 2010, it spread quickly along the east coast, <a href="https://www.nespthreatenedspecies.edu.au/media/njzno05b/1-4-3-imminent-extinction-of-australian-myrtaceae-trees-and-shrubs-by-myrtle-rust-findings-factsheet_v5.pdf">infecting 358</a> different native plant species including eucalypts, bottle brushes and lilly pillies. It has caused major declines and local extinctions of many species. Other <a href="https://www.agriculture.gov.au/biosecurity-trade/pests-diseases-weeds/plant/myrtle-rust#:%7E:text=Myrtle%20rust%20(exotic%20strains)%20is,damaging%20to%20our%20eucalyptus%20trees.">exotic myrtle rust strains</a> occur outside Australia. These present serious threats to Australia’s natural environment and to commercial native forest plantations. Importing infected plant material is the main risk of introduction. </p>
<h2>7. Savannah cats</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546388/original/file-20230905-15-sjem6n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close up of a patterned black and tan cat with large pointy ears." src="https://images.theconversation.com/files/546388/original/file-20230905-15-sjem6n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546388/original/file-20230905-15-sjem6n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546388/original/file-20230905-15-sjem6n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546388/original/file-20230905-15-sjem6n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546388/original/file-20230905-15-sjem6n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546388/original/file-20230905-15-sjem6n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546388/original/file-20230905-15-sjem6n.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">Savannah cats are bred by crossing a domestic cat with an African serval.</span>
<span class="attribution"><span class="source">Jason Douglas/Wikimedia Commons</span></span>
</figcaption>
</figure>
<p><a href="https://www.nespthreatenedspecies.edu.au/news-and-media/media-releases/banning-savannah-cats-in-australia-was-good-science">Savannah cats</a> are two to three times the size of domestic cats. In 2008 the federal government banned the importation of savannah cats. A <a href="https://www.mdpi.com/2076-2615/9/10/795">scientific assessment</a> found pet savannah cats had the potential to establish and roam across 97% of the country if they escaped or were released. They can take down prey twice as large as feral cats, so 90% of Australia’s native land mammals would be at risk. Demand for the species from the pet trade raises the risk of smuggling or illegal trade.</p>
<h2>8. Black spined toad</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546389/original/file-20230905-24-tyy3v6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A brown toad with black markings on dried orange leaves." src="https://images.theconversation.com/files/546389/original/file-20230905-24-tyy3v6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546389/original/file-20230905-24-tyy3v6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546389/original/file-20230905-24-tyy3v6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546389/original/file-20230905-24-tyy3v6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546389/original/file-20230905-24-tyy3v6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546389/original/file-20230905-24-tyy3v6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546389/original/file-20230905-24-tyy3v6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A black spined toad in Taiwan.</span>
<span class="attribution"><span class="source">LiCheng Shih/Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The <a href="https://www.agriculture.gov.au/biosecurity-trade/import/arrival/pests/black-spined-toad">black spined toad</a> is potentially more damaging than the cane toad because it could survive across a bigger region including in the colder parts of Australia. It would prey on native frogs and other small animals, be toxic to larger animals, and probably carry exotic parasites or disease. It is a common stowaway in shipping cargo. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/97-of-australians-want-more-action-to-stop-extinctions-and-72-want-extra-spending-on-the-environment-207811">97% of Australians want more action to stop extinctions and 72% want extra spending on the environment</a>
</strong>
</em>
</p>
<hr>
<h2>Prioritising nature</h2>
<p>Australia’s biosecurity system has generally served our country well, but it is under constant and <a href="https://www.igb.gov.au/sites/default/files/documents/environmental-biosecurity-risk_2.pdf">growing strain</a>. Historically, the environment has also been the <a href="https://www.aph.gov.au/Parliamentary_Business/Committees/Senate/Environment_and_Communications/biosecurity/Report/c03">poor cousin of agriculture</a> at the biosecurity table.</p>
<p>Preparedness and responses for environmental threats remain <a href="https://www.mdpi.com/1999-4907/10/4/336">chronically underfunded</a>, especially when compared to those developed for industry.</p>
<p>A well-resourced independent body focused on the prevention and early elimination of new environmental pests and diseases would be a major step toward achieving our <a href="https://www.dcceew.gov.au/sites/default/files/documents/threatened-species-action-plan-2022-2032.pdf">global commitments</a> to end extinction.</p>
<hr>
<p>
<em>
<strong>
Read more:
<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">Hear me out – we could use the varroa mite to wipe out feral honey bees, and help Australia's environment</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/212850/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jaana Dielenberg is based at The University of Melbourne and works for the Biodiversity Council. She is a member of Invertebrates Australia and the Ecological Society of Australia. She previously worked for the now ended Threatened Species Recovery Hub of the Australian Government's National Environmental Science Program. She thanks James Trezise for his contribution to this article. </span></em></p><p class="fine-print"><em><span>Patrick O'Connor receives funding from the Australian Research Council and Australian and State Governments. He is a councilor on the Biodiversity Council and affiliated with the Nature Conservation Society of South Australia and the Australian Landcare movement. </span></em></p>Australia’s biosecurity system is on high alert for alien invaders. Here’s a hit list of eight baddies we believe pose the greatest threat to Australia’s biodiversity.Jaana Dielenberg, University Fellow, Charles Darwin UniversityPatrick O'Connor, Associate Professor, University of AdelaideLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2114922023-08-17T22:30:34Z2023-08-17T22:30:34ZThousands of migratory birds will make NZ landfall in spring – will they bring a deadly bird flu with them?<figure><img src="https://images.theconversation.com/files/543122/original/file-20230816-28-ks4mxf.jpg?ixlib=rb-1.1.0&rect=0%2C114%2C3824%2C2006&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock/Imogen Warren</span></span></figcaption></figure><p>A highly pathogenic bird flu is currently <a href="https://www.who.int/news/item/12-07-2023-ongoing-avian-influenza-outbreaks-in-animals-pose-risk-to-humans">sweeping the world</a> – and New Zealand could be better prepared for its potential arrival.</p>
<p>Over the past few years, more and more birds have come to harbour new strains of this deadly virus as it continues to evolve to infect new species. It is now causing a panzootic (a pandemic of animals) among wild aquatic birds. </p>
<p>The virus, known as highly pathogenic avian influenza virus, has likely already killed thousands of birds worldwide (the exact number is <a href="https://www.theguardian.com/environment/2023/jul/22/avian-flu-may-have-killed-millions-of-bird-as-outbreak-hits-south-america-aoe">difficult to estimate</a>). What’s more, spillovers to non-avian hosts such as mammals are becoming increasingly common. </p>
<p>While only a few human cases have been reported, <a href="https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON476">cats</a>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8544991/">foxes</a> and <a href="https://www.theguardian.com/environment/2023/mar/21/bird-flu-peru-sea-lions-suffer-death-beach-aoe-h5n1">sea lions</a> are being infected at an alarming rate.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1682696057744916480"}"></div></p>
<p>Despite intercontinental transmission of highly pathogenic bird flu variants during the past 20 years, <a href="https://www.mpi.govt.nz/biosecurity/pests-and-diseases-not-in-new-zealand/animal-diseases-not-in-nz/high-pathogenicity-avian-influenza-and-the-risk-to-nz/">no cases</a> have been reported in New Zealand – yet. Australia is also considered free of the virus, although a few years ago a strain in <a href="https://theconversation.com/nearly-half-a-million-poultry-deaths-there-are-3-avian-influenza-outbreaks-in-victoria-should-we-be-worried-145325">chickens</a> was thought to have evolved locally.</p>
<p>One reason we emphasise “yet” is because each spring, thousands of migratory birds arrive in Aotearoa New Zealand. Will they bring these deadly strains of avian influenza with them? An unwanted viral hitchhiker of this type could have devastating consequences for our biota and industries.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/bird-flu-uk-is-seeing-its-largest-ever-outbreak-which-may-prove-particularly-deadly-for-wild-birds-194694">Bird flu: UK is seeing its largest ever outbreak – which may prove particularly deadly for wild birds</a>
</strong>
</em>
</p>
<hr>
<h2>How bird flu could get to New Zealand</h2>
<p>New Zealand is conventionally assumed to be at <a href="https://www.mpi.govt.nz/biosecurity/pests-and-diseases-not-in-new-zealand/animal-diseases-not-in-nz/high-pathogenicity-avian-influenza-and-the-risk-to-nz/">low risk</a> from highly pathogenic avian influenza. We are thought to be too far away from other landmasses and not on routes that migratory waterfowl usually take. </p>
<p>Any migratory shore and seabirds that do usually make landfall in New Zealand are thought likely to <a href="https://www.mpi.govt.nz/biosecurity/pests-and-diseases-not-in-new-zealand/animal-diseases-not-in-nz/high-pathogenicity-avian-influenza-and-the-risk-to-nz/">die of the disease before reaching our shores</a>.</p>
<p>But some wild birds might experience <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1661592/">asymptomatic infections</a>, even of strains that are typically highly pathogenic. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/avian-flu-has-jumped-into-wild-seabirds-and-is-spreading-fast-185058">Avian flu has jumped into wild seabirds and is spreading fast</a>
</strong>
</em>
</p>
<hr>
<p>Also, the recent expansion of susceptible host species, including to <a href="https://www.washingtonpost.com/business/2023/06/13/h5n1-explainer-bird-flu-in-mammals-sparks-fear-of-virus-spreading-in-humans/06eaac30-0a10-11ee-8132-a84600f3bb9b_story.html">marine mammals</a>, increases the risk that some species might carry the virus here. </p>
<p>As for geography, <a href="https://www.nature.com/articles/s41598-022-13447-z">research</a> suggests wild bird migrations are responsible for transmitting the virus from Europe to the Americas across the Atlantic, as well as <a href="https://academic.oup.com/mbe/article/40/2/msad019/7005671">throughout Eurasia</a>. So why not to New Zealand? Are we really just too far away?</p>
<h2>How to prepare for an outbreak</h2>
<p>If this highly pathogenic avian influenza virus were to arrive, New Zealand is not as prepared as it could be. The major reason is that we have very little active virus surveillance of wildlife.</p>
<p>New Zealand monitors livestock, including cows, sheep and poultry, for a range of diseases. But the impact of this virus on people and non-poultry livestock is likely to be minimal. </p>
<p>The first signs might be the death of seabirds or marine mammals. While perhaps not as iconic as a kiwi or kākāpō, New Zealand is home to a great many seabirds found nowhere else on the planet. </p>
<figure class="align-center ">
<img alt="A pair of fairy terns, tara iti." src="https://images.theconversation.com/files/543126/original/file-20230817-23-7snpd3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543126/original/file-20230817-23-7snpd3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543126/original/file-20230817-23-7snpd3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543126/original/file-20230817-23-7snpd3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543126/original/file-20230817-23-7snpd3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543126/original/file-20230817-23-7snpd3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543126/original/file-20230817-23-7snpd3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Highly endangered species, such as the fairy tern or tara iti, are particularly vulnerable.</span>
<span class="attribution"><span class="source">Shutterstock/Lei Zhu NZ</span></span>
</figcaption>
</figure>
<p>Some species, such as tara iti (or fairy tern) are critically endangered, with only about 50 individuals left. A virus such as this could directly drive the extinction of species with such low numbers.</p>
<p>Given this risk, the US took action to <a href="https://www.nature.com/articles/d41586-023-01760-0">vaccinate the Californian condor</a> against avian influenza – but only after finding 21 dead condors (4% of the remaining population) which had tested positive for the H5N1 strain.</p>
<p>What should New Zealand watch for and how can we be better prepared to detect any incursions early? </p>
<ul>
<li><p><strong>Raising awareness:</strong> unexpected deaths in animals are a red flag. Usually, such events are investigated by the Ministry for Primary Industries. But we must better inform the public about <a href="https://www.mpi.govt.nz/biosecurity/how-to-find-report-and-prevent-pests-and-diseases/report-a-pest-or-disease/">what to do</a> if they spot a dead bird or sea lion. </p></li>
<li><p><strong>Testing:</strong> ramp up active and targeted surveillance of known pathogens. Wild birds have been surveyed annually since 2004 for avian influenza. However, since 2010 the focus has shifted away from migratory birds to sampling resident wildfowl in the summer months, concentrating on a small number of coastal locations visited by migratory shorebirds. This is based on the lack of positive samples from migratory bird prior to 2010, but the global situation and consequences of an incursion warrant revisiting active migratory bird surveillance across more locations.</p></li>
<li><p><strong>Genomics:</strong> use the viral genomics capabilities we have already established during the COVID-19 pandemic. In Europe, for instance, there are some circulating variants of avian influenza that seem to <a href="https://www.cidrap.umn.edu/avian-influenza-bird-flu/european-scientists-highlight-worrisome-h5n1-avian-flu-mutations">better infect mammals</a>. If the virus arrives here, viral genomics can be used effectively to let us know what form we are dealing with, and inform our response.</p></li>
</ul>
<hr>
<p>
<em>
<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>
</strong>
</em>
</p>
<hr>
<p>It is clear that to first spot and then stop a virus such as this, we need to look at the entire ecosystem – that is, where humans, animals and the environment are interconnected. This is known as the “<a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1010537">One Health</a>” approach.</p>
<p>While this makes intuitive sense, the reality is that disease surveillance affecting humans, domestic animals and wildlife is largely siloed and under-resourced. There is limited integration of activities across these domains. The result is that we are currently ill-equipped to track and respond rapidly to this deadly virus were it to arrive in New Zealand. </p>
<p>We are advocating defragmentation of our surveillance for emerging pathogens. It is time to provide a more enhanced and integrated One Health surveillance system, involving expertise across universities, research institutes and government departments to re-evaluate our pandemic (and panzootic) preparedness.</p><img src="https://counter.theconversation.com/content/211492/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jemma Geoghegan receives funding from the Royal Society Te Apārangi, the Marsden Fund and the Health Research Council of New Zealand.</span></em></p><p class="fine-print"><em><span>Nigel French receives funding from Te Niwha, the New Zealand Ministry for Primary Industries and the New Zealand Ministry for Business, Innovation and Employment. He is Emeritus Director of the New Zealand Food Safety Science and Research Centre.</span></em></p>The first sign of a new bird flu might be a dead seabird or marine mammal. Better surveillance of migratory birds and wildlife – and better public awareness – is crucial.Jemma Geoghegan, Professor and Webster Family Chair in Viral Pathogenesis, University of OtagoNigel French, Distinguished Professor of Infectious Disease Epidemiology and Public Health, Massey UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2052822023-05-14T11:19:08Z2023-05-14T11:19:08ZLearning from COVID-19: The global health emergency has ended. Here’s what is needed to prepare for the next one<figure><img src="https://images.theconversation.com/files/525793/original/file-20230512-21-xs50y1.jpg?ixlib=rb-1.1.0&rect=998%2C22%2C5682%2C3507&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The World Health Organization has declared an end to COVID-19's status as a public health emergency of international concern.</span> <span class="attribution"><span class="source">(Shutterstock)</span></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/learning-from-covid-19--the-global-health-emergency-has-ended--here-s-what-is-needed-to-prepare-for-the-next-one" width="100%" height="400"></iframe>
<p>When the World Health Organization formally <a href="https://doi.org/10.1038/d41586-023-01559-z">declared an end</a> to the COVID-19 pandemic’s designation as a Public Health Emergency of International Concern (PHEIC), it may seem to have had<a href="https://theconversation.com/covid-is-officially-no-longer-a-global-health-emergency-heres-what-that-means-and-what-weve-learned-along-the-way-205080">little, if any, perceivable impact</a> on the daily lives of most people. </p>
<p>However, it would be a mistake to assume that this is a mere formality.</p>
<p>A PHEIC, like the one <a href="https://www.who.int/news/item/30-01-2020-statement-on-the-second-meeting-of-the-international-health-regulations-(2005)-emergency-committee-regarding-the-outbreak-of-novel-coronavirus-(2019-ncov)">adopted for COVID-19 on Jan. 30, 2020</a>, is declared if a public health event is <a href="https://www.who.int/news/item/05-05-2023-statement-on-the-fifteenth-meeting-of-the-international-health-regulations-(2005)-emergency-committee-regarding-the-coronavirus-disease-(covid-19)-pandemic">determined to constitute</a>:</p>
<ol>
<li>an extraordinary event; </li>
<li>a public health risk to other states through the international spread, and </li>
<li>potentially requiring a co-ordinated international response. </li>
</ol>
<p>Under the <a href="https://www.who.int/health-topics/international-health-regulations#tab=tab_1">International Health Regulations (IHR)</a> — a legally-binding agreement which commits governments to certain actions when responding to the international spread of disease — the declaration of a PHEIC permits the WHO to issue temporary recommendations to national governments to support a co-ordinated and effective global response to such events. </p>
<figure class="align-center ">
<img alt="A man with a moustache adjusts his glasses in front of a World Health Organization logo on a blue wall." src="https://images.theconversation.com/files/525821/original/file-20230512-23-qjsrry.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/525821/original/file-20230512-23-qjsrry.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/525821/original/file-20230512-23-qjsrry.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/525821/original/file-20230512-23-qjsrry.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/525821/original/file-20230512-23-qjsrry.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/525821/original/file-20230512-23-qjsrry.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/525821/original/file-20230512-23-qjsrry.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">Tedros Adhanom Ghebreyesus, director-general of the World Health Organization, talks to the media at WHO headquarters in Geneva on Jan. 30, 2020, the day COVID-19 was declared a public health emergency or international concern.</span>
<span class="attribution"><span class="source">(Jean-Christophe Bott/Keystone via AP)</span></span>
</figcaption>
</figure>
<p>A PHEIC means the WHO is <a href="https://theindependentpanel.org/wp-content/uploads/2021/05/COVID-19-Make-it-the-Last-Pandemic_final.pdf">sounding the loudest possible alarm</a> to national governments to act together with urgency. A total of seven <a href="https://doi.org/10.1093%2Fjtm%2Ftaaa227">PHEICS have been declared</a> since the IHR took effect in 2007: H1N1, Ebola, Polio, a second Ebola outbreak, Zika, COVID-19 <a href="https://www.who.int/europe/news/item/23-07-2022-who-director-general-declares-the-ongoing-monkeypox-outbreak-a-public-health-event-of-international-concern">and Mpox</a>. </p>
