tag:theconversation.com,2011:/uk/topics/infectious-diseases-402/articlesInfectious diseases – The Conversation2024-03-19T12:23:24Ztag:theconversation.com,2011:article/2237062024-03-19T12:23:24Z2024-03-19T12:23:24ZFemale mosquitoes rely on one another to choose the best breeding sites − and with the arrival of spring, they’re already on the hunt<figure><img src="https://images.theconversation.com/files/582309/original/file-20240315-26-7bf0sq.jpg?ixlib=rb-1.1.0&rect=30%2C0%2C6789%2C4468&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">_Aedes aegypti_, found across much of the U.S., spread Zika, dengue, chikungunya and other viruses.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/aedes-aegypti-mosquito-pernilongo-with-white-spots-royalty-free-image/1282216815">Mailson Pignata/iStock via Getty Images</a></span></figcaption></figure><p><em>Aedes aegypti</em> mosquitoes, one of the <a href="https://www.cdc.gov/mosquitoes/mosquito-control/professionals/range.html">most common species in the U.S.</a>, love everything about humans. They love our <a href="http://dx.doi.org/10.1126/science.adi8213">body heat and odors</a>, which enable them to find us. They love to feed on our blood to make their eggs mature. They even love all the standing water that we create. Uncovered containers, old tires and junk piles collect water and are perfect for breeding. </p>
<p>And with the advent of warm weather across the southern U.S., <a href="https://www.mosquitomagnet.com/articles/mosquito-season">mosquito breeding season is already underway</a>.</p>
<p>Given all the options that <em>Aedes</em> females have in urban areas, how do these cosmopolitan mosquitoes find the perfect site to lay their eggs? Scientists previously thought this was a solitary act, but now research shows that female <em>Aedes aegypti</em> mosquitoes – the main vector in the U.S. for diseases such as <a href="https://theconversation.com/explainer-where-did-zika-virus-come-from-and-why-is-it-a-problem-in-brazil-53425">Zika, dengue, chikungunya</a> and other viruses – can rely on one another for good reviews of breeding sites. </p>
<p>Our <a href="https://www.degennarolab.org/">Laboratory of Tropical Genetics</a> at Florida International University discovered a new behavior in which these mosquitoes <a href="https://doi.org/10.1038/s42003-024-05830-5">work together to find suitable egg-laying sites</a>. These findings, recently published in Communications Biology, show that mosquitoes regulate their own population density at breeding sites – an insight that could inform future mosquito control efforts.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/581972/original/file-20240314-30-jxgzpm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A half-dozen mosquitoes spread along the inside of a container." src="https://images.theconversation.com/files/581972/original/file-20240314-30-jxgzpm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581972/original/file-20240314-30-jxgzpm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=750&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581972/original/file-20240314-30-jxgzpm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=750&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581972/original/file-20240314-30-jxgzpm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=750&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581972/original/file-20240314-30-jxgzpm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=943&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581972/original/file-20240314-30-jxgzpm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=943&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581972/original/file-20240314-30-jxgzpm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=943&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"><em>Aedes aegypti</em> female mosquitoes laying their eggs in a laboratory breeding container.</span>
<span class="attribution"><span class="source">Kaylee Marrero</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Where and why female mosquitoes cluster</h2>
<p>Scientists know that female mosquitoes can be picky when it comes to where they lay their eggs. <em>Aedes aegypti</em> look for human-made breeding sites with relatively clean water, such as birdbaths, tires or even water-filled trash. But given two equal choices, you might expect them to spread evenly between the two. </p>
<p>On the contrary, when we released females in a two-choice test where both breeding site options were equivalent, we repeatedly found more mosquitoes in one chamber than in the other. Furthermore, this occurred irrespective of where the preferred chamber was positioned, whether the mosquitoes could touch water or whether mosquito eggs were already present at the breeding sites. </p>
<p>Female mosquitoes clearly were following one another in small groups to one breeding site rather than another – a newly discovered behavior in <em>Aedes aegypti</em> that we call aggregation. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/581971/original/file-20240314-26-70qvqk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two ramekins, one with a few black spots in it, the other with many spots." src="https://images.theconversation.com/files/581971/original/file-20240314-26-70qvqk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581971/original/file-20240314-26-70qvqk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=319&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581971/original/file-20240314-26-70qvqk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=319&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581971/original/file-20240314-26-70qvqk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=319&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581971/original/file-20240314-26-70qvqk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=401&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581971/original/file-20240314-26-70qvqk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=401&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581971/original/file-20240314-26-70qvqk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=401&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 black spots in the container on the right indicate that <em>Aedes aegypti</em> females have chosen it as a place to lay their eggs over the identical site on the left.</span>
<span class="attribution"><span class="source">Kaylee Marrero</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The insects evidently preferred not to lay their eggs alone. When we tested 30 mosquitoes in our trials, they chose one site over another by a 2-to-1 margin. However, this changed as the test population increased beyond 30 mosquitoes. When we tested 60 or 90 females, the aggregation disappeared.</p>
<p>This tells us that females can regulate their own density at breeding sites – a response that likely is a mechanism to limit larval competition.</p>
<h2>Mosquitoes are smelling each other</h2>
<p>Mosquitoes largely sense the world through smell, using three families of <a href="https://www.britannica.com/science/olfactory-receptor">olfactory receptors</a>. These receptors detect odors when females are choosing where to lay eggs. But how do females sense each other to regulate their densities at breeding sites? </p>
<p>We explored this question by first placing 15 mosquitoes at one of our two test breeding sites. Other females seeking a place to lay preferred the unoccupied site over the one that was already occupied, even though we had already observed that the mosquitoes preferred not to lay their eggs alone. Something was directing them away from the occupied breeding site; we speculated that it might be carbon dioxide, which is an important cue for mosquitoes in all stages of their life cycle. </p>
<p>When female mosquitoes are looking for a blood meal, they fly toward the odor of CO₂, which all vertebrate animals <a href="https://theconversation.com/why-are-some-people-mosquito-magnets-and-others-unbothered-a-medical-entomologist-points-to-metabolism-body-odor-and-mindset-187957">exhale and release through their skin</a>. After feeding, they fly away from it, likely to avoid the risk of being killed by the host. </p>
<p>Mosquitoes also emit CO₂, and normally other mosquitoes can smell it, thanks to a receptor component called Gr3 in their olfactory organs. But when we released mutant females that lacked a functional Gr3 receptor to seek a place to lay eggs in our two-site test, we found that these insects, which could not detect CO₂, were willing to lay their eggs at preoccupied breeding sites. This suggested that normal mosquitoes might be avoiding the preoccupied laying site because they smelled CO₂ emitted by mosquitoes that were already there.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/EUrOcquy8IU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Female mosquitoes lay eggs on or near still bodies of water.</span></figcaption>
</figure>
<p>To confirm this, we offered two unoccupied breeding sites to females seeking a place to lay. However, we increased CO₂ levels around one of the sites to between 600 and 750 parts per million, compared with the normal level of about 450 to 500 ppm at the other site. We found that <em>Aedes aegypti</em> females avoided the unoccupied sites with elevated CO₂. This behavior appears designed to keep occupied breeding sites from becoming too crowded. </p>
<p>Overall, we found that two families of receptors play a role in the interactions between <em>Aedes aegypti</em> females when they seek breeding sites. Odorant receptors detect an unknown odor, which draws females toward a site; gustatory receptors detect CO₂, which deters females from breeding sites when the carbon dioxide level is high. The balance between these attractive and repellent odors will ultimately determine whether a female chooses or avoids a particular site. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/582583/original/file-20240318-20-i9yyck.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graphic showing common mosquito breeding sites around home, including gutters and pet dishes." src="https://images.theconversation.com/files/582583/original/file-20240318-20-i9yyck.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/582583/original/file-20240318-20-i9yyck.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/582583/original/file-20240318-20-i9yyck.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/582583/original/file-20240318-20-i9yyck.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/582583/original/file-20240318-20-i9yyck.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/582583/original/file-20240318-20-i9yyck.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/582583/original/file-20240318-20-i9yyck.jpeg?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"></a>
<figcaption>
<span class="caption">Mosquitoes breed in many wet spots, large and small.</span>
<span class="attribution"><a class="source" href="https://www.cabq.gov/environmentalhealth/urban-biology/mosquitoes">City of Albuquerque</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Implications for mosquito control</h2>
<p>Suppressing mosquito populations in urban areas using <a href="https://www.cdc.gov/mosquitoes/mosquito-control/community/larvicides.html">biolarvicides</a> – pesticides made from live bacteria that are toxic to mosquito larvae – is a primary control strategy to limit the spread of deadly diseases such as West Nile virus and Zika virus. This is especially true for <em>Aedes aegypti</em>, which is the most common urban mosquito species that reproduces in artificial breeding sites that humans create. Other control tactics, such as <a href="https://undark.org/2019/10/25/when-residents-say-no-to-aerial-mosquito-spraying/">spraying pesticides over large areas</a>, target beneficial insects as well as mosquitoes and can be controversial. </p>
<p>Knowing that female <em>Aedes aegypti</em> use social cues to pick the best breeding grounds for their young and will move on from a breeding site when it becomes too crowded could lead to new control measures. Interrupting the female mosquito reproductive cycle would reduce the spread of mosquitoes and the spread of diseases that these insects carry.</p><img src="https://counter.theconversation.com/content/223706/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kaylee Marrero receives funding from the National Institutes of Health.</span></em></p><p class="fine-print"><em><span>Andre Luis Costa-da-Silva receives funding from the Centers for Disease Control and Prevention, the Southeastern Center of Excellence in Vector-borne Disease and the National Institutes of Health. Views expressed in this article are his own. </span></em></p><p class="fine-print"><em><span>Matthew DeGennaro receives funding from the Centers for Disease Control and Prevention (CDC), the Southeastern Center of Excellence in Vector-borne Disease and the National Institutes of Health. Views expressed in this article are his own.</span></em></p>Female mosquitoes don’t want to lay their eggs alone, but they don’t want sites that are too crowded either. Understanding what guides their choice could inform new control strategies.Kaylee Marrero, Ph.D. Student and Transdisiplinary Biomolecular and Biomedical Sciences Fellow, Florida International UniversityAndre Luis da Costa da Silva, Research Assistant Professor of Biological Sciences, Florida International UniversityMatthew DeGennaro, Associate Professor of Biological Sciences, Florida International UniversityLicensed as Creative Commons – attribution, no derivatives.tag: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>
<figure class="align-center ">
<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">
<figcaption>
<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>
</figcaption>
</figure>
<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>
<figure class="align-center ">
<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">
<figcaption>
<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>
</figcaption>
</figure>
<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>
<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>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 30,000+ readers who’ve subscribed so far.</a></em></p>
<hr><img src="https://counter.theconversation.com/content/222306/count.gif" alt="The Conversation" width="1" height="1" />
<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/2235232024-03-08T13:37:11Z2024-03-08T13:37:11ZImmune cells can adapt to invading pathogens, deciding whether to fight now or prepare for the next battle<figure><img src="https://images.theconversation.com/files/579022/original/file-20240229-16-4ad8vr.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2000%2C1500&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Understanding the flexibility of T cell memory can lead to improved vaccines and immunotherapies.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/maturing-t-lymphocyte-illustration-royalty-free-illustration/1489195717">Juan Gaertner/Science Photo Library via Getty Images</a></span></figcaption></figure><p>How does your immune system decide between fighting invading pathogens now or preparing to fight them in the future? Turns out, it can <a href="https://doi.org/10.1016/j.immuni.2023.12.006">change its mind</a>.</p>
<p>Every person has <a href="https://doi.org/10.1073/pnas.1409155111">10 million to 100 million unique T cells</a> that have a critical job in the immune system: patrolling the body for invading pathogens or cancerous cells to eliminate. Each of these T cells has a unique receptor that allows it to recognize foreign proteins on the surface of infected or cancerous cells. When the right T cell encounters the right protein, it rapidly forms many copies of itself to destroy the offending pathogen. </p>
<p>Importantly, this process of proliferation gives rise to both short-lived effector T cells that shut down the immediate pathogen attack and long-lived memory T cells that provide protection against future attacks. But how do T cells decide whether to form cells that kill pathogens now or protect against future infections?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/580789/original/file-20240308-16-w72oqc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram of cytotoxic T cell killing a target cell" src="https://images.theconversation.com/files/580789/original/file-20240308-16-w72oqc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580789/original/file-20240308-16-w72oqc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580789/original/file-20240308-16-w72oqc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580789/original/file-20240308-16-w72oqc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580789/original/file-20240308-16-w72oqc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=526&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580789/original/file-20240308-16-w72oqc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=526&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580789/original/file-20240308-16-w72oqc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=526&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Cytotoxic T cells bind to foreign proteins on infected or cancerous cells and subsequently destroy those target cells by releasing molecules like granzyme and perforin.</span>
<span class="attribution"><a class="source" href="https://pressbooks.ccconline.org/bio106/chapter/lymphatic-levels-of-organization/">Anatomy & Physiology/SBCCOE</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p><a href="https://www.researchgate.net/scientific-contributions/Kathleen-Abadie-2232092055">We are</a> <a href="https://www.researchgate.net/scientific-contributions/Elisa-Clark-2148857839">a team</a> <a href="https://scholar.google.com/citations?user=ckyY7T8AAAAJ&hl=en">of bioengineers</a> studying how immune cells mature. In our <a href="https://doi.org/10.1016/j.immuni.2023.12.006">recently published research</a>, we found that having multiple pathways to decide whether to kill pathogens now or prepare for future invaders boosts the immune system’s ability to effectively respond to different types of challenges.</p>
<h2>Fight or remember?</h2>
<p>To understand when and how T cells decide to become effector cells that kill pathogens or memory cells that prepare for future infections, we <a href="https://doi.org/10.1016/j.immuni.2023.12.006">took movies of T cells dividing</a> in response to a stimulus mimicking an encounter with a pathogen. </p>
<p>Specifically, we tracked the activity of a gene called T cell factor 1, or TCF1. This gene is essential for the longevity of memory cells. We found that stochastic, or probabilistic, silencing of the TCF1 gene when cells confront invading pathogens and inflammation <a href="https://doi.org/10.1016/j.immuni.2023.12.006">drives an early decision</a> between whether T cells become effector or memory cells. Exposure to higher levels of pathogens or inflammation increases the probability of forming effector cells.</p>
<p>Surprisingly, though, we found that some effector cells that had turned off TCF1 early on were able to <a href="https://doi.org/10.1016/j.immuni.2023.12.006">turn it back on</a> after clearing the pathogen, later becoming memory cells. </p>
<p>Through mathematical modeling, we determined that this flexibility in decision making among memory T cells is critical to generating the right number of cells that respond immediately and cells that prepare for the future, appropriate to the severity of the infection. </p>
<h2>Understanding immune memory</h2>
<p>The proper formation of persistent, long-lived T cell memory is critical to a person’s ability to fend off diseases ranging from the common cold to COVID-19 to cancer.</p>
<p>From a <a href="https://doi.org/10.1016/0377-2217(93)E0210-O">social and cognitive science perspective</a>, flexibility allows people to adapt and respond optimally to uncertain and dynamic environments. Similarly, for immune cells responding to a pathogen, flexibility in decision making around whether to become memory cells may enable greater responsiveness to an evolving immune challenge.</p>
<p>Memory cells can be <a href="https://doi.org/10.1016/j.immuni.2018.02.010">subclassified into different types</a> with distinct features and roles in protective immunity. It’s possible that the pathway where memory cells diverge from effector cells early on and the pathway where memory cells form from effector cells later on give rise to particular subtypes of memory cells. </p>
<p>Our study focuses on T cell memory in the context of acute infections the immune system can successfully clear in days, such as cold, the flu or food poisoning. In contrast, chronic conditions such as HIV and cancer require persistent immune responses; long-lived, memory-like cells are critical for this persistence. Our team is investigating whether flexible memory decision making also applies to chronic conditions and whether we can leverage that flexibility to improve cancer immunotherapy.</p>
<p>Resolving uncertainty surrounding how and when memory cells form could help improve vaccine design and therapies that boost the immune system’s ability to provide long-term protection against diverse infectious diseases.</p>
<p><em>This article was updated to replace a figure of T cell differentiation with cytotoxic T cell activity.</em></p><img src="https://counter.theconversation.com/content/223523/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kathleen Abadie was funded by a NSF (National Science Foundation) Graduate Research Fellowships. She performed this research in affiliation with the University of Washington Department of Bioengineering. </span></em></p><p class="fine-print"><em><span>Elisa Clark performed her research in affiliation with the University of Washington (UW) Department of Bioengineering and was funded by a National Science Foundation Graduate Research Fellowship (NSF-GRFP) and by a predoctoral fellowship through the UW Institute for Stem Cell and Regenerative Medicine (ISCRM). </span></em></p><p class="fine-print"><em><span>Hao Yuan Kueh receives funding from the National Institutes of Health.</span></em></p>When faced with a threat, T cells have the decision-making flexibility to both clear out the pathogen now and ready themselves for a future encounter.Kathleen Abadie, Ph.D. Candidate in Bioengineering, University of WashingtonElisa Clark, Ph.D. Candidate in Bioengineering, University of WashingtonHao Yuan Kueh, Associate Professor of Bioengineering, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2159892024-03-05T03:00:57Z2024-03-05T03:00:57ZLumpy skin disease is a threat to Australia and could decimate our cattle industries – we need to know how it could enter and spread<figure><img src="https://images.theconversation.com/files/577190/original/file-20240221-22-67ggd8.jpg?ixlib=rb-1.1.0&rect=26%2C8%2C5964%2C3979&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/calf-has-sick-lumpy-skin-disease-2028066140">assiduousness, Shutterstock</a></span></figcaption></figure><p>Australian authorities are on high alert amid the spread of <a href="https://www.abc.net.au/news/rural/2022-03-04/lumpy-skin-disease-detected-in-indonesia/100881842">lumpy skin disease</a> in cattle and buffalo across South-East Asia. While <a href="https://www.agriculture.gov.au/biosecurity-trade/pests-diseases-weeds/animal/lumpy-skin-disease/australias-freedom-from-lsd">Australia remains free of the disease</a>, the virus is likely to breach our borders at some stage.</p>
<p>Detection of the disease in Australia’s livestock industries would lead to <a href="https://animalhealthaustralia.com.au/download/1653/">restrictions on cattle, meat and dairy exports</a>, with serious consequences for the economy. </p>
<p>The federal government has a <a href="https://www.agriculture.gov.au/biosecurity-trade/pests-diseases-weeds/animal/lumpy-skin-disease/australias-freedom-from-lsd">plan to detect and respond</a> to an outbreak. But we need to go one better – to predict where the disease is likely to appear and how it might spread. </p>
<p>Our team is developing a model we hope will provide this vital information. It will help Australia prepare and respond not just to the current threat, but to any future biosecurity breach.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/4w58jXPreXg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Lumpy skin disease is on Australia’s doorstep, with fears the threat is going unnoticed | ABC News (September 2022)</span></figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/stop-killing-brown-snakes-they-could-be-a-farmers-best-friend-222142">Stop killing brown snakes – they could be a farmer's best friend</a>
</strong>
</em>
</p>
<hr>
<h2>What is lumpy skin disease?</h2>
<p><a href="https://animalhealthaustralia.com.au/lumpy-skin-disease/">Lumpy skin disease is a viral disease</a> that affects cattle and buffalo, not humans. The incubation period is up to 28 days. </p>
<p>First reported in Zambia in 1929, the <a href="http://www.doi.org/10.14202/vetworld.2022.2764-2771">disease has spread</a> across Africa, the Middle East, Eastern Europe and Asia. It reached <a href="https://www.abc.net.au/news/rural/2022-03-04/lumpy-skin-disease-detected-in-indonesia/100881842">Indonesia in 2022</a>.</p>
<p>Early symptoms include fever and increased tear production. Lumps then appear on the skin and can cover the entire body, gradually hardening as the disease develops. Sometimes the lumps slough off, leaving holes on the skin that are susceptible to infections. </p>
<p>Typically only 1-5% of cattle die from the disease, but those that recover may not return to full health.</p>
<p>Milk production is reduced in cows. Meat yield from infected cattle is likely to be reduced, although it does not contain lumps and is safe to eat. Temporary or permanent infertility in both cows and bulls can also develop during the first month of infection.</p>
<p>The virus is mainly spread by biting insects such as <a href="https://doi.org/10.1136/vr.g5808">mosquitoes, stable flies and ticks</a>. <a href="https://doi.org/10.1007/s11250-021-02786-0">Higher temperature</a> and <a href="https://doi.org/10.1002/vms3.434">increased rainfall</a> can increase insect populations and activity, and have triggered outbreaks of disease overseas.</p>
<p>The disease can also be transmitted by <a href="https://doi.org/10.1186/1297-9716-43-1">close contact between cattle</a>, such as exposure to body fluids.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576654/original/file-20240220-18-l9zg5j.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map showing where lumpy skin disease has been reported in South-East Asia over the last five years" src="https://images.theconversation.com/files/576654/original/file-20240220-18-l9zg5j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576654/original/file-20240220-18-l9zg5j.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=593&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576654/original/file-20240220-18-l9zg5j.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=593&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576654/original/file-20240220-18-l9zg5j.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=593&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576654/original/file-20240220-18-l9zg5j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=746&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576654/original/file-20240220-18-l9zg5j.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=746&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576654/original/file-20240220-18-l9zg5j.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=746&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Where lumpy skin disease has been reported over the last five years in South-East Asia, as at February 19 this year, using data from the Food and Agriculture Organization of the United Nations.</span>
<span class="attribution"><span class="source">The University of Queensland</span></span>
</figcaption>
</figure>
<h2>A testing time with Indonesia and Malaysia</h2>
<p>In July last year, Indonesian authorities claimed 13 cows from Australia had <a href="https://www.abc.net.au/news/2023-07-31/lumpy-skin-disease-cattle-from-australia-exports-indonesia/102668870">tested positive</a> days after arrival. At the time, Australian authorities <a href="https://www.agriculture.gov.au/about/news/lsd-detection-in-cattle-exported-to-indonesia">demonstrated</a> that the nation was free of the disease. </p>
<p>Nonetheless, trade between Indonesia and four of Australia’s cattle export holding yards was <a href="https://www.abc.net.au/news/2023-07-30/lsd-in-australian-cattle-in-indonesia/102666812">suspended</a> immediately. Then <a href="https://www.theaustralian.com.au/nation/second-country-suspends-live-cattle-exports-from-australia-over-disease-fears/news-story/d94648994297f0be4497ca0eeda965b5">Malaysia went further and stopped accepting</a> any Australian live cattle and buffalo. </p>