<p>However, the heightened state of emergency under a PHEIC is not meant to be sustained indefinitely. The recommendations are temporary and require review every three months.</p>
<h2>Significance of the end of the COVID-19 PHEIC</h2>
<p>The lifting of PHEIC status for COVID-19 is significant for two reasons. </p>
<p>First, ending the emergency stands down the WHO’s formal authority to guide national COVID-19 policies. While the acute phase of the pandemic appears to have passed, this must still be balanced with continued response efforts aligned with the <a href="https://doi.org/10.1126/science.adi5890">ongoing risk posed by the ever-evolving SARS-CoV-2</a>. </p>
<p>Moreover, the phrase “<a href="https://www.gavi.org/vaccineswork/no-one-safe-until-everyone-safe?gclid=Cj0KCQjwpPKiBhDvARIsACn-gzBnSxNtyGxTap5iEuFfiao9E2LqUxZvbVZbDeVhaPTcwixcTQEMJDkaAimnEALw_wcB">no one is safe until everyone is safe</a>” may have become a familiar tagline during the pandemic. Yet, many people, mostly in low- and middle-income countries, still <a href="https://data.undp.org/vaccine-equity/">struggle to access</a> COVID-19 vaccines, diagnostics and treatments. Others, such as the immuno-compromised, remain subject to severe health outcomes. </p>
<p>With the impact of COVID-19 continuing to disproportionately affect vulnerable populations worldwide, the pandemic remains far from over.</p>
<p>Second, the standing down of the PHEIC declaration is accompanied by an understandable desire — and necessity — to “move on” from COVID-19 after three difficult years. Many high-income countries have been steadily returning to <a href="https://www.nytimes.com/2023/05/05/health/covid-who-emergency-end.html">pre-COVID-19 life</a>. </p>
<figure class="align-center ">
<img alt="A row of five coronaviruses in different shades, changing from red to purple" src="https://images.theconversation.com/files/525824/original/file-20230512-17-p1d3hs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/525824/original/file-20230512-17-p1d3hs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=217&fit=crop&dpr=1 600w, https://images.theconversation.com/files/525824/original/file-20230512-17-p1d3hs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=217&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/525824/original/file-20230512-17-p1d3hs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=217&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/525824/original/file-20230512-17-p1d3hs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=272&fit=crop&dpr=1 754w, https://images.theconversation.com/files/525824/original/file-20230512-17-p1d3hs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=272&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/525824/original/file-20230512-17-p1d3hs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=272&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">While the acute phase of the pandemic appears to have passed, this must still be balanced with continued response efforts aligned with the ongoing risk posed by the ever-evolving SARS-CoV-2 virus.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>However, the critical and challenging process of learning lessons from the pandemic — let alone addressing the shortcomings in the global response to COVID-19 — has just begun. Governments must ensure that “moving on” does not mean losing the opportunity to capture critical insights that will determine the effectiveness of future pandemic preparedness and response.</p>
<p>Perhaps the biggest lessons has been the failure of countries to co-ordinate on many aspects of the global COVID-19 response, such as access to vaccines and <a href="https://doi.org/10.1136/bmjgh-2020-004537">use of travel measures</a>. The lack of real-world authority by the WHO to enforce the legally binding IHR has become abundantly clear. </p>
<h2>Global co-ordination fell short</h2>
<p>The <a href="https://theindependentpanel.org/">Independent Panel for Pandemic Preparedness and Response</a>, convened by the WHO to review the global response to the pandemic, characterized February 2020 as a “<a href="https://theindependentpanel.org/wp-content/uploads/2021/05/COVID-19-Make-it-the-Last-Pandemic_final.pdf">lost month</a>” due to the overwhelming inaction of many countries after the PHEIC was declared. </p>
<p>Governments eventually began to take emergency action but only after the WHO made the strategic decision in March 2020 to <a href="https://www.who.int/director-general/speeches/detail/who-director-general-s-opening-remarks-at-the-media-briefing-on-covid-19---11-march-2020">declare COVID-19 a pandemic</a>. Still, what ensued fell far short of a co-ordinated global effort.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/covid-19-vaccine-inequity-allowed-omicron-to-emerge-173361">COVID-19 vaccine inequity allowed Omicron to emerge</a>
</strong>
</em>
</p>
<hr>
<p>The need for collective action during global public health emergencies like COVID-19 has only been reinforced by the past three years. Our research on the <a href="https://www.pandemics-borders.org/">use of travel measures in response to COVID-19</a> has identified key policy areas where improving effectiveness depends on how willing countries are to act in a co-ordinated way. </p>
<p>For example, the chaos caused by varied and changing use of travel measures was due in part to the lack of an agreed risk-based approach. Among those that applied risk analysis, <a href="https://www.migrationpolicy.org/research/risk-analysis-border-covid19">how risk was defined and approached varied substantially</a>.</p>
<p>Additionally, travel measures implemented in <a href="https://www.theglobeandmail.com/opinion/article-by-reducing-air-travel-within-canada-covid-19-has-opened-another/">response to COVID-19</a>, and in <a href="https://doi.org/10.1016/S0140-6736(15)00946-0">previous PHEICs</a>, fell inequitably upon different population groups. <a href="https://www.pandemics-borders.org/projects/equity-canada-us-border-measures">Further research</a> is needed to understand and mitigate unfair impacts. Once again, better risk-based public health responses with more equitable outcomes will require countries to renew their commitment to work together.</p>
<p>If future co-ordination efforts are to be successful, governments must begin by understanding and addressing the shortcomings of existing legal frameworks, including the PHEIC and IHR.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-whos-international-pandemic-treaty-meaningful-public-engagement-must-inform-canadas-negotiations-203747">The WHO’s international pandemic treaty: Meaningful public engagement must inform Canada's negotiations</a>
</strong>
</em>
</p>
<hr>
<p>Towards this end, WHO member states have begun simultaneous negotiation of <a href="https://www.who.int/news/item/21-04-2023-governments-hold-third-round-discussions-on-proposed-amendments-to-the-international-health-regulations-(2005)">IHR amendments</a>, alongside a <a href="https://www.who.int/news/item/03-03-2023-countries-begin-negotiations-on-global-agreement-to-protect-world-from-future-pandemic-emergencies">new pandemic legal instrument</a>. </p>
<p>Previous outbreaks of concern, <a href="https://www.canada.ca/en/public-health/services/reports-publications/learning-sars-renewal-public-health-canada.html">notably SARS-CoV-1</a> and <a href="https://www.phac-aspc.gc.ca/about_apropos/evaluation/reports-rapports/2010-2011/h1n1/pdf/h1n1-eng.pdf">H1N1</a>, initially prompted new attention and investments in pandemic preparedness. However, these efforts were not sufficiently sustained. Whether and to what extent current efforts will compel countries to act in the collective interest is the crux of the issue.</p>
<p>Meanwhile, a new pandemic may already be on the horizon as the global and interspecies spread of <a href="https://doi.org/10.1038/d41586-023-00201-2">highly pathogenic avian influenza</a> is raising growing alarm. The adoption and now lifting of the PHEIC declaration during the COVID-19 pandemic, and actions taken by governments in between, offer clear lessons if the world is willing to learn them.</p><img src="https://counter.theconversation.com/content/205282/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julianne Piper is funded by the Pacific Institute on Pathogens, Pandemics and Society which receives funding from the BC Ministry of Health</span></em></p><p class="fine-print"><em><span>Kelley Lee receives funding from the Canadian Institutes of Health Research, New Frontiers for Research Fund, and Social Sciences and Humanities Research Council of Canada. The Pacific Institute on Pathogens, Pandemics and Society (PIPPS) receives funding from the BC Ministry of Health.</span></em></p>After previous public health emergencies likes SARS and H1N1, there was renewed investment in pandemic preparedness, but it was not sustained. We cannot make the same mistake after COVID-19.Julianne Piper, Research Fellow, Health Sciences, Simon Fraser UniversityKelley Lee, Professor and Canada Research Chair in Global Health Governance; Scientific Director, Pacific Institute on Pathogens, Pandemics and Society, Simon Fraser UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2020842023-05-08T12:18:30Z2023-05-08T12:18:30ZGain-of-function research is more than just tweaking risky viruses – it’s a routine and essential tool in all biology research<figure><img src="https://images.theconversation.com/files/523909/original/file-20230502-4095-u8oni1.jpg?ixlib=rb-1.1.0&rect=0%2C94%2C1500%2C1221&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Gain-of-function experiments in the lab can help researchers get ahead of viruses naturally gaining the ability to infect people in the wild.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/molecule-illustration-royalty-free-illustration/1423893041">KTSDesign/Science Photo Library via Getty Images</a></span></figcaption></figure><p>The term “gain of function” is often taken to refer to research with viruses that puts society at risk of an infectious disease outbreak for questionable gain. Some research on emerging viruses can result in variants that gain the ability to infect people but this does not necessarily mean the research is dangerous or that it is not fruitful. Concerns have focused on lab research on the <a href="https://www.theguardian.com/world/2012/mar/28/bird-flu-mutant-strains">virus that causes bird flu</a> in 2012 and on the <a href="https://theconversation.com/why-gain-of-function-research-matters-162493">virus that causes COVID-19</a> since 2020. The National Institutes of Health had previously implemented a <a href="https://www.science.org/content/article/nih-lifts-3-year-ban-funding-risky-virus-studies">three-year moratorium</a> on gain-of-function research on certain viruses, and some U.S. legislatures have <a href="https://www.washingtonexaminer.com/news/senate/texas-state-ban-gain-function-research-covid-pandemic">proposed bills prohibiting</a> gain-of-function research on “potentially pandemic pathogens.”</p>
<p>The possibility that a genetically modified virus could escape the lab needs to be taken seriously. But it does not mean that gain-of-function experiments are inherently risky or the purview of mad scientists. In fact, gain-of-function approaches are a fundamental tool in biology used to study much more than just viruses, contributing to many, if not most, modern discoveries in the field, including <a href="https://doi.org/10.3201%2Feid2305.161556">penicillin</a>, <a href="https://theconversation.com/anti-cancer-car-t-therapy-reengineers-t-cells-to-kill-tumors-and-researchers-are-expanding-the-limited-types-of-cancer-it-can-target-196471">cancer immunotherapies</a> and <a href="https://www.sciencedaily.com/releases/2015/02/150204134119.htm">drought-resistant crops</a>.</p>
<p>As <a href="https://scholar.google.com/citations?user=IXDoiY4AAAAJ&hl=en">scientists who</a> <a href="https://scholar.google.com/citations?user=GBQiazwAAAAJ&hl=en">study viruses</a>, we believe that misunderstanding the term “gain of function” as something nefarious comes at the cost of progress in human health, ecological sustainability and technological advancement. Clarifying what gain-of-function research really is can help clarify why it is an essential scientific tool.</p>
<h2>What is gain of function?</h2>
<p>To study how a living thing operates, scientists can change a specific part of it and then observe the effects. These changes sometimes result in the organism’s gaining a function it didn’t have before or losing a function it once had. </p>
<p>For example, if the goal is to enhance the tumor-killing ability of immune cells, researchers can take a sample of a person’s immune cells and modify them to express a protein that specifically targets cancer cells. This mutated immune cell, called a <a href="https://theconversation.com/anti-cancer-car-t-therapy-reengineers-t-cells-to-kill-tumors-and-researchers-are-expanding-the-limited-types-of-cancer-it-can-target-196471">CAR-T cell</a> thereby “gains the function” of being able to bind to cancerous cells and kill them. The advance of similar immunotherapies that help the immune system attack cancer cells is based on the exploratory research of scientists who synthesized such “<a href="https://doi.org/10.1007/BF00820662">Frankenstein” proteins</a> in the 1980s. At that time, there was no way to know how useful these chimeric proteins would be to cancer treatment today, some 40 years later. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/mXADrg_ckhI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">CAR-T cell therapy involves giving a patient’s immune cells an increased ability to target cancer cells.</span></figcaption>
</figure>
<p>Similarly, by adding specific genes into rice, corn or wheat plants that increase their production in diverse climates, scientists have been able to produce plants that are able to grow and thrive in geographical regions they previously could not. This is a critical advance to maintain food supplies in the face of climate change. Well-known examples of food sources that have their origins in gain-of-function research <a href="https://www.sciencenews.org/article/rice-agriculture-feeds-world-climate-change-drought-flood-risk">include rice plants</a> that can grow in high flood plains or in drought conditions or that contain vitamin A to reduce malnutrition.</p>
<h2>Medical advances from gain-of-function research</h2>
<p>Gain-of-function experiments are ingrained in the scientific process. In many instances, the benefits that stem from gain-of-function experiments are not immediately clear. Only decades later does the research bring a new treatment to the clinic or a new technology within reach. </p>
<p>The development of most antibiotics have relied on the <a href="https://doi.org/10.3389/fcimb.2021.684515">manipulation of bacteria or mold</a> in gain-of-function experiments. Alexander Fleming’s initial discovery that the mold <em>Penicillium rubens</em> could produce a compound toxic to bacteria was a profound medical advance. But it wasn’t until scientists experimented with <a href="https://www.sciencemuseum.org.uk/objects-and-stories/how-was-penicillin-developed">growth conditions and mold strains</a> that therapeutic use of penicillin became feasible. Using a specific growth medium allowed the mold to gain the function of increased penicillin production, which was essential for its mass production and widespread use as a drug. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/523678/original/file-20230501-1518-hmu9o0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Worker monitoring penicillin capsules coming down production line" src="https://images.theconversation.com/files/523678/original/file-20230501-1518-hmu9o0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523678/original/file-20230501-1518-hmu9o0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=759&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523678/original/file-20230501-1518-hmu9o0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=759&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523678/original/file-20230501-1518-hmu9o0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=759&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523678/original/file-20230501-1518-hmu9o0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=954&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523678/original/file-20230501-1518-hmu9o0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=954&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523678/original/file-20230501-1518-hmu9o0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=954&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Gain-of-function research played a key role in the development and mass production of penicillin.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/penicillin-capsules-being-checked-as-they-come-off-the-news-photo/2667016">Wesley/Stringer/Hulton Archive via Getty Images</a></span>
</figcaption>
</figure>
<p>Research on <a href="https://doi.org/10.1128%2FAAC.02381-18">antibiotic resistance</a> also relies heavily on gain-of-function approaches. Studying how bacteria <a href="https://theconversation.com/looming-behind-antibiotic-resistance-is-another-bacterial-threat-antibiotic-tolerance-200226">gain resistance</a> against drugs is essential to developing new treatments microbes are unable to evade quickly.</p>
<p>Gain-of-function research in virology has also been critical to the advancement of science and health. <a href="https://www.cancer.gov/news-events/cancer-currents-blog/2018/oncolytic-viruses-to-treat-cancer">Oncolytic viruses</a> are genetically modified in the laboratory to infect and kill cancerous cells like melanoma. Similarly, the <a href="https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/overview-COVID-19-vaccines.html">Johnson & Johnson COVID-19 vaccine</a> contains an adenovirus altered to produce the spike protein that helps the COVID-19 virus infect cells. Scientists developed <a href="https://onlinelibrary.wiley.com/doi/10.1002/(SICI)1099-1654(199910/12)9:4%3C237::AID-RMV252%3E3.0.CO;2-G">live attenuated flu vaccines</a> by adapting them to grow at low temperatures and thereby lose the ability to grow at human lung temperatures. </p>
<p>By giving viruses new functions, scientists were able to develop new tools to treat and prevent disease.</p>
<h2>Nature’s gain-of-function experiments</h2>
<p>Gain-of-function approaches are needed to advance understanding of viruses in part because these processes already occur in nature.</p>
<p>Many viruses that infect such nonhuman animals as bats, pigs, birds and mice have the potential to <a href="https://theconversation.com/what-is-spillover-bird-flu-outbreak-underscores-need-for-early-detection-to-prevent-the-next-big-pandemic-200494">spill over into people</a>. Every time a virus copies its genome, it makes mistakes. Most of these mutations are detrimental – they reduce a virus’s ability to replicate – but some may allow a virus to replicate faster or better in human cells. Variant viruses with these rare, beneficial mutations will spread better than other variants and therefore come to dominate the viral population – that is <a href="https://www.amnh.org/exhibitions/darwin/evolution-today/natural-selection-vista">how natural selection works</a>.</p>
<p>If these viruses can replicate even a little bit within people, they have the potential to adapt and thereby thrive in their new human hosts. That is nature’s gain-of-function experiment, and <a href="https://doi.org/10.1093/ve/veaa016">it is</a> <a href="https://doi.org/10.1016/j.chom.2020.08.011">happening constantly</a>.</p>
<p>Gain-of-function experiments in the lab can help scientists <a href="https://doi.org/10.1126%2Fscience.1222526">anticipate the changes</a> viruses may undergo in nature by understanding what specific features allow them to transmit between people and infect them. In contrast to nature’s experiments, these are conducted in <a href="https://www.cdc.gov/labs/BMBL.html">highly controlled lab conditions</a> designed to limit infection risk to laboratory personnel and others, including air flow control, personal protective equipment and waste sterilization.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/523674/original/file-20230501-20-lxf4la.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="People in protective clothing collecting dead pelicans on a beach" src="https://images.theconversation.com/files/523674/original/file-20230501-20-lxf4la.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523674/original/file-20230501-20-lxf4la.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523674/original/file-20230501-20-lxf4la.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523674/original/file-20230501-20-lxf4la.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523674/original/file-20230501-20-lxf4la.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523674/original/file-20230501-20-lxf4la.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523674/original/file-20230501-20-lxf4la.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">Researchers and public health officials are concerned that the bird flu virus is evolving to more readily infect people.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/BirdFluMutations/6895d38a33de468c93c14da427b4dfff">Guadalupe Pardo/AP Photo</a></span>
</figcaption>
</figure>
<p>It is important that researchers carefully observe lab safety to minimize the theoretical risk of infecting the general population. It is equally important that virologists continue to apply the tools of modern science to gauge the risk of natural viral spillovers before they become outbreaks. </p>
<p>A <a href="https://theconversation.com/as-bird-flu-continues-to-spread-in-the-us-and-worldwide-whats-the-risk-that-it-could-start-a-human-pandemic-4-questions-answered-200204">bird flu outbreak</a> is currently raging across multiple continents. While the H5N1 virus is primarily infecting birds, some people have gotten sick too. More spillover events can change the virus in ways that would allow it to <a href="https://doi.org/10.1126/science.adi1013">transmit more efficiently among people</a>, potentially leading to a pandemic. </p>
<p>Scientists have a better appreciation of the tangible risk of bird flu spillover because of <a href="https://doi.org/10.1126/science.1213362">gain-of-function experiments</a> <a href="https://doi.org/10.1038/nature10831">published a decade ago</a>. Those lab studies showed that bird flu viruses could be transmitted through the air between ferrets within a few feet of one another. They also revealed multiple features of the evolutionary path the H5N1 virus would need to take before it becomes transmissible in mammals, informing what signatures researchers need to look out for during surveillance of the current outbreak.</p>
<h2>Oversight on gain of function</h2>
<p>Perhaps this sounds like a semantic argument, and in many respects it is. <a href="https://www.statnews.com/2021/12/23/gain-of-function-research-advances-knowledge-and-saves-lives/">Many researchers</a> would likely agree that gain of function as a general tool is an important way to study biology that should not be restricted, while also arguing that it should be curtailed for research on specific dangerous pathogens. The problem with this argument is that pathogen research needs to include gain-of-function approaches in order to be effective – just as in any area of biology.</p>
<p><a href="https://doi.org/10.1128/jvi.00089-23">Oversight of gain-of-function research</a> on potential pandemic pathogens already exists. Multiple layers of safety measures at the institutional and national levels minimize the risks of virus research.</p>
<p>While updates to current oversight are not unreasonable, we believe that <a href="https://www.nih.gov/about-nih/who-we-are/nih-director/statements/statement-report-national-science-advisory-board-biosecurity">blanket bans or additional restrictions</a> on gain-of-function research do not make society safer. They may instead slow research in areas ranging from cancer therapies to agriculture. Clarifying which specific research areas are of concern regarding gain-of-function approaches can help identify how the current oversight framework can be improved.</p><img src="https://counter.theconversation.com/content/202084/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Seema Lakdawala receives funding from National Institutes of Health and the Flu Lab. </span></em></p><p class="fine-print"><em><span>Anice Lowen receives research funding from the National Institutes of Health and Flu Lab. </span></em></p>From cancer immunotherapy and antibiotics to GMO crops and pandemic surveillance, gain of function is a cornerstone of basic research.Seema Lakdawala, Associate Professor of Microbiology and Immunology at Emory University and Adjunct Professor Microbiology and Molecular Genetics, University of PittsburghAnice Lowen, Associate Professor of Microbiology and Immunology, Emory UniversityLicensed 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>
<figure class="align-center zoomable">
<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>
<figcaption>
<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>
<hr>
<p>
<em>
<strong>
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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</p>
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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>
<hr>
<p>
<em>
<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>
</strong>
</em>
</p>
<hr>
<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/2033612023-04-20T14:29:55Z2023-04-20T14:29:55ZUK poultry can roam free outside again – but bird flu risk hasn’t gone away<figure><img src="https://images.theconversation.com/files/521675/original/file-20230418-24-gwlihx.jpg?ixlib=rb-1.1.0&rect=35%2C0%2C4000%2C2664&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/indoors-chicken-farm-feeding-1042657945">David Tadevosian/Shutterstock</a></span></figcaption></figure><p>The <a href="https://www.gov.uk/government/news/bird-keepers-must-maintain-scrupulous-biosecurity-standards-as-housing-measures-set-to-be-lifted">UK government</a> recently announced that as of April 18, poultry and captive birds <a href="https://www.bbc.co.uk/news/science-environment-65244151">can be kept outside</a> again as the threat from bird flu eases. These mandatory housing measures were introduced across England and Wales <a href="https://www.gov.uk/government/news/avian-influenza-housing-order-to-be-introduced-across-england">in the autumn of 2022</a> following the unprecedented spread of bird flu in the UK and Europe.</p>
<p>Indeed, the past two winters in the UK have seen our largest and most prolonged outbreak of <a href="https://www.gov.uk/government/publications/avian-influenza-influenza-a-h5n1-technical-briefings/investigation-into-the-risk-to-human-health-of-avian-influenza-influenza-a-h5n1-in-england-technical-briefing-3">bird flu</a> in modern times, leading to substantial controls in poultry production, the mass death of seabirds, cases in wild mammals and a single human case. </p>
<p>So how did we get here, and has the threat in the UK really receded? Let’s take a look.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/bird-flu-domestic-chicken-keepers-could-be-putting-themselves-and-others-at-risk-175187">Bird flu: domestic chicken keepers could be putting themselves – and others – at risk</a>
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</em>
</p>
<hr>
<p>Avian influenza, commonly known as <a href="https://www.nhs.uk/conditions/bird-flu/">bird flu</a>, is caused by the influenza A virus which can lead to disease in many hosts including humans. However, its ability to infect and transmit to different hosts depends on which subtype or serotype of influenza A is involved.</p>
<p>Influenza A serotypes are designated based on <a href="https://www.cdc.gov/flu/about/viruses/types.htm">two proteins</a> found on the virus’s surface called neuraminidase (N) and haemagglutinin (H), each of which come in several different types. The combination of H and N types (for example, H5N1, H1N1 or H3N2) defines the serotype. Within the serotype there can also be a number of variants called clades. </p>
<p>The current outbreak in the UK and elsewhere is caused by a <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">2.3.4.4b clade</a> of the H5N1 serotype. Typically, horse strains of influenza A are H3N8 and H7N7, pigs and humans are susceptible to H1N1 and H3N2, and avian influenza encompasses H5 and H7 serotypes. </p>
<p>In general, human influenza viruses have little capacity to infect animal species and vice versa, but sporadic infections can sometimes occur between species. </p>
<h2>How did the current outbreak spread?</h2>
<p>The origins of all influenza A serotypes are thought to be in aquatic birds such as ducks, geese, gulls and wading birds. The <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">2.3.4.4b clade</a> of the H5N1 serotype, for example, is descended from the goose/Guangdong lineage, first isolated in a goose in Guangdong, China.</p>
<p>This clade emerged around 2021 and has caused <a href="https://theconversation.com/when-should-we-worry-about-bird-flu-making-us-sick-when-we-see-human-to-human-transmission-and-theres-no-evidence-of-that-yet-200710">several outbreaks globally</a>, including in Europe, Asia, and the Americas, most likely spread by migratory birds. As many geese and duck species can carry the virus and shed it in their droppings without becoming ill they can easily transmit virus to other bird species.</p>
<p>Normally in the UK we see a number of localised bird flu outbreaks each winter, but the levels of the current virus – identified in more than 300 UK <a href="https://www.gov.uk/government/publications/avian-influenza-influenza-a-h5n1-technical-briefings">poultry farms</a> in the past two years – is unprecedented in modern times. </p>
<p>And while avian flu has traditionally been a problem primarily for chickens and other domestic birds, this outbreak has been unusual in its capacity to cause disease and death in <a href="https://theconversation.com/avian-flu-has-jumped-into-wild-seabirds-and-is-spreading-fast-185058">wild birds</a> too. This strain has been found to cause disease in <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">over 60 wild bird species</a> in the UK, including many not previously known to be affected. </p>
<p>The reasons for this are not clear but could include changes to migratory flyways (the routes birds use for migration) and increased susceptibility due to climate change or pollution affecting the general health and immune systems of seabirds.</p>
<p>This outbreak has unquestionably been deadly. Across 37 countries affected, more than <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">50 million birds</a> have been culled. </p>
<h2>Beyond birds</h2>
<p>Mammals can become infected with bird flu as a result eating infected birds – through predation or scavenging – or from coming into contact with bird faeces. In the UK most <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">mammalian cases</a> are in species likely to have consumed infected birds including foxes, otters and weasels.</p>
<p>The UK Health Security Agency has a zero to six level of threat for pandemic avian influenza. The alert level has remained at <a href="https://www.gov.uk/government/publications/avian-influenza-influenza-a-h5n1-technical-briefings/investigation-into-the-risk-to-human-health-of-avian-influenza-influenza-a-h5n1-in-england-technical-briefing-3">level 3</a> (limited transmission in mammals other than humans) for some time, with the only evidence of transmission between mammals from a <a href="https://www.science.org/content/article/incredibly-concerning-bird-flu-outbreak-spanish-mink-farm-triggers-pandemic-fears">mink farm in Spain</a>. </p>
<figure class="align-center ">
<img alt="Two otters on a bed of kelp." src="https://images.theconversation.com/files/521854/original/file-20230419-18-5b2c34.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521854/original/file-20230419-18-5b2c34.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521854/original/file-20230419-18-5b2c34.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521854/original/file-20230419-18-5b2c34.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521854/original/file-20230419-18-5b2c34.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521854/original/file-20230419-18-5b2c34.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521854/original/file-20230419-18-5b2c34.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">Bird flu has been detected in mammals such as otters.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/european-otter-lutra-mother-cub-sleeping-1670937586">Chrispo/Shutterstock</a></span>
</figcaption>
</figure>
<p>Since December 2021 there have been <a href="https://www.gov.uk/government/publications/avian-influenza-influenza-a-h5n1-technical-briefings/investigation-into-the-risk-to-human-health-of-avian-influenza-influenza-a-h5n1-in-england-technical-briefing-3">seven reports</a> of human infection with 2.3.4.4b H5N1 around the world. Generally, the risk of transmission of avian influenza to humans is low. Most cases are through direct contact with live chickens or ducks.</p>
<p>In the current outbreak cases in Spain and the US were found in <a href="https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON420">poultry workers</a> and the <a href="https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2022.27.5.2200061">single UK case</a> in a man keeping infected ducks in the household. A <a href="https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON434">nine-year-old girl</a> from Ecuador who contracted the virus was reported to be in contact with backyard poultry.</p>
<h2>Balancing risk with animal welfare</h2>
<p>Over the past two winters mandatory orders to house birds, including free-range and backyard flocks, have helped reduce the potential for transmission into, within and from poultry. The greatest risk of influenza to poultry is through the autumn and winter months with the migration of birds, such as barnacle geese. </p>
<p>As we move out of peak influenza season, the risk should be lower in the short term. The removal of housing restrictions is a decision that balances infection risk with animal welfare. </p>
<p>Almost two-thirds of <a href="https://www.farminguk.com/news/free-range-now-accounts-for-two-thirds-of-uk-egg-production_59376.html">UK egg production</a> is free range and it’s thought there could be as many as <a href="https://www.dailymail.co.uk/news/article-8136277/Chickens-five-times-popular-pets-hamsters.html">one million UK households</a> that keep backyard chickens. Allowing these birds back outside will benefit their health. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/avian-flu-has-jumped-into-wild-seabirds-and-is-spreading-fast-185058">Avian flu has jumped into wild seabirds and is spreading fast</a>
</strong>
</em>
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<p>That said, it’s increasingly likely that H5N1 is here to stay and will remain a problem for poultry production and wild birds, and a threat to other species. For now, advice to avoid contact with infected birds and report any <a href="https://www.gov.uk/guidance/avian-influenza-bird-flu">suspected cases</a> is sensible. We will need ongoing surveillance of poultry, wild birds and mammals to assess risk and potential emergence of more transmissible strains in the future.</p><img src="https://counter.theconversation.com/content/203361/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Wigley receives funding from BBSRC and MRC. </span></em></p>This latest outbreak has been deadly for many millions of birds. The risk to humans, however, is very low.Paul Wigley, Professor in Animal Microbial Ecosystems, Bristol Veterinary School, University of BristolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2025942023-04-12T12:09:29Z2023-04-12T12:09:29ZHuman metapneumovirus, or HMPV, is filling ICUs this spring – a pediatric infectious disease specialist explains this little-known virus<figure><img src="https://images.theconversation.com/files/520067/original/file-20230410-5874-jymbdf.jpg?ixlib=rb-1.1.0&rect=34%2C22%2C7634%2C4207&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Human metapneumovirus, or HMPV, peaks in North America from February to May, just on the heels of flu season.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/doctor-visiting-young-mother-at-home-for-routine-royalty-free-image/1471832871?phrase=children%20lung%20infection&adppopup=true">martin-dm/E+ via Getty Images</a></span></figcaption></figure><p>In the year 2000, Dutch scientists went on a mission of exploration – not to discover lands or riches, but to identify unknown causes of acute respiratory infections. </p>
<p>These illnesses, from the common cold to pneumonia, have been a plague on mankind throughout history. Most are caused by viruses, so if you’ve ever been told “you probably have a virus” by a clinician, they were likely correct. However, respiratory illnesses can be much more severe than simple colds.</p>
<p>Respiratory infections are the <a href="https://doi.org/10.1016/S0140-6736(12)60560-1">leading cause of death in children under 5 globally</a> and a major reason for hospitalization of children in developed countries. They are also a major cause of disease and death among people at high risk for severe disease, such as premature infants, older adults and those with underlying conditions. </p>
<p>However, meticulous research studies by many groups over decades had failed to identify a virus or bacteria in every person with an acute respiratory illness. Did this failure to detect a microbe result from tests that weren’t good enough, or viruses that doctors and scientists didn’t know about? The answer was partly the first; modern molecular tests are much better, so doctors find more known viruses. </p>
<p>But the Dutch group discovered a new virus, <a href="https://doi.org/10.1038/89098">human metapneumovirus</a>, abbreviated HMPV or MPV, which turns out to be a leading cause of respiratory infections. HMPV often presents like other common respiratory viruses, with congestion, cough and fever.</p>
<p>As a <a href="https://www.pediatrics.pitt.edu/people/john-v-williams-md">pediatric infectious disease specialist and virologist</a>, I have led my team in <a href="https://scholar.google.com/citations?user=Bar0h_8AAAAJ&hl=en">HMPV research for over 20 years</a>, and I’ve personally cared for many children with this infection. I’ve received emails from colleagues, clinicians and parents all over the country and the world with questions about severe and tragically fatal cases. </p>
<p>The U.S. saw a <a href="https://www.cdc.gov/surveillance/nrevss/hmpv/natl-trend.html">spike in HMPV detections</a> during the first few months of 2023. This trend is similar to the <a href="https://theconversation.com/rsv-treatments-for-young-children-are-lacking-but-the-record-2022-cold-and-flu-season-highlights-the-urgency-for-vaccines-and-other-preventive-strategies-195700">higher-than-normal case rates</a> of <a href="https://www.cdc.gov/surveillance/nrevss/rsv/natl-trend.html">respiratory syncytial virus, or RSV</a>, and influenza in the fall of 2022 and winter of 2023, likely related to decreased population immunity after two years of wearing face masks and social distancing. </p>
<p>Still, I find that many people even in health care are unfamiliar with this virus.</p>
<p><iframe id="eIbPJ" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/eIbPJ/2/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>Origins of human metapneumovirus</h2>
<p>The human metapneumovirus was isolated from people with acute respiratory infection and sequenced in 2001 using a combination of specialized culture and molecular techniques.</p>
<p>It is related to RSV, which is the <a href="https://doi.org/10.1136/thoraxjnl-2018-212212">leading cause of serious respiratory infection in children</a> and a major problem in adults. Both viruses are in the same large group with measles, mumps and parainfluenza viruses, all of which are <a href="https://doi.org/10.1128/CMR.00015-11">leading causes of childhood disease</a>. </p>
<p>However, abundant data shows that HMPV is distinct from its cousin RSV in many ways. First, the order of genes in its <a href="https://doi.org/10.1006/viro.2001.1355">genome is quite different</a>. In addition, HMPV is missing two genes that RSV uses to overcome the immune response that would normally target it; yet HMPV has its own ways to <a href="https://doi.org/10.3390/v10090505">block immunity</a>.</p>
<p>Third, genetic analysis by several different groups shows that the <a href="https://doi.org/10.1099/vir.0.2008/006957-0">closest recent ancestor of HMPV</a> is a bird virus, <a href="https://doi.org/10.1099/vir.0.19043-0">avian metapneumovirus</a>. This is an agricultural pathogen of chickens and turkeys. Evolutionary and genetic analysis suggests that the human virus diverged from the bird virus <a href="https://doi.org/10.1371/journal.pone.0152962">several hundred years ago</a>. This is an example of a zoonosis: an <a href="https://theconversation.com/what-is-spillover-bird-flu-outbreak-underscores-need-for-early-detection-to-prevent-the-next-big-pandemic-200494">animal virus that jumps to humans</a>. In this case, HMPV became established as a permanent pathogen of humans. </p>
<p>Understanding how HMPV successfully made the leap might help predict which other animal viruses could be capable of transforming into primary human pathogens. The <a href="https://theconversation.com/as-bird-flu-continues-to-spread-in-the-us-and-worldwide-whats-the-risk-that-it-could-start-a-human-pandemic-4-questions-answered-200204">recent H5N1 bird flu outbreak</a> – which has been transmitted to humans only to a limited extent – illustrates this risk.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/sbkeFJOQhO4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">HMPV is a common respiratory illness during the spring months that can cause a narrowing of the airways, a barking cough and other nasty symptoms, particularly in children and older adults.</span></figcaption>
</figure>
<h2>HMPV in children</h2>