<p><a href="https://www.agriculture.gov.au/about/news/malaysian-authorities-lift-temporary-suspension">Malaysia</a> and <a href="https://www.agriculture.gov.au/about/news/indonesia-lifts-trade-restrictions">Indonesia</a> each lifted their restrictions in early September, after <a href="https://www.agriculture.gov.au/about/news/australia-remains-free-from-lumpy-skin-disease">more than 1,000 cattle</a> were tested across Western Australia, Queensland and the Northern Territory. The Australian government also <a href="https://www.theaustralian.com.au/nation/indonesia-lifts-ban-on-live-cattle-exports-from-australia/news-story/891378279957dfb5dec102a9fe504749">agreed</a> to boost surveillance and biosecurity measures, including testing on farms and <a href="https://www.beefcentral.com/live-export/alec-welcomes-resumption-of-indonesian-cattle-trade/">disinfecting departing export vessels</a>.</p>
<p>Since the lifting of restrictions, the Indonesian government has <a href="https://www.abc.net.au/news/2023-10-11/cattle-rejected-live-export-indonesia-skin-blemishes-lsd/102956626">reportedly</a> rejected Australian cattle with skin blemishes – in some cases, this comprised up to 30% of cattle in a shipment.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1698551902873747831"}"></div></p>
<h2>How could lumpy skin disease enter Australia?</h2>
<p>The Australian government has introduced <a href="https://animalhealthaustralia.com.au/download/1653/">strict biosecurity measures</a> at international ports to minimise the risk of infected animals entering the country. These include disinfection and disinsection (spraying to remove insects) of vessels and cargo.</p>
<p>However, there’s a high risk of <a href="https://www.agriculture.gov.au/sites/default/files/documents/ausvet-lsd-quantitative-assessment.pdf">infected insects entering Australia</a> through international ports or by travelling across the sea to northern Australia. Some infected flying insects may be able to <a href="https://doi.org/10.1111/tbed.12378">cover long distances, aided by strong winds</a>.</p>
<p>Another possible mode of entry for infected insects is through <a href="https://www.abc.net.au/news/rural/2023-12-13/illegal-fishing-in-wa-sparks-biosecurity-fears/103195314">illegal fishers landing on the Australian coast</a>.</p>
<h2>What can be done to prevent the spread of lumpy skin disease?</h2>
<p>In countries where lumpy skin disease is common, <a href="https://doi.org/10.1136/vr.g5808">live vaccines have been used to control the disease</a>. However, this is not practical in disease-free countries such as Australia, because vaccinated animals <a href="https://doi.org/10.1136/vr.i2800">cannot be distinguished</a> from infected animals. This means Australia could not be confirmed free of disease, leading to <a href="https://doi.org/10.1136/vr.g5808">international trade restrictions</a>.</p>
<p>The Australian government <a href="https://minister.agriculture.gov.au/Watt/media-releases/lsd-vaccine-supply-secured">secured a supply of lumpy skin disease vaccines</a> in October. These are being securely stored overseas in case of an outbreak. The vaccines will also be available to neighbouring Papua New Guinea and Timor-Leste.</p>
<p><a href="https://www.woah.org/en/document/lumpy-skin-disease-technical-disease-card/">Preventing the spread of lumpy skin disease</a> requires early detection of the disease, isolation of potentially infected animals and restrictions around their movement. Once initial diagnosis is confirmed, culling of infected animals and insect control would likely follow.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1757570391793360913"}"></div></p>
<h2>What can be done to prepare Australia?</h2>
<p>Australia has a <a href="https://animalhealthaustralia.com.au/download/1653/">veterinary emergency response plan</a> to enact if the disease enters the country. The federal government has also <a href="https://www.agriculture.gov.au/biosecurity-trade/pests-diseases-weeds/animal/lumpy-skin-disease/australias-freedom-from-lsd">boosted surveillance</a> and begun <a href="https://www.agriculture.gov.au/about/news/getting-ready-to-respond">offering training</a> for veterinarians, industry and government staff on how to prevent and control the spread of the disease.</p>
<p>However, innovative models are needed to assess the likely introduction and spread of the disease in Australia. Our team is developing a framework to carry out such modelling. Our model will include data describing the current status of reports of the disease outside of Australia, Australia’s landscape and climate, distribution and movement of cattle, and local insect populations.</p>
<p>These models will produce maps that can be used to identify areas in Australia more suitable to receiving the disease, such as areas with favourable environmental conditions for the survival of imported infected insects. These maps will inform decisions around surveillance and response plans, and help farmers prepare for a potential outbreak of the disease.</p>
<p>Maintaining a high level of preparedness and awareness of the disease among cattle producers, farmers, veterinarians and other relevant individuals is paramount if we are to maintain our disease-free status as an international exporter. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australias-shot-hole-borer-beetle-invasion-has-begun-but-we-dont-need-to-chop-down-every-tree-under-attack-222610">Australia's shot-hole borer beetle invasion has begun, but we don't need to chop down every tree under attack</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/215989/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kei Owada works for the University of Queensland. The research team at the University of Queensland working on lumpy skin disease modelling is jointly supported by the Queensland Government Department of Agriculture and Fisheries and the University of Queensland.</span></em></p><p class="fine-print"><em><span>Ben Hayes receives funding from the University of Queensland and the Queensland Government Department of Agriculture and Fisheries.</span></em></p><p class="fine-print"><em><span>Ricardo J. Soares Magalhaes receives funding from the University of Queensland and the Queensland Government Department of Agriculture and Fisheries.. </span></em></p><p class="fine-print"><em><span>Timothy J. Mahony works for the University of Queensland. The research team at the University of Queensland working on lumpy skin disease modelling and vaccine development is jointly supported by the Queensland Government Department of Agriculture and Fisheries and the University of Queensland.</span></em></p>A disfiguring disease of cattle and buffalo has arrived on our doorstep. We need to keep lumpy skin disease out of Australia, while preparing for the almost inevitable outbreak.Kei Owada, Postdoctoral Research Fellow, School of Veterinary Science, The University of QueenslandBen Hayes, Director, Centre for Animal Science, The University of QueenslandRicardo J. Soares Magalhaes, Professor, School of Veterinary Science, The University of QueenslandTimothy J. Mahony, Professor, Centre for Animal Science, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2244932024-03-01T13:33:21Z2024-03-01T13:33:21ZMeasles is one of the deadliest and most contagious infectious diseases – and one of the most easily preventable<figure><img src="https://images.theconversation.com/files/578746/original/file-20240228-16-96qj3k.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2119%2C1414&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Young children, pregnant people and the immunocompromised are among the most vulnerable to measles.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/measles-royalty-free-image/534079149">CHBD/E+ via Getty Images</a></span></figcaption></figure><p>“You don’t count your children until the measles has passed.” <a href="https://www.nytimes.com/2022/11/05/health/samuel-katz-dead.html">Dr. Samuel Katz</a>, one of the pioneers of the first measles vaccine in the late 1950s to early 1960s, regularly heard this tragic statement from parents in countries where the measles vaccine was not yet available, because they were so accustomed to losing their children to measles.</p>
<p>I am a <a href="https://som.cuanschutz.edu/Profiles/Faculty/Profile/25677">pediatrician and preventive medicine physician</a>, and I have anxiously watched measles cases rise worldwide while <a href="https://www.cdc.gov/media/releases/2023/p1116-global-measles.html">vaccination rates have dropped</a> since the early days of the COVID-19 pandemic due to disruptions in vaccine access and the spread of vaccine misinformation.</p>
<p>In 2022 alone, there were <a href="http://dx.doi.org/10.15585/mmwr.mm7246a3">over 9 million measles cases and 136,000 deaths worldwide</a>, an 18% and 43% increase from the year before, respectively. The World Health Organization warned that <a href="https://www.reuters.com/business/healthcare-pharmaceuticals/more-than-half-world-faces-high-measles-risk-who-says-2024-02-20/">over half the world’s countries</a> are at high risk of measles outbreaks this year.</p>
<p>The U.S. is no exception. The country is on track to have one of the worst measles years since 2019, when Americans experienced the <a href="https://www.cdc.gov/measles/cases-outbreaks.html">largest measles outbreak</a> in 30 years. As of mid-February 2024, <a href="https://www.cdc.gov/measles/cases-outbreaks.html">at least 15 states</a> have reported measles cases and multiple ongoing, uncontained outbreaks.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/QUFqJwcKlh0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Measles is on the rise across the U.S. once again, despite being eliminated in 2000.</span></figcaption>
</figure>
<p>While this measles crisis unfolds, U.S. measles vaccination rates are at the <a href="http://dx.doi.org/10.15585/mmwr.mm7245a2">lowest levels in 10 years</a>. Prominent figures like the <a href="https://www.washingtonpost.com/health/2024/02/22/florida-measles-outbreak-ladapo/">Florida surgeon general</a> are responding to local outbreaks in ways that run counter to science and public health recommendations. The spread of <a href="https://www.nbcnews.com/health/health-news/measles-outbreaks-anti-vaccine-misinformation-rcna136994">misinformation and disinformation</a> from anti-vaccine activists online further promotes misguided ideas that measles is not a serious health threat and measles vaccination is not essential. </p>
<p>However, the evidence is clear: Measles is <a href="https://www.cdc.gov/measles/symptoms/complications.html">extremely dangerous</a> for everyone, and especially for young children, pregnant people and people with compromised immune systems. But simple and effective tools are available to prevent it.</p>
<h2>Measles is a serious illness</h2>
<p>Measles is one of the most deadly infectious diseases in human history. Before a vaccine became available in 1963, around 30 million people were infected with measles and <a href="https://doi.org/10.1016/j.eclinm.2024.102502">2.6 million people died from the disease</a> every year worldwide. In the U.S., measles was responsible for an estimated 3 million to 4 million infections. Among reported cases, there were 48,000 hospitalizations, 1,000 cases of encephalitis, or brain swelling, and 500 deaths <a href="https://www.cdc.gov/measles/about/history.html">every year</a>. </p>
<p>Measles is also one of the most contagious infectious diseases. According to the Centers for Disease Control and Prevention, <a href="https://www.cdc.gov/measles/about/parents-top4.html">up to 9 out of 10 people</a> exposed to an infected person will become infected if they don’t have protection from vaccines. The measles virus can stay in the air and infect others for up to two hours after a contagious person has left the room. Measles can also hide in an unknowing victim for <a href="https://www.cdc.gov/vaccines/pubs/surv-manual/chpt07-measles.html">one to two weeks and sometimes up to 21 days</a> before symptoms begin. Infected people can <a href="https://www.cdc.gov/measles/transmission.html">spread measles</a> for up to four days before they develop its characteristic rash, and up to four days after. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/578749/original/file-20240228-20-nsp7wf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of abdomen with red measles rash" src="https://images.theconversation.com/files/578749/original/file-20240228-20-nsp7wf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578749/original/file-20240228-20-nsp7wf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578749/original/file-20240228-20-nsp7wf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578749/original/file-20240228-20-nsp7wf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578749/original/file-20240228-20-nsp7wf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578749/original/file-20240228-20-nsp7wf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578749/original/file-20240228-20-nsp7wf.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">One characteristic measles symptom is a rash that spreads from the face to the rest of the body.</span>
<span class="attribution"><a class="source" href="https://phil.cdc.gov/details.aspx?pid=3168">CDC/Heinz F. Eichenwald, MD</a></span>
</figcaption>
</figure>
<p>The <a href="https://www.cdc.gov/measles/symptoms/signs-symptoms.html">initial symptoms</a> of measles are similar to those of many other common viral illnesses in the U.S.: fever, cough, runny nose and red eyes. Several days after symptoms begin, characteristic tiny white spots develop inside the mouth, and a facial rash spreads to the rest of the body. </p>
<p>While most people’s symptoms improve, 1 in 5 unvaccinated children will be hospitalized, 1 out of every 1,000 will develop brain swelling that can lead to brain damage, and up to <a href="https://www.cdc.gov/measles/symptoms/complications.html#">3 of every 1,000 will die</a>. For unvaccinated people who are pregnant, measles infection can lead to miscarriage, stillbirth, premature birth and low birth weight.</p>
<p>The risk of severe complications from measles persists even after a person appears to be fully recovered. In rare cases, people can experience a brain disease called <a href="https://www.ninds.nih.gov/health-information/disorders/subacute-sclerosing-panencephalitis#">subacute sclerosing panencephalitis</a> that develops seven to 10 years after infection and leads to memory loss, involuntary movements, seizures, blindness and eventually death.</p>
<p>Beyond these individual health effects, the <a href="https://www.idsociety.org/science-speaks-blog/2022/estimating-the-impact-how-much-does-a-measles-outbreak-cost/#/+/0/publishedDate_na_dt/desc/">financial cost</a> to society for containing measles outbreaks is significant. For example, a 2019 measles outbreak in Washington state is estimated to have cost <a href="https://doi.org/10.1542/peds.2020-027037">US$3.4 million</a>. Necessary efforts to control measles outbreaks pull millions of dollars’ worth of critical resources away from other essential public health functions such as ensuring food safety, preventing injuries and chronic diseases, and responding to disasters.</p>
<h2>Vaccines protect against measles</h2>
<p>Why put communities at risk and allow these societal costs from measles when effective and safe tools are available to protect everyone?</p>
<p>Measles vaccines have been so effective, providing lifelong protection to <a href="https://www.cdc.gov/measles/vaccination.html">over 97% of people</a> who receive two vaccine doses, that they are victims of their own success. Initial widespread measles vaccination had reduced measles cases by 99% compared to before the vaccine was available, and consequently, most people in the U.S. are unaware of the seriousness of this disease.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/578753/original/file-20240228-7861-io367m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Person looking at Florida Health measles and MMR shot information sheet" src="https://images.theconversation.com/files/578753/original/file-20240228-7861-io367m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578753/original/file-20240228-7861-io367m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=454&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578753/original/file-20240228-7861-io367m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=454&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578753/original/file-20240228-7861-io367m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=454&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578753/original/file-20240228-7861-io367m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=570&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578753/original/file-20240228-7861-io367m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=570&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578753/original/file-20240228-7861-io367m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=570&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Measles is a highly preventable disease.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/measles-information-sheet-is-seen-posted-at-the-orange-news-photo/1141724959">Paul Hennessy/NurPhoto via Getty Images</a></span>
</figcaption>
</figure>
<p>Despite the success of highly effective vaccination programs in the U.S., anyone can still come into contact with measles in their community. Measles is most often brought into the U.S. by <a href="https://www.cdc.gov/measles/about/parents-top4.html">unvaccinated American travelers</a> returning home and sometimes from foreign visitors. For people traveling out of the country, the threat of measles exposure is even greater, with widespread outbreaks occurring in <a href="https://wwwnc.cdc.gov/travel/notices/level1/measles-globe">many travel destinations</a>.</p>
<p>Public health leaders who embrace and promote vaccination and follow simple, proven infectious disease containment measures can help prevent measles disease spread. Every single preventable illness, complication, hospitalization or death from measles is one too many.</p><img src="https://counter.theconversation.com/content/224493/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Higgins is affiliated with Immunize Colorado, a nonprofit that works to protect Colorado families, schools and communities from vaccine-preventable diseases (volunteer non-paid board of directors member) and American Academy of Pediatrics (volunteer non-paid chapter immunization representative for the Colorado chapter).</span></em></p>A pediatrician and preventive medicine physician explains how measles vaccines became victims of their own success and the risk that rising outbreaks pose to everyone.David Higgins, Research Fellow and Instructor in Pediatrics, University of Colorado Anschutz Medical CampusLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2237162024-02-25T14:16:50Z2024-02-25T14:16:50ZFAQ: Why are syphilis cases on the rise in Canada?<figure><img src="https://images.theconversation.com/files/577183/original/file-20240221-24-guk2fk.jpg?ixlib=rb-1.1.0&rect=39%2C4%2C3253%2C2552&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Syphilis is a sexually transmitted infection (STI) caused by the Treponema pallidum bacterium.</span> <span class="attribution"><span class="source">(NIAID, cropped from original)</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Canada has been experiencing an <a href="https://www.canada.ca/en/services/health/campaigns/syphilis.html">increasing number of syphilis diagnoses since 2016</a>. Numerous provinces have declared outbreaks in recent years, with the highest rates observed in the <a href="https://www.canada.ca/en/public-health/services/reports-publications/canada-communicable-disease-report-ccdr/monthly-issue/2023-49/issue-10-october-2023/infectious-congenital-syphilis-canada-2022.html">Northwest Territories, Saskatchewan and Manitoba</a>.</p>
<p>During Sexual Health Week this month, the Chief Public Health Officer of Canada, Dr. Theresa Tam, said the country has experienced an <a href="https://globalnews.ca/news/10294073/canada-syphilis-cases-phac/">“alarming increase” in syphilis cases</a>.</p>
<p>As an infectious disease physician, I know how important it is that Canadians have answers to common questions about syphilis, why it’s spreading and what the symptoms are.</p>
<p>Syphilis is an infection caused by the bacterium <em><a href="https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/treponema-pallidum-pathogen-safety-data-sheet.html">Treponema pallidum</a></em>, and is transmitted either through sexual exposure or from an infected pregnant woman into the developing fetus, resulting in congenital syphilis. </p>
<h2>Why is Canada seeing an increase in cases?</h2>
<p>In 2022, <a href="https://www.canada.ca/en/public-health/news/2024/02/statement-from-the-chief-public-health-officer-of-canada-on-syphilis.html">there were 13,953 reported syphilis cases, the highest seen in recent times, with rates increasing by 109 per cent compared to 2018</a>. While historically, gay, bisexual and other men who have sex with men remain at high risk of syphilis infections, recent years saw a surge in infections in heterosexual women, comprising of 35 per cent of all cases in 2022. This has led to a 600 per cent increase in the rates of congenital syphilis compared to previous years. </p>
<p>The reasons for this dramatic increase are not fully known, <a href="https://doi.org/10.14745%2Fccdr.v48i23a01">but may be attributed to several factors</a>: </p>
<ul>
<li><p>health-care disparity and lack of public health investment in surveillance and prevention as well as mistrust of the health-care system among some populations, such as Indigenous people, Black people and those who use substances, </p></li>
<li><p>introduction of highly effective HIV treatment as well as <a href="https://www.catie.ca/pre-exposure-prophylaxis-prep-0">pre-exposure prophylaxis (PrEP)</a> for HIV prevention may result in a decrease in condom use, </p></li>
<li><p>easier access to sex via online dating portals, and </p></li>
<li><p>rising rates of use of drugs while having sex, called party and play (PnP), coincides with increasing rates of syphilis infections.</p></li>
</ul>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/as-an-indigenous-doctor-i-see-the-legacy-of-residential-schools-and-ongoing-racism-in-todays-health-care-162048">As an Indigenous doctor, I see the legacy of residential schools and ongoing racism in today's health care</a>
</strong>
</em>
</p>
<hr>
<h2>Who is most at risk?</h2>
<p>Since syphilis is typically a <a href="https://www.canada.ca/en/public-health/services/infectious-diseases/sexual-health-sexually-transmitted-infections/canadian-guidelines/syphilis/risk-factors-clinical-manifestation.html">sexually transmitted infection</a>, certain <a href="https://doi.org/10.14745%2Fccdr.v48i23a01">high-risk practices</a> are associated with high risk of syphilis infection:</p>
<ul>
<li><p>Individuals who have unprotected sexual intercourse with multiple sex partners.</p></li>
<li><p>Commercial sex workers or those who exchange sex for drugs or money.</p></li>
<li><p>People living with HIV. Canadian studies have estimated the reported prevalence of syphilis to range <a href="https://www.canada.ca/en/public-health/services/emergency-preparedness-response/rapid-risk-assessments-public-health-professionals/risk-profile-infectious-syphilis-outbreaks-emergence-congenital-syphilis.html">between eight and 56 per cent</a> in this group.</p></li>
<li><p>Gay, bisexual and other men who have sex with men.</p></li>
<li><p>People who have been incarcerated and those who inject recreational substances.</p></li>
<li><p>Health Canada has also identified certain <a href="https://www.canada.ca/en/services/health/publications/diseases-conditions/syphilis-epidemiological-report.html#4">high-risk populations</a>, such as those experiencing health and social inequities, predominantly due to lack of accessible health care and screening.</p></li>
</ul>
<h2>What are the symptoms?</h2>
<p>The <a href="https://www.canada.ca/en/public-health/services/diseases/syphilis.html">symptoms of syphilis</a> can be divided into different stages, typically defined by when symptoms begin:</p>
<p><strong>1) Early Syphilis</strong> comprises primary and secondary syphilis, which typically occur within weeks to months following the exposure. This also includes early latent syphilis, an asymptomatic stage of the infection.</p>
<ul>
<li><p><strong>A)</strong> <strong>Primary syphilis</strong> is characterized by appearance of a painless sore at the site of infection, typically on the genitals or inside the mouth.</p></li>
<li><p><strong>B)</strong> <strong>Secondary syphilis</strong> is a systemic illness involving different organ systems. It presents with a diffuse body rash, fever, fatigue and sore throat. Wart-like skin lesions known as condyloma lata, alopecia (hair loss) and hepatitis may also occur in this stage.</p></li>
<li><p><strong>C)</strong> <strong>Early latent syphilis</strong> is an asymptomatic stage of the infection within a year of the initial exposure. It is diagnosed with positive blood tests in the absence of any symptoms. </p></li>
</ul>
<p><strong>2) Late Syphilis</strong> occurs in infected patients who do not receive treatment in the earlier stages and usually develops anywhere from one to 30 years after the initial infection. It is categorized into tertiary syphilis and late latent syphilis.</p>
<ul>
<li><p><strong>A)</strong> <strong>Tertiary syphilis</strong> involves chronic inflammation of the body, and may include skin, bones and other internal organs, specifically the cardiovascular system, brain and spinal cord. </p></li>
<li><p><strong>B)</strong> <strong>Late latent syphilis</strong>, much like early latent syphilis, is an asymptomatic stage of the infection, but in this case acquired more than a year previously. It is diagnosed based on positive blood tests. </p></li>
</ul>
<p><strong>3) Neurosyphilis</strong> can occur at any time during the course of infection, and may present in different forms, including meningitis, stroke, or vision or hearing loss. </p>
<h2>How is it transmitted?</h2>
<p>Syphilis is transmitted through direct exposure to an infectious lesion or sore on the skin (also called a chancre) <a href="https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/treponema-pallidum-pathogen-safety-data-sheet.html">during sexual intercourse or activity, including oral sex</a>. Additionally, <a href="http://www.bccdc.ca/health-info/diseases-conditions/syphilis">sharing sex toys</a> can also transmit infection between an infected individual and an uninfected one. </p>
<p>Congenital syphilis is acquired when the bacteria is passed through the placenta to a developing fetus, from an untreated pregnant person.</p>
<p>It should be noted that syphilis does not transmit through sharing utensils, toilet seats, bathtubs, swimming pools or clothes because the bacterium dies quickly outside the body. </p>
<h2>How is syphilis treated?</h2>
<p>Syphilis is an <a href="https://www.canada.ca/en/public-health/services/infectious-diseases/sexual-health-sexually-transmitted-infections/canadian-guidelines/syphilis.html#a1.4">easily treatable infection and duration of antibiotics is determined by the stage of the disease</a>. Early syphilis is treated with a one-time injection of the penicillin antibiotic into the buttock. Late syphilis is treated with three injections of penicillin, each a week apart, over three weeks. Neurosyphilis and syphilis involving the eyes or ears is typically treated with intravenous antibiotics for two weeks.</p>
<p>Alternative options for people who are either allergic to penicillins or cannot tolerate it include oral antibiotics, such as doxycycline or a once-daily intravenous antibiotic, called ceftriaxone. </p>
<h2>How can it be prevented?</h2>
<figure class="align-center ">
<img alt="Photo of two condoms in red packages" src="https://images.theconversation.com/files/577185/original/file-20240221-20-6rivan.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/577185/original/file-20240221-20-6rivan.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=432&fit=crop&dpr=1 600w, https://images.theconversation.com/files/577185/original/file-20240221-20-6rivan.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=432&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/577185/original/file-20240221-20-6rivan.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=432&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/577185/original/file-20240221-20-6rivan.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=543&fit=crop&dpr=1 754w, https://images.theconversation.com/files/577185/original/file-20240221-20-6rivan.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=543&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/577185/original/file-20240221-20-6rivan.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=543&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Studies suggest that condoms reduce the risk of syphilis by around 90 per cent when used consistently.</span>
<span class="attribution"><span class="source">(Pixabay)</span></span>
</figcaption>
</figure>
<p>Syphilis is a preventable disease. It is important for high-risk and sexually active individuals to access counselling about safe sex practices and the importance of screening for sexually transmitted infections (STI screening). </p>
<p>Studies suggest that <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4660551/">condoms reduce the risk of syphilis</a> by around 90 per cent when used consistently.</p>
<p>Several <a href="https://www.cdc.gov/std/treatment/doxycycline-as-pep-toe.htm">recently published studies</a> have reported promising outcomes in STI prevention (including gonorrhea, chlamydia and syphilis) with the use of an oral antibiotic — 200 milligrams of doxycycline — taken once within 24 to 72 hours after high-risk or condom-less sexual exposure. This is called post-exposure prophylaxis.</p>
<p>Additionally, easy and early access to health care and STI screening, as well as availability of post-exposure prophylaxis with the oral antibiotics, is important in preventing transmission to others. </p>
<p>With syphilis cases on the rise in Canada, it is important to know that the infection is treatable. Prevention is key not only to individual health but also to slowing its spread.</p><img src="https://counter.theconversation.com/content/223716/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Huma Saeed 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>With the alarming rise in syphilis cases in recent years, it’s important to know what it is, how it’s spread and who is most at risk.Huma Saeed, Assistant Professor of Medicine, Division of Infectious Diseases, Schulich School of Medicine and Dentistry, Western UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2234702024-02-21T13:17:46Z2024-02-21T13:17:46ZWhat is Alaskapox? A microbiologist explains the recently discovered virus that just claimed its first fatality<figure><img src="https://images.theconversation.com/files/575275/original/file-20240211-16-m5e8r4.jpg?ixlib=rb-1.1.0&rect=29%2C32%2C993%2C617&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Red-backed voles may be harboring Alaskapox.</span> <span class="attribution"><a class="source" href="https://ecuador.inaturalist.org/">iNaturalist Ecuador</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span></figcaption></figure><p><em>Alaskapox, a virus in the same family as smallpox, cowpox and mpox, <a href="https://abcnews.go.com/Health/wireStory/alaskapox-recent-death-brings-attention-virus-small-animals-107207953">claimed its first fatality</a> in January 2024 when an elderly Alaskan man died of the illness.</em></p>
<p><em>The virus, which was discovered in 2015, had previously resulted in only relatively mild illnesses in the six other people infected by it. So why did the Alaskan man die?</em></p>
<p><em>Raúl Rivas González, a microbiologist at the University of Salamanca in Spain, explains what we know about Alaskapox, what happened to the man in Alaska, and the threat posed by the thousands of similar viruses out there.</em></p>
<h2>What’s the origin of Alaskapox?</h2>
<p>Alaskapox is an orthopox virus <a href="https://doi.org/10.1093%2Fcid%2Fcix219">discovered in 2015</a> in the Fairbanks area of Alaska. </p>
<p>Until the most recent case, there were only six known human infections, which all involved mild illnesses consisting of a localized rash and the swelling of lymph nodes. </p>
<h2>How did the man in Alaska die?</h2>
<p>In mid-September 2023, the man was living on the Kenai Peninsula, south of the city of Anchorage, Alaska, and <a href="https://abcnews.go.com/Health/wireStory/alaskapox-recent-death-brings-attention-virus-small-animals-107207953">undergoing drug treatment for cancer</a>, and so had a suppressed immune system. He noticed a tender red papule – a type of skin lesion – in his right armpit.</p>
<p>Understandably, he was scared and decided to go to the doctor immediately. Over the next six weeks, he made several visits to the primary care center and the local emergency department for clinical evaluation of the lesion.</p>
<p>The case was confusing and the possible infection difficult to identify. He did not respond to antibiotic treatment. A needle biopsy revealed no evidence of malignancy or bacterial infection. The health care providers were puzzled. </p>
<p>After the situation worsened, the man was hospitalized in Anchorage. Eventually, doctors performed an extensive battery of tests and sent a sample to the Centers for Disease Control and Prevention, which determined he had <a href="http://www.doi.org/10.3390/v11080708">Alaskapox</a>.</p>
<p>He was immediately given treatment for the virus, but it was too late and he died at the end of January. Officials <a href="https://epi.alaska.gov/bulletins/docs/b2024_02.pdf">confirmed the cause of death</a> was Alaskapox in February.</p>
<h2>Where do viruses like Alaskapox come from?</h2>
<p>Currently, more than <a href="https://doi.org/10.1128%2Fjcm.00337-22">10,000 species of viruses</a> have been recognized by the International Committee on Taxonomy of Viruses. We know that about 270 of them can infect people. </p>
<p>Some of these viruses have been known for centuries, such as polio and smallpox, while others like Alaskapox have only recently emerged. In fact, viruses constitute about <a href="https://doi.org/10.1098%2Frstb.2011.0354">two-thirds of all new human pathogens</a>. These new viruses differ widely in their risk to human health, ranging from the rare and mild illness caused by the Menangle virus to the <a href="https://covid.cdc.gov/covid-data-tracker/#datatracker-home">devastating public health impact</a> of the virus that causes COVID-19. </p>
<p>Of the viruses known to infect humans, about 80% are naturally occurring in nonhuman hosts, primarily <a href="https://doi.org/10.1016%2Fj.scitotenv.2020.142372">in mammals and birds</a> and, to a lesser extent, in arthropods and other wildlife. </p>
<p>Infectious agents transmitted from animals to humans are estimated to constitute about 60% of known human pathogens and up to <a href="https://doi.org/10.1073/pnas.1919176117">75% of emerging human pathogens</a>. Unfortunately, there is insufficient knowledge about wild animals that may harbor thousands of unknown virus species that could be human pathogens. </p>
<p>The evidence so far indicates that the Alaskapox virus is present in several species of <a href="https://doi.org/10.1093%2Fcid%2Fcix219">small mammals</a>, most notably shrews and the red-backed vole. In other words, Alaskapox is a new example of an infectious disease that can make the leap from animals to humans, a process known as zoonosis. Although available data suggests that the public health impact of Alaskapox virus is limited, it is likely widespread in small mammal populations in Alaska, and other infections in people may not have been diagnosed. </p>
<p>At present, no person-to-person transmission of Alaskapox has been documented. However, because some types of orthopoxviruses can be transmitted by direct contact with skin lesions, it is recommended that people with wounds that are suspected to be caused by Alaskapox keep the affected area covered with a bandage.</p>
<h2>What other orthopoxviruses pose a risk?</h2>
<p>In addition to Alaskapox virus, some other orthopoxviruses have recently been recognized, such as Akhmeta virus and/or Abatino virus, that highlight the possibility of unknown members of this genus with <a href="https://doi.org/10.1056%2FNEJMoa1407647">zoonotic potential</a>. </p>
<p>Other orthopoxviruses with zoonotic potential, such as mpox virus and cowpox virus, are increasingly being reported as a cause of human disease. In fact, the ongoing mpox outbreak that started in May 2022 has resulted in more than <a href="https://www.cdc.gov/poxvirus/mpox/response/2022/index.html">93,000 cases and 177 deaths</a>. This situation may have been facilitated by the discontinuation of routine vaccination against the eradicated human smallpox, as this vaccine gave rise to <a href="https://doi.org/10.1038/s41392-023-01574-6">some degree of population immunity</a> against other orthopoxviruses.</p>
<p>In addition to the above, there are many other orthopoxviruses that infect mammals. Examples are the ectromelia virus that causes mousepox, camelpox, raccoonpox, gerbilpox and skunkpox or some sublineages of vaccinia virus such as rabbitpox and buffalopox. </p>
<p>Poxviruses infect a broad spectrum of hosts, including insects, birds, reptiles and mammals. The wide host range, the wide geographical distribution and the constant global emergence of zoonotic viruses, including new orthopoxviruses, pose a global health threat that requires close monitoring and appropriate preventive measures. </p>
<p>In this situation, I believe the most prudent course of action is to urgently adopt a <a href="https://www.cdc.gov/onehealth/basics/index.html">One Health approach</a> that recognizes that the health of humans, animals, plants and the wider environment are interconnected, and accept that we cannot address human health without also addressing animal and environmental health.</p><img src="https://counter.theconversation.com/content/223470/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Raúl Rivas González does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Alaskapox was discovered in 2015 and has generally only caused mild illness – until now.Raúl Rivas González, Catedrático de Microbiología. Miembro de la Sociedad Española de Microbiología., Universidad de SalamancaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2169752024-02-06T13:29:24Z2024-02-06T13:29:24ZPerils of pet poop – so much more than just unsightly and smelly, it can spread disease<figure><img src="https://images.theconversation.com/files/571526/original/file-20240125-23-k5liyr.jpg?ixlib=rb-1.1.0&rect=16%2C37%2C959%2C684&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Responsible pet owners are on diligent poop patrol.</span> <span class="attribution"><span class="source">Hannah Sussman</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Have you ever been out on a walk and as you take that next step, you feel the slippery squish of poop under your foot?</p>
<p>It’s not just gross. Beyond the mess and the smell, it’s potentially infectious. That’s why signs reminding pet owners to “curb your dog” and scoop their poop have been joined in some places by posted warnings that pet waste can spread disease.</p>
<p><a href="https://scholar.google.com/citations?user=QiTnXH8AAAAJ&hl=en&oi=ao">As a small-animal primary care veterinarian</a>, I deal with the diseases of dog and cat poop on a daily basis. Feces represent potential <a href="https://www.britannica.com/science/zoonotic-disease">zoonotic hazards</a>, meaning they can transmit disease from the animals to people.</p>
<p>The reality is that waste left to wash into the soil, whether in a neighborhood, trail or dog park, <a href="https://pubmed.ncbi.nlm.nih.gov/28316698/">can spread life-threatening</a> <a href="https://www.cdc.gov/parasites/transmission/index.html">parasites</a> not just among dogs and cats, but also <a href="https://doi.org/10.1128/spectrum.02532-21">to wild animals</a> and <a href="https://www.cdc.gov/parasites/transmission/index.html#animal">people of all ages</a>. A 2020 study found <a href="https://doi.org/10.1186/s13071-020-04147-6">intestinal parasites in 85% of off-leash dog parks</a> across the United States.</p>
<p>While human diseases caused by soil-transmitted parasites are considered uncommon in the U.S., they infect as many as an <a href="https://www.cdc.gov/parasites/ascariasis/index.html">estimated billion people worldwide</a>. Signs that remind you to pick up after your pet are not just trying to keep public spaces clean; they’re urging you to help safeguard your community’s health.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/571223/original/file-20240124-27-qinn2d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="bottom of a child's foot showing open lesions by the toes" src="https://images.theconversation.com/files/571223/original/file-20240124-27-qinn2d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571223/original/file-20240124-27-qinn2d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=395&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571223/original/file-20240124-27-qinn2d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=395&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571223/original/file-20240124-27-qinn2d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=395&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571223/original/file-20240124-27-qinn2d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=496&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571223/original/file-20240124-27-qinn2d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=496&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571223/original/file-20240124-27-qinn2d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=496&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Parasites can enter your body through broken skin and set up shop, as in this hookworm infection.</span>
<span class="attribution"><a class="source" href="https://phil.cdc.gov/Details.aspx?pid=5204">CDC</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Abandoned poop’s impact on people</h2>
<p>Common dog poop parasites include <a href="http://www.cdc.gov/parasites/resources/roundworms_hookworms.html">hookworms, roundworms</a>, <a href="https://www.britannica.com/science/coccidium">coccidia</a> and <a href="https://www.britannica.com/animal/whipworm">whipworms</a>. Hookworms and roundworms can thrive in a variety of species, including humans.</p>
<p>Their microscopic larvae can get into your body through small scratches in your skin after contact with contaminated soil or via accidental oral ingestion. Remember that next time you’re outside and wipe sweat from your face with a dirty hand and then lick your lips or take a drink – it’s that simple. After hose or rain water has rinsed contaminated poop into the soil, these parasite eggs can <a href="https://www.cdc.gov/parasites/toxocariasis/epi.html">survive and infect for months or years</a> to come.</p>
<p>Once in the human body, both hookworm and roundworm larvae can mature and migrate through the bloodstream into the lungs. From there, coughs help them gain access to <a href="https://www.merckmanuals.com/home/infections/parasitic-infections-nematodes-roundworms/hookworm-infection">the digestive tract of their host</a>, where they leach nutrients by attaching to the intestinal wall. People with healthy immune systems may show no clinical signs of infection, but in sufficient quantities these parasites <a href="https://www.cdc.gov/parasites/hookworm/disease.html">can lead to anemia and malnourishment</a>. They can even <a href="https://doi.org/10.1016/j.revmed.2015.12.023">cause an intestinal obstruction</a> which may require surgical intervention, especially in young children.</p>
<p>Additionally, larval stages of roundworms <a href="https://doi.org/10.1016/bs.apar.2020.01.001">can move into the human eye</a> and, in rare cases, <a href="https://www.cdc.gov/parasites/toxocariasis/disease.html">lead to permanent blindness</a>. Hookworms can create a <a href="https://www.cdc.gov/parasites/zoonotichookworm/disease.html">severely itchy condition called cutaneous larva migrans</a> <a href="https://wwwnc.cdc.gov/travel/yellowbook/2024/infections-diseases/cutaneous-larva-migrans">as the larval worm moves</a> just under the skin of its host.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/571669/original/file-20240126-27-e6h7di.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="about a dozen little white worms next to a wooden match" src="https://images.theconversation.com/files/571669/original/file-20240126-27-e6h7di.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571669/original/file-20240126-27-e6h7di.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571669/original/file-20240126-27-e6h7di.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571669/original/file-20240126-27-e6h7di.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571669/original/file-20240126-27-e6h7di.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571669/original/file-20240126-27-e6h7di.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571669/original/file-20240126-27-e6h7di.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">Adult hookworms.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/adult-hookworms-of-a-dog-in-the-institute-for-parasitology-news-photo/162781943">Agency-Animal-Picture via Getty Images</a></span>
</figcaption>
</figure>
<p>Once the parasite’s life cycle is complete, it may exit the host’s body as an intact adult worm, which looks like a small piece of cooked spaghetti.</p>
<h2>The impact on other animals</h2>
<p><a href="https://doi.org/10.1016/s0195-5616(87)50005-5">Dogs and cats can also develop</a> the same symptoms people do due to parasitic infections. In addition to risks of hookworms and roundworms, pets are also vulnerable to whipworm, giardia and coccidia.</p>
<p>Beyond parasites, unattended poop may also be contaminated with canine or feline viruses, <a href="https://doi.org/10.1016/j.vetmic.2020.108760">such as parvovirus</a>, <a href="https://doi.org/10.1016/B0-72-160422-6/50016-4">distemper virus and canine coronavirus</a>, that can create life-threatening disease in other dogs and cats, especially in adult animals that are unvaccinated and puppies and kittens.</p>
<p><a href="https://www.avma.org/resources-tools/pet-owners/petcare/canine-distemper">These viruses</a> <a href="https://www.avma.org/resources-tools/pet-owners/petcare/canine-parvovirus">attack rapidly dividing cells</a>, in particular the intestinal lining and bone marrow, leaving them unable to absorb nutrients appropriately and unable to produce replacement red and white blood cells that help defend against these and other viruses. Vaccination can protect pets.</p>
<p>Many species of local wildlife are within the canid and felid family groups. They, too, are susceptible to many of the same parasites and viruses as pet dogs and cats – while being much less likely to have received the benefit of vaccinations. Coyotes, wolves, foxes, raccoons, minks and bobcats are <a href="https://cwhl.vet.cornell.edu/disease/parvovirus#:%7E:text=Parvoviruses%20are%20capable%20of%20infecting,infect%20domestic%20cats%20and%20dogs">at risk of contracting parvovirus</a>, coronavirus <a href="https://vtfishandwildlife.com/learn-more/living-with-wildlife/wildlife-diseases/canine-distemper">and distemper</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/571667/original/file-20240126-15-giuwd9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="person dropping a bag of dog poop into bin with dog watching" src="https://images.theconversation.com/files/571667/original/file-20240126-15-giuwd9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571667/original/file-20240126-15-giuwd9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571667/original/file-20240126-15-giuwd9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571667/original/file-20240126-15-giuwd9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571667/original/file-20240126-15-giuwd9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571667/original/file-20240126-15-giuwd9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571667/original/file-20240126-15-giuwd9.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">Be prepared to deal with poop on every walk.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/teenager-putting-a-filled-biodegradable-dog-poop-royalty-free-image/1335287112">Elva Etienne/Moment via Getty Images</a></span>
</figcaption>
</figure>
<h2>Responsible pet poop management</h2>
<p>So, wherever your dog or cat relieves himself – at the park, in the woods, on the sidewalk, or even in your yard – pick up that poop but always avoid contact with your skin. It’s safest to use a shovel to place the poop directly into a plastic bag, or put a baggie over your hand to grab the poop and then pull the plastic bag over it. While it’s tempting to leave the “soft-serve” or watery poops behind, these are often the more likely culprits for spreading diseases.</p>
<p>Tie up the bag and make sure to place it in a trash can – not on top – to avoid inadvertent contamination of a neighbor or sanitation worker. Promptly <a href="https://www.cdc.gov/handwashing/when-how-handwashing.html">wash your hands</a>, particularly before touching your face or eating or drinking. Hand sanitizers can take care of many viruses on your skin, but they <a href="https://doi.org/10.3347/kjp.2016.54.1.103">won’t kill parasite eggs</a>.</p>
<p>Other potential sources of poop – and parasite – exposure are the <a href="https://doi.org/10.1155/1994/786090">sandbox, beaches and park sand</a> found under and around playgrounds. Sand is comfortable to lounge on, fun to construct into castles, and softens the impact if you fall off a play structure. But cats and other small mammals love to use it as a litter box since it’s easy to dig and absorbs moisture. Covering sandboxes when not in use and closely monitoring your environment at the beach and playground are key steps toward minimizing the risks of exposure for everyone.</p>
<p>By <a href="https://capcvet.org/guidelines">keeping your pets on regular parasite prevention</a> protocols, with annual testing for intestinal parasites and routine removal of fecal material from the environment, you can help to minimize the potential for these diseases among all the mammals in your environment – human, pet and wild.</p>
<p>Key points to remember to avoid parasites and minimize the impact on your ecosystem:</p>
<ul>
<li>Pick waste up and safely throw it out regardless of where your pet poops. Sanitize your hands afterward.</li>
<li>Wash your hands before eating or touching your face while gardening or working in the yard.</li>
<li>Avoid rinsing poop into the soil. Using rain or a garden hose only removes the visible mess, not the microscopic issues.</li>
<li>Make sure sandboxes are covered when not in use.</li>
<li>Keep your pets on <a href="https://capcvet.org/guidelines">monthly intestinal parasite deworming</a> schedules.</li>
<li>Have your vet test your pet’s poop annually for intestinal parasites.</li>
</ul><img src="https://counter.theconversation.com/content/216975/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julia Wuerz does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The signs that remind you to pick up after your pet are not just trying to keep public spaces clean; they’re urging you to help safeguard your community’s health.Julia Wuerz, Clinical Assistant Professor of Small Animal Clinical Sciences, University of FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2221442024-01-31T04:43:32Z2024-01-31T04:43:32ZMeasles is on the rise around the world – we can’t let vaccination rates falter<figure><img src="https://images.theconversation.com/files/572324/original/file-20240131-29-6uve5g.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5176%2C3445&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/viral-disease-measles-rash-concept-doctor-1323694607">fotohay/Shutterstock</a></span></figcaption></figure><p>In recent weeks a series of measles alerts have been issued <a href="https://www.news.com.au/lifestyle/health/health-problems/sydney-canberra-melbourne-put-on-alert-after-airport-measles-cases/news-story/6f2c44209c20ad319fe1ff4036070be0">around Australia</a>, including in <a href="https://www.health.nsw.gov.au/news/Pages/20240124_01.aspx">New South Wales</a>, <a href="https://www.health.vic.gov.au/health-alerts/new-measles-cases-in-victoria">Victoria</a> and <a href="https://metrosouth.health.qld.gov.au/news/measles-alert-for-brisbane-south-0">Queensland</a>, after the identification of a small number of cases in travellers returning from overseas. </p>
<p>Meanwhile, places such as the <a href="https://emergency.cdc.gov/newsletters/coca/2024/012524.html">United States</a> and the <a href="https://www.dailymail.co.uk/health/article-12982153/Measles-resurgence-fears-spark-national-call-action-health-chief-warns-UK-forgotten-illness-like-HALF-children-areas-not-jabbed-rates-slump-10-year-low-wake-Covid-anti-vax-movement.html">United Kingdom</a> have been contending with larger measles outbreaks.</p>
<p>In fact, the World Health Organization reported a <a href="https://www.bbc.com/news/health-68068226">45-fold increase</a> in measles cases in Europe last year, with 42,200 cases recorded in 2023 compared to 941 in 2022.</p>
<p>In South Asia, <a href="https://www.who.int/india/health-topics/measles">India</a> and <a href="https://www.cdc.gov/globalhealth/measles/data/global-measles-outbreaks.html">Pakistan</a> have also recently reported outbreaks.</p>
<p>So what’s the risk of a larger outbreak in Australia? Fortunately it’s likely to be quite low – but ensuring we continue to have high rates of vaccination coverage is crucial.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1750407589782012382"}"></div></p>
<h2>Remind me – what is measles?</h2>
<p>Measles is a <a href="https://www.rch.org.au/kidsinfo/fact_sheets/Measles/">highly infectious</a> viral disease. It spreads through tiny droplets when an infected person coughs or sneezes. Measles is so contagious that if one infected person comes into contact with ten unvaccinated people, they can infect <a href="https://www.theguardian.com/world/2024/jan/23/first-edition-measles-outbreak">nine of them</a>.</p>
<p>It can take around ten to 12 days for symptoms to appear after a person has been exposed to the virus. Although measles is characterised by a rash, symptoms are generally cold-like to begin with, including a fever, runny nose, fatigue, and sore or red eyes. The rash, which is not itchy, emerges two or three days later and spreads from the face down the body. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/measles-in-samoa-how-a-small-island-nation-found-itself-in-the-grips-of-an-outbreak-disaster-128467">Measles in Samoa: how a small island nation found itself in the grips of an outbreak disaster</a>
</strong>
</em>
</p>
<hr>
<p>Sometimes measles can lead to secondary infections such as an ear infection, diarrhoea or pneumonia. In rare cases measles can cause encephalitis (inflammation of the brain). </p>
<p>In severe cases measles can lead to hospitalisation and death. We saw this in 2019 in the Pacific Island nation of Samoa. Out of <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30044-X/fulltext">5,667 infections</a> in a four-month period, 81 died, mostly young children.</p>
<h2>Vaccination works</h2>
<p>Vaccination is the most effective strategy to protect against measles. Two doses of the MMR vaccine (given to children at <a href="https://www.healthywa.wa.gov.au/Articles/J_M/Measles-mumps-rubella-MMR-vaccine">12 months and 18 months</a> in Australia) provide protection against measles, mumps and rubella.</p>
<p>Babies under one year have natural protection from their mums that wears off gradually. Infants six to 11 months <a href="https://www.health.nsw.gov.au/Infectious/measles/Pages/measles-vax-qanda.aspx">can be vaccinated</a> if they will be travelling internationally, but will still need to take a further two doses.</p>
<p>Once vaccinated, the chance of getting measles is <a href="https://www.mayoclinic.org/diseases-conditions/measles/expert-answers/getting-measles-after-vaccination/faq-20125397">very low</a> and you are considered protected for life. </p>
<p>However, <a href="https://www.health.nsw.gov.au/Infectious/measles/Pages/measles-vax-qanda.aspx#howeff">about one in 100 people</a> who are vaccinated may still contract measles if they’re exposed to the virus. Although it’s not entirely clear why this happens, the infection in a vaccinated person is generally mild.</p>
<h2>Vaccination rates are faltering</h2>
<p>Globally, there has been <a href="https://www.dailymail.co.uk/health/article-12982153/Measles-resurgence-fears-spark-national-call-action-health-chief-warns-UK-forgotten-illness-like-HALF-children-areas-not-jabbed-rates-slump-10-year-low-wake-Covid-anti-vax-movement.html">a drop in childhood vaccinations</a> over the course of the COVID pandemic. This is likely due to a <a href="https://jamanetwork.com/journals/jama/fullarticle/2813910?guestAccessKey=417a7c3d-66ff-4692-9312-0eaf0256d5ca&utm_source=silverchair&utm_campaign=jama_network&utm_content=healthpolicy_highlights&u">range of factors</a> including declining trust in vaccines, misinformation and disruptions to access.</p>
<p>In Europe, the <a href="https://www.bbc.com/news/health-68068226">proportion of children</a> who received a first dose of the MMR vaccine dropped from 96% in 2019 to 93% in 2022, and from 93% to 91% for the second dose. This is important because about <a href="https://www.who.int/news-room/questions-and-answers/item/herd-immunity-lockdowns-and-covid-19#:%7E:text=The%20percentage%20of%20people%20who,among%20those%20who%20are%20vaccinated.">95% vaccination coverage</a> is needed to achieve herd immunity against measles. Under this scenario, those who are not vaccinated will be protected because the virus won’t spread.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/measles-has-been-identified-in-nsw-qld-and-sa-5-things-to-know-about-the-virus-202945">Measles has been identified in NSW, Qld and SA. 5 things to know about the virus</a>
</strong>
</em>
</p>
<hr>
<p>In the UK, health authorities <a href="https://www.dailymail.co.uk/health/article-12982153/Measles-resurgence-fears-spark-national-call-action-health-chief-warns-UK-forgotten-illness-like-HALF-children-areas-not-jabbed-rates-slump-10-year-low-wake-Covid-anti-vax-movement.html">have expressed alarm</a> at the number of children who have not been vaccinated, with reports up to almost half of children in parts of London have not received both shots.</p>