<p>Despite its being recognized only two decades ago, many studies have confirmed that HMPV is a major cause of respiratory infection in humans. Initial research groups focused on children and quickly discovered that HMPV caused respiratory infections in children worldwide, including <a href="https://doi.org/10.3201/eid0906.030017">Canada</a>, <a href="https://doi.org/10.3201/eid1708.051239">Australia</a>, <a href="https://doi.org/10.1128/JCM.42.1.126-132.2004">Japan</a>, <a href="https://doi.org/10.3201/eid0906.030009">Hong Kong</a>, <a href="https://doi.org/10.1097/INF.0b013e3180621192">South Africa</a> and <a href="https://doi.org/10.1086/383350">Argentina</a>. </p>
<p>Indeed, HMPV is a common cause of acute respiratory disease in children in <a href="https://doi.org/10.1016/S2214-109X(20)30393-4">every country</a> examined, and most children get the infection <a href="https://doi.org/10.1128/JCM.43.3.1213-1219.2005">for the first time by age 5</a>. One study using samples collected over 25 years in the U.S. found that HMPV was the <a href="https://doi.org/10.1056/NEJMoa025472">second most common</a> cause of lung infection in children after RSV. Other studies of multiple children’s hospitals in U.S. cities found that HMPV was the second most common cause of respiratory infections, leading to <a href="https://doi.org/10.1056/NEJMoa1204630">hospitalization</a> and <a href="https://doi.org/10.1056/NEJMoa1405870">pneumonia</a>.</p>
<p>Children with underlying risk factors, such as <a href="https://doi.org/10.2147/RRN.S76270">those born prematurely</a> and those with conditions like <a href="https://doi.org/10.1097/INF.0000000000002038">asthma</a>,
or those who have compromised immune systems, such as organ transplant recipients or children being treated for cancer, are at <a href="https://doi.org/10.1093/jpids/piu100">higher risk for severe HMPV</a>. Most children who become hospitalized with HMPV are otherwise healthy before they acquire it, yet <a href="https://doi.org/10.1093/jpids/piv027">many require intensive care</a> from the illness. </p>
<h2>Not just for kids</h2>
<p>HMPV is also a common cause of <a href="https://doi.org/10.1097/INF.0b013e3181684dac">serious lung infections among adults</a>. This is especially true in adults over 65 years old, or those with underlying conditions. A New York study over four winters found that HMPV was as common in hospitalized older adults as RSV or influenza, <a href="https://doi.org/10.1001/archinte.168.22.2489">with similar rates of ICU care and death</a>. </p>
<p>Studies over three winters in Nashville of adults over age 50 detected <a href="https://doi.org/10.1093/infdis/jis309">rates of HMPV hospitalization</a> and <a href="https://doi.org/10.1111/irv.12234">emergency department visits</a> that were similar to RSV and influenza. HMPV and RSV were more common than the flu in people 65 and older, presumably because many were vaccinated against the flu.</p>
<p>Another national study of adults hospitalized for pneumonia showed that <a href="https://doi.org/10.1056/NEJMoa1500245">HMPV was as common as RSV</a>, and nearly as common as influenza. As in children, HMPV is a particular problem for adults with chronic conditions such as <a href="https://doi.org/10.1086/444392">asthma</a>, <a href="https://doi.org/10.1002/cncr.30599">cancer</a> or <a href="https://doi.org/10.1016/j.jinf.2005.11.010">chronic obstructive pulmonary disease, also called COPD</a>.</p>
<p>Similar to the dire effects of flu and <a href="https://www.politico.com/news/2023/02/15/pandemic-nursing-home-covid-00082913">COVID-19 in nursing homes</a>, HMPV has also caused numerous outbreaks among vulnerable older adults in <a href="https://doi.org/10.3201/eid2502.181298">long-term care facilities</a>.</p>
<h2>Why HMPV is still so underrecognized</h2>
<p>Despite being a common cause of serious respiratory disease, HMPV remains underdiagnosed by clinicians and little recognized by the general population. Most people with an acute respiratory illness don’t get any testing, and if they do, only complex molecular testing can detect HMPV. But this testing is usually done only for hospitalized patients under select circumstances. </p>
<p>People tend to believe what they see, and therefore even health care professionals are most aware of diseases they test for frequently. But HMPV circulates predictably every year, and in North America the <a href="https://doi.org/10.1056/NEJMoa025472">peak is typically February through May</a>. So if you’ve had a cold recently this winter or spring, <a href="https://www.cdc.gov/surveillance/nrevss/hmpv/natl-trend.html">HMPV was a likely culprit</a>. Children’s hospitals around the country are seeing an <a href="https://time.com/6264539/respiratory-virus-not-covid-spring-2023/">increased number of cases</a>, including many in the ICU. Based on past research, this is almost certainly happening in adults too – it’s just that usually only those patients with severe illness are tested for HMPV. </p>
<h2>A dearth of treatments</h2>
<p>Right now, there are no specific antiviral drugs to treat HMPV as there are for flu and COVID-19. As with the many other respiratory viruses that cause colds, most infected people will do just fine with rest and fluids. </p>
<p>But some may develop trouble breathing and need to seek medical attention. Children or adults with serious underlying conditions should be especially careful, and just as with COVID-19, using hand sanitizer and washing hands can <a href="https://theconversation.com/yes-we-should-be-keeping-the-healthier-hand-washing-habits-we-developed-at-the-start-of-the-pandemic-169892">reduce transmission</a>.</p>
<p>Preventive vaccines and antibodies for HMPV are <a href="https://doi.org/10.1128/CVI.00230-15">in development</a> but are still a way off. So, for the moment, wear a mask if you’re sick and avoid others who are sick. You may dodge a repeat engagement with this virus that you’ve had but hadn’t heard of.</p><img src="https://counter.theconversation.com/content/202594/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John V. Williams receives funding from the NIH and CDC. He previously served on a scientific advisory board for Quidel and an independent data monitoring committee for GlaxoSmithKline, neither related to the subject of the article. </span></em></p>Similar to the patterns seen with COVID-19, flu and RSV, HMPV is making a comeback after years of being repressed by people wearing masks and social distancing.John V. Williams, Professor of Pediatrics, Microbiology and Molecular Genetics, University of PittsburghLicensed 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/2010562023-03-16T14:47:46Z2023-03-16T14:47:46ZBird flu: Nigeria is on major migratory bird routes, new strains keep appearing<figure><img src="https://images.theconversation.com/files/514989/original/file-20230313-28-msyt5e.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2464%2C1648&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Nigeria has to step up biosecurity measures to check frequent bird flu outbreaks. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/dozens-of-birds-are-carried-in-wheel-barrows-to-a-dump-site-news-photo/1211936110?phrase=bird%20flu%20in%20nigeria&adppopup=true">Pius Utomi Ekpei/AFP via Getty Images</a></span></figcaption></figure><p><em>Avian influenza is a highly contagious viral infection of birds, commonly called “bird flu”, which has been recurring in Nigeria <a href="https://www.cidrap.umn.edu/avian-influenza-bird-flu/nigeria-has-africas-first-h5n1-bird-flu-outbreak">since 2006</a>. It has <a href="https://www.one-health.panafrican-med-journal.com/content/article/2/16/full/">resulted in</a> the loss of millions of birds and income for people who rely on the poultry industry. Nigeria is currently grappling with another outbreak which <a href="https://www.cdc.gov/flu/avianflu/poultry.htm">started in 2021</a>.</em> </p>
<p><em>The Conversation Africa asked Clement Meseko, a virologist and expert on animal influenza, to explain the disease’s re-occurrences.</em></p>
<hr>
<h2>What is bird flu? How does it spread? Is it dangerous to humans?</h2>
<p>Bird flu is scientifically known as avian influenza and the pathogenic form as highly pathogenic avian influenza. It is <a href="https://link.springer.com/chapter/10.1007/978-3-030-25385-1_17">a disease in birds</a> (specifically poultry) caused by an influenza virus. It is highly pathogenic, meaning it causes tissue and organ damage in the host, and can kill <a href="https://pubmed.ncbi.nlm.nih.gov/20591211/">more than 75%</a> of the infected flock.</p>
<p>Waterfowls like ducks are natural reservoirs of the disease. They can harbour avian flu without <a href="https://www.ajol.info/index.php/nvj/article/view/178945">showing any symptoms</a>. Many waterfowls and other wild birds are migratory, moving across and between continents – this brings them into contact with resident birds and domestic poultry. Their body secretions and excretions may contain virus that can then infect other birds and poultry.</p>
<p><a href="https://www.ajol.info/index.php/nvj/article/view/68949">The symptoms</a> in infected poultry include sudden death, respiratory distress, cough and haemorrhages in tissue and organs. Other animals, including pigs, horses and dogs can also be infected – and so can humans. In fact, it is zoonotic and therefore <a href="https://www.nature.com/articles/s41598-018-24371-6">can be fatal</a> for humans too. Highly pathogenic avian influenza H5N1 virus infections have infected <a href="https://www.who.int/docs/default-source/wpro---documents/emergency/surveillance/avian-influenza/ai_20230224.pdf?sfvrsn=5f006f99_111">more than</a> 880 people with about 50% case fatality globally. </p>
<p>The virus also has the capacity to cause a pandemic: an influenza virus of avian origin, but not the currently circulating strain, caused the 1918 pandemic that ultimately <a href="https://www.cdc.gov/flu/pandemic-resources/1918-commemoration/1918-pandemic-history.htm">killed about 50 million people</a> – worse than the current <a href="https://www.frontiersin.org/articles/10.3389/fcimb.2023.1145235/full">COVID-19 pandemic </a>.</p>
<h2>How many outbreaks have there been in Nigeria since 2006?</h2>
<p>Nigeria’s first outbreak of bird flu was confirmed in January 2006, the <a href="https://www.eurosurveillance.org/content/10.2807/ese.13.42.19007-en?crawler=true">first epidemic in poultry in Africa</a>. It killed millions of birds and millions more were culled to contain its spread. The economic and livelihood loss was huge as the disease spread all over the country with 100% mortality in many cases.
The estimate of the <a href="https://www.researchgate.net/publication/320419066_Economic_Losses_and_Implications_of_Highly_Pathogenic_Avian_Influenza_HPAI_H5N1_Resurgence_in_Nigeria">economic cost</a> of bird flu outbreak in Nigeria was over nine billion Nigerian naira (about
US$32 million) – with people losing investment, livelihood and jobs.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/515817/original/file-20230316-28-qkc7jr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/515817/original/file-20230316-28-qkc7jr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/515817/original/file-20230316-28-qkc7jr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/515817/original/file-20230316-28-qkc7jr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/515817/original/file-20230316-28-qkc7jr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/515817/original/file-20230316-28-qkc7jr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/515817/original/file-20230316-28-qkc7jr.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">
<figcaption>
<span class="caption">Dead birds are gathered in a dump for burning in Kano 11 February, 2006.</span>
<span class="attribution"><span class="source">Pius Utomi EkpeiAFP via Getty Images</span></span>
</figcaption>
</figure>
<p>The disease was brought under control by 2008 thanks to stringent biosecurity measures like depopulation (culling), decontamination and control of poultry movement. In 2015 <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4480409/">another strain</a> emerged in Nigeria. Since then, new strains <a href="https://onlinelibrary.wiley.com/doi/10.1111/tbed.14000">keep appearing</a>. </p>
<p>Live bird markets, common across Nigeria, are the main points of spread of bird flu while wetlands are the points of initial transmissions. Local waterfowls and other birds that may harbour avian flu come into contact with other bird species and with people. In 2006, <a href="https://www.eurosurveillance.org/content/10.2807/ese.13.42.19007-en?crawler=true/">312 cases</a> and in 2015, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4480409/">256 outbreaks</a> of highly pathogenic avian influenza were recorded.</p>
<h2>What should Nigeria be doing differently?</h2>
<p>The disease may become endemic in Nigeria if circulation continuous and detection of the same strain is established. If a disease is constantly circulating in reservoir hosts it will lead to spill over to poultry and humans. </p>
<p>If that’s the case, biosecurity measures must be stepped up. For instance, the government may consider other measures in addition to biosecurity. This may include controlled and regulated vaccination. There are vaccines. They have been <a href="https://pubmed.ncbi.nlm.nih.gov/24026475/">used in</a> Egypt, China, Indonesia with a mixture of failure and success. Vaccines only reduce the impact of the disease but do not prevent infection or re-infection.</p>
<p>Those in the agricultural sector also need to introduce effective control measures at live bird markets and in the way poultry is traded more broadly. Measures would include restructuring the live bird markets, discouraging the mixing of species, the introduction of plastic cages and crates that can be easily cleaned and disinfected. Frequent cleaning, disinfection and decontamination of live bird market environments is very important for disease containment.</p>
<h2>You’ve described as Nigeria was an “ecological sink” for such viruses. Please explain</h2>
<p>In the <a href="https://www.nature.com/articles/s41467-019-13287-y">research</a> that examined the outbreak of the 2015-2016 bird flu, we found that west Africa was the epicentre of the virus that was later found in other sub-Saharan African regions – the central, eastern and southern African countries. In particular, within west Africa, Nigeria was the most important point of virus introduction and a central hub in the virus spread. </p>
<p>Bird flu is mostly introduced into Nigeria through the presence and activities of wild birds. For instance, in the 2015-2016 outbreak <a href="https://www.nature.com/articles/s41467-019-13287-y">we identified</a> four virus introductions into Nigeria likely from east Europe.</p>
<p>These birds travel across continents and countries through multiple international migratory routes, in much the same way that airlines move across the world on designated routes. Three major wild bird migratory routes from Asia and Europe transverse Nigeria. That’s good news for biodiversity but bad news for disease control.</p>
<p>Bird watchers and ornithologists <a href="https://www.environewsnigeria.com/how-bird-migrated-from-germany-to-nigeria-in-122-days/">have found</a> that migratory birds from Europe move into Nigeria every year during the cold harmattan season (November - February). This is the peak time for avian flu outbreaks. </p>
<p><a href="https://www.nature.com/articles/s41467-019-13287-y">Nigeria is</a> the most affected African country in terms of the frequency and burden of avian flu. This makes it the destination “sink” of the strains that may be circulating in Europe at any given time. </p>
<p>Because we can’t change birds’ routes or habits, it would be up to Nigerian authorities to make sure it keeps its local birds and people as safe as possible. This would include surveillance of wild birds at wetlands and the monitoring of viral infections. Early detection is vital for early warning, risk analysis and control of infection.</p><img src="https://counter.theconversation.com/content/201056/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Clement Meseko receives funding from National Veterinary Research Institute. He is affiliated with OIE/FAO (OFFLU) Expert Working Group on Animal Influenza.</span></em></p>Bird flu has been recurring in Africa since 2006 and Nigeria is heavily affected. High-level biosecurity measures are required to keep people and animals safe.Clement Meseko, Veterinarian & Virologist, National Veterinary Research Institute, Vom, JosLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2002042023-03-16T12:31:51Z2023-03-16T12:31:51ZAs bird flu continues to spread in the US and worldwide, what’s the risk that it could start a human pandemic? 4 questions answered<figure><img src="https://images.theconversation.com/files/515263/original/file-20230314-2882-8ul2k1.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C8243%2C5475&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Bird flu is transmitted mainly by wild birds, like these snow geese in Ruthsberg, Md., in January 2023.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/snow-geese-take-off-from-a-field-in-ruthsburg-maryland-on-news-photo/1246532637">Photo by JIM WATSON/AFP via Getty Images</a></span></figcaption></figure><p><em>An outbreak of H5N1 avian influenza that started in 2021 has become the largest bird flu outbreak in history, both in the U.S. and worldwide. In the U.S. the virus has led to the destruction of millions of commercially raised chickens, turkeys, ducks and geese, and has killed thousands of wild birds.</em> </p>
<p><em>Many virologists are concerned that this virus could spill over to humans and cause a new human pandemic. University of Colorado Boulder virologists Sara Sawyer, Emma Worden-Sapper and Sharon Wu summarize the compelling story of H5N1 and why scientists are closely watching the outbreak.</em></p>
<h2>1. Is this virus a serious threat to humans?</h2>
<p>H5N1 is a specific type of influenza virus, predominantly harbored by birds, that was first detected on a <a href="https://doi.org/10.1111/j.1863-2378.2012.01497.x">goose farm in China in 1996</a>. Recently it has begun infecting an exploding diversity of bird and mammalian species around the globe. </p>
<p>The virus is highly pathogenic to birds, meaning that infections often cause extreme symptoms, including death. But its impact on humans is complicated. There have been relatively few human infections detected – <a href="https://www.who.int/publications/m/item/cumulative-number-of-confirmed-human-cases-for-avian-influenza-a(h5n1)-reported-to-who-2003-2022-5-jan-2023">fewer than 900 documented</a> globally over several decades – but about half of those infected individuals have died. </p>
<p>The good news about H5N1 for humans is that it currently <a href="https://www.cdc.gov/flu/avianflu/h5n1-human-infections.htm">doesn’t spread well</a> between people. Most people who have contracted H5N1 have gotten it directly from interacting with <a href="https://www.who.int/news-room/fact-sheets/detail/influenza-(avian-and-other-zoonotic)">infected poultry</a> – specifically chickens, turkeys, ducks and geese, which often are raised in close quarters on large commercial farms. </p>
<p>There are only <a href="https://www.cdc.gov/flu/avianflu/h5n1-human-infections.htm">a small handful of examples</a> of human-to-human spread. Because H5N1 doesn’t spread well between people, and because direct infection of humans by infected birds is still relatively rare, H5N1 has not yet erupted into a human epidemic or pandemic.</p>
<h2>2. Why is this outbreak suddenly getting so much attention?</h2>
<p>The first reason that so much attention is being paid to bird flu right now is that currently H5N1 is causing the <a href="https://www.france24.com/en/environment/20230113-largest-global-bird-flu-outbreak-in-history-shows-no-sign-of-slowing">largest “bird pandemic” ever recorded</a>. A certain viral variant that arose in 2020, called H5N1 2.3.4.4b, is driving this outbreak. </p>
<p>In agricultural poultry flocks, if a few birds test positive for H5N1, the whole <a href="https://www.cdc.gov/flu/avianflu/avian-in-birds.htm">flock is killed</a> regardless of symptoms or infection status. <a href="https://www.npr.org/sections/health-shots/2023/02/05/1153434486/eggs-prices-drop-but-the-threat-from-avian-flu-isnt-over-yet">Higher prices for eggs</a> and <a href="https://money.com/turkeys-cost-more-thanksgiving/">poultry meat</a> in the U.S. are one result. The Biden administration is considering <a href="https://www.nytimes.com/2023/03/06/us/politics/bird-flu-vaccine-chickens.html">vaccinating farmed poultry flocks</a>, but the logistics could be quite complicated.</p>
<p>The second reason for increased attention is that H5N1 is now infecting more bird and mammalian species than ever before. The virus has been detected in a broad array of <a href="https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/avian-influenza/hpai-2022/2022-hpai-wild-birds">wild birds</a> and in <a href="https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/avian-influenza/hpai-2022/2022-hpai-mammals">diverse mammals</a>, including badgers, black bears, bobcats, coyotes, ferrets, fisher cats, foxes, leopards, opossums, pigs, skunks and sea lions. </p>