<p>As of September 2023, the <a href="https://www.health.gov.au/topics/immunisation/immunisation-data/childhood-immunisation-coverage/immunisation-coverage-rates-for-all-children">Australian government</a> reported immunisation rates across all childhood vaccinations of 93.26% for one-year-olds, 91.22% for two-year-olds, and 94.04% for five-year-olds. There are slight disparities between different states and territories and among some population groups. </p>
<h2>Boosting vaccination coverage</h2>
<p>While we appear to be quite close to the herd immunity threshold for measles and not in immediate danger of an outbreak, we still need to be vigilant. </p>
<p>Australia has an excellent outbreak surveillance in place in all states for infectious diseases including measles. But outbreaks are <a href="https://www.cdc.gov/globalhealth/measles/data/global-measles-outbreaks.html">occurring globally</a>, and are liable to take hold when people are unvaccinated or under-vaccinated. So we need to be alert in all states, increase surveillance at international transit points, and continue to increase immunisation coverage, especially among young children. Educating parents and the wider community about the importance of MMR vaccines is key.</p>
<p>It’s never too late to be vaccinated against measles if you missed out as a child, or are unsure if you’ve had two doses. As a single infected traveller can cause an outbreak, vaccination is particularly important if you travel frequently. If you’re unsure of your vaccination status, you can ask your GP or check your own or your children’s record through the <a href="https://www.betterhealth.vic.gov.au/health/healthyliving/How-to-find-your-immunisation-records">Australian Immunisation Register</a>. </p>
<p>If you suspect you or someone in your family is infected it’s important to stay isolated and contact your doctor. They will confirm the infection by <a href="https://www.health.vic.gov.au/health-alerts/new-measles-cases-in-victoria">referring you</a> for a blood test and possibly a RT-PCR test.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-people-born-between-1966-and-1994-are-at-greater-risk-of-measles-and-what-to-do-about-it-110167">Why people born between 1966 and 1994 are at greater risk of measles – and what to do about it</a>
</strong>
</em>
</p>
<hr>
<p><em>The Australian department of health in collaboration with the Australian Academy of Science has developed a set of <a href="https://www.science.org.au/curious/people-medicine/measles-everything-you-need-know">useful resources</a> on measles which can assist travellers, the general public and health professionals.</em></p><img src="https://counter.theconversation.com/content/222144/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jaya Dantas is Professor of International Health in the Curtin School of Population Health and leads a program of research in refugee and migrant health. She is currently lead CI on grants funded by Healthway and Lotterwest and CI on a DISER grant. Jaya is the International Health SIG Convenor of the Public Health Association of Australia, has been appointed to the Committee of Women in Global Health, Australia and is on the Editorial Advisory Group of the Medical Journal of Australia. She has lived experience of infectious disease in India and Africa.</span></em></p>Though the outbreaks overseas are bigger, a number of cases have also been detected in Australia so far this year.Jaya Dantas, Deputy Chair, Academic Board; Dean International, Faculty of Health Sciences and Professor of International Health, Curtin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2202852024-01-25T20:46:49Z2024-01-25T20:46:49ZThe emergence of JN.1 is an evolutionary ‘step change’ in the COVID pandemic. Why is this significant?<figure><img src="https://images.theconversation.com/files/571359/original/file-20240125-15-2lt45r.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C7667%2C3900&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/evolution-covid19-sarscov2-mutating-coronavirus-virus-2344854903">Lightspring/Shutterstock</a></span></figcaption></figure><p>Since it was detected in <a href="https://www.gavi.org/vaccineswork/seven-things-you-need-know-about-jn1-covid-19-variant">August 2023</a>, the JN.1 variant of COVID has <a href="https://news.un.org/en/story/2023/12/1145012">spread widely</a>. It has become dominant in Australia and <a href="https://outbreak.info/situation-reports?xmin=2023-07-05&xmax=2024-01-05&pango=JN.1">around the world</a>, driving the <a href="https://www.cdc.gov/respiratory-viruses/whats-new/JN.1-update-2024-01-05.html">biggest COVID wave</a> seen in many jurisdictions for at least the past year.</p>
<p>The World Health Organization (WHO) <a href="https://news.un.org/en/story/2023/12/1145012">classified</a> JN.1 as a “variant of interest” in December 2023 and in January <a href="https://x.com/UNGeneva/status/1745782729558348212?s=20">strongly stated</a> COVID was a continuing global health threat causing “far too much” preventable disease with worrying potential for long-term health consequences. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1745782729558348212"}"></div></p>
<p>JN.1 is significant. First as a pathogen – it’s a surprisingly new-look version of SARS-CoV-2 (the virus that causes COVID) and is rapidly displacing other circulating strains (omicron XBB). </p>
<p>It’s also significant because of what it says about COVID’s evolution. Normally, SARS-CoV-2 variants look quite similar to what was there before, accumulating just a few mutations at a time that give the virus a meaningful advantage over its parent. </p>
<p>However, occasionally, as was the case when omicron (B.1.1.529) arose two years ago, variants emerge seemingly out of the blue that have markedly different characteristics to what was there before. This has significant implications for disease and transmission. </p>
<p>Until now, it wasn’t clear this “step-change” evolution would happen again, especially given the ongoing success of the steadily evolving omicron variants. </p>
<p>JN.1 is so distinct and causing such a wave of new infections that many are wondering whether the <a href="https://www.who.int/activities/tracking-SARS-CoV-2-variants">WHO</a> will recognise JN.1 as the next variant of concern with its own Greek letter. In any case, with JN.1 we’ve entered a new phase of the pandemic.</p>
<h2>Where did JN.1 come from?</h2>
<p>The JN.1 (or BA.2.86.1.1) story begins with the emergence of its <a href="https://erictopol.substack.com/p/from-a-detour-to-global-dominance">parent lineage</a> BA.2.86 around mid 2023, which originated from a much earlier (2022) omicron sub-variant BA.2.</p>
<p><a href="https://www.nature.com/articles/d41586-022-01613-2">Chronic infections</a> that may linger unresolved for months (if not years, in some people) likely play a role in the emergence of these step-change variants. </p>
<p>In chronically infected people, the virus silently tests and eventually retains many mutations that help it avoid immunity and survive in that person. For BA.2.86, this resulted in <a href="https://theconversation.com/how-evasive-and-transmissible-is-the-newest-omicron-offshoot-ba-2-86-that-causes-covid-19-4-questions-answered-212453">more than 30 mutations</a> of the spike protein (a protein on the surface of SARS-CoV-2 that allows it to attach to our cells). </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/covid-is-surging-in-australia-and-only-1-in-5-older-adults-are-up-to-date-with-their-boosters-220839">COVID is surging in Australia – and only 1 in 5 older adults are up to date with their boosters</a>
</strong>
</em>
</p>
<hr>
<p>The sheer volume of infections occurring globally sets the scene for major viral evolution. SARS-CoV-2 continues to have a <a href="https://nextstrain.org/ncov/gisaid/global/all-time?dmin=2021-04-07&l=clock">very high rate of mutation</a>. Accordingly, JN.1 itself is already <a href="https://twitter.com/dfocosi/status/1744982175508771190">mutating and evolving</a> quickly.</p>
<h2>How is JN.1 different to other variants?</h2>
<p>BA.2.86 and now JN.1 are behaving in a manner that looks unique in laboratory studies in two ways.</p>
<p>The first relates to how the virus evades immunity. JN.1 has inherited <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(23)00813-7/fulltext#%20">more than 30 mutations</a> in its spike protein. It also acquired a new mutation, <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(23)00744-2/fulltext">L455S</a>, which further decreases the ability of antibodies (one part of the immune system’s protective response) to bind to the virus and prevent infection.</p>
<p>The second involves changes to the way JN.1 <a href="https://www.nature.com/articles/s41580-021-00418-x">enters</a> and replicates in our cells. Without delving in to the molecular details, recent high-profile lab-based research from the <a href="https://www.cell.com/action/showPdf?pii=S0092-8674%2823%2901400-9">United States</a> and <a href="https://www.cell.com/action/showPdf?pii=S0092-8674%2823%2901399-5">Europe</a> observed BA.2.86 to enter cells from the lung in a similar way to pre-omicron variants like delta. However, in contrast, preliminary work by Australia’s Kirby Institute <a href="https://www.biorxiv.org/content/10.1101/2023.09.22.558930v2">using different techniques</a> finds replication characteristics that are aligned better with omicron lineages. </p>
<p>Further research to resolve these different cell entry findings is important because it has implications for where the virus may prefer to replicate in the body, which could affect disease severity and transmission. </p>
<p>Whatever the case, these findings show JN.1 (and SARS-CoV-2 in general) can not only navigate its way around our immune system, but is finding new ways to infect cells and transmit effectively. We need to further study how this plays out in people and how it affects clinical outcomes.</p>
<h2>Is JN.1 more severe?</h2>
<figure class="align-center ">
<img alt="A woman in a supermarket wearing a mask." src="https://images.theconversation.com/files/571362/original/file-20240125-17-9zn8rj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571362/original/file-20240125-17-9zn8rj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571362/original/file-20240125-17-9zn8rj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571362/original/file-20240125-17-9zn8rj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571362/original/file-20240125-17-9zn8rj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571362/original/file-20240125-17-9zn8rj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571362/original/file-20240125-17-9zn8rj.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">JN.1 has some characteristics which distinguish it from other variants.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/alarmed-female-wears-medical-mask-against-1708365295">Elizaveta Galitckaia/Shutterstock</a></span>
</figcaption>
</figure>
<p>The step-change evolution of BA.2.86, combined with the immune-evading features in JN.1, has given the virus a <a href="https://www.who.int/docs/default-source/coronaviruse/18122023_jn.1_ire_clean.pdf?sfvrsn=6103754a_3">global growth advantage</a> well beyond the XBB.1-based lineages we faced in 2023. </p>
<p>Despite these features, evidence suggests our <a href="https://www.news-medical.net/news/20231208/T-cells-can-recognize-and-fight-the-Pirola-variant-new-study-suggests.aspx">adaptive immune system</a> could still recognise and respond to BA.286 and JN.1 effectively. Updated monovalent vaccines, tests and treatments <a href="https://publichealth.jhu.edu/2024/jn1-the-dominant-variant-in-the-covid-surge">remain effective</a> against JN.1. </p>
<p>There are two elements to “severity”: first if it is more “intrinsically” severe (worse illness with an infection in the absence of any immunity) and second if the virus has greater transmission, causing greater illness and deaths, simply because it infects more people. The latter is certainly the case with JN.1. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-long-does-immunity-last-after-a-covid-infection-221398">How long does immunity last after a COVID infection?</a>
</strong>
</em>
</p>
<hr>
<h2>What next?</h2>
<p>We simply don’t know if this virus is on an evolutionary track to becoming the “next common cold” or not, nor have any idea of what that timeframe might be. While <a href="https://www.science.org/content/article/four-cold-causing-coronaviruses-may-provide-clues-covids-future">examining the trajectories</a> of four historic coronaviruses could give us a glimpse of where we may be heading, this should be considered as just one possible path. The emergence of JN.1 underlines that we are experiencing a continuing epidemic with COVID and that looks like the way forward for the foreseeable future. </p>
<p>We are now in a new pandemic phase: post-emergency. Yet COVID remains the major infectious disease causing harm globally, from both acute infections and <a href="https://theconversation.com/long-covid-symptoms-can-improve-but-their-resolution-is-slow-and-imperfect-212015">long COVID</a>. At a societal and an individual level we need to re-think the risks of accepting wave after wave of infection. </p>
<p>Altogether, this underscores the importance of <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(22)01585-9/fulltext">comprehensive strategies to reduce COVID transmission and impacts</a>, with the least imposition (such as <a href="https://www.mja.com.au/journal/2022/217/11/healthy-indoor-air-our-fundamental-need-time-act-now">clean indoor air interventions</a>). </p>
<p>People are <a href="https://www.health.vic.gov.au/health-alerts/increase-in-covid-19-cases">advised</a> to continue to take active steps to protect themselves and those around them. </p>
<p>For better pandemic preparedness for emerging threats and an improved response to the current one it is crucial we <a href="https://www.who.int/publications/m/item/virtual-press-conference-on-global-health-issues-transcript-10-january-2024">continue global surveillance</a>. The low representation of low- and middle- income countries is a concerning blind-spot. Intensified research is also crucial.</p><img src="https://counter.theconversation.com/content/220285/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Suman Majumdar, through the Burnet Institute receives grant funding from the Australian Government via the National Health & Medical Research Council of Australia, the Medical Research Future Fund and DFAT's Centre for Health Security.</span></em></p><p class="fine-print"><em><span>Brendan Crabb and the Institute he leads receives research grant funding from the National Health & Medical Research Council of Australia, the Medical Research Future Fund, DFAT's Centre for Health Security and other Australian federal and Victorian State Government bodies. He is the Chair of The Australian Global Health Alliance and the Pacific Friends of Global Health, both in an honorary capacity. And he serves on the Board of the Telethon Kids Institute, on advisory committees of mRNA Victoria, the Sanger Institute (UK), the Institute for Health Transformation (at Deakin University), The Brain Cancer Centre (Australia), the WHO Malaria Vaccine Advisory Committee; MALVAC, and is a member of OzSAGE and The John Snow Project, all honorary positions.</span></em></p><p class="fine-print"><em><span>Stuart Turville receives funding from NHMRC through an Ideas Grant and MRFF grant related to SARS CoV-2 immunology. </span></em></p><p class="fine-print"><em><span>Emma Pakula does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The JN.1 variant has become dominant in Australia and around the world, causing large waves of infections. Here’s what we know about it so far – and why it’s so important.Suman Majumdar, Associate Professor and Chief Health Officer - COVID and Health Emergencies, Burnet InstituteBrendan Crabb, Director and CEO, Burnet InstituteEmma Pakula, Senior Research and Policy Officer, Burnet InstituteStuart Turville, Associate Professor, Immunovirology and Pathogenesis Program, Kirby Institute, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2217002024-01-23T18:38:01Z2024-01-23T18:38:01ZStrep A explainer: Why invasive cases are increasing, how it spreads and what symptoms to look for<figure><img src="https://images.theconversation.com/files/570704/original/file-20240122-27145-c07mvm.png?ixlib=rb-1.1.0&rect=12%2C48%2C1968%2C1488&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An increase in cases of diseases caused by group A Streptococcus has been seen in several countries including Canada.</span> <span class="attribution"><span class="source">(National Institute of Allergy and Infectious Diseases (NIAID))</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>A jump in the number of people with serious illness caused by group A Streptococcus — also referred to as Streptococcus pyogenes or Strep A — has made headlines recently. There has also been a <a href="https://www.cbc.ca/news/canada/toronto/ontario-strep-deaths-invasive-group-a-streptococcal-disease-1.7085755">higher than usual number of deaths</a> from group A Streptococcus infections, including in children, leaving people with questions about why and how these infections are spreading, and what symptoms to be aware of.</p>
<p>Shortly after the number of COVID-19 infections diminished worldwide, a <a href="https://www.bbc.com/news/health-64122989">considerable increase</a> in patients diagnosed with diseases caused by group A Streptococcus began in different parts of the world. </p>
<p>Specifically in Canada, Public Health Ontario is currently reporting a large increase in <a href="https://www.publichealthontario.ca/-/media/Documents/I/2023/igas-enhanced-epi-2023-2024.pdf?rev=f16466608245457a984dcfa738930ad4&sc_lang=en">invasive group A Streptococcus cases</a>. A similar <a href="https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON429">increase in cases</a> has also been reported in multiple countries across Europe, mainly affecting children under 10 years old. </p>
<h2>Why did these bacteria suddenly become a global concern?</h2>
<p>To answer this question, it is essential to know some specifics of this disease to gain a better understanding of its cause. Group A Streptococcus exclusively affects humans, and its spread occurs <a href="https://doi.org/10.1016/S2666-5247(21)00332-3">via airborne droplets as well as person-to-person contact</a>. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/570753/original/file-20240122-23-nvfuw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscopic view of group A Streptococcus bacteria" src="https://images.theconversation.com/files/570753/original/file-20240122-23-nvfuw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/570753/original/file-20240122-23-nvfuw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=938&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570753/original/file-20240122-23-nvfuw5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=938&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570753/original/file-20240122-23-nvfuw5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=938&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570753/original/file-20240122-23-nvfuw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1179&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570753/original/file-20240122-23-nvfuw5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1179&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570753/original/file-20240122-23-nvfuw5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1179&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Group A Strep bacteria have several factors that promote infection and allow it to invade, colonize and survive in different tissues.</span>
<span class="attribution"><span class="source">(NIAID)</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Among the different illnesses caused by this organism are respiratory tract infections such as tonsillitis and pharyngitis (symptoms of classic <a href="https://www.cdc.gov/groupastrep/diseases-public/strep-throat.html">strep throat</a>), as well as superficial skin infections and skin infections <a href="https://doi.org/10.4103%2F1947-2714.101997">known as pyoderma</a>. </p>
<p>However, Group A Streptococcus can sometimes develop into invasive infections that put patients’ lives at risk, such as <a href="https://www.cdc.gov/groupastrep/diseases-public/necrotizing-fasciitis.html">necrotizing fasciitis</a>, <a href="https://my.clevelandclinic.org/health/diseases/21539-septicemia">septicemia</a> (blood poisoning) and <a href="https://www.cdc.gov/groupastrep/diseases-public/streptococcal-toxic-shock-syndrome.html">streptococcal toxic shock syndrome</a>. </p>
<p>To generate this wide range of diseases in different parts of the body, the organism has several factors that promote infection and allow the bacteria to invade, colonize and survive in different tissues. These include molecules such as superantigens, exotoxins and adhesins that help pathogens evade the host immune system.</p>
<p>A new variant of group A Streptococcus called M1UK was <a href="https://doi.org/10.1016/S1473-3099(19)30446-3">first reported in the United Kingdom</a>, where it has been linked to an increase in scarlet fever cases as well as an increase in invasive infections. </p>
<p><a href="https://doi.org/10.1038/s41467-023-36717-4">Members of the M1UK sublineage</a> exhibit an ability to enhance the expression of the superantigen SpeA due to a single genetic mutation. The over-production of SpeA may be responsible for increased transmission and survival, as well as the aggressiveness of these infections, although this is currently being studied.</p>
<h2>What could account for the current spike in cases?</h2>
<p>Up to <a href="https://doi.org/10.1542/peds.2009-2648">approximately 10 per cent of school-aged children</a> will commonly carry these bacteria in their throats and upper respiratory tract without having any symptoms, and over time will develop some level of immunity to it. </p>
<p>It is likely that during the COVID-19 pandemic, children were at home and not being exposed to the bacteria as much as before and so their immune systems are probably <a href="https://doi.org/10.1016%2FS0262-4079(21)00716-8">not as good at fighting these infections</a>. Without this exposure, some children are likely to be more susceptible to infection. </p>
<p>The spread of the new M1UK strain is also probably why there’s an increased number of cases, although this is something that is currently being studied.</p>
<h2>Should people be concerned about these rising numbers?</h2>
<p>Generally, Canadians should not be overly concerned because serious infections with group A Streptococcus are still quite rare. </p>
<p>However, people should also not ignore strep throat, and should get treatment from a doctor and be wary of symptoms that might suggest an invasive infection. </p>
<p>Strep throat requires treatment, as untreated strep throat can lead to other problems including invasive infections.</p>
<h2>How to protect yourself and when to seek medical care</h2>
<figure class="align-center ">
<img alt="A health professional out of frame swabbing a girl's throat" src="https://images.theconversation.com/files/570754/original/file-20240122-24-has9cu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570754/original/file-20240122-24-has9cu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570754/original/file-20240122-24-has9cu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570754/original/file-20240122-24-has9cu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570754/original/file-20240122-24-has9cu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570754/original/file-20240122-24-has9cu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570754/original/file-20240122-24-has9cu.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">A rapid strep test can diagnose strep throat. If the test is positive, antibiotics can be prescribed.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Because group A Streptococcus are common and many carriers are asymptomatic, it can be difficult to avoid exposure. Practising good hand hygiene, covering coughs and sneezes, staying home when you’re sick and not sending children to school if they have a very sore throat are all good measures.</p>
<p>If you believe you have a strep infection such as <a href="https://www.aboutkidshealth.ca/article?contentid=11&language=english">strep throat</a> with painful swallowing, fever, swollen tonsils or a rash, talk to a family physician to determine if the infection is caused by group A Streptococcus. A <a href="https://www.healthlinkbc.ca/tests-treatments-medications/medical-tests/rapid-strep-test-strep-throat">rapid strep test</a> can be done with a throat swab. If the test is positive, antibiotics can be prescribed. </p>
<p>Invasive group A strep infections are very dangerous and are a medical emergency, although initial symptoms may not be obvious. These could include fever, chills, flu-like symptoms and nausea or vomiting, but in particular red and warm skin infections that may be very painful and spread rapidly.</p>
<p>There is strong evidence that <a href="https://doi.org/10.1542/peds.105.5.e60">prior viral infections such as chickenpox</a> can predispose people for developing invasive group A Streptococcus. Children with chickenpox should be watched carefully for symptoms of invasive group A Strep. </p>
<p>Currently, there is no vaccine against group A Streptococcus, although there is a vaccine for chickenpox. Multiple research teams around the world, <a href="https://www.mccormicklab.ca/">including our own lab</a>, are working towards developing an effective vaccine against this human pathogen.</p><img src="https://counter.theconversation.com/content/221700/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John McCormick receives funding from the Canadian Institutes of Health Research (CIHR), the Natural Sciences and Engineering Council of Canada (NSERC) and the Leducq Foundation. </span></em></p><p class="fine-print"><em><span>Juan Manuel Diaz receives funding from Canadian Institutes of Health Research. </span></em></p>An increase in serious illnesses caused by group A Streptococcus has recently made Strep A a growing concern in Canada and elsewhere. Here’s why and how it’s spreading, and what symptoms to look for.John McCormick, Professor of Microbiology and Immunology, Western UniversityJuan Manuel Diaz, Postdoctoral Associate, department of Microbiology and Immunology, Western UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2201682024-01-17T13:37:40Z2024-01-17T13:37:40ZDengue fever: the tropical disease spreading across Europe<figure><img src="https://images.theconversation.com/files/566586/original/file-20231214-23-8x6yy5.jpg?ixlib=rb-1.1.0&rect=73%2C73%2C5390%2C3563&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The dengue virus is spread through bites from infected Aedes mosquitoes.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/es/image-photo/striped-mosquitoes-eating-blood-on-human-1510102085">Witsawat.S/Shutterstock</a></span></figcaption></figure><p>If you were looking for information on dengue fever and only had access to older textbooks, it would likely be found in the sections on tropical and subtropical diseases.</p>
<p>The disease is, indeed, spreading rapidly in warmer regions: Peru – which has mixed subtropical and tropical climates – has recently recorded some of <a href="https://www.unicef.org/peru/comunicados-prensa/mas-37-mil-ninas-ninos-adolescentes-enfermaron-de-dengue-primeros-meses-2023-recomendaciones-especialista">the highest numbers of the virus</a> (both cases and deaths) within memory. This has led to the declaration of a state of emergency in most of its regions, as cases continue to climb year after year.</p>
<h2>Record numbers of cases in 2023</h2>
<p>We are also seeing more and more new cases outside of Latin America. There have been increasing numbers of locally transmitted cases in the <a href="https://www.cdc.gov/dengue/statistics-maps/historic-data.html">USA</a>, <a href="https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2023.28.37.2300471">Italy</a> and <a href="https://www.santepubliquefrance.fr/en/autochthonous-dengue-in-mainland-france-2022-geographical-expansion-and-increase-in-incidence">France</a>, as well as the first recorded cases in many years in <a href="https://www.sanidad.gob.es/profesionales/saludPublica/ccayes/alertasActual/docs/20230228_ERR_Dengue_autoctono.pdf">Spain</a>.</p>
<p>In 2022, there were <a href="https://www3.paho.org/data/index.php/es/temas/indicadores-dengue/boletin-anual-arbovirosis-2022.html">2.8 million registered cases of dengue</a> on the American continent alone. This was more than double the 1.2 million cases in 2021.</p>
<p>Although the majority of cases affect <a href="https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON448">tropical and subtropical areas of America, Asia and Africa</a>, a significant increase has recently been observed in more temperate areas, such as Europe. This is especially true in the south of the continent, where the disease has been present since the 1970s.</p>