<p>As H5N1 infects more species, it also increases its geographical range and produces more viral variants that could have new biological properties.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/515270/original/file-20230314-3867-pgw6hr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A dead pelican on a beach, shown from its feet." src="https://images.theconversation.com/files/515270/original/file-20230314-3867-pgw6hr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/515270/original/file-20230314-3867-pgw6hr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=366&fit=crop&dpr=1 600w, https://images.theconversation.com/files/515270/original/file-20230314-3867-pgw6hr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=366&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/515270/original/file-20230314-3867-pgw6hr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=366&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/515270/original/file-20230314-3867-pgw6hr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=460&fit=crop&dpr=1 754w, https://images.theconversation.com/files/515270/original/file-20230314-3867-pgw6hr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=460&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/515270/original/file-20230314-3867-pgw6hr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=460&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Peru decreed a 90-day health emergency in December 2022 after more than 13,000 pelicans died on its beaches, possibly infected with H5N1.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/dead-pelican-is-seen-on-the-beach-in-lima-peru-on-december-news-photo/1245471384">Klebher Vasquez/Anadolu Agency via Getty Images</a></span>
</figcaption>
</figure>
<p>The third and most worrisome reason that this virus is getting so much press is that H5N1 now seems to be transmitting well between individuals of at least one mammalian species. In late 2022, <a href="http://dx.doi.org/10.1001/jama.2023.1317">mammal-to-mammal spread</a> occurred in Spain in <a href="https://doi.org/10.2807/1560-7917.ES.2023.28.3.2300001">farmed minks</a>. H5N1 spread very efficiently between the minks and caused clinical signs of illness and death in the mink populations where it was detected. </p>
<p><a href="https://www.cnn.com/2023/03/06/americas/bird-flu-sea-lion-deaths-peru-intl-latam/index.html">Sea lions in Peru</a> are also succumbing to H5N1 virus in massive numbers. It hasn’t been confirmed definitively whether the sea lions are spreading the virus to each other or are contracting it from birds or H5N1-infected water.</p>
<p>Here’s the key question: If H5N1 can achieve spread in minks and possibly sea lions, why not humans? We are also mammals. It is true that the farmed minks were confined in close quarters, like chickens on a poultry farm, so that may have contributed. But humans also live in high densities in many cities around the world, providing the virus similar tinder should a human-compatible variant arise.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/XiqG7_z5b9M?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The World Health Organization is closely monitoring and analyzing the spread of H5N1 in mammals.</span></figcaption>
</figure>
<h2>3. What features could help H5N1 spread well in humans?</h2>
<p>Birds experience influenza as a gastrointestinal infection and spread flu predominantly through <a href="https://www.aphis.usda.gov/animal_health/downloads/animal_diseases/ai/wild-bird-strategic-plan.pdf">defecating in water</a>. By contrast, humans experience influenza as a respiratory infection and spread it by breathing and coughing. </p>
<p>Over the centuries, some of these avian influenza viruses have been passed from birds to humans and other mammalian species, although this is a relatively rare event.</p>
<p>This is because bird influenza viruses must mutate in several ways <a href="https://doi.org/10.7554/eLife.18491">to infect mammals efficiently</a>. The most important mutational changes affect the <a href="http://dx.doi.org/10.1371/journal.ppat.1005519">tissue tropism</a> of the virus – its ability to infect a specific part of the body.</p>
<p>Avian flu viruses have evolved to infect cells of the intestine, while human flu viruses have evolved to infect cells of the respiratory tract. However, sometimes a flu virus can acquire mutations that allow it to infect cells in a different part of the body. </p>
<p>Which cells influenza infects is partially dictated by the specific receptor that it binds. Receptors are the molecules on the surface of host cells that a virus exploits to enter those cells. Once viruses are in cells, they may be able to <a href="https://www.science.org/doi/10.1126/science.ade6985">produce copies of themselves</a>, at which point an infection has been achieved.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/515273/original/file-20230314-2488-xzd7zs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graphic showing precautions for handling poultry to avoid bird flu infection." src="https://images.theconversation.com/files/515273/original/file-20230314-2488-xzd7zs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/515273/original/file-20230314-2488-xzd7zs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=464&fit=crop&dpr=1 600w, https://images.theconversation.com/files/515273/original/file-20230314-2488-xzd7zs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=464&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/515273/original/file-20230314-2488-xzd7zs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=464&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/515273/original/file-20230314-2488-xzd7zs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=583&fit=crop&dpr=1 754w, https://images.theconversation.com/files/515273/original/file-20230314-2488-xzd7zs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=583&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/515273/original/file-20230314-2488-xzd7zs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=583&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Bird flu infections in people are rare, but possible. Most reported bird flu infections in people have happened after unprotected contact with infected birds or contaminated surfaces.</span>
<span class="attribution"><a class="source" href="https://www.cdc.gov/flu/pdf/avianflu/avian-flu-transmission.pdf">USCDC</a></span>
</figcaption>
</figure>
<p>Both human and bird influenza viruses use receptors called sialic acids that are common on the surfaces of cells. Bird influenza viruses, such as H5N1, use a version called α2,3-linked sialic acid, while human flu viruses use α2,6-linked sialic acid – the predominant variant in the human upper respiratory tract. Thus, to become efficient at infecting humans, H5N1 would likely need to mutate to use α2,6-linked sialic acid as its receptor. </p>
<p>This is a concern because studies have shown that only <a href="http://dx.doi.org/10.1128/JVI.02737-09">one or two mutations</a> in the viral genome are enough to switch receptor binding from α2,3-linked sialic acid to the human α2,6-linked sialic acid. That doesn’t seem like much of a genetic obstacle.</p>
<h2>4. Why don’t we make a vaccine just in case?</h2>
<p>With avian influenza viruses, it is not possible to make effective human vaccines in advance, because we don’t know exactly what the genetics of the virus will be if it starts to spread well in humans. Remember that the seasonal flu vaccine must be remade every year, even though the general types of flu viruses that it protects against are the same, because the specific genetic variants that affect humans change from year to year. </p>
<p>Right now, the best way people can protect themselves from H5N1 is to avoid contact with infected birds. For more information about prevention, especially for people who keep domesticated birds or are bird-watching hobbyists, the Centers for Disease Control has a list of guidelines for <a href="https://www.cdc.gov/flu/avianflu/prevention.htm#anchor_1647619251544">avoiding H5N1 and other bird flu viruses</a>.</p><img src="https://counter.theconversation.com/content/200204/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sara Sawyer is a co-founder of Darwin Biosciences. She receives funding from the National Institutes of Health.</span></em></p><p class="fine-print"><em><span>Emma Worden-Sapper and Sharon Wu do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Avian influenza viruses have evolved to infect birds, but the current H5N1 outbreak is also infecting a wide range of mammals. This suggests that it could mutate into forms that threaten humans.Sara Sawyer, Professor of Molecular, Cellular and Developmental Biology, University of Colorado BoulderEmma Worden-Sapper, PhD Student in Molecular, Cellular and Developmental Biology, University of Colorado BoulderSharon Wu, PhD Student in Interdisciplinary Quantitative Biology and Molecular, Cellular, and Developmental Biology, University of Colorado BoulderLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2012362023-03-13T16:38:55Z2023-03-13T16:38:55ZHow free-range eggs became the norm in supermarkets – and sold customers a lie<figure><img src="https://images.theconversation.com/files/514443/original/file-20230309-28-t3glwf.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5615%2C3741&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/freshly-laid-free-range-eggs-farmers-467379797">MJHeritage/Shutterstock</a></span></figcaption></figure><p>The UK is in the grip of its <a href="https://lordslibrary.parliament.uk/bird-flu-2022-dealing-with-the-uks-largest-ever-outbreak/">largest ever outbreak of bird flu</a>. As its name suggests, avian influenza primarily affects birds, but it can also infect humans and other mammals. The virus first emerged in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5702979/">China in 1996</a> and the highly pathogenic H5N1 is the <a href="https://www.gov.uk/government/publications/avian-influenza-influenza-a-h5n1-technical-briefings/investigation-into-the-risk-to-human-health-of-avian-influenza-influenza-a-h5n1-in-england-technical-briefing-1">predominant variant</a> causing havoc <a href="https://www.bmj.com/content/380/bmj.p401">at the moment</a>. </p>
<p>The confinement and transportation of farmed birds has allowed H5N1 to spread rapidly, leaving devastation in its wake. It is not just poultry that is affected. The current outbreak is killing wildlife on an <a href="https://www.nature.com/articles/d41586-022-01338-2">unprecedented scale</a>, from <a href="https://www.rspb.org.uk/birds-and-wildlife/advice/how-you-can-help-birds/disease-and-garden-wildlife/avian-influenza-updates/">seabirds</a> in the UK to <a href="https://www.nhm.ac.uk/discover/news/2023/march/bird-flu-kills-thousands-south-american-sea-lions-outbreak-continues.html">sea lions</a> in Peru.</p>
<p>Though the UK government currently assesses the risk to the wider public as <a href="https://ukhsa.blog.gov.uk/2021/11/26/what-is-avian-flu/">very low</a>, some strains of bird flu can pass to humans after sustained close contact. The producers of David Attenborough’s latest television series had to pull plans for him to film close to seabirds on the island of Skomer for fears he might <a href="https://www.theguardian.com/tv-and-radio/2023/mar/07/producers-feared-david-attenborough-would-catch-bird-flu-and-die-during-filming">catch the disease</a>.</p>
<p>As a result of the outbreak, <a href="https://www.gov.uk/government/news/avian-influenza-housing-order-to-be-introduced-across-england">mandatory housing</a> of chickens has been in place in England since November 2022. This means that no eggs produced in England are currently “free-range”. There is no defined end to this situation and as of February, all free-range eggs have been <a href="https://www.freerangeinfo.com/">relabelled</a>. </p>
<p>Some customers are <a href="https://twitter.com/isthatamyj/status/1630952218240118785">unhappy</a> with buying eggs from chickens without access to the outdoors. But exploring the history of free-range eggs in the UK reveals why their preferred purchases may never have been that safe or ethical in the first place.</p>
<h2>The fall and rise of free-range</h2>
<p>The RSPCA defines free-range eggs as those coming “from birds that, during the daytime, enjoy <a href="https://www.rspcaassured.org.uk/rspca-assured-products/free-range-eggs/">unlimited access to outdoor pastures</a>”. Before the mid-20th century, almost all eggs in the UK were free-range. Aside from some semi-intensive systems, where chickens were kept permanently in sheds, there were no alternatives.</p>
<p>The mass adoption of battery cages from the 1950s onwards transformed the egg industry. Battery farming sees hens packed into cages to control their environment and increase the number of eggs they lay. In the UK, free-range eggs accounted for 80% of all eggs produced in 1951. By 1980, the figure was <a href="https://link.springer.com/book/10.1057/9780230599963">1%</a>.</p>
<p>The welfare of chickens kept in battery farms naturally suffered. Ruth Harrison’s 1964 book Animal Machines was among the first to reveal the cruelty of modern poultry production. </p>
<p>In it, she described the “<a href="https://www.cabidigitallibrary.org/doi/book/10.1079/9781780642840.0000">miserable and debilitated</a>” life of battery hens. This became a focal point of activism and sparked a <a href="https://discovery.nationalarchives.gov.uk/details/r/C2106199">government investigation</a> into farm animal welfare just a year later. </p>
<p>But it was not until a panic over the alleged presence of salmonella in eggs in <a href="http://news.bbc.co.uk/onthisday/hi/dates/stories/december/3/newsid_2519000/2519451.stm">1988</a> that public opinion began to change. Thanks to that and other scares, such as the outbreak of “mad cow” disease on beef farms in the 1990s, the public perception of intensively farmed food shifted from <a href="https://www.tandfonline.com/doi/abs/10.1080/09505431.2011.563574">safe to risky</a>.</p>
<figure class="align-center ">
<img alt="Hens poke their heads out of metal cages above a trough filled with eggs." src="https://images.theconversation.com/files/514445/original/file-20230309-22-1bzzvh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/514445/original/file-20230309-22-1bzzvh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/514445/original/file-20230309-22-1bzzvh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/514445/original/file-20230309-22-1bzzvh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/514445/original/file-20230309-22-1bzzvh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/514445/original/file-20230309-22-1bzzvh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/514445/original/file-20230309-22-1bzzvh.jpg?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">Hens raised in battery cages are unable to express their natural behaviour.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/battery-cage-layer-chickens-multilevel-production-1034569678">Mai.Chayakorn/Shutterstock</a></span>
</figcaption>
</figure>
<p>Alternative systems for producing eggs became more popular as a result. From their 1981 nadir, free-range eggs now constitute over 60% of the <a href="https://www.egginfo.co.uk/egg-facts-and-figures/industry-information/data">11.3 billion eggs</a> produced in the UK annually, according to a 2021 industry estimate.</p>
<h2>Safe and ethical?</h2>
<p>Free-range eggs are <a href="https://www.tandfonline.com/doi/abs/10.1080/08927936.2017.1310986">perceived</a> as safer by consumers and an easier ethical choice. Supermarkets offer an abundance of free-range products and there is no great difference in price compared with eggs from caged hens. </p>
<p>However, free-range egg farms differ from the advertised scenes of chickens roaming free in open fields. Even RSPCA assured free-range flocks can number <a href="https://www.rspcaassured.org.uk/rspca-assured-products/free-range-eggs/">16,000 hens</a> a shed, with daytime access to the outside provided by holes in the perimeter. </p>
<p><a href="https://www.bhwt.org.uk/beak-trimming/">Beaks are trimmed</a> to prevent birds harming each other as a result of the stress in this unnatural environment. More expensive <a href="https://www.soilassociation.org/take-action/organic-living/what-is-organic/organic-eggs/">organic eggs</a>, produced by much smaller flocks on farms where beak trimming is banned, are a <a href="https://www.egginfo.co.uk/egg-facts-and-figures/industry-information/data">minority</a> of those eaten in the UK.</p>
<p>Free-range egg farming is seen as both safer and more ethical than other forms of production. Though free from the worst excesses of battery farming, eggs with the free-range label are still produced on densely packed farms. Large, intensive systems such as these are implicated in the spread of bird flu, devastating poultry and wildlife alike. </p>
<p>Along with <a href="https://www.reuters.com/world/uk/uk-salad-shortage-weighs-supermarket-sales-niq-2023-03-07/">salad shortages</a> and “<a href="https://news.sky.com/story/milk-cheese-and-eggs-push-inflation-to-highest-rate-in-four-decades-12748651">milkflation</a>”, the disappearance of free-range eggs from English supermarkets is symptomatic of a food system responding to environmental stresses. The risks to animal welfare and the environment inherent in this system will remain without more radical changes to the scale and density of animal agriculture.</p>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?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">
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<p class="fine-print"><em><span>Joel Mead receives funding from the ESRC-funded North West Social Science Doctoral Training Partnership.</span></em></p>Though preferable to battery farms, free-range eggs are not as safe and ethical as customers think.Joel Mead, PhD Candidate in History, University of LiverpoolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2007102023-02-28T19:04:13Z2023-02-28T19:04:13ZWhen should we worry about bird flu making us sick? When we see human-to-human transmission – and there’s no evidence of that yet<p>Bird flu has been causing growing concern in recent months, with hundreds of millions of birds dying of the virus since October 2021. This is the <a href="https://wahis.woah.org/">largest</a> global outbreak. </p>
<p><a href="https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON445">Last week</a>, an 11-year-old child in Cambodia died from bird flu, prompting concern about spillover from wild birds and poultry to humans. But the cases we’ve seen in Cambodia are a different bird flu strain to that causing the massive bird deaths around the world. </p>
<p>While a small proportion of people have become ill while in contact with infected birds, there is no evidence either strain has spread from human to human. </p>
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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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<h2>What is bird flu?</h2>
<p>Many types of bird flu naturally circulate in wild birds. These are generally low pathogenic avian influenza viruses (LPAI), which typically cause few or no signs of disease.</p>
<p>However, some viruses are classified as highly pathogenic avian influenza (HPAI) and this is the case for the virus causing the global bird flu outbreak. </p>
<p>Avian influenza viruses are also categorised by subtype (creating the H and N number combination, here H5N1) and specific clades within the H5 subtype (equivalent to SARS-CoV-2 variants). The one we’re currently concerned about is H5N1 clade 2.3.4.4b. </p>
<p>The current strain of bird flu emerged in 2020/21, and spread rapidly causing outbreaks in Europe and Asia. The virus spread to <a href="https://doi.org/10.1038/s41598-022-13447-z">North America in December 2021</a>, causing substantial <a href="https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/avian-influenza/hpai-2022/">outbreaks</a> in wild birds and poultry since. </p>
<p>The virus entered South America in December 2022, with catastrophic outbreaks in <a href="https://www.science.org/doi/10.1126/science.adg2271">wild birds</a> and <a href="https://doi.org/10.1101/2023.02.08.527769">marine mammals</a>. </p>
<p>Only <a href="https://doi.org/10.1101/2023.02.06.527378">Australia</a> and the Antarctic remain free. </p>
<h2>How does it get to humans?</h2>
<p>The virus which causes bird flu is the same species that causes seasonal human influenza, swine influenza, equine influenza, and canine influenza, although different subtypes and strains are involved. </p>
<p>However, viruses are able to jump the species barrier. This is called “spillover”. We see strains of human influenza in <a href="https://doi.org/10.1128/JVI.00316-18">Australian pigs</a>, for example, and some strains of canine influenza <a href="https://doi.org/10.1128/JVI.00521-15">originated in horses</a>. There is also <a href="https://www.nature.com/articles/nature04230">evidence</a> that human flu strains emerged from birds. </p>
<p>Scientists are concerned about the large numbers of spillover events with this strain of bird flu. Cases have been <a href="https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/avian-influenza/hpai-2022/2022-hpai-mammals">detected</a> in <a href="https://www.biorxiv.org/content/10.1101/2023.02.08.527769v1">marine mammals</a> in Peru and New England, wild foxes, skunks, otters, bobcats, bears and raccoons in North America and other countries, and in <a href="https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2023.28.3.2300001">farmed mink</a> in Spain.</p>
<h2>What’s happening in Cambodia?</h2>
<p>Last week, a child with H5N1 died in the Prey Veng province of Cambodia. Of <a href="https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON445">12 contacts</a> identified, only one tested positive: the child’s parent, who is currently asymptomatic. </p>
<p>Both infections appear to be due to exposure to infected birds, which were found on the family’s property. Human-to-human transmission is unlikely. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1630125935096889345"}"></div></p>
<p>Rapid <a href="https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON445">genetic sequencing of the virus</a> determined it was a lineage commonly found in Cambodia (2.3.2.1c), and distinct from the clade 2.3.4.4b lineage causing concerns globally. </p>
<p>This is not the first report of spillover into humans. Recently a child in Ecuador was infected with 2.3.4.4b, most likely <a href="https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON434">originating</a> from sick poultry. <a href="https://cdn.who.int/media/docs/default-source/influenza/avian-and-other-zoonotic-influenza/h5-risk-assessment-dec-2022.pdf?sfvrsn=a496333a_1&download=true">Human cases</a> due to 2.3.4.4 have <a href="https://www.science.org/doi/10.1126/science.abo1232">occured</a> in Russia, China, the United Kingdom, the United States, Spain, Vietnam. So far, all human cases have occurred in people exposed to infected birds.</p>
<p>Spillover events like these occur when people are in contact with sick birds. Thankfully, spillover events do not often lead to human-to-human transmission of the virus. </p>
<p>However, if the virus develops the capability to spread in a new host, then outbreaks (and even pandemics) can occur. Scientists are closely monitoring for any evidence of bird flu adapting and spreading between mammals including humans.</p>
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Read more:
<a href="https://theconversation.com/bird-flu-continues-to-spread-in-mammals-what-this-means-for-humans-and-wildlife-199371">Bird flu continues to spread in mammals – what this means for humans and wildlife</a>
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<hr>
<h2>Why (and how) do viruses switch hosts?</h2>
<p>As part of their natural evolution, some viruses are particularly good at “jumping” to new hosts. For example, mpox (which used to be called monkeypox) and SARS-CoV-2 are both zoonotic viruses. </p>
<p>It is thought that mpox <a href="https://www.who.int/news-room/fact-sheets/detail/monkeypox">naturally infects rodents</a>. Mpox spills over into humans every few years, including a spillover last year that has continued into a widespread, ongoing <a href="https://www.who.int/emergencies/situations/monkeypox-oubreak-2022">outbreak</a>.</p>
<p>We <a href="https://academic.oup.com/gbe/article/14/2/evac018/6524630">expect</a> the ancestral lineage of SARS-CoV-2 was circulating in bat populations before it spilled over into humans. SARS-CoV-2 might have infected an <a href="https://www.science.org/doi/10.1126/science.abf6097">intermediate host</a> before jumping into the human population, picking up some advantageous mutations that allowed it to spread rapidly in humans. Several animals have been suggested as potential intermediate hosts, including mink and pangolins.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/512621/original/file-20230228-16-39ikhv.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/512621/original/file-20230228-16-39ikhv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/512621/original/file-20230228-16-39ikhv.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=595&fit=crop&dpr=1 600w, https://images.theconversation.com/files/512621/original/file-20230228-16-39ikhv.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=595&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/512621/original/file-20230228-16-39ikhv.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=595&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/512621/original/file-20230228-16-39ikhv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=747&fit=crop&dpr=1 754w, https://images.theconversation.com/files/512621/original/file-20230228-16-39ikhv.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=747&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/512621/original/file-20230228-16-39ikhv.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=747&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">While the top two panels are currently occurring, and there is suspicion that the third panel has occurred, the bottom panel is the type of evolution we want to avoid with bird flu.</span>
<span class="attribution"><span class="source">Ash Porter</span></span>
</figcaption>
</figure>
<p>Based on genomic surveillance, cases of bird flu in mammals almost always contain the same mutation. There is concern that further mutations may arise when circulating in an intermediate host which may allow the virus to better transmit between mammals, such as the spillover in mink farms, where mink-to-mink transmission <a href="https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2023.28.3.2300001?crawler=true">was suspected</a> to have occurred. </p>
<p>To date, the risk of human-to-human transmission of bird flu remains <a href="https://www.who.int/docs/default-source/wpro---documents/emergency/surveillance/avian-influenza/ai_20230203.pdf">low</a>. But as ferrets (which are related to minks) are a model animal for influenza infection in humans, if mink-to-mink transmission occurred on the farm in Spain, human-to-human transmission is plausible.</p>
<h2>What might happen next?</h2>
<p>Climate change and urbanisation are pushing humans and wildlife closer together, meaning there is more opportunity to interact with infected animals. </p>
<p>Our history of influenza pandemics caused by viruses with combinations of swine, avian and human influenza A virus genes shows we need consistent and ongoing surveillance of influenza A viruses, particularly in <a href="https://royalsocietypublishing.org/doi/10.1098/rsos.211573#:%7E:text=It%20has%20been%20argued%20that,resistance%20and%20low%20genetic%20diversity.">farms</a> along with wild-living and captive animal populations. </p>
<p>Government agencies and researchers across the globe are actively working on detection, response and genomic surveillance of bird flu outbreaks in birds and mammals. Genomic sequencing and surveillance can help inform us about where viruses are spreading, and how viruses is adapting to new hosts. </p>
<p>The World Organization for Animal Health <a href="https://www.woah.org/en/disease/avian-influenza/#ui-id-3">recommends</a> avoiding direct contact with sick or dead wild birds, poultry and wild animals and reporting outbreaks to local authorities. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/bird-flu-domestic-chicken-keepers-could-be-putting-themselves-and-others-at-risk-175187">Bird flu: domestic chicken keepers could be putting themselves – and others – at risk</a>
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<img src="https://counter.theconversation.com/content/200710/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michelle Wille receives funding from the Australian Research Council and is a member of the National Avian Influenza Wild Bird Steering Group. </span></em></p><p class="fine-print"><em><span>Ash Porter 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>While a small proportion of people have become ill while in contact with infected birds, there is no evidence it has spread from human to human.Ash Porter, Research officer, The Peter Doherty Institute for Infection and ImmunityMichelle Wille, Australian Research Council Discovery Early Career Researcher Award Fellow, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2004942023-02-24T20:48:52Z2023-02-24T20:48:52ZWhat is spillover? Bird flu outbreak underscores need for early detection to prevent the next big pandemic<figure><img src="https://images.theconversation.com/files/512225/original/file-20230224-1884-kmbqrq.jpg?ixlib=rb-1.1.0&rect=170%2C186%2C5231%2C3414&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Wild birds like pelicans and ducks are getting infected with – and dying from – a new strain of avian influenza and have spread it to farm animals around the world.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/dead-pelican-is-seen-on-the-beach-in-lima-peru-on-december-news-photo/1245471646?phrase=bird%20flu&adppopup=true">Klebher Vasquez/Anadolu Agency via Getty Images</a></span></figcaption></figure><p>The current epidemic of avian influenza has killed <a href="https://www.cdc.gov/flu/avianflu/data-map-commercial.html">over 58 million birds</a> in the U.S. as of February 2023. Following on the heels of the COVID-19 pandemic, large outbreaks of viruses like bird flu raise the specter of another disease jumping from animals into humans. This process is called spillover.</p>
<p>I’m a veterinarian and a researcher who studies how diseases spread between animals and people. I was on the Colorado State University <a href="https://source.colostate.edu/avian-bird-flu-egg-prices/">veterinary diagnostic team</a> that helped detect some of the earliest cases of H5N1 avian influenza in U.S. birds in 2022. As this year’s outbreak of bird flu grows, people are understandably worried about spillover.</p>
<p>Given that the next potential pandemic will likely originate from animals, it’s important to understand how and why spillover occurs – and what can be done to stop it.</p>
<figure class="align-center ">
<img alt="A cup of water containing viruses inside of it, with a fruit bat, chicken and pig standing on top of it. A drop of water with a new virus is falling toward a person, spreading more virus through coughing." src="https://images.theconversation.com/files/512088/original/file-20230223-1774-77sguf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/512088/original/file-20230223-1774-77sguf.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=548&fit=crop&dpr=1 600w, https://images.theconversation.com/files/512088/original/file-20230223-1774-77sguf.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=548&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/512088/original/file-20230223-1774-77sguf.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=548&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/512088/original/file-20230223-1774-77sguf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=689&fit=crop&dpr=1 754w, https://images.theconversation.com/files/512088/original/file-20230223-1774-77sguf.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=689&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/512088/original/file-20230223-1774-77sguf.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=689&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">Viral spillover occurs when a virus spills out from an animal population into people.</span>
<span class="attribution"><span class="source">Treana Mayer/BioRender</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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</figure>
<h2>How spillover works</h2>
<p>Spillover involves any type of disease-causing pathogen, be it a virus, parasite or bacteria, jumping into humans. The pathogen can be something never before seen in people, such as a new <a href="https://doi.org/10.1126/science.aaw7864">Ebola virus carried by bats</a>, or it could be something well known and recurring, like <a href="https://www.theguardian.com/environment/2021/aug/10/why-salmonella-is-a-food-poisoning-killer-that-wont-go-away-in-the-us"><em>Salmonella</em> from farm animals</a>. </p>
<p>The term spillover evokes images of a container of liquid overflowing, and this image is a great metaphor for how the process works.</p>
<p>Imagine water being poured into a cup. If the water level keeps increasing, the water will flow over the rim, and anything nearby could get splashed. In viral spillover, the cup is an animal population, the water is a zoonotic disease capable of spreading from an animal to a person, and humans are the ones standing in the splash zone. </p>
<p>The probability that a spillover will occur depends on many <a href="https://doi.org/10.1038/nrmicro.2017.45">biological and social factors</a>, including the rate and severity of animal infections, environmental pressure on the disease to evolve and the amount of close contact between infected animals and people.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/512231/original/file-20230224-1926-7gbjli.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A sign telling people to wear masks, stay 6 feet apart and wash hands." src="https://images.theconversation.com/files/512231/original/file-20230224-1926-7gbjli.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/512231/original/file-20230224-1926-7gbjli.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=391&fit=crop&dpr=1 600w, https://images.theconversation.com/files/512231/original/file-20230224-1926-7gbjli.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=391&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/512231/original/file-20230224-1926-7gbjli.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=391&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/512231/original/file-20230224-1926-7gbjli.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=492&fit=crop&dpr=1 754w, https://images.theconversation.com/files/512231/original/file-20230224-1926-7gbjli.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=492&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/512231/original/file-20230224-1926-7gbjli.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=492&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Epidemiologists estimate that three-quarters of all new infectious human diseases originated in animals.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/sign-listing-the-safety-guidelines-of-the-getty-museum-is-news-photo/1233106978?phrase=covid%20closed%20sign%20california&adppopup=true">Valerie Macon/AFP via Getty Images</a></span>
</figcaption>
</figure>
<h2>Why spillover matters</h2>
<p>While not all animal viruses or other pathogens are capable of spilling over into people, up to <a href="https://doi.org/10.1590%2F1678-4685-GMB-2020-0355">three-quarters of all new human infectious diseases</a> have originated from animals. There’s a good chance the next big pandemic risk will <a href="https://www.mdpi.com/2078-1547/13/2/35">arise from spillover</a>, and the more that’s known about how spillovers occur, the better chance there is at preventing it.</p>
<p>Most spillover research today is focused on <a href="https://doi.org/10.1146/annurev-virology-100120-015057">learning about and preventing viruses</a> – including coronaviruses, like the one that causes COVID-19 and certain viral lineages of avian influenza – from jumping into humans. These <a href="https://doi.org/10.1007%2Fs00018-014-1785-y">viruses mutate very quickly</a>, and random changes in their genetic code could eventually allow them to infect humans.</p>
<p>Spillover events can be <a href="https://doi.org/10.1007%2Fs00018-014-1785-y">hard to detect</a>, flying under the radar without leading to bigger outbreaks. Sometimes a virus that transfers from animals to humans poses no risk to people if the virus is not well adapted to human biology. But the more often this jump occurs, the higher the chances a dangerous pathogen will <a href="https://doi.org/10.1098/rspb.2021.0900">adapt and take off</a>.</p>
<h2>Spillover is becoming more likely</h2>
<p>Epidemiologists are projecting that the risk of spillover from wildlife into humans will increase in coming years, in large part because of the <a href="https://www.theguardian.com/world/2021/jun/04/end-destruction-of-nature-to-stop-future-pandemics-say-scientists">destruction of nature</a> and encroachment of humans into previously wild places. </p>
<p>Because of <a href="https://doi.org/10.1016%2FS2542-5196(21)00031-0">habitat loss, climate change and changes in land use,</a> humanity is collectively jostling the table that is holding up that cup of water. With less stability, spillover becomes more likely as animals are stressed, crowded and on the move.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/512237/original/file-20230224-1648-ddddz0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Houses and a farm next to some woods." src="https://images.theconversation.com/files/512237/original/file-20230224-1648-ddddz0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/512237/original/file-20230224-1648-ddddz0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/512237/original/file-20230224-1648-ddddz0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/512237/original/file-20230224-1648-ddddz0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/512237/original/file-20230224-1648-ddddz0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/512237/original/file-20230224-1648-ddddz0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/512237/original/file-20230224-1648-ddddz0.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">As housing and farmland expand into wild places, the risk of spillover increases.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/urban-development-on-the-edge-of-a-farm-field-royalty-free-image/1210310779?phrase=urban%20forest%20interface&adppopup=true">Cavan/Getty Images</a></span>
</figcaption>
</figure>
<p>As development expands into new habitats, wild animals come into closer contact with people – and, importantly, the food supply. The mixing of <a href="https://doi.org/10.1073/pnas.1208059110">wildlife and farm animals</a> greatly amplifies the risk that a disease will jump species and spread like wildfire among farm animals. Poultry across the U.S. are experiencing this now, thanks to a <a href="https://www.cdc.gov/flu/avianflu/avian-flu-summary.htm">new form of avian flu</a> that experts think spread to chicken farms mostly through <a href="https://doi.org/10.3201%2Feid2805.220318">migrating ducks</a>.</p>
<h2>Current risk from bird flu</h2>
<p>The new avian influenza virus is a distant descendant of the original H5N1 strain that has caused <a href="https://asm.org/Articles/2022/July/Avian-Influenza-Past,-Present,-Future">human epidemics of bird flu</a> in the past. Health officials are detecting cases of this new flu virus jumping from <a href="https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/avian-influenza/hpai-2022/2022-hpai-mammals">birds to other mammals</a> – like foxes, skunks and bears. </p>
<p>On Feb. 23, 2023, news outlets began reporting a few confirmed infections of people in Cambodia, including one infection leading to the death of an 11-year-old girl. While this new strain of bird flu can infect people in rare situations, it isn’t very good at doing so, because it is <a href="https://www.cdc.gov/flu/avianflu/spotlights/2022-2023/avian-flu-highly-pathogenic.htm">not able to bind to cells in human respiratory tracts</a> very effectively. For now, the Centers for Disease Control and Prevention thinks there is <a href="https://www.cdc.gov/flu/avianflu/spotlights/2022-2023/avian-flu-highly-pathogenic.htm">low risk to the general public</a>.</p>
<p>Active monitoring of wild animals, farm animals and humans will allow health officials to detect the first sign of spillover and help prevent a small viral splash from turning into a large outbreak. Moving forward, researchers and policymakers can take steps to prevent spillover events by preserving nature, keeping wildlife wild and separate from livestock and improving early detection of novel infections in people and animals.</p><img src="https://counter.theconversation.com/content/200494/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Treana Mayer receives funding from the NIH/NCATS Colorado CTSA Grant Number TL1 TR002533. Contents are the authors’ sole responsibility and do not necessarily represent official NIH views.</span></em></p>A biologist who studies how viruses spread from animals to people explains the process of spillover and the risks posed by the new bird flu that has spread across the globe.Treana Mayer, Postdoctoral Fellow in Microbiology, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1993712023-02-13T16:50:52Z2023-02-13T16:50:52ZBird flu continues to spread in mammals – what this means for humans and wildlife<p>As bird flu continues to decimate poultry and wild bird populations <a href="https://www.france24.com/en/environment/20230113-largest-global-bird-flu-outbreak-in-history-shows-no-sign-of-slowing">around the world</a>, the virus – a deadly strain called H5N1 – appears to be spreading to mammals. The virus has already been confirmed in foxes and otters in the UK, and more recently in <a href="https://www.gov.uk/government/publications/bird-flu-avian-influenza-findings-in-non-avian-wildlife/confirmed-findings-of-influenza-of-avian-origin-in-non-avian-wildlife">four dead seals</a>.</p>
<p>Bird flu refers to influenza A viruses that mainly infect birds. These viruses naturally circulate in wild waterfowl, usually without causing any symptoms. </p>
<p>But when they spread into poultry, some subtypes of the virus can evolve into forms that are highly infectious and deadly (classified as “highly pathogenic”), and can rapidly spread and kill domestic birds. </p>