<p>According to statistics from the <a href="https://www.ecdc.europa.eu/en/dengue-monthly">European Centre for Disease Prevention and Control</a>, 71 locally transmitted cases of dengue were reported in 2022 in mainland EU countries. This is an increase of over 20% compared to 2021.</p>
<h2>Small bites, big consequences</h2>
<p><a href="https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue">Dengue</a> is a disease caused by one of the four strains of dengue virus (DENV). It has been reported that all four strains can circulate together, and that they can cause the same set of symptoms. Special attention should be given to severe or haemorrhagic dengue, which is usually caused by exposure to one strain after previous exposure to another.</p>
<p>DENV is <a href="https://www.cdc.gov/dengue/transmission/index.html">transmitted</a> through bites from infected <em>Aedes</em> mosquitoes, primarily <em>Aedes aegypti</em>, but also to a lesser extent <em>Aedes albopictus</em>, also known as the Tiger Mosquito. These insects, which feed on human blood and transmit the virus through their saliva, are found in tropical and subtropical areas. However, in recent decades they have become more and more common in temperate areas.</p>
<p>The virus is not transmitted directly, but works in a cycle, passing from human to mosquito to human. When an infected female <em>Aedes</em> mosquito bites a person, it introduces DENV into their system and begins the cycle. The incubation period is usually between 3 and 10 days, although it can vary depending on external factors such as temperature.</p>
<p>Symptoms then begin to develop, usually fever, headaches, muscle aches, joint pain, nausea and vomiting. In severe cases, it can lead to haemorrhage, organ failure and death.</p>
<p><em>Aedes</em> mosquitoes breed in standing or stagnant water, such as water containers, unused swimming pools, old tyres, and so on. In the absence of vaccines and effective treatments, it is important to eliminate mosquito breeding sites to prevent the transmission of the disease. This can not only prevent the spread of dengue, but also the mosquito-borne viruses that cause Zika and chikungunya.</p>
<h2>The role of climate change and globalisation</h2>
<p>Climate change is one of the <a href="https://pubmed.ncbi.nlm.nih.gov/30884421/">driving forces behind the rise in dengue cases</a>, both in America and Europe. Increased temperatures and longer mosquito breeding seasons (due to warmer and longer summers) may help the spread of <em>Aedes aegypti</em>.</p>
<p>These mosquitoes are able to survive in temperatures above 10C, and thanks to global warming they are able expand their range to more temperate zones. Changes in rainfall patterns – caused by climate change – also increase the volume of standing water, providing an ideal breeding ground.</p>
<p>In addition, increased international travel and trade with areas where dengue fever is common, as well as the growth of cities, make the spread of the disease all the more likely.</p>
<h2>Will dengue become endemic in Europe?</h2>
<p>Against this backdrop, the possibility of dengue becoming endemic in Europe is a real possibility. Environmental conditions such as climate change and globalisation are making it easier for mosquitoes – and the diseases they carry – to spread. These are factors that cannot easily be brought under control, at least for the time being.</p>
<p>If dengue were to become endemic in Europe, it could have a significant impact on public health. For this reason, <a href="https://climate-adapt.eea.europa.eu/en/observatory/evidence/health-effects/vector-borne-diseases/dengue-factsheet">European health authorities are already working</a> to prevent its spread by addressing the factors that can currently be controlled. This includes monitoring cases, educating populations on how to prevent mosquito bites, and taking measures to control new mosquito populations as soon as their presence is detected, as has been happening on the Spanish island of <a href="https://www.ull.es/portal/noticias/2023/sanidad-activa-con-ayuda-de-la-ull-el-protocolo-ante-la-deteccion-de-un-mosquito-aedes-albopictus-en-santa-cruz-de-tenerife/">Tenerife</a>.</p><img src="https://counter.theconversation.com/content/220168/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Raimundo Seguí López-Peñalver no recibe salario, ni ejerce labores de consultoría, ni posee acciones, ni recibe financiación de ninguna compañía u organización que pueda obtener beneficio de este artículo, y ha declarado carecer de vínculos relevantes más allá del cargo académico citado.</span></em></p>Climate change is causing dengue-carrying mosquitoes to spread. Could the disease become endemic in Europe?Raimundo Seguí López-Peñalver, Profesor de Epidemiología en VIU, Universidad Internacional de ValenciaLicensed 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>
<figure class="align-center ">
<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">
<figcaption>
<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>
</figcaption>
</figure>
<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/2149192024-01-15T13:33:10Z2024-01-15T13:33:10ZWhat if every germ hit you at the exact same time? An immunologist explains<figure><img src="https://images.theconversation.com/files/565348/original/file-20231212-15-ba3kr2.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2121%2C1412&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Your immune system encounters a legion of potential pathogens every day.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/woman-shielding-eyes-by-large-green-coronavirus-royalty-free-image/1250588799">Klaus Vedfelt/DigitalVision via Getty Images</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&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><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>What would happen if all the diseases in the world hit us at the exact same time? – Gabriella, age 12, Irving, Texas</strong></p>
</blockquote>
<hr>
<p>When I was younger, I would watch “Batman” on my black-and-white television after school. Usually, Batman would face either the Joker, the Penguin, the Puzzler, Catwoman or any one of his usual opponents. However, on some occasions, Batman would have to face them all at the same time.</p>
<p>What would happen if, like Batman, the immune system had to face all of its rivals at once?</p>
<p><a href="https://scholar.google.com/citations?user=6JOQvNwAAAAJ&hl=en">I am an immunologist</a> who teaches the fundamentals of immunology to college undergraduates. My research generally focuses on factors that regulate immune responses and prevent autoimmune diseases – conditions where the immune system attacks your own body. As a scientist studying how we build immunity against pathogens such as the virus that causes COVID-19, understanding how the immune system combats multiple threats at the same time is immensely important to me. </p>
<p>There’s no reason why you can’t come down with strep throat at the same time as when you have a cold. In fact, sometimes fighting off one enemy can leave a hole in your defenses that another opportunistic pathogen can take advantage of.</p>
<h2>BAM! Understanding the rivals</h2>
<p>The first point to consider is what your immune system protects you from. The potential bad guys <a href="https://theconversation.com/immune-cells-that-fight-cancer-become-exhausted-within-hours-of-first-encountering-tumors-new-research-210947">include cancer cells</a> and dangerous microorganisms – including bacteria, viruses, fungi and more – that cause infections. The immune system must also be careful <a href="https://theconversation.com/immune-health-is-all-about-balance-an-immunologist-explains-why-both-too-strong-and-too-weak-an-immune-response-can-lead-to-illness-215217">not to damage</a> healthy cells and beneficial microorganisms that live on and inside you. </p>
<p>You interact with <a href="https://kids.frontiersin.org/articles/10.3389/frym.2022.629355">thousands of microorganisms</a> with every breath of air you take. Is the immune system facing off against all of them? Sort of. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565525/original/file-20231213-27-oegbgf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscope images of two T regulatory cells wrapped around an antigen-presenting cell" src="https://images.theconversation.com/files/565525/original/file-20231213-27-oegbgf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565525/original/file-20231213-27-oegbgf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565525/original/file-20231213-27-oegbgf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565525/original/file-20231213-27-oegbgf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565525/original/file-20231213-27-oegbgf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565525/original/file-20231213-27-oegbgf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565525/original/file-20231213-27-oegbgf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">T regulatory cells (red) determine whether an immune response should be mounted.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/SjQFf7">NIAID/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>It takes a <a href="https://theconversation.com/how-does-fever-help-fight-infections-theres-more-to-it-than-even-some-scientists-realize-210240">tremendous amount of energy</a> to fight a battle once a rival gains a foothold within your blood or tissues, so your immune system works to <a href="https://theconversation.com/how-do-viruses-get-into-cells-their-infection-tactics-determine-whether-they-can-jump-species-or-set-off-a-pandemic-216139">prevent it from getting in the body</a> in the first place. Your skin, <a href="https://theconversation.com/why-do-our-noses-get-snotty-when-we-are-sick-a-school-nurse-explains-the-powers-of-mucus-212949">snot</a>, saliva and <a href="https://theconversation.com/can-you-cry-underwater-205464">tears</a> form a critical <a href="https://www.ncbi.nlm.nih.gov/books/NBK279396/">first line of defense</a>. This is why <a href="https://doi.org/10.1089%2Fsur.2013.134">burn victims</a> who lose too much skin often die from overwhelming infection – their defensive barriers are too compromised and pathogens pour in.</p>
<p>The immune system greatly prefers <a href="https://theconversation.com/a-pediatric-nurse-explains-the-science-of-sneezing-160970">catching a microbe in snot</a> and blowing it out of your nose, or giving you time to wash it off the skin of your hands, over having to wage a cellular war. Gathering an army of <a href="https://theconversation.com/coronavirus-b-cells-and-t-cells-explained-141888">immune cells</a> to fight pathogens takes a lot of energy and makes you feel awful. </p>
<p>For example, the immune system <a href="https://theconversation.com/how-does-fever-help-fight-infections-theres-more-to-it-than-even-some-scientists-realize-210240">increases your body temperature</a> to make it an uncomfortable place for microorganisms to live and grow, but that fever can also make you want to lie down for days.</p>
<h2>BOOM! Where are their weaknesses?</h2>
<p>When Batman faced multiple opponents, he would find a weakness shared by all of the opponents and target it to foil their plans. The immune system uses the exact same strategy.</p>
<p>Certain microbes are considered pathogens largely because they are in the wrong place – such as inside your body instead of on your skin – and causing damage. Pathogens have specific parts on their surfaces called <a href="https://doi.org/10.1038/s41392-021-00687-0">pathogen associated molecular patterns, or PAMPs</a>.</p>
<p>Very importantly, your body doesn’t make PAMPS. This means if your immune system comes across a PAMP, it knows it isn’t supposed to be there and will mount an attack. Because the same PAMP is present on many different pathogens, a strategy to combat one PAMP can defeat many pathogens.</p>
<p>There are molecules in cells all over your body that can recognize PAMPS and destroy anything those PAMPS are on. It’s as though your immune system set up booby traps that can only attack your enemies.</p>
<p>Many of those booby traps are <a href="https://doi.org/10.1038/35100529">toll-like receptors</a>. This family of molecules is located on the surface and inside of many of your cells. Once microbes contact these booby traps, they trigger an alarm that warn other cells of potential danger. In technical terms, this alarm is <a href="https://theconversation.com/what-is-inflammation-two-immunologists-explain-how-the-body-responds-to-everything-from-stings-to-vaccination-and-why-it-sometimes-goes-wrong-193503">called inflammation</a>.</p>
<h2>SPLAT! Raising an army of defenders</h2>
<p>Whereas Batman would need to think of a new strategy to combat the Joker, the Penguin and Catwoman, your immune system devised a plan long ago. </p>
<p>When the virus that causes COVID-19 emerged in 2019, it was something people’s immune systems likely had never seen before. However, some people already had immune cells that could target components of the virus. How is that possible?</p>
<p>The immune system makes many immune cells that are specific to antigens, or unique and recognizable parts of cancers and microorganisms, it hasn’t encountered before. This occurs through a process where pieces of your DNA <a href="https://doi.org/10.1038/nri2941">randomly recombine to form</a> unique immune cell receptors. The DNA in each of these immune cells is different from the DNA in any other cell in your body. Researchers believe that each person can generate <a href="https://www.ncbi.nlm.nih.gov/books/NBK27140/">at least a trillion different combinations</a> of immune receptors, which is <a href="https://doi.org/10.1038/nrmicro2644">more than the number of pathogens</a> an average person would ever face in their lifetime overall.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Na-Zc-xWCLE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Your immune system can churn out billions of unique antibodies.</span></figcaption>
</figure>
<p>Although the immune system makes a lot of immune cells, most of them aren’t used because you’re not exposed to the antigen they’re made to recognize. However, when an immune cell recognizes an antigen, it rapidly <a href="https://bio.libretexts.org/Bookshelves/Microbiology/Microbiology_(Boundless)/11%3A_Immunology/11.07%3A_Antibodies/11.7C%3A_Clonal_Selection_of_Antibody-Producing_Cells">makes many copies of itself</a>. Since pathogens can also multiply rapidly, clonal selection allows you to rapidly raise an army to fight them.</p>
<p>Usually this strategy works well with <a href="https://theconversation.com/when-covid-19-or-flu-viruses-kill-they-often-have-an-accomplice-bacterial-infections-187056">one or two coinfections</a>, such as if you have the common cold and an eye infection at the same time. But what if you were infected with a trillion pathogens at the same time? It would take a tremendous amount of energy and time to build an appropriate army against each microorganism all at once. Unfortunately, the immune system likely would be overwhelmed by this challenge, and you would probably die. </p>
<p>Fortunately, your immune system – like Batman – usually figures out the best way to shift a battle against rivals to its favor, pulling out a victory in the final minutes of the episode.</p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/214919/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joseph Larkin III receives funding from the Grayson Jockey Research Foundation, The National Institutes of Health, and industry. </span></em></p>Your immune system is often able to fend off pathogens it’s never seen before. But defending your body against all of them all at once is a tough challenge.Joseph Larkin III, Associate Professor of Microbiology and Cell Science, University of FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2191992024-01-09T13:23:53Z2024-01-09T13:23:53ZRabies is an ancient, unpredictable and potentially fatal disease − two rabies researchers explain how to protect yourself<figure><img src="https://images.theconversation.com/files/567905/original/file-20240104-24-3ionkc.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2048%2C2048&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Rabies virus (red) has an incubation period that can last from days to months.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/2mM8QjD">NIAID/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p><em>A <a href="https://www.usatoday.com/story/news/nation/2023/11/28/nebraska-kitten-with-rabies/71733608007/">feral kitten</a> in Omaha, Nebraska, tested positive for rabies in November 2023. It died of the raccoon variant of the virus, which is typically found only in the Appalachian Mountains. Detecting this variant hundreds of miles away in the Midwest raised concerns about a potential outbreak and launched a public health task force to vaccinate all raccoons in the area.</em></p>
<p><em>While the case was likely contained, a better understanding of how rabies is transmitted can help prevent future outbreaks. Researchers <a href="https://scholar.google.com/citations?user=8XtvOZ8AAAAJ&hl=en">Rodney Rohde</a> and <a href="https://www.researchgate.net/profile/Charles-Rupprecht-2">Charles Rupprecht</a> explain how rabies vaccination works and how to protect yourself from infection.</em></p>
<h2>What causes rabies?</h2>
<p><a href="https://asm.org/articles/2021/september/the-one-health-of-rabies-it-s-not-just-for-animals">Rabies</a> is an ancient viral disease that has been around for <a href="https://doi.org/10.1016/j.antiviral.2017.03.013">thousands of years</a>. Considered a <a href="https://doi.org/10.1186/s44149-023-00078-8">neglected tropical disease</a>, rabies typically occurs in <a href="https://www.who.int/health-topics/neglected-tropical-diseases">poorer communities without the infrastructure</a> for adequate surveillance, prevention and control.</p>
<p>Rabies is <a href="https://pubmed.ncbi.nlm.nih.gov/12144896/">unpredictable</a>. <a href="https://www.ncbi.nlm.nih.gov/books/NBK448076/">Stages of infection</a> include an incubation period that ranges from days to months, early flu-like symptoms, a period of severe neurological effects, coma and then death. Common early-stage symptoms in people, such as fatigue, fever and nausea, are often nonspecific. Neurological symptoms can involve aggression, confusion, difficulty swallowing and paralysis.</p>
<p>The pathogens that cause rabies belong to a <a href="https://doi.org/10.1007/s00705-022-05546-z">genus of viruses called <em>Lyssavirus</em></a> that target warm-blooded vertebrates. Although researchers believe that all mammals are susceptible to infection, only certain animals are <a href="https://doi.org/10.3201%2Feid0812.010317">reservoirs</a>: environments, habitats or populations where a pathogen can live, multiply and transmit. In the U.S., the <a href="https://www.elsevier.com/connect/8-things-you-may-not-know-about-rabies-but-should">highest-risk animal reservoirs</a> for rabies are skunks, bats, foxes, coyotes and raccoons.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/8KGcLs2O-BI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A kitten found in Omaha infected with rabies spurred a push to vaccinate local wildlife.</span></figcaption>
</figure>
<p>Most people who become infected with rabies get it from <a href="https://www.cdc.gov/rabies/transmission/index.html">an animal bite</a>. Less common routes include contact with open wounds or the mucous membranes of the eyes, nose or mouth. Once the virus <a href="https://www.ncbi.nlm.nih.gov/books/NBK8618/">enters the body</a>, it can begin replicating in muscle tissue or after traveling directly to the brain. Once it spreads to other organs, patients typically die of brain inflammation.</p>
<h2>Are rabies cases increasing?</h2>
<p>Measuring the global burden of rabies is difficult because <a href="https://connect.h1.co/prime/reports/b/9/9">surveillance is often inadequate</a>.</p>
<p>While human incidence of rabies are rare in the U.S., averaging <a href="https://www.cdc.gov/rabies/location/usa/surveillance/human_rabies.html">one to three cases per year</a>, this disease causes <a href="https://doi.org/10.1371/journal.pntd.0003709">tens of thousands of deaths worldwide</a> annually. </p>
<p>Rabies rates in animals vary each year. During 2021, 54 U.S. jurisdictions reported <a href="https://doi.org/10.2460/javma.23.02.0081">3,663 rabid animals</a>, an 18.2% decrease from the previous year. Lower- and middle-income countries, especially <a href="https://doi.org/10.1093/jtm/taad009">since the COVID-19 pandemic</a>, have experienced disruptions to animal vaccination for rabies due to vaccine production and access issues and increased feral animal populations.</p>
<p>Human rabies cases have risen in several countries because of <a href="https://doi.org/10.3390/idr14060097">multiple ecological and socioeconomic factors</a>. For example, in China, rabies cases are associated with proximity to urban populations and transportation hubs. The closer a susceptible animal is to a community experiencing an outbreak, the greater the likelihood for spread.</p>
<p>Increased temperatures due to climate change are also linked to increased rabies transmission because of changes in animal ranges. For example, as regions warm, the relative distribution and abundance of certain reservoirs, such as tropical species like <a href="https://doi.org/10.1371/journal.pone.0192887">vampire bats</a>, may increase. Rising Arctic temperatures may increase how often <a href="https://doi.org/10.1111/zph.12848">red and Arctic foxes</a> interact and lead to outbreaks.</p>
<p>Higher rates of interactions between humans and animals, as well as lower levels of rabies education and prevention measures, are also linked to an increased risk of infection.</p>
<h2>Has controlling rabies in wildlife been successful?</h2>
<p>Prior attempts to control rabies include animal culling and vaccination. <a href="https://doi.org/10.1111%2Fj.1365-2656.2012.02033.x">Culling animal populations</a> did not lead to reduced infection. Rather, it raised significant economic, ecological and ethical concerns. Besides killing likely healthy animals, culling also isn’t cost-effective. </p>
<p><a href="https://doi.org/10.1007/s10806-021-09868-x">Animal vaccination</a>, on the other hand, can protect both animals and humans with minimal risk and reduced costs. Oral rabies vaccination of wildlife <a href="https://www.npr.org/2023/11/01/1198908463/raccoon-rabies-usda-vaccination-program-airdrop-oral-vaccine">began during the 1970s</a> with the distribution of vaccine-laden baits in the local environment. Officials saw success in rabies control among coyote, fox and raccoon populations in Europe and North America.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/567950/original/file-20240104-25-gwzc6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two stray dogs playing with each other on a street" src="https://images.theconversation.com/files/567950/original/file-20240104-25-gwzc6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567950/original/file-20240104-25-gwzc6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567950/original/file-20240104-25-gwzc6j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567950/original/file-20240104-25-gwzc6j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567950/original/file-20240104-25-gwzc6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567950/original/file-20240104-25-gwzc6j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567950/original/file-20240104-25-gwzc6j.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">Vaccination of strays can reduce the spread of rabies.</span>
<span class="attribution"><a class="source" href="https://phil.cdc.gov/Details.aspx?pid=23838">CDC/Nicholas S. Tenorio, Health Communication Specialist</a></span>
</figcaption>
</figure>
<p>We both participated in the inaugural <a href="https://doi.org/10.2460/javma.2005.227.785">oral rabies vaccination campaign in Texas</a>. This effort eventually led to the elimination of canine rabies <a href="https://www.dshs.texas.gov/rabies/oral-rabies-vaccination-program-orvp">in the state</a>. </p>
<p>Oral vaccines are also being considered for the prevention and control of rabies in animals in other countries, such as <a href="https://doi.org/10.1017%2FS0950268823001334">dogs in India</a> <a href="https://www.who.int/news/item/03-05-2021-oral-rabies-vaccine-a-new-strategy-in-the-fight-against-rabies-deaths">and Thailand</a>.</p>
<h2>How do rabies vaccines work?</h2>
<p>There is <a href="https://pubmed.ncbi.nlm.nih.gov/30747124/">no proven treatment for rabies</a>, so prevention through education and vaccination is critical. Rabies can be prevented by avoiding exposure or receiving vaccination before or after an exposure.</p>
<p><a href="https://www.cdc.gov/rabies/prevention/pre-exposure_vaccinations.html">Preexposure prophylaxis, or PrEP</a>, involves exposing the immune system to a harmless version of the virus to prevent a future infection. For people who work in high-risk occupations, such as wildlife biologists, veterinarians and animal control personnel, two doses of a rabies vaccine can offer <a href="https://www.cdc.gov/rabies/prevention/pre-exposure_vaccinations.html">significant protection</a>. </p>
<p>The Centers for Disease Control and Prevention <a href="http://dx.doi.org/10.15585/mmwr.mm7118a2">currently recommends</a> a booster dose for people at elevated risk of exposure. People traveling to areas with a high prevalence of rabies may also want to consider vaccination.</p>
<p><a href="https://www.cdc.gov/rabies/medical_care/index.html">Postexposure prophylaxis, or PEP</a>, means taking a vaccine or medications to prevent an infection as soon as possible after exposure. In most cases, this involves a dose of <a href="https://www.cdc.gov/rabies/medical_care/hrig.html">human rabies immune globulin, or HRIG</a>, as well as a rabies vaccine dose on the day of exposure. </p>
<p>Also known as passive immunization, HRIG gives your body the antibodies to neutralize rabies virus until your immune system can produce its own antibodies. Three more doses of the rabies vaccine are given three to 14 days after exposure. People who are immunocompromised may receive a fifth dose as well.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/567947/original/file-20240104-21-nh61r5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscopy image of clusters of dark circles called Negri bodies against a background of pink brain tissue" src="https://images.theconversation.com/files/567947/original/file-20240104-21-nh61r5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567947/original/file-20240104-21-nh61r5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=394&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567947/original/file-20240104-21-nh61r5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=394&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567947/original/file-20240104-21-nh61r5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=394&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567947/original/file-20240104-21-nh61r5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=495&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567947/original/file-20240104-21-nh61r5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=495&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567947/original/file-20240104-21-nh61r5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=495&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Negri bodies (purple) are proteins that collect in neurons containing rabies virus.</span>
<span class="attribution"><a class="source" href="https://phil.cdc.gov/Details.aspx?pid=3981">CDC/Dr. Daniel P. Perl</a></span>
</figcaption>
</figure>
<p>Regular and appropriate <a href="https://www.cdc.gov/rabies/prevention/animals.html">pet and livestock vaccinations</a> are also important to help curb rabies virus exposures. Animals typically receive a <a href="https://www.cdc.gov/rabies/specific_groups/veterinarians/vaccination.html">yearly rabies booster</a>.</p>
<p>There are <a href="https://doi.org/10.1016/j.vaccine.2018.08.039">several new rabies vaccines for animals and people</a> in development to improve their safety, cost and efficacy. Researchers are also <a href="https://doi.org/10.15252/emmm.202216394">developing treatments</a> to control rabies when the infection reaches the central nervous system.</p>
<h2>How do you protect yourself from rabies?</h2>
<p>Some people may not realize they were bitten by an animal if the bites are small. Because of the long incubation period of the virus, they also may not recall a previous interaction with an infected animal.</p>
<p><a href="https://www.elsevier.com/connect/8-things-you-may-not-know-about-rabies-but-should">Laboratory tests</a> can confirm whether an animal has rabies, as well as <a href="https://pubmed.ncbi.nlm.nih.gov/9406651/">which rabies virus variant is present</a>. A physician may begin vaccination even without laboratory confirmation based on the risk factors of a case. For example, since most recent fatal rabies cases in the U.S. have been from unknown bat bites, rabies vaccination is recommended after any <a href="https://www.cdc.gov/rabies/exposure/animals/bats.html">suspected bat exposure</a>.</p>
<p>There are many practical ways to <a href="https://www.elsevier.com/connect/8-things-you-may-not-know-about-rabies-but-should">protect yourself from rabies</a> such as: </p>
<ul>
<li>Vaccinating and supervising your pets.</li>
<li>Never handling wild animals that seem to be acting strangely.</li>
<li>Not touching sick, injured or dead animals.</li>
<li>Never attempting to feed wildlife.</li>
<li>Treating animals respectfully. Do not tease an animal, disturb its sleep or handle its offspring.</li>
<li>Always reporting a bite to an animal control officer, game warden or health care professional.</li>
</ul>
<p><a href="https://www.contagionlive.com/view/on-world-rabies-day-a-reminder-how-far-we-have-come-in-the-us-but-global-concerns-remain">World Rabies Day</a>, which marks the death of rabies vaccine developer <a href="https://theconversation.com/louis-pasteurs-scientific-discoveries-in-the-19th-century-revolutionized-medicine-and-continue-to-save-the-lives-of-millions-today-191395">Louis Pasteur</a>, is <a href="https://www.who.int/campaigns/world-rabies-day">Sept. 28</a>.</p><img src="https://counter.theconversation.com/content/219199/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rodney E. Rohde has received funding from the American Society of Clinical Pathologists, American Society for Clinical Laboratory Science, U.S. Department of Labor (OSHA), and other public and private entities/foundations. Rohde is affiliated with ASCP, ASCLS, ASM, and serves on several scientific advisory boards.</span></em></p><p class="fine-print"><em><span>Charles Rupprecht is a global biomedical consultant for academia, government, industry and NGOs. He is affiliated with LYSSA LLC.</span></em></p>An unexpected case of rabies found in an animal can raise concerns for a potential outbreak. Proactive vaccination of both wildlife and people can help protect everyone.Rodney E. Rohde, Regents' Professor & Chair, Medical Laboratory Science, Texas State UniversityCharles Rupprecht, Affiliate Professor of Veterinary Medicine, Auburn UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2188082023-12-21T19:08:25Z2023-12-21T19:08:25ZI have COVID. How likely am I to get long COVID?<figure><img src="https://images.theconversation.com/files/566456/original/file-20231219-29-8osoax.jpg?ixlib=rb-1.1.0&rect=26%2C646%2C5964%2C3341&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/woman-in-pink-jacket-lying-on-gray-couch-imAfCYq7KH0">Adrian Swancar/Unsplash</a></span></figcaption></figure><p>EG.5 or the Eris COVID variant is dominant in parts of <a href="https://www.health.nsw.gov.au/Infectious/covid-19/Documents/respiratory-surveillance-20231202.pdf">Australia</a>. Eris, along with other circulating strains, are descendants of Omicron. </p>
<p>While these strains appear less severe than the original Alpha and Delta variants, the risk of long COVID remains.</p>
<p>So what does the latest data say about the chance of long COVID? What symptoms should you look out for? And what can be done to support people with long COVID?</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/were-in-a-new-covid-wave-what-can-we-expect-this-time-216820">We're in a new COVID wave. What can we expect this time?</a>
</strong>
</em>
</p>
<hr>
<h2>When COVID becomes ‘long COVID’</h2>
<p>For most people, long COVID means not getting better after a COVID infection.</p>
<p>The World Health Organization <a href="https://www.who.int/publications-detail-redirect/WHO-2019-nCoV-Post_COVID-19_condition-Clinical_case_definition-2021.1">defines long COVID</a> as continuing or new symptoms at least three months from the start of a COVID infection that last at least two months and cannot be explained by an alternative diagnosis. </p>
<p>The most <a href="https://link.springer.com/article/10.1007/s10654-022-00962-6">common symptoms</a> include fatigue, brain fog, breathlessness, headaches and abdominal pain. But people with long COVID can experience <a href="https://www.sciencedirect.com/science/article/pii/S1684118222001864?via%3Dihub">a wide range</a> of problems including cardiovascular issues, mental health problems such as depression and anxiety, insomnia, muscle and joint pain, and gastrointestinal problems.</p>
<h2>How common is long COVID?</h2>
<p>Australian data on long COVID <a href="https://www.mja.com.au/journal/2023/218/10/long-covid-australia-achieving-equitable-access-supportive-health-care">remains limited</a> compared to <a href="https://www150.statcan.gc.ca/n1/pub/75-006-x/2023001/article/00015-eng.htm">international data</a>, and estimates of its prevalence have varied. A report from Australia’s parliamentary inquiry into long COVID, <a href="https://parlinfo.aph.gov.au/parlInfo/download/committees/reportrep/RB000006/toc_pdf/SickandtiredCastingalongshadow.pdf">published in April</a>, suggested 2%-20% of people may develop long COVID following an infection.</p>
<p>A recent Australian study conducted when vaccines were widely available indicates earlier Omicron variants <a href="https://doi.org/10.3390/ijerph20186756">saw 10% of people</a> who caught COVID develop long COVID.</p>
<p>Another recent study, yet to be peer-reviewed, found <a href="https://www.medrxiv.org/content/10.1101/2023.08.06.23293706v1">18.2%</a> of those infected went on to have long COVID. The wide-ranging estimates are likely to be because of different COVID variants, differences in vaccination, and different long COVID definitions and assessment methods. </p>
<p>The risk is lower in children. One Australian study indicated persistent symptoms in <a href="https://www.thelancet.com/journals/lanchi/article/PIIS2352-4642(21)00124-3/fulltext">8% of children</a> who had COVID in 2020, while <a href="https://www.medrxiv.org/content/10.1101/2023.03.14.23287239v1">preliminary research</a> points to a slightly lower risk among children infected in 2021.</p>
<p>But more research is needed, especially as the virus continues to evolve. This can be complicated because typical long COVID symptoms are common to many other health problems. As in other countries, more research is now underway <a href="https://www.apprise.org.au/broad-research-area/insights-into-long-covid/">in Australia</a> to determine the accurate prevalence of the condition using a definition and methods that carefully exclude other causes.</p>
<p>Although research on long COVID risk factors with new variants is ongoing, we expect being female, having more severe initial disease and having other health conditions will <a href="https://doi.org/10.1001/jamainternmed.2023.0750">increase a person’s chance</a> of getting long COVID. </p>
<h2>What’s different this time?</h2>
<p>Research shows COVID vaccines offer <a href="https://www.mdpi.com/1660-4601/19/19/12422">protection</a> against long COVID. As well as vaccinations, immunity from previous COVID infections and antiviral treatments are contributing to less severe COVID and potentially <a href="https://theconversation.com/could-antivirals-reduce-your-risk-of-long-covid-where-the-research-is-up-to-on-prevention-and-treatment-216529">less long COVID</a> than we saw earlier in the pandemic. </p>
<p>But while the Omicron waves may lead to <a href="https://www.smh.com.au/national/newer-virus-strains-less-likely-to-cause-long-covid-20231123-p5emag.html">fewer cases of long COVID</a> than the earlier Alpha and Delta variants, because so many Australians are contracting COVID, this will still result in a large number of people with long COVID. And each <a href="https://www150.statcan.gc.ca/n1/pub/75-006-x/2023001/article/00015-eng.htm">repeat infection</a> presents a new risk of prolonged symptoms.</p>
<h2>Long COVID can affect all aspects of life</h2>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1735193183166824721"}"></div></p>
<p>Long COVID can <a href="https://doi.org/10.1093/ije/dyad033">impact</a> a person’s life in many ways. Fatigue following exertion, brain fog and other symptoms can reduce capacity to perform tasks such as concentrating at a computer, manual labour, and even normal household tasks.</p>
<p>Many people with long COVID submitted evidence to the recent <a href="https://www.aph.gov.au/Parliamentary_Business/Committees/House/Health_Aged_Care_and_Sport/LongandrepeatedCOVID/Report/Chapter_4_-_Lived_experiences_of_long_COVID">parliamentary inquiry</a> that they were unsupported, stigmatised, isolated, and not taken seriously by health professionals.</p>
<p>Evidence suggests many symptoms <a href="https://www.thelancet.com/journals/lanepe/article/PIIS2666-77622200250-2/fulltext">will improve</a> in most people over <a href="https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(23)00138-4/fulltext">12 to 18 months</a>, although recovery time can differ between symptoms. Some, including gastrointestinal and respiratory symptoms, tend to <a href="https://www.nature.com/articles/s41579-022-00846-2">resolve sooner than others</a>, such as cognitive symptoms.</p>
<h2>I think I have long COVID, what can I expect from my doctor?</h2>
<p>Long COVID is the kind of challenge Australia’s <a href="https://dx.doi.org/10.5694/mja2.51950">health system finds most difficult</a>. GPs are stretched and the small number of specialist <a href="https://www.abc.net.au/news/2023-12-12/long-covid-clinics-are-closing-as-us-clinic-expands/103186272">long COVID clinics</a> are struggling to maintain funding. </p>
<p>Australia has trailed behind the US, the UK and Europe in rolling out care for long COVID, and in collecting data on the condition.</p>
<p>As a result, support for long COVID in Australia is <a href="https://doi.org/10.3389/phrs.2023.1606084">hard to access</a>, expensive and patchy.</p>
<figure class="align-center ">
<img alt="Doctor talks to patient" src="https://images.theconversation.com/files/566458/original/file-20231219-23-7ascec.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566458/original/file-20231219-23-7ascec.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566458/original/file-20231219-23-7ascec.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566458/original/file-20231219-23-7ascec.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566458/original/file-20231219-23-7ascec.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566458/original/file-20231219-23-7ascec.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566458/original/file-20231219-23-7ascec.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">Long COVID support is hard to find.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/doctor-wearing-safety-protective-mask-supporting-1852862014">Ground Picture/Shutterstock</a></span>
</figcaption>
</figure>
<p>However, there is consensus on what constitutes good care. Clinicians seeing patients with possible long COVID should:</p>
<ul>
<li><p>validate the person’s experience of symptoms and the impact their symptoms are having on their functioning, particularly when the cause is not clear</p></li>
<li><p>diagnose and treat any other health conditions that are part of the picture</p></li>
<li><p>support people to minimise the impairment their symptoms cause by pacing of physical and cognitive activities. Importantly, this doesn’t involve pushing through fatigue.</p></li>
</ul>
<p>These steps are not a cure but they may improve a person’s ability to function in their day-to-day life, at work and to fulfil their caring responsibilities.</p>
<h2>We still need to focus on reducing COVID transmission</h2>
<p>The best way to prevent long COVID is to avoid contracting – and spreading – COVID. This means:</p>
<ul>
<li><p>getting vaccinated or boosted, if you’re eligible</p></li>
<li><p>staying home if you feel unwell</p></li>
<li><p>wearing a mask to protect yourself and vulnerable community members</p></li>
<li><p>testing for COVID if you have symptoms and if you test positive, taking antivirals (if eligible) and isolating until your symptoms resolve.</p></li>
</ul>
<p>Long COVID is not going away, but we all have a role to play in preventing and responding to it. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-are-the-new-covid-booster-vaccines-can-i-get-one-do-they-work-are-they-safe-217804">What are the new COVID booster vaccines? Can I get one? Do they work? Are they safe?</a>
</strong>
</em>
</p>
<hr>
<p><em>Ruby Biezen from the APPRISE Network and the University of Melbourne and Andrew Lloyd from the Kirby Institute at UNSW contributed to this article.</em></p><img src="https://counter.theconversation.com/content/218808/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Baillie is a Conjoint Professor of Allied Health at Sydney Local Health District, a Member of the Australian Psychological Society (APS) and a Fellow of the Clinical College of the APS.</span></em></p><p class="fine-print"><em><span>Amelia Gulliver is a senior research fellow at the Centre for Mental Health Research, National Centre for Epidemiology and Population Health, ANU College of Health & Medicine, and has lived experience of Long COVID.</span></em></p><p class="fine-print"><em><span>Lena Sanci is the co-lead of the APPRISE initiative which has received commonwealth funding. She is the Chief GP advisor for the state department of health and the president of the Australasian School Based Health Association.</span></em></p><p class="fine-print"><em><span>Lucette Cysique is a Senior Research Fellow based at the Kirby Institute, UNSW, and manages the DoHAC-funded APPRISE Long COVID initiative. Lucette Cysique receives support from the Peter Duncan Neuroscience Unit at the St. Vincent's Applied Medical Research Centre which contributed to her involvement in the neurological substudy of the St. Vincent's Hospital COVID-19 ADAPT study.</span></em></p><p class="fine-print"><em><span>Philip Britton is Conjoint Associate Professor in Child Health at the University of Sydney. He has received funding from the NHMRC, MRFF and Royal Australasian College of Physicians</span></em></p>For most people, long COVID means not getting better after a COVID infection. So how has long COVID changed throughout the pandemic, and how likely are you to get it with this infection?Andrew Baillie, Professor of Allied Health, University of SydneyAmelia Gulliver, Senior Research Fellow, ANU College of Health and Medicine, Australian National UniversityLena Sanci, Professor, Department of General Practice and Primary Care, The University of MelbourneLucette Cysique, Senior Research Fellow, Viral Immunology Systems Program, The Kirby Institute, UNSW SydneyPhilip Britton, Associate Professor, Child and Adolescent Health, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2189672023-12-04T15:39:27Z2023-12-04T15:39:27ZChildhood pneumonia is surging in many countries – while the germs causing it are known, the effects of co-infections aren’t<figure><img src="https://images.theconversation.com/files/563296/original/file-20231204-23-ogevti.jpg?ixlib=rb-1.1.0&rect=8%2C0%2C5331%2C3554&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/cough-elbow-prevention-barrier-gestures-curb-1693522387">castiglioni veronica/Shutterstock</a></span></figcaption></figure><p>You may have heard reports about outbreaks of pneumonia affecting children in <a href="https://www.foxnews.com/health/childhood-pneumonia-surge-reported-netherlands-outbreak-china">the Netherlands</a>, <a href="https://www.dailymail.co.uk/health/article-12808991/Denmark-battles-surge-pneumonia-sparking-fears-China.html">Denmark</a> and parts of <a href="https://www.independent.co.uk/news/health/white-lung-pneumonia-outbreak-ohio-b2457652.html">the US</a> and <a href="https://news.sky.com/story/china-suffers-walking-pneumonia-outbreak-as-many-other-countries-see-spike-in-infections-13020285">China</a>, which are higher than usual for this time of year. Parents are keeping a watchful eye on the news, while public health officials monitor the global incidence of severe respiratory infections and record cases and causes. However, there is no new virus or other type of new pathogen to worry about in these outbreaks. </p>
<p>Here’s what we know.</p>
<p>Pneumonia is inflammation of the lungs, usually caused by bacterial or viral infections. It may affect deeper lung tissues than bronchitis, which is airway tube inflammation, and can have symptoms such as fever, breathing problems and chest pain, showing up as a white shade in lung chest X-rays. There is no special designation of “<a href="https://www.independent.co.uk/news/health/white-lung-pneumonia-outbreak-ohio-b2457652.html">white lung pneumonia</a>”, <a href="https://www.mirror.co.uk/news/health/what-white-lung-syndrome-mystery-31571473">scary as it may sound</a>. </p>
<p>This season, known respiratory germs, including respiratory syncytial virus (RSV) and <em>Mycoplasma pneumoniae</em> bacteria, have been recorded and are quite expected for this time of year. Mycoplasma outbreaks flare up <a href="https://www.cdc.gov/pneumonia/atypical/mycoplasma/surv-reporting.html">every few years</a> and can be <a href="https://bestpractice.bmj.com/topics/en-gb/605">resistant</a> to common antibiotics. </p>
<p>Most infected children and adults will develop flu-like symptoms that will clear up on their own after a few days, but some may develop into more serious inflammation of the lungs requiring treatment and, in some cases, hospitalisation. </p>
<p>But why do some people get more severe diseases? And are there any differences this season?</p>
<figure class="align-center ">
<img alt="Chest X-ray showing a white shadow on the lung" src="https://images.theconversation.com/files/563341/original/file-20231204-15-59vaa6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563341/original/file-20231204-15-59vaa6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563341/original/file-20231204-15-59vaa6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563341/original/file-20231204-15-59vaa6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563341/original/file-20231204-15-59vaa6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563341/original/file-20231204-15-59vaa6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563341/original/file-20231204-15-59vaa6.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">Pneumonia can show up as a white shadow on a chest X-ray.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/chest-xray-film-patient-left-lung-1819284152">Tomatheart/Shutterstock</a></span>
</figcaption>
</figure>
<p>Healthy children make the most of passing harmless respiratory viruses to each other at an early age, helping to educate their immune systems and build immunity to similar germs in the future. </p>
<p>Over 200 viruses can cause respiratory infection, including RSV, adenoviruses, enteroviruses, rhinoviruses and coronaviruses. Symptoms can be more serious in the young when similar infections have not been previously encountered. It takes about <a href="https://en.wikipedia.org/wiki/Adaptive_immune_system">a week</a> for specific immunity to develop its arsenal to a new pathogen. </p>
<p>After the infection is cleared, memory cells remain to protect against future infections. We appreciate that antibodies to common cold viruses such as coronaviruses <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8319587/">wane</a> after around two years and RSV-specific antibodies in infants may wane <a href="https://academic.oup.com/jid/article/226/12/2064/6582314">even faster</a>. However, memory cells persist, so to escape immunity, viruses mutate to avoid recognition. </p>
<p>There are no differences in expected viral infections this year, and the known culprits were reported in expected waves based on pre-pandemic levels, <a href="https://www.independent.co.uk/news/health/pneumonia-outbreak-china-cases-map-b2456410.html">according to the World Health Organization</a>. <em>Mycoplasma pneumoniae</em> flares are also as expected. However, waning mycoplasma-specific herd immunity has been <a href="https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(23)00182-9/fulltext">flagged up</a> with a warning to watch out for the resurgence of severe cases following the pandemic restrictions.</p>
<h2>Unknown effects of co-infection</h2>
<p>COVID restrictions are a thing of the past and people that mix in schools, nursing homes and other high-risk environments are likely to come across several infectious diseases at the same time.</p>
<p>Studies in children with acute severe hepatitis <a href="https://www.nature.com/articles/s41586-023-05948-2">in the UK</a> and <a href="https://www.nature.com/articles/s41586-023-05949-1">the US</a> showed that multiple viral infections were causing unexpected liver damage. Multiple infections can lead to more severe disease, where even viruses that can be <a href="https://www.nature.com/articles/d41586-023-00570-8">considered harmless</a> can add to tissue injury. </p>
<p>In science labs, it has been shown that being infected with more than one respiratory virus (known as “co-infection”) can lead to <a href="https://www.nature.com/articles/s41564-022-01242-5">hybrid viruses</a>. These hybrid viruses may behave differently from the individual viruses – causing different symptoms and perhaps even evading the immune system.</p>
<p>So what do we need to know to determine if a new dangerous outbreak occurs? The incidence of known infections and symptoms are recorded and reported so that any new, potentially more dangerous variants can be detected. Hospitals can become overwhelmed during <a href="https://www.cdc.gov/flu/about/season/index.html">flu season</a>, but flu does not circulate in isolation and symptoms can worsen when people are simultaneously infected with more than one respiratory virus.</p>
<p>Respiratory infections can cause lung injury, which takes time to heal. Having one respiratory infection followed by another can prolong this healing time, leading to more severe symptoms and longer illness. This is particularly felt by <a href="https://www.cdc.gov/asthma/respinf.html">asthma sufferers</a>, who are advised to take their annual flu jab and avoid catching seasonal infections. </p>
<p>Pneumonia-causing infections are contagious. The COVID pandemic has highlighted tips to avoid catching a respiratory infection, which include avoiding contact with infected people, effective ventilation, masking and hand hygiene. Given what we now know about the impact of “harmless” infections, particularly simultaneous infections with more than one pathogen, it is critical to take action to stop the spread.</p><img src="https://counter.theconversation.com/content/218967/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Zania Stamataki 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>Hybrid viruses can emerge from co-infections. And we don’t know their effects.Zania Stamataki, Associate Professor in Viral Immunology, University of BirminghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2185342023-12-01T11:41:15Z2023-12-01T11:41:15ZYes, you can get syphilis of the eye – professor of ophthalmology explains<p>A cluster of cases of ocular syphilis has <a href="https://arstechnica.com/health/2023/11/five-women-got-eye-syphilis-from-the-same-man-raising-questions/">been reported</a> in Michigan, US. The five women infected all contracted the disease from the same sexual partner. </p>
<p>While ocular syphilis is not that common overall, accounting for <a href="https://journals.lww.com/stdjournal/fulltext/2022/10000/reported_neurologic,_ocular,_and_otic.11.aspx">1% of all syphilis cases</a> this probably represents an underestimate of its prevalence.</p>
<p>Why is this important? Ocular syphilis has been described as the great imitator. It can manifest in a multitude of ways and as such the diagnosis can be missed. This is important because it can easily be treated and cured. </p>
<p>Untreated, it can progress over many years causing more damage to multiple organ systems. It is a tragedy if missed. It can affect virtually every tissue in the eye. This <a href="https://www.tandfonline.com/doi/full/10.1080/09273948.2023.2217246">includes</a> the cornea, the iris, the orbit, the eyelids, the retina, the optic nerve and the sclera. It usually presents as an inflammation, but sometimes the presentation is more subtle.</p>
<figure class="align-center ">
<img alt="An anatomy diagram showing parts of the human eye." src="https://images.theconversation.com/files/562769/original/file-20231130-25-k3nu1e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562769/original/file-20231130-25-k3nu1e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562769/original/file-20231130-25-k3nu1e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562769/original/file-20231130-25-k3nu1e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562769/original/file-20231130-25-k3nu1e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562769/original/file-20231130-25-k3nu1e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562769/original/file-20231130-25-k3nu1e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=377&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Parts of the eye.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/human-eye-anatomy-isolated-on-white-1935787477">ImagineDesign/Shutterstock</a></span>
</figcaption>
</figure>
<p>If syphilis is missed, other important treatable infections may also be missed. For example, HIV infection is also common in patients with syphilis. HIV infection <a href="https://www.tandfonline.com/doi/full/10.1080/09273948.2023.2217246">can accelerate the progression of ocular syphilis</a>. Missing an ocular syphilis diagnosis might mean missing an HIV diagnosis too and, again, not treating a treatable disease.</p>
<p>The five women described in Michigan, all infected by the same man, illustrate this point as they had different signs and symptoms, ranging from inflammation in the eye through to paralysis of cranial nerves. In these acute cases, thankfully, a correct diagnosis was promptly made and treatment started. </p>
<p>But sometimes ocular syphilis is not diagnosed and a slow grumbling infection can occur in the retina. This may resemble an inherited eye condition called <a href="https://www.hopkinsmedicine.org/health/conditions-and-diseases/retinitis-pigmentosa">retinitis pigmentosa</a>. </p>
<p>So a patient may be told there is nothing that can be done as they are thought to have a genetic eye disease and their sight can be left to deteriorate. They may develop further syphilitic complications, such as syphilis affecting the brain. </p>
<h2>Still very prevalent today</h2>
<p>In my own practice, I have “cured” several incurable cases of retinitis pigmentosa because I tested for syphilis and found that the patient <a href="https://www.nature.com/articles/eye1996182">actually had ocular syphilis</a>. So it is important to be aware that sexually transmitted infections are increasing. </p>
<p>Syphilis is caused by a bacterium called <em>Treponema pallidum</em>. It is thought of as an old disease – possibly introduced to Europe by <a href="https://www.tandfonline.com/doi/full/10.1080/09273948.2023.2217246?scroll=top&needAccess=true">Christopher Columbus in 1493</a> – but it is still very prevalent today. Syphilis infections in the UK increased to 8,692 in 2022, up 15% compared with 2021 (7,543). This is the <a href="https://www.gov.uk/government/news/gonorrhoea-and-syphilis-at-record-levels-in-2022">largest number</a> of confirmed infections since 1948.</p>
<p>Doctors must not be shy in testing for it and explaining to patients why it is necessary to do so. In my experience, patients are happy to be tested as it offers the potential to cure their eye condition.</p>
<p>The message from these Michigan cases is that syphilis is increasing as a sexually transmitted disease. It can affect multiple organs including the eye. It can be missed and doctors should always think of the “great imitator” and not be shy in testing for it. If detected, it can be swiftly treated with antibiotics, which is not the case with many other eye diseases.</p><img src="https://counter.theconversation.com/content/218534/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Lotery 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>Unlike many eye conditions, ocular syphilis is a highly treatable disease. But it needs to be correctly identified.Andrew Lotery, Professor of Ophthalmology, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2187432023-11-29T13:44:11Z2023-11-29T13:44:11ZFirst case of swine flu in humans detected in UK – expert Q&A<figure><img src="https://images.theconversation.com/files/562192/original/file-20231128-23-by0qnb.jpg?ixlib=rb-1.1.0&rect=0%2C30%2C6720%2C4436&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/many-adult-pigs-pig-farm-livestock-2068194197">Dusan Petkovic/Shutterstock</a></span></figcaption></figure><p><em>A British man has contracted swine flu, the first detected human case recorded in the UK. Here’s what you need to know about the disease.</em></p>
<p><strong>Why is swine flu currently in the news?</strong></p>
<p>A new variant of the influenza virus has been <a href="https://www.gov.uk/government/news/ukhsa-detects-human-case-of-influenza-ah1n2v">identified in a man from North Yorkshire</a>, following a routine flu screening test.</p>
<p>Flu or influenza is classified using two molecules on the surface of the virus: haemagglutinin (H, there are 18 subtypes) and neuraminidase (N, with 11 subtypes).