<p>The H5N1 virus causing the current outbreak is one such highly pathogenic virus. Since its emergence in 1996, scientists have feared it poses a <a href="https://www.theguardian.com/uk-news/2021/dec/29/uk-health-chiefs-expected-imminent-pandemic-in-1997">pandemic threat</a>. The virus has shown a propensity to jump to humans (called “spillover”) with a high mortality rate. </p>
<p>World Health Organization (WHO) <a href="https://www.who.int/docs/default-source/wpro---documents/emergency/surveillance/avian-influenza/ai_20230106.pdf?sfvrsn=5f006f99_108">figures</a> show that between January 2003 to November 2022, there have been 868 cases of human infection with H5N1, more than half of which were fatal.</p>
<p>The foxes and otters that died were probably exposed to the virus by scavenging infected dead birds. The bodies of these birds have very high amounts of virus. Exposure to such a large dose might explain how the virus was able to overcome the species barrier. </p>
<p>Given that these cases occurred seemingly singly in different locations and times, they are probably dead ends – that is, unlikely to have caused further transmission in mammals. Evidence in the cases of seals in the UK also points to spillover (the virus going from birds to seals) rather than spread (going from seal to seal).</p>
<p>In contrast, the outbreak reported in a <a href="https://www.science.org/content/article/incredibly-concerning-bird-flu-outbreak-spanish-mink-farm-triggers-pandemic-fears">Spanish mink farm in October 2022</a> is more worrying. It is more likely that it spread from mink to mink due to the cramped conditions in which the animals live. Over 50,000 mink had to be euthanised.</p>
<p>Viruses from the mink appear to have <a href="https://doi.org/10.2807/1560-7917.ES.2023.28.3.2300001">acquired several changes</a> in their genes, at least one of which may help it grow better in mammals. How the virus spread to mink is not clear, but it is known that farmed mink are often <a href="https://www.nytimes.com/2023/02/08/health/avian-flu-mink-h5n1.html">fed raw poultry</a>. They are also not completely isolated from contact with other animals, such as wild birds.</p>
<figure class="align-center ">
<img alt="Mink in a cage." src="https://images.theconversation.com/files/509458/original/file-20230210-26-t5exqi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/509458/original/file-20230210-26-t5exqi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/509458/original/file-20230210-26-t5exqi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/509458/original/file-20230210-26-t5exqi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/509458/original/file-20230210-26-t5exqi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/509458/original/file-20230210-26-t5exqi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/509458/original/file-20230210-26-t5exqi.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">Bird flu spread among mink is more concerning.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/farmed-american-mink-383860660">Lynsey Grosfield/Shutterstock</a></span>
</figcaption>
</figure>
<p>In the wild, the virus has also recently been implicated in the <a href="https://www.cidrap.umn.edu/avian-influenza-bird-flu/peru-confirms-h5n1-avian-flu-marine-mammals-part-southward-spread#:%7E:text=In%20a%20follow%2Dup%2C%20SENASA,as%20the%20cause%20of%20death.">mass death of sea lions in Peru</a> in seven protected marine areas. And there are reports of the virus killing hundreds of seals in the <a href="https://inews.co.uk/news/politics/mass-death-of-seals-raises-fears-bird-flu-is-jumping-between-mammals-threatening-new-pandemic-2121376">Caspian Sea</a>, off the coast of Dagestan in Russia. If confirmed, the number of animals involved would suggest mammalian transmission.</p>
<p>All these infections do not mean that a virus capable of causing a pandemic will emerge. But the growing range of the virus gives more opportunities for it to evolve and for humans to come into contact with it.</p>
<p>H5N1 is a long-anticipated threat. Even so, having a clear idea of its evolution will help design more effective vaccines and treatments. Additionally, the virus is already having a devastating effect on wildlife and could spread to further endangered species. </p>
<p>Therefore, surveillance – testing for the virus and sequencing samples from animals and humans at high risk of exposure – is crucial. We also need to consider vaccinations in obvious sources such as poultry and shutting down mink farms entirely.</p>
<p>“Since H5N1 first emerged in 1996, we have only seen rare and non-sustained transmission of H5N1 to and between humans,” Tedros Adhanom Ghebreyesus, director general of the WHO, said in a <a href="https://www.who.int/news-room/speeches/item/who-director-general-s-opening-remarks-at-the-media-briefing---8-february-2023">press briefing</a> last week. “But we cannot assume that will remain the case, and we must prepare for any change in the status quo.”</p><img src="https://counter.theconversation.com/content/199371/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Divya Venkatesh receives funding from the Biotechnology and Biological Sciences Research Council (BBSRC). </span></em></p>Bird flu has been confirmed in four dead seals in Scotland.Divya Venkatesh, Research Fellow, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1981592023-01-23T01:04:57Z2023-01-23T01:04:57ZAustralia’s iconic black swans have a worrying immune system deficiency, new genome study finds<figure><img src="https://images.theconversation.com/files/505731/original/file-20230122-8930-yqnx7k.jpg?ixlib=rb-1.1.0&rect=31%2C10%2C3418%2C2603&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/npYQqEqiu3o">Conor O'Reagan/Unsplash</a></span></figcaption></figure><p>For years, scientists have known bird flu kills every black swan it infects. This means if the disease made it to the Australian continent, it would be an existential threat to this iconic Aussie species.</p>
<p>A new study <a href="https://doi.org/10.1186/s13059-022-02838-0">published today in Genome Biology</a> finally reveals the gene contributions that make black swans particularly prone to falling victim to infectious diseases.</p>
<p>The relative geographic isolation of the black swan (<em>Cygnus atratus</em>) may have resulted in a limited immune toolbox, making them more susceptible to the infectious avian diseases Australia <a href="https://www.agriculture.gov.au/biosecurity-trade/pests-diseases-weeds/animal/avian-influenza">has been largely shielded from</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/505746/original/file-20230123-38684-rfuj6n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A black swan standing among at least 20 white swans" src="https://images.theconversation.com/files/505746/original/file-20230123-38684-rfuj6n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505746/original/file-20230123-38684-rfuj6n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505746/original/file-20230123-38684-rfuj6n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505746/original/file-20230123-38684-rfuj6n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505746/original/file-20230123-38684-rfuj6n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505746/original/file-20230123-38684-rfuj6n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505746/original/file-20230123-38684-rfuj6n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mute swans are the iconic white species found throughout the Northern Hemisphere, while black swans are native to Australia.</span>
<span class="attribution"><span class="source">Paul Wishart/Shutterstock</span></span>
</figcaption>
</figure>
<h2>A DNA puzzle</h2>
<p>Unlike mallard ducks (<em>Anas platyrhynchos</em>) and the white-coloured mute swan (<em>Cygnus olor</em>), the black swan is extremely sensitive to highly pathogenic avian influenza or HPAI, commonly known as “bird flu”. </p>
<p>In May 2021 a collaborative effort between University of Western Australia and University of Queensland mapped the DNA puzzle of the black swan, which was released open-source <a href="https://www.dnazoo.org/post/emblem-of-western-australia">through DNA Zoo</a>. </p>
<p>To understand whether the geographically-isolated black swan has a different immune gene repertoire compared to its relatives, for the past two years we have worked on comparing the black swan genome to that of the closely related – yet genetically distinct – Northern Hemisphere mute swans. This work was done by a large team of scientists from Australia, New Zealand, Sweden, Germany, Japan, USA and UK.</p>
<p>Harnessing the power of high-performance computing, we mapped and compared tens of thousands of genes between the two species, to better understand why black swans fall victim to the virus so easily while mute swans do not. Such work is akin to finding a needle in a haystack.</p>
<p>Our work has now provided insights into how these species diverge genetically in response to the deadly bird flu and other viruses in the same family.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/505698/original/file-20230121-15434-hny19b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A black swan with a red beak against a light background of rippling water" src="https://images.theconversation.com/files/505698/original/file-20230121-15434-hny19b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505698/original/file-20230121-15434-hny19b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505698/original/file-20230121-15434-hny19b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505698/original/file-20230121-15434-hny19b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505698/original/file-20230121-15434-hny19b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505698/original/file-20230121-15434-hny19b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505698/original/file-20230121-15434-hny19b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Black swans aren’t just a different colour from the white ones – the differences in genome run much deeper.</span>
<span class="attribution"><span class="source">Parwinder Kaur</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Some missing genes</h2>
<p>Notably, we found the black swan showed undetectable gene expression in toll-like receptor (TLR-7), a class of proteins responsible for the immune system’s reaction to foreign viruses. In other words, they have the gene for it, but it’s not turning on for some reason. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/505700/original/file-20230121-8930-3no87.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A woman in a dark salwar kameez dress standing next to a black swan on a grassy background" src="https://images.theconversation.com/files/505700/original/file-20230121-8930-3no87.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/505700/original/file-20230121-8930-3no87.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=664&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505700/original/file-20230121-8930-3no87.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=664&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505700/original/file-20230121-8930-3no87.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=664&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505700/original/file-20230121-8930-3no87.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=834&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505700/original/file-20230121-8930-3no87.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=834&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505700/original/file-20230121-8930-3no87.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=834&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dr Parwinder Kaur pictured with a black swan in Matilda Bay, Perth. The birds are the subject of a major collaboration in genome comparison studies.</span>
<span class="attribution"><span class="source">Parwinder Kaur</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The TLR-7 family has been extensively studied in humans, as it is known to play a role in virus and tumour cell recognition. A 2021 study showed TLR-7 is crucial to the pattern recognition receptors (the molecules that can detect pathogens) <a href="https://www.frontiersin.org/articles/10.3389/fimmu.2021.756262/full">of SARS-CoV-2 in humans</a>.</p>
<p>In infected endothelial cells – the cells lining blood vessels and the heart – of the black swan, we found a dysregulated (abnormal) pro-inflammatory response. When the immune system reacts to a threat, some inflammatory response is normal, but it’s possible it can cause a more severe reaction if dysregulated. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/black-swans-and-other-deviations-like-evolution-all-scientific-theories-are-a-work-in-progress-95544">Black swans and other deviations: like evolution, all scientific theories are a work in progress</a>
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<h2>Risking a wipe-out</h2>
<p>Our work has also found the black swan genome was contractive. This means that from their last common ancestor with mute swans, black swans lost more genes in total than they gained.</p>
<p>Specifically, 39 immune-related gene families of the black swan were contractive as compared to the mute swan. This could be because being relatively isolated in Australia, they were less exposed to infectious bird diseases.</p>
<p>The data gathered by this sequencing project indicate the immune system of the black swan is more susceptible to any avian viral infection if it were to arrive in its native habitat. In other words, bird flu could even risk wiping out this species. </p>
<p>Now that we understand the potential underlying mechanism for black swans’ susceptibility to bird flu – and given TLR-7 is such an extensively studied gene in humans – there are several ways we can save our precious swans.</p>
<p>One way would be to look for natural variation that exists for this particular gene family in different black swan populations across Australia, Tasmania and New Zealand. There are likely to be individuals with higher resistance to bird flu, and we could use them to develop a strategic breeding program for this species.</p>
<p>Otherwise – and a more expensive path – would be to develop immunotherapy treatments, such as we have developed for humans. The good news is we now know what could be done to protect these swans.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/friday-essay-a-rare-bird-how-europeans-got-the-black-swan-so-wrong-161654">Friday essay: a rare bird — how Europeans got the black swan so wrong</a>
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<img src="https://counter.theconversation.com/content/198159/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>Why are Australian black swans so quick to die from bird flu? A new genome study comparing them to their bird brethren helps to unravel the mystery.Parwinder Kaur, Associate Professor | Director, DNA Zoo Australia, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1946942022-11-22T17:07:41Z2022-11-22T17:07:41ZBird flu: UK is seeing its largest ever outbreak – which may prove particularly deadly for wild birds<figure><img src="https://images.theconversation.com/files/496718/original/file-20221122-24-ckat74.jpg?ixlib=rb-1.1.0&rect=7%2C7%2C5239%2C3482&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">In the UK, more than 150 cases of bird flu have been reported between September and November of this year alone.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/egg-factory-plant-agriculture-poultry-chicken-1587664702">Mark Agnor/ Shutterstock</a></span></figcaption></figure><p>The outbreak of avian influenza which has hit the UK since the autumn of 2021 is the largest the country has ever seen. And the picture is the same across <a href="https://www.ecdc.europa.eu/en/publications-data/avian-influenza-overview-september-2022">Europe</a> and <a href="https://www.cdc.gov/flu/avianflu/data-map-commercial.html">the US</a>, which are reporting a similar picture. To date, this outbreak has led to the death of <a href="https://lordslibrary.parliament.uk/bird-flu-2022-dealing-with-the-uks-largest-ever-outbreak/">nearly 100 million poultry birds</a> around the world. </p>
<p>But the disease doesn’t only threaten poultry and egg production – it also threatens <a href="https://eprints.glos.ac.uk/11845/">wild bird populations</a> in a way that it never has before. While drastic action has been taken to control the spread of avian flu in domestic birds, these efforts may be insufficient alone to mitigate the impact on wild bird populations.</p>
<p>Typically, western Europe’s avian flu season starts in the autumn, when millions of migratory birds from colder climates – such as geese, ducks and swans – <a href="https://www.rspb.org.uk/our-work/rspb-news/rspb-news-stories/which-birds-migrate-to-the-uk-in-autumn/#:%7E:text=UK%20winter%20waders&text=Many%20knots%20migrate%20from%20Canadian,to%20the%20UK%20every%20year.">arrive for the winter</a>. If these wild birds come into contact with domestic poultry, any pathogens they’re carrying can spread to these populations. It’s a time that poultry farmers and other bird keepers dread, as certain strains of bird flu (in particular highly pathogenic avian influenza, also known as HPAI) can be extremely deadly. Come springtime, when wild migratory birds return to their summer breeding grounds in eastern Europe and Asia, avian flu wanes with their departure. </p>
<p>Or, at least, that was the pattern in recent decades. But, since the autumn of 2020, this has changed.</p>
<p>Previous outbreaks of HPAI among UK poultry have been relatively rare. But between <a href="https://webarchive.nationalarchives.gov.uk/ukgwa/20221018152851/https:/www.gov.uk/guidance/avian-influenza-bird-flu-cases-and-disease-control-zones-in-england#disease-control-zones-no-longer-in-force">November 2020 to March 2021</a>, 24 cases of HPAI were reported. This situation has only worsened since then, with more than <a href="https://www.gov.uk/government/publications/avian-influenza-in-wild-birds">150 confirmed cases of HPAI</a> between September 5 and November 17 of this year alone. </p>
<p>Similarly, <a href="https://www.gov.uk/government/publications/avian-influenza-in-wild-birds">between 2017 and 2019</a>, only 40 UK wild birds tested after their death were found to be positive for HPAI. But this rose to 317 in 2020-2021 and 1,468 since October 1 this year. </p>
<p>Usually, HPAI causes mass mortality among poultry while the majority of wild birds seem less affected. This is one feature that makes the current avian flu outbreak so unique. To date, <a href="https://eprints.glos.ac.uk/11845/">15 species of seabirds</a> have tested positive for HPAI for the first time, and die-offs in some species, <a href="https://doi.org/10.3390/v14020212">such as great skuas</a>, are worrying due to their magnitude and potential to threaten the species’ persistence in the UK. </p>
<p>Moreover, the seasonal downturn in cases of avian flu didn’t happen during the spring as confirmed outbreaks continued among poultry and wild birds over the summer. </p>
<h2>Avian flu virus</h2>
<p>Bird flu is caused primarily by an influenza A virus, which is closely related to other influenza viruses. These mutate rapidly and can combine genetic material from other influenza viruses into their genomes in order to produce new variants. </p>
<p><a href="https://www.proquest.com/openview/578bfa8c3034653f91e2efca55b2321b/1?pq-origsite=gscholar&cbl=2041027">New strains</a> of avian flu are typically imported during each bird migration season. But we are increasingly witnessing <a href="https://www.mdpi.com/1999-4915/13/2/259">new strains</a> emerging within the UK and other European countries over winter. The current H5N1 strain of HPAI, seems to be <a href="https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/j.efsa.2022.7289">more infectious and more fatal to poultry</a>, and more persistent in wild bird populations. It’s also able to affect a greater diversity of species than previous strains. </p>
<p>And, with a greater number of wild birds infected, this is likely to mean that there have been more opportunities for infected or contaminated wild birds to come into contact with poultry. This may also have contributed to the current high number of cases.</p>
<figure class="align-center ">
<img alt="A great skua stands on rocks by the sea." src="https://images.theconversation.com/files/496719/original/file-20221122-12-bfaj5g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/496719/original/file-20221122-12-bfaj5g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/496719/original/file-20221122-12-bfaj5g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/496719/original/file-20221122-12-bfaj5g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/496719/original/file-20221122-12-bfaj5g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/496719/original/file-20221122-12-bfaj5g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/496719/original/file-20221122-12-bfaj5g.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">Great skuas have been particularly affected.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/great-skua-stercorarius-large-seabird-family-1202597158">Gestur Gislason/ Shutterstock</a></span>