The new virus is classed as H1N2 – a group previously rare in people and more often found in pigs. </p>
<p>It is not clear if the 2023 H1N2 virus has gained new characteristics that should concern us. Its genetic pattern shows some distinct features, but as the COVID pandemic showed us, viral genes change steadily over time. </p>
<p><strong>Is it the same virus that caused the 2009 swine flu pandemic?</strong></p>
<p>No. The 2023 virus differs considerably from the H1N1 that caused a <a href="https://www.the-scientist.com/infographics/timeline-investigating-the-origins-of-the-2009-pandemic-69519">pandemic in 2009</a>. To protect us against H1N1, this variant has been included in many annual vaccine combinations offered in the UK since 2012. </p>
<p>Influenza viruses continually change their genes and surface molecules through processes known as <a href="https://www.cdc.gov/flu/about/viruses/change.htm#:%7E:text=When%20a%20flu%20virus%20has,and%20fighting%20against%20the%20virus.">“shift” and “drift”</a>. They often cause outbreaks in autumn, but have the potential to cause global epidemics or pandemics when a novel virus evades human immune defences. </p>
<p>Historically, some influenza outbreaks have been “zoonotic”, spilling over from animals to humans when a shift or drift drives a change of host. Influenza can infect most birds, pigs, horses, whales, cats, dogs and seals, usually with specific HN types.</p>
<p><strong>How dangerous is it?</strong></p>
<p>The risks posed by the new H1N2 are unclear. </p>
<p>On the plus side, the infected man from North Yorkshire – the so-called “index case” – was not very unwell and did not need admission to a hospital. This suggests the virus is not a powerful pathogen. </p>
<p>It is reassuring, too, that in Yorkshire there have been no reports of unexplained illness in large numbers of children, elderly, pregnant people or those with compromised immune systems – or, indeed, farm animals, including pigs. So the index case does not appear to be part of a wider human or animal outbreak. </p>
<p>So how did he become infected if he had no contact with pigs? One possibility is that he is one of many infected with this virus. This is a troubling interpretation because it would suggest there has been an efficient spread of a new influenza virus among humans. </p>
<p>It is difficult to stop person-to-person viral spread, as the COVID pandemic showed us. This week and next, a range of careful and strategic screening checks will take place in various communities in Yorkshire to establish if others with mild respiratory illnesses, or perhaps no illness, are carrying this virus. </p>
<p>Such investigation will probably also involve pig herds, because pig wellbeing is an important component of this probable viral spillover from animals. </p>
<p>The alert raised by this positive finding shows the value of processing samples from GP surgeries. Such alerts, however, require considerable follow-up to address the potential dangers. </p>
<figure class="align-center ">
<img alt="Older adult receiving a flu vaccine." src="https://images.theconversation.com/files/562405/original/file-20231129-24-2nydo6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562405/original/file-20231129-24-2nydo6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562405/original/file-20231129-24-2nydo6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562405/original/file-20231129-24-2nydo6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562405/original/file-20231129-24-2nydo6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562405/original/file-20231129-24-2nydo6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562405/original/file-20231129-24-2nydo6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The annual flu vaccine includes protection from the strain that caused the 2009 ‘swine flu’ pandemic.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/vaccinating-elderly-person-173815904">Image Point Fr/Shutterstock</a></span>
</figcaption>
</figure>
<p><strong>Is it different from regular flu?</strong></p>
<p>Based on the information from the one case, this virus is just like several other influenza viruses that cause upper respiratory tract infections (coughs and colds) in people.</p>
<p><strong>What are the symptoms?</strong></p>
<p>Typical flu symptoms include a raised temperature, a cough, sore throat and nasal stuffiness, along with muscle pains, headache and fatigue. There may be some vomiting and diarrhoea, too, particularly in children. </p>
<p>A few patients may get a lung infection or even heart problems – but this is very rare. Other rare problems include brain swelling, sepsis and secondary bacterial infections.</p>
<p><strong>How is it treated?</strong></p>
<p>Recommended treatments for influenza-like symptoms include rest, drinking lots of fluids and drugs to control fever and pain. You should seek medical advice if any symptom becomes severe because influenza of any type can be fatal – although this is very rare.</p>
<p><strong>Can I get it from eating pork?</strong></p>
<p>There are no known cases of contracting influenza from eating pork.</p>
<p><strong>Will wearing a mask and washing my hands protect me?</strong></p>
<p>Both masks and handwashing reduce all the risks of contracting respiratory diseases for all of us wherever we live. These simple interventions are often overlooked, or not performed as well as they should be. </p>
<p><strong>Who is most at risk?</strong></p>
<p>As yet, we do not know who is most likely to contract the new H1N2 influenza. This information should become more clearly defined by the studies being carried out at present. </p>
<p><strong>Is there a vaccine against it?</strong></p>
<p>There is no vaccine against the new H1N2. Thankfully, however, global preparedness has never been so well attuned to the challenge of vaccine development. </p>
<p>A vaccine for a newly discovered virus variant can be made within months using existing technologies. Safety testing and regulatory processes will extend this, but the capabilities and collaborations are in place should they be required. </p>
<p><strong>How serious a threat to public health is it?</strong></p>
<p>No available evidence suggests this new virus is a risk to public health. However, some important elements of information about H1N2 are required, along with plans to contain any spread from the index case in Yorkshire.</p><img src="https://counter.theconversation.com/content/218743/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Colin Michie 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 British man is confirmed to have swine flu. The UK Health Security Agency said it is monitoring the situation closely.Colin Michie, Deputy Lead, School of Medicine, University of Central LancashireLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2179202023-11-29T03:33:38Z2023-11-29T03:33:38ZDo you really need antibiotics? Curbing our use helps fight drug-resistant bacteria<p><em>Antimicrobial resistance is <a href="https://www.who.int/news-room/fact-sheets/detail/antimicrobial-resistance">one of the biggest global threats</a> to health, food security and development. This month, The Conversation’s experts <a href="https://theconversation.com/au/topics/the-dangers-of-antibiotic-resistance-146983">explore how we got here and the potential solutions</a>.</em></p>
<hr>
<p>Antibiotic resistance occurs when a microorganism changes and no longer responds to an antibiotic that was previously effective. It’s <a href="https://thelancet.com/journals/eclinm/article/PIIS2589-5370(21)00502-2/fulltext">associated with</a> poorer outcomes, a greater chance of death and higher health-care costs. </p>
<p>In Australia, antibiotic resistance means some patients are admitted to hospital because oral antibiotics are <a href="https://www.who.int/news-room/fact-sheets/detail/antibiotic-resistance">no longer effective</a> and they need to receive intravenous therapy via a drip. </p>
<p>Antibiotic resistance is rising to high levels in certain parts of the world. Some hospitals <a href="https://www.reactgroup.org/news-and-views/news-and-opinions/year-2022/the-impact-of-antibiotic-resistance-on-cancer-treatment-especially-in-low-and-middle-income-countries-and-the-way-forward/">have to consider</a> whether it’s even viable to treat cancers or perform surgery due to the risk of antibiotic-resistant infections.</p>
<p>Australia is <a href="https://www.safetyandquality.gov.au/our-work/antimicrobial-resistance/antimicrobial-use-and-resistance-australia-aura/aura-2023-fifth-australian-report-antimicrobial-use-and-resistance-human-health">one of the highest users</a> of antibiotics in the developed world. We need to use this precious resource wisely, or we risk a future where a simple infection could kill you because there isn’t an effective antibiotic. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-rise-and-fall-of-antibiotics-what-would-a-post-antibiotic-world-look-like-213450">The rise and fall of antibiotics. What would a post-antibiotic world look like?</a>
</strong>
</em>
</p>
<hr>
<h2>When should antibiotics not be used?</h2>
<p>Antibiotics only work for some infections. They work against bacteria but <a href="https://www.safetyandquality.gov.au/publications-and-resources/resource-library/do-i-really-need-antibiotics">don’t treat</a> infections caused by viruses. </p>
<p>Most community acquired infections, even those caused by bacteria, are likely to get better without antibiotics. </p>
<p>Taking an antibiotic when you don’t need it won’t make you feel better or recover sooner. But it can increase your chance of side effects like nausea and diarrhoea.</p>
<p>Some people think green mucus (or snot) is a sign of bacterial infection, requiring antibiotics. But it’s actually <a href="https://www.safetyandquality.gov.au/sites/default/files/2023-11/aura_2023_do_i_really_need_antibiotics.pdf">a sign</a> your immune system is working to fight your infection.</p>
<h2>If you wait, you’ll often get better</h2>
<p><a href="https://www.tg.org.au/">Clinical practice guidelines</a> for antibiotic use aim to ensure patients receive antibiotics when appropriate. Yet 40% of GPs say they prescribe antibiotics <a href="https://doi.org/10.1071/HI13019">to meet patient expectations</a>. And <a href="https://pubmed.ncbi.nlm.nih.gov/35973750/">one in five</a> patients expect antibiotics for respiratory infections. </p>
<figure class="align-center ">
<img alt="Man blows nose and looks at thermometre" src="https://images.theconversation.com/files/562071/original/file-20231128-19-5kijmo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562071/original/file-20231128-19-5kijmo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562071/original/file-20231128-19-5kijmo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562071/original/file-20231128-19-5kijmo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562071/original/file-20231128-19-5kijmo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562071/original/file-20231128-19-5kijmo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562071/original/file-20231128-19-5kijmo.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">Doctors sometimes tell patients to ‘watch and wait’.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/senior-man-blowing-his-nose-checking-2276021157">Shutterstock</a></span>
</figcaption>
</figure>
<p>It can be difficult for doctors to decide if a patient has a viral respiratory infection or are at an early stage of serious bacterial infection, particularly in children. One option is to “watch and wait” and ask patients to return if there is clinical deterioration. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/no-antibiotics-arent-always-needed-heres-how-gps-can-avoid-overprescribing-213981">No, antibiotics aren't always needed. Here's how GPs can avoid overprescribing</a>
</strong>
</em>
</p>
<hr>
<p>An alternative is to prescribe an antibiotic but advise the patient to not have it dispensed unless specific symptoms occur. This can <a href="https://doi.org/10.1002/14651858.CD004417.pub5">reduce antibiotic use by 50%</a> with no decrease in patient satisfaction, and no increase in complication rates. </p>
<h2>Sometimes antibiotics are life-savers</h2>
<p>For some people – particularly those with a weakened immune system – a simple infection can become more serious. </p>
<p>Patients with life-threatening suspected infections should receive an appropriate antibiotic <a href="https://www.safetyandquality.gov.au/our-work/clinical-care-standards/antimicrobial-stewardship-clinical-care-standard">immediately</a>. This includes serious infections such as <a href="https://www.hopkinsmedicine.org/health/conditions-and-diseases/bacterial-meningitis#:%7E:text=What%20is%20bacterial%20meningitis%3F,can%20cause%20life%2Dthreatening%20problems.">bacterial meningitis</a> (infection of the membranes surrounding the brain)
and <a href="https://clinicalexcellence.qld.gov.au/priority-areas/safety-and-quality/sepsis/adult-sepsis#:%7E:text=Adult%20patients%20with%20sepsis%20also,adult%20emergency%20department%20sepsis%20pathway.">sepsis</a> (which can lead to organ failure and even death).</p>
<h2>When else might antibiotics be used?</h2>
<p>Antibiotics are sometimes used to prevent infections in patients who are undergoing surgery and are at significant risk of infection, such as those undergoing bowel resection. These patients will <a href="https://www.tg.org.au">generally receive</a> a single dose before the procedure.</p>
<p>Antibiotics may also <a href="https://www.tg.org.au">be given</a> to patients undergoing chemotherapy for solid organ cancers (of the breast or prostate, for example), if they are at high risk of infection. </p>
<p>While most sore throats are caused by a virus and usually resolve on their own, some high risk patients with a bacterial strep A infection which can cause “scarlet fever” are given antibiotics to prevent a more serious infection like <a href="https://www.rhdaustralia.org.au/">acute rheumatic fever</a>. </p>
<h2>How long is a course of antibiotics?</h2>
<p>The recommended duration of a course of antibiotics depends on the type of infection, the likely cause, where it is in your body and how effective the antibiotics are at killing the bacteria. </p>
<p>In the past, courses were largely arbitrary and based on assumptions that antibiotics should be taken for long enough to eliminate the infecting bacteria. </p>
<figure class="align-center ">
<img alt="Pharmacist handing over antibiotics to a patient" src="https://images.theconversation.com/files/562075/original/file-20231128-23-l3ap7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562075/original/file-20231128-23-l3ap7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562075/original/file-20231128-23-l3ap7p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562075/original/file-20231128-23-l3ap7p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562075/original/file-20231128-23-l3ap7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562075/original/file-20231128-23-l3ap7p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562075/original/file-20231128-23-l3ap7p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The duration of antibiotic courses has shortened.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pharmasict-serving-customer-drug-store-1855116610">Shutterstock</a></span>
</figcaption>
</figure>
<p>More recent research does not support this and shorter courses are <a href="https://www.acpjournals.org/doi/full/10.7326/M19-1509">nearly always as effective as longer ones</a>, particularly for community acquired respiratory infections. </p>
<p>For <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6736742/">community acquired pneumonia</a>, for example, research shows a three- to five-day course of antibiotics is at least as effective as a seven- to 14-day course. </p>
<p>The “take until all finished” approach is no longer recommended, as the longer the antibiotic exposure, the greater the chance the bacteria will develop resistance. </p>
<p>However, for infections where it is more difficult to eradicate the bacteria, such as tuberculosis and bone infections, a combination of antibiotics for many months is usually required. </p>
<h2>What if your infection is drug-resistant?</h2>
<p>You may have an antibiotic-resistant infection if you don’t get better after treatment with standard antibiotics. </p>
<p>Your clinician will collect samples for lab testing if they suspect you have antibiotic-resistant infection, based on your travel history (especially if you’ve been hospitalised in a country with high rates of antibiotic resistance) and if you’ve had a recent course of antibiotics that hasn’t cleared your infection. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-do-bacteria-actually-become-resistant-to-antibiotics-213451">How do bacteria actually become resistant to antibiotics?</a>
</strong>
</em>
</p>
<hr>
<p>Antibiotic-resistant infections are managed by prescribing broad-spectrum antibiotics. These are like a sledgehammer, wiping out many different species of bacteria. (Narrow-spectrum antibiotics conversely can be thought of as a scalpel, more targeted and only affecting one or two kinds of bacteria.) </p>
<p>Broad-spectrum antibiotics are usually more expensive and come with more severe side effects.</p>
<h2>What can patients do?</h2>
<p>Decisions about antibiotic prescriptions should be made using <a href="https://www.safetyandquality.gov.au/our-work/partnering-consumers/shared-decision-making/decision-support-tools-specific-conditions">shared decision aids</a>, where patients and prescribers discuss the risks and benefits of antibiotics for conditions like a sore throat, middle ear infection or acute bronchitis.</p>
<p>Consider asking your doctor questions such as:</p>
<ul>
<li>do we need to test the cause of my infection?</li>
<li>how long should my recovery take?</li>
<li>what are the risks and benefits of me taking antibiotics?</li>
<li>will the antibiotic affect my regular medicines?</li>
<li>how should I take the antibiotic (how often, for how long)?</li>
</ul>
<p>Other ways to fight antibiotic resistance include:</p>
<ul>
<li>returning leftover antibiotics to a pharmacy for safe disposal</li>
<li>never consuming leftover antibiotics or giving them to anyone else</li>
<li>not keeping prescription repeats for antibiotics “in case” you become sick again </li>
<li>asking your doctor or pharmacist what you can do to feel better and ease your symptoms rather than asking for antibiotics.</li>
</ul>
<hr>
<p><em>Read the other articles in The Conversation’s series on the dangers of antibiotic resistance <a href="https://theconversation.com/au/topics/the-dangers-of-antibiotic-resistance-146983">here</a>. Listen to the podcast <a href="https://theconversation.com/antibiotic-resistance-microbiologists-turn-to-new-technologies-in-the-hunt-for-solutions-podcast-217615">here</a>.</em></p><img src="https://counter.theconversation.com/content/217920/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Minyon Avent has received funding from the Metro North Hospital and Health Service, the Children’s Hospital Foundation Queensland, the Department of Health, MSD and the Society of Hospital Pharmacists of Australia.</span></em></p><p class="fine-print"><em><span>Fiona Doukas has received funding from the Society of Hospital Pharmacists Australia and Hospira. She works for the Australian Commission on Safety and Quality in Health Care. She is part of an NGO called Hepatitis B Free. She works at two Sydney Hospitals. </span></em></p><p class="fine-print"><em><span>Kristin Xenos works for the Australian Commission on Safety and Quality in Health Care.</span></em></p>Australia is one of the highest users of antibiotics in the developed world. So when do we actually need antibiotics to treat an infection? And when should we avoid them?Minyon Avent, Antimicrobial Stewardship Pharmacist, The University of QueenslandFiona Doukas, PhD candidate, University of SydneyKristin Xenos, Research Assistant, College of Health, Medicine and Wellbeing, School of Biomedical Science and Pharmacy, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2179152023-11-26T19:20:59Z2023-11-26T19:20:59ZMillions of high-risk Australians aren’t getting vaccinated. A policy reset could save lives<p>Each year, vaccines prevent thousands of deaths and hospitalisations in Australia. </p>
<p>But millions of high-risk older Australians <a href="https://grattan.edu.au/report/a-fair-shot-ensuring-all-australians-can-get-the-vaccines-they-need/">aren’t getting</a> recommended vaccinations against COVID, the flu, pneumococcal disease and shingles. </p>
<p>Some people are more likely to miss out, such as migrant communities and those in rural areas and poorer suburbs. </p>
<p>As our new <a href="https://grattan.edu.au/report/a-fair-shot-ensuring-all-australians-can-get-the-vaccines-they-need/">Grattan report shows</a>, a policy reset to encourage more Australians to get vaccinated could save lives and help ease the pressure on our struggling hospitals.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/millions-of-australian-adults-are-unvaccinated-and-its-increasing-disease-risk-for-all-of-us-74991">Millions of Australian adults are unvaccinated and it's increasing disease risk for all of us</a>
</strong>
</em>
</p>
<hr>
<h2>Adult vaccines reduce the risk of serious illness</h2>
<p>Vaccines slash the risk of <a href="https://www.ncirs.org.au/sites/default/files/2021-03/Influenza-fact-sheet_31%20March%202021_Final.pdf">hospitalisation</a> and serious illness, <a href="https://ncirs.org.au/recent-covid-19-vaccination-highly-effective-against-death-caused-sars-cov-2-infection-older">often by more than half</a>. </p>
<p>COVID has already caused more than <a href="https://www.abs.gov.au/statistics/health/causes-death/provisional-mortality-statistics/latest-release">3,000 deaths in Australia this year</a>. On average, the flu kills about <a href="https://www.doherty.edu.au/news-events/news/statement-on-the-doherty-institute-modelling">600 people a year</a>, although a bad flu season, like 2017, can mean <a href="https://www.abs.gov.au/ausstats/abs@.nsf/Lookup/by%20Subject/3303.0%7E2017%7EMain%20Features%7EAustralia's%20leading%20causes%20of%20death,%202017%7E2">several thousand deaths</a>. And pneumococcal disease may also kill <a href="https://www.aihw.gov.au/getmedia/49809836-8ead-4da5-81c4-352fa64df75b/aihw-phe-263.pdf?inline=true">hundreds</a> of people a year. Shingles is rarely fatal, but can be extremely painful and cause <a href="https://www.healthdirect.gov.au/shingles#complications">long-term nerve damage</a>. </p>
<p>Even before COVID, vaccine-preventable diseases caused tens of thousands of potentially preventable hospitalisations each year – more than <a href="https://www.aihw.gov.au/reports/primary-health-care/disparities-in-potentially-preventable-hospitalisa/data">80,000 in 2018</a>.</p>
<p>Vaccines offered in Australia have been tested for safety and efficacy and have been found to be <a href="https://www.health.gov.au/topics/immunisation/about-immunisation/vaccine-safety#:%7E:text=serious%20side%20effects.-,Vaccine%20safety%20monitoring,approved%20for%20use%20in%20Australia.">very safe</a> for people who are <a href="https://www.health.gov.au/topics/immunisation/when-to-get-vaccinated/national-immunisation-program-schedule">recommended to get them</a>.</p>
<h2>Too many high-risk people are missing out</h2>
<p>Our <a href="https://grattan.edu.au/report/roundabouts-overpasses-carparks-hauling-the-federal-government-back-to-its-proper-role-in-transport-projects">report</a> shows that before winter this year, only 60% of high-risk Australians were vaccinated against the flu. </p>
<p>Only 38% had a COVID vaccination in the last six months. Compared to a year earlier, two million more high-risk people went into winter without a recent COVID vaccination.</p>
<p>Vaccination rates have fallen further since. Just over one-quarter (<a href="https://www.health.gov.au/sites/default/files/2023-11/covid-19-vaccine-rollout-update-10-november-2023.pdf">27%</a>) of people over 75 have been vaccinated in the last six months. That leaves more than 1.3 million without a recent COVID vaccination. </p>
<p>Uptake is also low for other vaccines. Among Australians in their 70s, <a href="https://ncirs.org.au/sites/default/files/2022-12/Coverage%20report%202021%20SUMMARY%20FINAL.pdf">less than half</a> are vaccinated against shingles and only one in five are vaccinated against pneumococcal disease.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-how-do-you-get-shingles-and-who-should-be-vaccinated-against-it-64436">Explainer: how do you get shingles and who should be vaccinated against it?</a>
</strong>
</em>
</p>
<hr>
<p>These vaccination rates aren’t just low – they’re also unfair. The likelihood that someone is vaccinated changes depending on where they live, where they were born, what language they speak at home, and how much they earn. </p>
<p>For example, at the start of winter this year, the COVID vaccination rate for high-risk Aboriginal and Torres Strait Islander adults was only 25%. This makes them about one-third less likely to have been vaccinated against COVID in the previous six months, compared to the average high-risk Australian. </p>
<p>For more than 750,000 high-risk adults who do not speak English at home, the COVID vaccination rate is below 20% – about half the level of the average high-risk adult. </p>
<p>Within this group, 250,000 adults aren’t proficient in English. They were 58% less likely to be vaccinated for COVID in the previous six months, compared to the average high-risk person. </p>
<p>High-risk adults who speak English at home have a flu vaccination rate of 62%. But for people from 29 other language groups, who aren’t proficient in English, the rate is less than 31%. These 39,000 people have half the vaccination rate of people who speak English at home. </p>
<p>These vaccination gaps contribute to the differences in people’s health. Australians born overseas don’t just have much lower rates of COVID vaccination, they also have much higher rates of death from COVID.</p>
<p>Where people live also affects vaccination rates. High-risk people living in remote and very remote areas are less likely to be vaccinated, and even within capital cities there are big differences between different areas.</p>
<h2>We need to set ambitious targets</h2>
<p>Australia needs a vaccination reset. A new National Vaccination Agreement between the federal and state governments should include ambitious but achievable targets for adult vaccines. </p>
<p>This can build on the success of targets for childhood and adolescent vaccination, setting targets for overall uptake and for communities that are falling behind. </p>
<p>The federal government should ask the Australian Technical Advisory Group on Immunisation (ATAGI) to advise on vaccination targets for COVID, flu, pneumococcal and shingles for all high-risk older adults. </p>
<figure class="align-center ">
<img alt="Nurse gives older man a vaccination." src="https://images.theconversation.com/files/561243/original/file-20231123-21-vhjtc4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/561243/original/file-20231123-21-vhjtc4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/561243/original/file-20231123-21-vhjtc4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/561243/original/file-20231123-21-vhjtc4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/561243/original/file-20231123-21-vhjtc4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/561243/original/file-20231123-21-vhjtc4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/561243/original/file-20231123-21-vhjtc4.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">Australia needs to encourage more older adults to get vaccinated.</span>
<span class="attribution"><a class="source" href="https://theconversation.com/drafts/217915/edit#">Shutterstock</a></span>
</figcaption>
</figure>
<h2>Different solutions for different barriers</h2>
<p>Barriers to vaccination range from the trivial to the profound. A new national vaccination strategy needs to dismantle high and low barriers alike. </p>
<p>First, to increase overall uptake, vaccination should be easier, and easier to understand. </p>
<p>The federal government should introduce vaccination “surges”, especially in the lead-up to winter, as <a href="https://www.who.int/europe/news/item/09-10-2023-vulnerable--vaccinate.-protecting-the-unprotected-from-covid-19-and-influenza">countries in Europe</a> do. </p>
<p>During surges, high-risk people should be able to get vaccinated even if they have had a recent infection or injection. This will make the rules simpler and make vaccination in aged care easier. </p>
<p>Surges should be reinforced with advertising explaining who should get vaccinated and why. High-risk people should get SMS reminders. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-when-do-adults-need-to-be-immunised-23258">Health Check: when do adults need to be immunised?</a>
</strong>
</em>
</p>
<hr>
<p>Second, targeted policies are needed for the many people who are happy to use mainstream primary care services, but who don’t get vaccinated – for example, due to <a href="https://theconversation.com/how-can-governments-communicate-with-multicultural-australians-about-covid-vaccines-its-not-as-simple-as-having-a-poster-in-their-language-156097">language barriers</a>, or living in <a href="https://theconversation.com/over-half-of-eligible-aged-care-residents-are-yet-to-receive-their-covid-booster-and-winter-is-coming-205403">aged care</a>. </p>
<p><a href="https://www.health.gov.au/our-work/phn/what-PHNs-are">Primary Health Networks</a> should get funding to coordinate initiatives such as vaccination events in aged care and disability care homes, workforce training to support culturally appropriate care, and provision of interpreters. </p>
<p>Third, tailored programs are needed to reach <a href="https://www.aihw.gov.au/reports/australias-health/health-promotion">people who are not comfortable or able to access mainstream health care</a>, who have the most complex barriers to vaccination – for example, distrust of the health system or poverty.</p>
<p>These communities are all very different, so one-size-fits-all programs don’t work. The pandemic showed that vaccination programs can succeed when they are designed and delivered with the communities they are trying to reach. Examples are “<a href="https://pubmed.ncbi.nlm.nih.gov/36366401/">community champions</a>” who challenge misinformation, or health services organising vaccination events where communities work, gather or <a href="https://www.theguardian.com/australia-news/2021/aug/11/hundreds-queue-for-hours-and-some-camp-overnight-at-pop-up-vaccine-clinic-in-sydneys-lakemba">worship</a>.</p>
<p>These programs should get ongoing funding, but also be accountable for achieving results. </p>
<p>Adult vaccines are the missing piece in Australia’s whole-of-life vaccination strategy. For the health and safety of the most vulnerable members of our community, we need to close the vaccination gap. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-are-the-new-covid-booster-vaccines-can-i-get-one-do-they-work-are-they-safe-217804">What are the new COVID booster vaccines? Can I get one? Do they work? Are they safe?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/217915/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Breadon's employer, Grattan Institute, has been supported in its work by government, corporates, and philanthropic gifts. A full list of supporting organisations is published at <a href="http://www.grattan.edu.au">www.grattan.edu.au</a>.</span></em></p><p class="fine-print"><em><span>Ingrid Burfurd's employer, Grattan Institute, has been supported in its work by government, corporates, and philanthropic gifts. A full list of supporting organisations is published at <a href="http://www.grattan.edu.au">www.grattan.edu.au</a>.</span></em></p>Millions of high-risk older Australians aren’t getting recommended vaccinations against COVID, the flu, pneumococcal disease and shingles.Peter Breadon, Program Director, Health and Aged Care, Grattan InstituteIngrid Burfurd, Senior Associate, Health Program, Grattan Institute, Grattan InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2134602023-11-23T19:02:31Z2023-11-23T19:02:31ZDrug resistance may make common infections like thrush untreatable<p><em>Antimicrobial resistance is <a href="https://www.who.int/news-room/fact-sheets/detail/antimicrobial-resistance">one of the biggest global threats</a> to health, food security and development. This month, The Conversation’s experts <a href="https://theconversation.com/au/topics/the-dangers-of-antibiotic-resistance-146983">explore how we got here and the potential solutions</a>.</em></p>
<hr>
<p>We’ve all heard about antibiotic resistance. This happens when bacteria develop strategies to avoid being destroyed by an antibiotic. </p>
<p>The consequences of antibiotic resistance mean an antibiotic previously used to cure bacterial infections no longer works effectively because the bacteria have become resistant to the drug. This means it’s getting harder to cure the infections some bacteria cause.</p>