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<p>There are still many things that we don’t know about the current outbreak of avian flu, which is why the government has set up a <a href="https://governmentscienceandengineering.blog.gov.uk/2022/06/20/apha-defra-and-bbsrc-have-today-announced-a-major-new-research-consortium-in-the-uks-battle-against-bird-flu/">task force</a> to investigate. One factor this task force is looking into is whether the current strain can survive in the environment outside an animal host (a phenomenon known as environmental persistence). If this is possible, it may help explain why so many wild birds are being infected by the current strain of HPAI – and why outbreaks continued over the summer.</p>
<h2>Containing the virus</h2>
<p>The UK government has introduced a range of measures to contain avian flu. All British poultry farms are required to implement stringent biosecurity practices to help prevent their flocks from catching the virus, including housing free-range birds to prevent contact with wild birds, and regularly cleaning and disinfecting housing. Dead wild birds and poultry suspected of having avian flu are also being <a href="https://www.gov.uk/guidance/avian-influenza-bird-flu">tested for the virus</a>. If a single bird in a poultry flock is found with avian flu, the entire flock <a href="https://www.gov.uk/guidance/avian-influenza-bird-flu-cases-and-disease-control-zones-in-england">must be culled</a> to prevent the disease from spreading.</p>
<p>Birds are not the only species that can become infected with avian flu. In the past, some strains have made the <a href="https://doi.org/10.3201/eid2711.211225">jump to mammals</a>, including humans. There were <a href="https://doi.org/10.1002/rmv.2099">883 reported human cases</a> of a H5N6 strain (which is not currently present in Europe) worldwide between 2017 and 2020. But this tended to manifest itself primarily among people working very closely with birds. There has only been one <a href="https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/j.efsa.2022.7289">human case</a> of H5N1 reported during the current UK outbreak, so risks to people are thought likely remain very low. The disease can also be effectively controlled with a course of <a href="https://doi.org/10.1016/j.jiph.2018.08.005">antiviral medication</a> if it does develop.</p>
<p>While measures to control avian flu help mitigate risks to poultry and people, they do little to help wild birds. This could be a problem both for the persistence of the current outbreak and the conservation of some threatened species, which are already under pressure due to human-induced changes to the environment. </p>
<p>The immediate future for HPAI looks rather bleak for the UK which can expect ongoing outbreaks among poultry and die-offs among wild birds continuing into next autumn and winter. The government’s task force will publish its findings next year, and will answer many questions about the current HPAI strain. But many more questions may need to be answered before we know how best to get the current outbreak under control.</p><img src="https://counter.theconversation.com/content/194694/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alastair Ward receives funding from the BBSRC and Defra. </span></em></p>The UK government has set up a special task force to investigate.Alastair Ward, Associate Professor of Biodiversity and Ecosystem Management, University of LeedsLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1926002022-10-17T02:55:55Z2022-10-17T02:55:55ZWhat is avian flu, the disease afflicting viral TikTok emu Emmanuel?<figure><img src="https://images.theconversation.com/files/489963/original/file-20221017-26-2i2s3x.png?ixlib=rb-1.1.0&rect=263%2C17%2C3449%2C1976&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Twitter/@Hiitaylorblake</span></span></figcaption></figure><p>Viral TikTok star Emmanuel – an emu who gained a vast online following thanks to videos shared by his owner at Knuckle Bump Farms in Florida – <a href="https://www.forbes.com/sites/brucelee/2022/10/16/tiktok-emu-emmanuel-is-ill-avian-flu-kills-99-birds-on-farm/?sh=593dfc255c7b">has reportedly</a> fallen sick with avian influenza.</p>
<p>Farm owner Taylor Blake wrote on Twitter that wild geese brought avian influenza to the farm, with many birds having since died. </p>
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<p>As a large outbreak sweeps poultry farms across <a href="https://abcnews.go.com/US/wireStory/bird-flu-case-prompts-omaha-zoo-close-exhibits-91591574">the US</a> and <a href="https://www.nationalgeographic.co.uk/environment-and-conservation/2022/09/the-uks-largest-avian-flu-outbreak-has-left-millions-of-birds-dead-and-scientists-extremely-concerned">the UK</a>, many people are now asking: what exactly is avian influenza, and what do I need to know?</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/ChfGnKEATaU","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
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Read more:
<a href="https://theconversation.com/nearly-half-a-million-poultry-deaths-there-are-3-avian-influenza-outbreaks-in-victoria-should-we-be-worried-145325">Nearly half a million poultry deaths: there are 3 avian influenza outbreaks in Victoria. Should we be worried?</a>
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</em>
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<h2>What is avian influenza?</h2>
<p>Avian influenza is a disease caused by an influenza A virus, affecting birds across many species. </p>
<p>It can have significant consequences for the poultry industry, due to its potential impact on bird health, production and even international trade.</p>
<p>Although avian influenza does not usually infect people, it is considered a zoonotic virus. That means it can be transmitted to humans through contact with infected birds, and sporadic cases have been seen when outbreaks happen in poultry. </p>
<p>Some avian influenza viruses are more pathogenic than others. Pathogenic means disease-causing, so if highly pathogenic avian influenza gets into a poultry farm, it can cause sudden and significant mortality. </p>
<p><a href="https://www.forbes.com/sites/brucelee/2022/10/16/tiktok-emu-emmanuel-is-ill-avian-flu-kills-99-birds-on-farm/?sh=593dfc255c7b">It has been reported</a> the outbreak underway on the farm where Emmanuel lives is a highly pathogenic strain, which has been affecting poultry and wild birds in the US <a href="https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/avian-influenza/2022-hpai">since January 2022</a>. </p>
<p>Even low pathogenic strains can make birds unwell and cause them to lay fewer eggs.</p>
<p>Avian influenza infections in humans can cause a range of clinical symptoms, from mild upper respiratory symptoms to severe pneumonia. </p>
<p>Some strains of avian influenza, such as highly pathogenic <a href="https://theconversation.com/au/topics/bird-flu-h5n1-2154">H5N1</a> and <a href="https://theconversation.com/au/topics/h7n9-6165">H7N9</a>, can cause significant disease in humans, and in some instances even death. </p>
<p><a href="https://www.cdc.gov/flu/avianflu/novel-av-treatment-guidance.htm">Recommended standard treatment</a> for humans is with antiviral drugs, and will depend on individual circumstances and severity of the symptoms. </p>
<p>In domestic birds, the most likely path of infection is through contact with infected wild birds. This could be direct contact or contact through water contaminated with wild bird droppings. </p>
<p>Generally, an outbreak of avian influenza on a poultry farm means many birds have to be culled in an effort to stop the spread.</p>
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<h2>Is there any avian flu in Australia?</h2>
<p>Australia is <a href="https://www.cdc.gov/flu/avianflu/novel-av-treatment-guidance.htm">classed by the World Organisation for Animal Health</a> as free of avian influenza in the domestic bird population. However, we do currently have a low-level circulation of low pathogenic influenza viruses among wild birds. </p>
<p>We have had several low and highly pathogenic avian influenza outbreaks in domestic poultry in Australia before, with the most recent one <a href="https://www.premier.vic.gov.au/victorians-achieve-national-freedom-avian-influenza">affecting</a> farms in Victoria. Many birds were culled to eradicate the disease and in all cases eradication was successful.</p>
<p>None of the viruses causing these outbreaks in Australia have caused disease in humans. However, it is important that we use hygienic practices and biosecurity when working with poultry. </p>
<p>We currently do not have H5N1 in Australia; waterfowl, the bird species most likely to carry this virus, do not migrate to Australia. In addition, Australia has very strict biosecurity measures to prevent disease introduction through imports. Therefore, the risk of introduction of this strain into the country is very low. </p>
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<p>Most measures aimed at reducing the risk of avian influenza outbreaks in poultry in Australia have focused on reducing contact between wild birds and farmed birds. </p>
<p>That means limiting the access wild birds can get to farms, as well as protecting and treating water sources. </p>
<p>In the past decade, we have seen an increase in the number of domestic outbreaks in Australia. <a href="https://www.sciencedirect.com/science/article/pii/S0167587718307712?via%3Dihub">Previous</a> <a href="https://www.sciencedirect.com/science/article/pii/S2352771420300434?via%3Dihub">research</a> <a href="https://www.frontiersin.org/articles/10.3389/fvets.2018.00068/full">suggests</a> this increase could be associated with an increase in free range poultry over the last 30 years. </p>
<p><a href="https://www.sciencedirect.com/science/article/pii/S0167587718307712?casa_token=i6oIULd0DFQAAAAA:48es3yMNgB-w_WDQACaa-7OEotjnNzDEAVn7G8MoTEteQIcvQ9vPkkgyJybaESvFEZbBDH65#!">A paper</a> I coauthored in 2019 modelled how intervention strategies could reduce risk, noting that:</p>
<blockquote>
<p>a shift of 25% of conventional indoor farms to free-range farming practices would result in a 6–7% increase in the risk of a highly pathogenic avian influenza outbreak. Current practices to treat water are highly effective, reducing the risk of outbreaks by 25–28% compared to no water treatment. </p>
<p>Halving wild bird presence in feed storage areas could reduce risk by 16–19% while halving wild bird access of potential bridge-species to sheds could reduce outbreak risk by 23–25%.</p>
</blockquote>
<p>A large outbreak in Australia would be enormously costly to industry, cause a vast number of birds to die and could potentially pose a health risk to humans. </p>
<p>Although vaccines for avian influenza for poultry are available, these would only be considered if an outbreak became widespread.</p>
<p>Following appropriate biosecurity practices on poultry farms continues to be the most important prevention tool we have to avoid outbreaks.</p><img src="https://counter.theconversation.com/content/192600/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Marta Hernandez-Jover receives funding from the Australian Research Council and the Australia's Rural Research and Development Corporations.</span></em></p>Viral TikTok star Emmanuel – a US-based emu who enjoys a vast online following – has fallen sick with avian influenza. So what is this disease and what’s the risk in Australia?Marta Hernandez-Jover, Professor in Veterinary Epidemiology and Public Health, Charles Sturt UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1850582022-06-14T13:52:23Z2022-06-14T13:52:23ZAvian flu has jumped into wild seabirds and is spreading fast<figure><img src="https://images.theconversation.com/files/468770/original/file-20220614-14-dwibs4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Seabirds like gannets appear to be particularly at risk.</span> <span class="attribution"><span class="source">Coatesy / shutterstock</span></span></figcaption></figure><p>After a series of localised outbreaks in the past few years, avian flu has re-emerged as a major driver of bird deaths across the UK. Until the past few weeks, the latest outbreak of the disease – also known as bird flu or, to scientists, highly pathogenic avian influenza – was treated primarily as a problem for chickens and other domestic birds. This triggered localised responses such as culls, and farmers were ordered to keep the animals indoors for six months over the winter, which is why the UK had a period with <a href="https://inews.co.uk/news/free-range-eggs-supermarkets-bird-flu-outbreak-keep-hens-indoors-1606150">no free-range eggs</a>.</p>
<p>But reports of large numbers of wild seabirds found dead in <a href="https://news.sky.com/story/highly-pathogenic-bird-flu-killing-hundreds-of-seabirds-along-scottish-coast-12631202">Scotland</a> and increasingly in <a href="https://www.thenorthernecho.co.uk/news/20206446.bird-flu-reports-dead-birds-north-east-beaches/">England</a> and Wales, suggest that avian flu is now prevalent in wild birds across most of northern Britain. I encountered a number of these birds myself on the Northumberland coast. </p>
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<p>Scenes like these will make the crisis far more visible to the general public, and naturally they will be asking what more we can do to tackle the outbreak.</p>
<h2>The 2021-22 avian flu outbreak</h2>
<p>The 2021-22 outbreak is a global problem, with cases of the virulent H5N1 subtype detected in West Africa, Asia, and nearly every country of Europe and <a href="https://www.cbc.ca/news/canada/nova-scotia/avian-flu-birds-cape-breton-shores-1.6479304">North America</a>. It is primarily a disease of domesticated birds, where it is thought to have originated, and has led to the culling of hundreds of millions of birds, including <a href="https://www.theguardian.com/environment/2022/jun/06/us-bird-flu-outbreak-millions-of-birds-culled-in-most-inhumane-way-available">38 million</a> in the US this year alone.</p>
<p>In the UK, the disease was first detected in October 2021. As elsewhere, the outbreak was at first largely confined to poultry, and farmers were forced to cull <a href="https://www.birdlife.org/news/2022/01/10/israel-and-uk-facing-record-breaking-bird-flu-outbreaks/">500,000 chickens and other birds</a>. In response the UK established an Avian Influenza Prevention Zone including buffer zones of 10km around detected cases, with restrictions on bird movement and enhanced biosecurity. </p>
<p>Over winter there were reports of a number of wild bird populations being affected by avian flu, including great skua, pink-footed geese and barnacle geese. These included the mass death of <a href="https://www.rspb.org.uk/our-work/rspb-news/rspb-news-stories/avian-flu-devastating-bird-populations/?from=hphero">4,000 birds on the Solway Firth</a>, representing one-third of the Svalbard barnacle goose population that spend winters in the area.</p>
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<p>As spring has turned to summer, there is now no doubt that avian flu is now spreading into <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1081982/HPAI_Europe_6_June_2022.pdf">a wider diversity of wild birds</a> in the UK. For some species this probably reflects their return to summer breeding colonies, and the increased mixing that involves (avian flu is spread by contact with saliva or droppings).</p>
<p>As this breeding season reaches its peak, a wide array of seabirds have been affected, including great skua, eider ducks, fulmar, terns, gannets and guillemots. The UK holds over half the world’s population of gannet and great skua, both of which have been officially recognised as birds of moderate conservation concern (“<a href="https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/great-skua/">amber status</a>”). Avian flu adds to the litany of problems these birds face – from climate change to entanglement in abandoned fishing gear – and increases the concerns of organisations such as RSPB and Birdlife, who already consider this outbreak to be <a href="https://community.rspb.org.uk/ourwork/b/birdflu/posts/bird-flu-update-june-2022">the worst the UK has ever faced</a>.</p>
<h2>More resources needed</h2>
<p>Conservation organisations have asked for more resources to help with monitoring and tackling the problem. Many bird wardens and reserve managers already work on the nature reserves most affected by avian flu, and so they will be an important part of the solution. We could also reduce the level of human disturbance at particularly sensitive sites, for example by introducing buffer zones or seasonal restrictions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/468784/original/file-20220614-16-xr7zgc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two birds on a rock" src="https://images.theconversation.com/files/468784/original/file-20220614-16-xr7zgc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468784/original/file-20220614-16-xr7zgc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=351&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468784/original/file-20220614-16-xr7zgc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=351&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468784/original/file-20220614-16-xr7zgc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=351&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468784/original/file-20220614-16-xr7zgc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=441&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468784/original/file-20220614-16-xr7zgc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=441&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468784/original/file-20220614-16-xr7zgc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=441&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Great skuas were already threatened by fishing lines and climate change. Now they’re fighting off the flu.</span>
<span class="attribution"><span class="source">Erni / shutterstock</span></span>
</figcaption>
</figure>
<p>But, more broadly, we simply need more surveillance of avian flu so that we can get a better idea of the problem. This will mean also giving the relevant government <a href="https://www.gov.uk/guidance/avian-influenza-bird-flu">departments</a> and <a href="https://aphascience.blog.gov.uk/2021/12/16/bird-flu-outbreak-2021/">agencies</a> the resources they need to monitor and test more wild birds.</p>
<p>In summer, avian flu retains infectivity in the environment for <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1081982/HPAI_Europe_6_June_2022.pdf">up to 18 days</a>. So the large number of dead birds on the coast with possible infections presents a continuing pathway for transmission to birds of prey and carrion feeders, particularly gulls, which are known to be susceptible to avian flu. Increasing the number of carcasses being collected would have the added benefit of removing the potential for carrion feeders to become infected, and so further infect other birds. </p>
<p>Given some of these seabirds can range over huge distances in search of food – <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/406991/OESEA2_North_Sea_Gannet_Tracking_Year3_Report.pdf">up to 400km for gannets</a>, for instance – we will need a national approach to this, with coordination across the four nations of the UK. And because the virus has been repeatedly transmitted between the domestic stocks and wild bird populations, we should also look again at biosecurity measures in the poultry industry.</p>
<h2>What next</h2>
<p>What does this mean for the general public? Although avian flu is a zoonotic disease like COVID-19, the risk to human health is very low, and cases in humans have almost exclusively arisen from close contact between bird keepers and their stock. The advice for the public is not to touch any dead birds you see and to <a href="https://www.gov.uk/guidance/avian-influenza-bird-flu#public">report them</a>. </p>
<p>If you feed wild birds, remember to wash and disinfect feeders every week and to clean bird baths every day, as avian flu is mainly transmitted via saliva and droppings. And if you’re out walking the dog, keep a closer eye on them when you’re on the beach or by water, and use a lead when you’re on a nature reserve or see a dead bird. </p>
<p>There is no doubt that the increased visibility of the deaths will bring home the scale of the problem to the general public. Bird flu has now “arrived” in our minds, and will take on more prominence as the summer continues and holidays begin. Though the risk to humans is very low, it serves as another reminder of how <a href="https://www.who.int/publications/m/item/one-health-high-level-expert-panel-annual-report-2021">connected we are to nature</a>, and how our interactions with the natural world have huge consequences for what we regard as “human” systems.</p><img src="https://counter.theconversation.com/content/185058/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Suggitt 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>Seabirds seem to be particularly at risk.Andrew Suggitt, Vice Chancellor's Senior Research Fellow, Northumbria University, NewcastleLicensed 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.