<p>But unfortunately, it’s only one part of the problem. The same phenomenon is also happening with other causes of infections in humans: fungi, viruses and parasites.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-rise-and-fall-of-antibiotics-what-would-a-post-antibiotic-world-look-like-213450">The rise and fall of antibiotics. What would a post-antibiotic world look like?</a>
</strong>
</em>
</p>
<hr>
<p>“Antimicrobial resistance” means the drugs used to treat diseases caused by microbes (bugs that cause infection) no longer work. This occurs with antibacterial agents used against bacteria, antifungal agents used against fungi, anti-parasitic agents used against parasites and antiviral agents used against viruses.</p>
<p>This means a wide range of previously controllable infections are becoming difficult to treat – and may become untreatable. </p>
<h2>Fighting fungi</h2>
<p>Fungi are responsible for a range of infections in humans. Tinea, ringworm and vulvovaginal candidiasis (thrush) are some of the more familiar and common superficial fungal infections. </p>
<p>There are also life-threatening fungal infections such as aspergillosis, cryptococcosis and invasive fungal bloodstream infections including those caused by <em>Candida albicans</em> and <em>Candida auris</em>. </p>
<p>Fungal resistance to antifungal agents is a problem for several reasons. </p>
<p>First, the range of antifungal agents available to treat fungal infections is limited, especially compared to the range of antibiotics available to treat bacterial infections. There are only four broad families of antifungal agents, with a small number of drugs in each category. Antifungal resistance further restricts already limited options.</p>
<p>Life-threatening fungal infections happen less frequently than life-threatening bacterial infections. But they’re rising in frequency, especially among people whose immune systems are compromised, including by <a href="https://7news.com.au/news/qld/first-heart-transplant-patient-to-die-from-fungal-infection-at-brisbanes-prince-charles-hospital-identified-as-mango-hill-gp-muhammad-hussain-c-12551559">organ transplants</a> and chemotherapy or immunotherapy for cancer. The threat of getting a drug-resistant fungal infection makes all of these health interventions riskier.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-do-candida-auris-and-other-fungi-develop-drug-resistance-a-microbiologist-explains-203495">How do _Candida auris_ and other fungi develop drug resistance? A microbiologist explains</a>
</strong>
</em>
</p>
<hr>
<p>The greatest <a href="https://www.frontiersin.org/articles/10.3389/fimmu.2017.00735/full">burden of serious fungal disease</a> occurs in places with limited health-care resources available for diagnosing and treating the infections. Even if infections are diagnosed and antifungal treatment is available, antifungal resistance reduces the treatment options that will work.</p>
<p>But even in Australia, common fungal infections are impacted by resistance to antifungal agents. Vulvovaginal candidiasis, known as thrush and caused by <em>Candida</em> species and some closely related fungi, is usually reliably treated by a topical antifungal cream, sometimes supplemented with an oral tablet. However, instances of <a href="https://www.theage.com.au/national/victoria/they-can-t-sit-properly-doctors-treat-growing-number-of-women-with-chronic-thrush-20230913-p5e499.html">drug-resistant thrush</a> are increasing, and new treatments are needed.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1584939012753862657"}"></div></p>
<h2>Targeting viruses</h2>
<p>Even <a href="https://theconversation.com/why-are-there-so-many-drugs-to-kill-bacteria-but-so-few-to-tackle-viruses-137480">fewer antivirals</a> are available than antibacterial and antifungal agents. </p>
<p>Most antimicrobial treatments work by exploiting differences between the microbe causing the infection and the host (us) experiencing the infection. Since viruses use our cells to replicate and cause their infection, it’s difficult to find antiviral treatments that selectively target the virus without damaging us. </p>
<p>With so few antiviral drugs available, any resistance that develops to one of them significantly reduces the treatment options available. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-are-there-so-many-drugs-to-kill-bacteria-but-so-few-to-tackle-viruses-137480">Why are there so many drugs to kill bacteria, but so few to tackle viruses?</a>
</strong>
</em>
</p>
<hr>
<p>Take COVID, for example. Two antiviral medicines are in widespread use to treat this viral infection: Paxlovid (containing nirmatrelvir and ritonavir) and Lagevrio (molnupiravir). So far, SARS-CoV-2, the virus that causes COVID, has not developed significant resistance to either of these <a href="https://www.cidrap.umn.edu/covid-19/low-levels-resistance-paxlovid-seen-sars-cov-2-isolates">treatments</a>. </p>
<p>But if SARS-CoV-2 develops resistance to either one of them, it halves the treatment options. Subsequently relying on one would likely lead to its increased use, which may heighten the risk that resistance to the second agent will develop, leaving us with no antiviral agents to treat COVID. </p>
<p>The threat of antimicrobial resistance makes our ability to treat serious COVID infections rather precarious.</p>
<h2>Stopping parasites</h2>
<p>Another group of microbes that cause infections in humans are single-celled microbes such as <em>Plasmodium</em>, <em>Giardia</em>, <em>Leishmania</em>, and <em>Trypanosoma</em>. These microbes are sometimes referred to as parasites, and they are becoming increasingly resistant to the very limited range of anti-parasitic agents used to treat the infections they cause. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/antibiotic-resistance-microbiologists-turn-to-new-technologies-in-the-hunt-for-solutions-podcast-217615">Antibiotic resistance: microbiologists turn to new technologies in the hunt for solutions – podcast</a>
</strong>
</em>
</p>
<hr>
<p>Several <em>Plasmodium</em> species cause malaria and anti-parasitic drugs have been the cornerstone of malaria treatment for decades. But their usefulness has been significantly reduced by the <a href="https://www.mmv.org/our-work/mmvs-pipeline-antimalarial-drugs/antimalarial-drug-resistance">development of resistance</a>. </p>
<p><em>Giardia</em> parasites cause an infection called giardiasis. This can resolve on its own, but it can also cause severe gastrointestinal symptoms such as diarrhea, nausea, and bloating. These microbes have <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6207226/">developed resistance</a> to the main treatments and patients infected with drug-resistant parasites can have protracted, unpleasant infections. </p>
<figure class="align-center ">
<img alt="3D illustration of Giardia lamblia protozoan" src="https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.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"><em>Giardia</em> parasites (illustrated here) cause giardiasis.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/giardia-lamblia-protozoan-causative-agent-giardiasis-1038065005">Shutterstock</a></span>
</figcaption>
</figure>
<h2>Resistance is a natural consequence</h2>
<p>Treating infections influences microbes’ evolutionary processes. Exposure to drugs that stop or kill them pushes microbes to either evolve or die. The exposure to antimicrobial agents provokes the evolutionary process, selecting for microbes that are resistant and can survive the exposure. </p>
<p>The pressure to evolve, provoked by the antimicrobial treatment, is called “selection pressure”. While most microbes will die, a few will evolve in time to overcome the antimicrobial drugs used against them. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-do-bacteria-actually-become-resistant-to-antibiotics-213451">How do bacteria actually become resistant to antibiotics?</a>
</strong>
</em>
</p>
<hr>
<p>The evolutionary process that leads to the emergence of resistance is inevitable. But some things can be done to minimise this and the problems it brings. </p>
<p>Limiting the use of antimicrobial agents is one approach. This means reserving antimicrobial agents for when their use is known to be necessary, rather than using them “just in case”.</p>
<p>Antimicrobial agents are precious resources, holding at bay many infectious diseases that would otherwise sicken and kill millions. It is imperative we do all we can to preserve the effectiveness of those that remain, and give ourselves more options by working to discover and develop new ones.</p>
<hr>
<p><em>Read the other articles in The Conversation’s series on the dangers of antibiotic resistance <a href="https://theconversation.com/au/topics/the-dangers-of-antibiotic-resistance-146983">here</a>.</em></p><img src="https://counter.theconversation.com/content/213460/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christine Carson receives funding from state and federal funding agencies, and the CUREator program, a national biotechnology incubator delivered by Brandon BioCatalyst. She has a commercial interest in companies developing diagnostic tests and preventing viral infections.</span></em></p>We’ve all heard of antibiotic resistance. The same thing is happening with other causes of infections in humans: fungi, viruses and parasites. This is making thrush and other infections hard to treat.Christine Carson, Senior Research Fellow, School of Medicine, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2168382023-11-22T14:35:36Z2023-11-22T14:35:36ZPatients’ beliefs about illness matter: the case of elephantiasis in rural Ghana<p>Would you take medication for an illness you didn’t believe you had? Or if you disagreed with healthcare workers about the cause of your condition? </p>
<p>This is the dilemma of many people who live in areas of Ghana where a mosquito-borne disease called <a href="https://www.who.int/news-room/fact-sheets/detail/lymphatic-filariasis#:%7E:text=Lymphatic%20filariasis%2C%20commonly%20known%20as,damage%20to%20the%20lymphatic%20system">lymphatic filariasis</a>, often referred to as elephantiasis, continues to spread. </p>
<p>Lymphatic filariasis, or LF as it is commonly known, is a neglected tropical disease which spreads through repeated bites by parasite-carrying mosquitoes. This infection results in the painful and debilitating swelling of legs, arms and genitals, and increases vulnerability to injury and secondary infections. </p>
<p>Although little known, lymphatic filariasis is a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3246437">significant</a>
and <a href="https://www.thelancet.com/journals/langlo/article/PIIS2214-109X(20)30323-5/fulltext">under-addressed</a> global cause of disability. According to the World Health Organization at least<a href="https://www.who.int/news-room/fact-sheets/detail/lymphatic-filariasis"> 51 million</a> people are infected with lymphatic filariasis. </p>
<p>The World Health Organization’s <a href="https://www.who.int/teams/control-of-neglected-tropical-diseases/lymphatic-filariasis/global-programme-to-eliminate-lymphatic-filariasis">Global Programme for Elimination of Lymphatic Filariasis</a> has greatly reduced the burden of the disease through preventive mass drug campaigns, mosquito control, veterinary public health and sanitation and hygiene measures.</p>
<p>Despite this concerted effort, however, lymphatic filariasis continues to be endemic and require mass drug administration in <a href="https://academic.oup.com/inthealth/article/13/Supplement_1/S22/6043665">31</a> African countries. The challenges to eradicating it are not well understood, and may hinge on better understanding how people with this disease view their condition. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-its-hard-to-end-elephantiasis-a-debilitating-disease-spread-by-mosquitoes-166627">Why it's hard to end elephantiasis, a debilitating disease spread by mosquitoes</a>
</strong>
</em>
</p>
<hr>
<p>Our research team brings together specialists in epidemiology, public health and human rights. In our recently published paper in <a href="https://journals.plos.org/globalpublichealth/article?id=10.1371/journal.pgph.0002476">PLOS Global Public Health</a> we take a different approach to the conventional medical focus that dominates research and interventions for this disease. </p>
<p>We examined the local perceptions and beliefs about the disease
and the personal experiences of those living with it in three rural communities in Ghana’s Ahanta West district. This coastal district in Ghana’s Western Region has a high rate of lymphatic filariasis infection and many people living with advanced stages of the disease. </p>
<p>Members of our research team had worked in this area for more than a decade, establishing the trust relationships that made this research possible.</p>
<p>Our findings may help provide insight into why lymphatic filariasis persists in certain settings and how best to tackle it.</p>
<h2>Cold, rain and curses</h2>
<p>We found that only <a href="https://journals.plos.org/globalpublichealth/article?id=10.1371/journal.pgph.0002476">18%</a> of respondents understood lymphatic filariasis as a disease. Fewer than 7% believed it to be a disease spread by mosquitoes. </p>
<p>Instead, people held a range of alternative beliefs attributing the condition to other sources, including spiritual causes (curses, witchcraft, evil spirits), cold or rainy weather, and other illnesses. In subsequent interviews, people described how, from their perspective, they encountered the disease. </p>
<p>One person explained, “When you are cold, then your leg gets swollen.” </p>
<p>Another noted, “There are some who just get jealous of and develop hatred for people for just walking and going about their normal duties and decide that they do not want this person or that person to progress, hence they buy the disease for them spiritually.” They added, “I strongly believe and have the conviction that someone bought mine for me spiritually.”</p>
<p>In contrast with these beliefs, which show very limited overlap with medical explanations, nearly half (<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6709921">45.8%</a>) of respondents reported receiving information about the disease from healthcare workers or drug campaigns. </p>
<p>These findings suggest we need to learn more about local beliefs in health and wellbeing in order to achieve more effective communication with patients. </p>
<p>Our research also demonstrates lymphatic filariasis is not only a medical condition, but also a social and economic one. </p>
<h2>Ashamed and stigmatised</h2>
<p>Almost <a href="https://journals.plos.org/globalpublichealth/article?id=10.1371/journal.pgph.0002476">80%</a> of respondents reported feeling ashamed or stigmatised by their condition. Some said it restricted their social lives and their willingness to go out in public. </p>
<p>Infection also limited the ability to earn a living. More than a third (<a href="https://journals.plos.org/globalpublichealth/article?id=10.1371/journal.pgph.0002476">36.2%</a>) said they could no longer work due to their condition. Many reported a need to depend on others for financial support. </p>
<p>Among those surveyed less than 3% reported that they were “doing well”. </p>
<p>These findings show an urgent need to address the unmet social, mental health and economic impacts of lymphatic filariasis.</p>
<h2>What needs to be done</h2>
<p>Drug campaigns are important but cannot be done in isolation. Existing research shows us that these <a href="https://academic.oup.com/inthealth/article/13/Supplement_1/S55/6043672">are more successful when offered in a broader context of care</a>. </p>
<p>Healthcare workers must be trained to avoid stigmatising patients. But eliminating stigma is not a simple task, nor can it be left to healthcare workers alone.</p>
<p>Further research is needed to better understand local beliefs about lymphatic filariasis, and to understand how stigma affects patients’ access to treatment and quality of life. This must include the strong links between the disease and poverty. </p>
<p>Lymphatic filariasis follows <a href="https://www.who.int/publications/i/item/WHO-IER-CSDH-08.1">the “social gradient”</a>. Those who are poorest are most likely to be affected. Factors associated with poverty increase the chances of being infected and of developing complications. These factors include poor quality housing, limited access to methods of prevention (mosquito nets, good quality footwear), difficulty getting medical care, living in remote rural communities, and working as subsistence farmers.</p>
<p>The disease also pushes poor people <a href="https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-021-10170-8">further into poverty</a> as it progresses.</p>
<p>As the number of people affected by it decreases, those who are left behind are more and more likely to be isolated, marginalised, stigmatised and impoverished. </p>
<p>As we argue in a <a href="https://www.taylorfrancis.com/chapters/edit/10.4324/9781003207672-15/examining-research-positionality-understanding-self-first-step-transnational-research-colleen-mcmillan-alexander-kwarteng-kristi-kenyon-mary-asirifi">recent book chapter</a>, these factors underscore the need for interdisciplinary research teams who are able to address lymphatic filariasis holistically. We need an approach that merges healthcare, health promotion, health systems, spiritual beliefs, social and cultural context, gender dynamics and economic impact. </p>
<p>We must put people with lymphatic filariasis – and their dignity – at the centre of research.</p><img src="https://counter.theconversation.com/content/216838/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kristi Heather Kenyon receives funding from the Canadian Institutes for Health Research.</span></em></p><p class="fine-print"><em><span>Alexander Kwarteng receives funding from the Canadian Institutes of Health Research</span></em></p><p class="fine-print"><em><span>Dr Colleen McMillan receives funding from the Canadian Institutes of Health Research. </span></em></p><p class="fine-print"><em><span>Mary Asirifi works for MacEwan University. She receives funding from CIHR. </span></em></p><p class="fine-print"><em><span>Regiane Garcia receives funding from Canadian Health Institutes Research</span></em></p>In rural Ghana, only 18% of patients believe elephantiasis is a disease. Some others think it is caused by curses or even rain. Only by understanding local beliefs can it be treated effectively.Kristi Heather Kenyon, Associate Professor, Human Rights, University of WinnipegAlexander Kwarteng, Senior Lecturer in Immunology of Infectious Diseases, Kwame Nkrumah University of Science and Technology (KNUST)Colleen McMillan, Scientific Co-Director and Associate Professor, University of WaterlooMary Asirifi, Assistant Professor, Department of Nursing Foundations, MacEwan UniversityRegiane Garcia, Research Associate, focus on health rights, laws and policies, Simon Fraser UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2161392023-11-21T13:26:58Z2023-11-21T13:26:58ZHow do viruses get into cells? Their infection tactics determine whether they can jump species or set off a pandemic<figure><img src="https://images.theconversation.com/files/560185/original/file-20231117-23-zg89fr.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2309%2C1299&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Surface proteins on a virus enable it to attach to and get inside a cell to start replicating.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/new-omicron-sub-variant-bq-1-1-royalty-free-image/1435658319">koto_feja/E+ via Getty Images</a></span></figcaption></figure><p>COVID-19, flu, mpox, noroviral diarrhea: How do the viruses that cause these diseases actually infect you?</p>
<p>Viruses <a href="https://www.khanacademy.org/science/biology/biology-of-viruses/virus-biology/a/intro-to-viruses">cannot replicate on their own</a>, so they must infect cells in your body to make more copies of themselves. The life cycle of a virus can thus be roughly described as: get inside a cell, make more virus, get out, repeat. </p>
<p>Getting inside a cell, or <a href="https://doi.org/10.1016/j.jmb.2018.03.034">viral entry</a>, is the part of the cycle that most vaccines target, as well as a key barrier for viruses jumping from one species to another. <a href="https://scholar.google.com/citations?user=OQ7vzu0AAAAJ&hl=en">My lab</a> and many others study this process to better anticipate and combat emerging viruses.</p>
<h2>How viruses enter cells</h2>
<p>Different viruses travel into the body in <a href="https://www.oregon.gov/oha/ph/diseasesconditions/communicabledisease/pages/transmission.aspx">various ways</a> – via airborne droplets, on food, through contact with mucous membranes or through injection. They typically first infect host cells near their site of entry – the cells lining the respiratory tract for most airborne viruses – then either remain there or spread throughout the body.</p>
<p>Viruses <a href="https://doi.org/10.1016/j.jmb.2018.06.024">recognize specific proteins or sugars</a> on host cells and stick to them. Each virus gets only one shot at putting its genome inside a cell – if their entry machinery misfires, they risk becoming inactivated. So they <a href="https://doi.org/10.1016/j.virol.2015.02.037">use several mechanisms</a> to prevent triggering entry prematurely.</p>
<p>After the virus binds to the cell, specific molecules on the cell’s surface or within the cell’s recycling machinery <a href="https://doi.org/10.1111/tra.12389">activate viral coat proteins for entry</a>. An example is the SARS-CoV-2 spike that COVID-19 vaccines target. These proteins need to modify the cell membrane to allow the viral genome to get through without killing the cell in the process. Different viruses use different tricks for this, but most work like cellular secretion – how cells release materials into their environment – in reverse. Specialized viral proteins help <a href="https://doi.org/10.1146/annurev-virology-111821-093413">merge the membranes of the virus and the cell</a> together and release the viral core into the interior of the cell.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/i__QSjC-pt0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">This animation depicts HIV fusing its membrane with a cell in order to release its contents inside.</span></figcaption>
</figure>
<p>At this point, the viral genome can enter the cell and <a href="https://doi.org/10.1016%2FB978-0-12-800947-5.00004-1">start replicating</a>. Some viruses use only the cell’s machinery to replicate, while others carry along portions of their own replication machinery and borrow some parts from the cell. After replicating their genomes, viruses assemble the components required to make new viruses.</p>
<p>Two central questions scientists are studying about viral entry are how your body’s defenses can disrupt it and what determines whether a virus from other species can infect people.</p>
<h2>Immune defenses against viruses</h2>
<p>Your body has a multilayered defense system against viral threats. But the part of your immune system called the <a href="https://doi.org/10.1016/j.jaci.2009.12.980">antibody response</a> is generally thought to be most effective at <a href="https://doi.org/10.1016/j.immuni.2022.10.017">sterilizing immunity</a> – preventing an infection from taking hold in the first place as opposed to just limiting its scope and severity. </p>
<p>For many viruses, antibodies target the part of the virus that binds to cells. This is the case not just for current COVID-19 vaccines but also the majority of immunity against influenza, whether from vaccines or from prior infection. </p>
<p>However, some antibodies target the entry machinery instead: Rather than preventing the virus from sticking, they prevent the virus from working altogether. Such antibodies are often harder for the viruses to escape from but are difficult to reproduce with vaccines. For that reason, developing antibodies that inhibit cell entry has the been the goal of many <a href="https://doi.org/10.1016/j.coviro.2016.02.002">next-generation vaccine efforts</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551885/original/file-20231003-25-cv0pnn.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram of the mechanisms of four classes of HIV antivirals" src="https://images.theconversation.com/files/551885/original/file-20231003-25-cv0pnn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551885/original/file-20231003-25-cv0pnn.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=496&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551885/original/file-20231003-25-cv0pnn.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=496&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551885/original/file-20231003-25-cv0pnn.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=496&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551885/original/file-20231003-25-cv0pnn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=623&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551885/original/file-20231003-25-cv0pnn.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=623&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551885/original/file-20231003-25-cv0pnn.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=623&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This diagram shows how four different classes of antiviral drugs inhibit HIV. One stops viruses from entering cells, and three inhibit different viral enzymes.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:HIV-drug-classes.svg">Thomas Splettstoesser/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Species-hopping and pandemics</h2>
<p>The other key question researchers are asking about viral entry is <a href="https://www.cdc.gov/flu/pandemic-resources/national-strategy/risk-assessment.htm">how to tell when</a> a virus from another species poses a threat to people. This is particularly important because many viruses are first identified in animals such as bats, birds and pigs before they spread to humans, but it’s unclear which ones may cause a pandemic.</p>
<p>The part of viruses that stick to human cells varies the most across species, while the part that gets the virus into cells <a href="https://doi.org/10.1016/bs.aivir.2016.08.004">tends to stay mostly the same</a>. Many researchers have thought that viruses changing in ways that bind better to human cells, like influenza viruses that bind to cells in the nose and throat, are some of the most important warning signs for pandemic risk. </p>
<p>However, coronaviruses – the family of viruses containing SARS-CoV-2 – are prompting re-examination of that idea. This is because several animal coronaviruses can actually <a href="https://doi.org/10.1038/s41564-020-0688-y">bind to human cells</a>, but only a few seem to be able to transmit well between people.</p>
<p>Only time will tell whether researchers need to broaden their pandemic prevention horizons or if their current prioritization of risky viruses is correct. The one grim reality of pandemic research, like earthquake research, is that there will always be another one – we just don’t know when or where, and we <a href="https://www.niaid.nih.gov/sites/default/files/pandemic-preparedness-plan.pdf">want to be ready</a>.</p><img src="https://counter.theconversation.com/content/216139/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Kasson receives funding from the National Institutes of Health, the National Science Foundation, the Commonwealth Health Research Board, and the Knut and Alice Wallenberg Foundation. He is affiliated with the University of Virginia, Uppsala University, and Georgia Institute of Technology.</span></em></p>Viruses can get into cells in several ways. Figuring out how to stop them from entering in the first place is a key to developing better vaccines and stopping future pandemics.Peter Kasson, Professor of Molecular Physiology and Biomedical Engineering, University of VirginiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2178382023-11-21T12:07:28Z2023-11-21T12:07:28ZNo compelling evidence that air purifiers prevent respiratory infections – new study<figure><img src="https://images.theconversation.com/files/560692/original/file-20231121-23-lg1s3r.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C8256%2C4634&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/air-purifier-comfortable-living-room-house-1914045592">Prathankarnpap/Shutterstock</a></span></figcaption></figure><p>The COVID pandemic led to many calls for improved <a href="https://time.com/6143799/covid-19-indoor-air-cleaning/">indoor air quality</a> with claims that doing so would reduce the risk of the <a href="https://www.scientificamerican.com/article/we-need-to-improve-indoor-air-quality-here-rsquo-s-how-and-why/">virus spreading</a>. But the real-world evidence to support these claims has been lacking and studies undertaken during the pandemic have not yet been reported. </p>
<p>So my colleagues and I reviewed the evidence before COVID and found that the balance of evidence was that air treatment does not, in fact, reduce illness from respiratory infections.</p>
<p>There are two main types of air treatment devices: <a href="https://link.springer.com/article/10.1007/s11157-015-9363-9">filters and air disinfectors</a>. Filters work by removing particles from the air that may contain infectious virus. Air disinfectors use ultraviolet radiation or ozone to inactivate viruses in the air.</p>
<p><a href="https://www.sciencedirect.com/science/article/pii/S0091743523003602">In our systematic review</a> we found 32 observational and experimental studies on the topic, conducted between 1970 and 2022. Overall, the evidence was that these technologies did not reduce either the frequency of illness or its severity. </p>
<p>When looking at the laboratory-confirmed influenza or norovirus infections, there was an apparent trend towards fewer infections. However, there was evidence of strong <a href="https://www.jclinepi.com/article/S0895-4356(99)00161-4/pdf">publication bias</a> – which is where significantly positive results are more likely to get published than negative results. </p>
<p>Publication bias makes the apparent impact of any intervention or treatment appear stronger than it is as those negative studies are simply not published.</p>
<p>Our review concluded that there is no strong evidence that air treatment technologies reduce the risks of respiratory transmitted illnesses.</p>
<p>None of the studies included in the review was directly about COVID, as none had been published during the study period. </p>
<p>However, a <a href="https://bmjopen.bmj.com/content/13/7/e072284">recent German study</a> (published in July), did investigate the effect of high-efficiency particulate air (Hepa) filters on COVID in kindergartens. The researchers compared illness rates in schools that had new filters installed with those that did not. </p>
<p>They found that there was no significant difference between the two. Indeed, infection rates were slightly higher in children in those schools that had the filters installed.</p>
<h2>What about ventilation?</h2>
<p>This study did not consider research on the effect of ventilation, such as keeping windows open, on the risk of illness. One possible issue with the studies of air treatment is that ventilation rates may have been reduced, thereby increasing risk. </p>
<p>There has been a recent systematic review of the effect of <a href="https://royalsocietypublishing.org/doi/full/10.1098/rsta.2023.0130">ventilation on COVID infection</a>. Although there was a bit more evidence in support of ventilation reducing infection, the studies were all of poor or very poor quality. As a result, the researchers concluded that the “level of confidence ascribed to this conclusion is low”. </p>
<p>So differences in ventilation are unlikely to explain the negative findings in the air treatment studies.</p>
<figure class="align-center ">
<img alt="A classroom with the window wide open." src="https://images.theconversation.com/files/560702/original/file-20231121-20-kzchb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/560702/original/file-20231121-20-kzchb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560702/original/file-20231121-20-kzchb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560702/original/file-20231121-20-kzchb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560702/original/file-20231121-20-kzchb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560702/original/file-20231121-20-kzchb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560702/original/file-20231121-20-kzchb.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">Ventilation is unlikely to explain the poor performance of air filters.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/table-background-opened-window-schoolbag-view-1467628820">S Photo/Shutterstock</a></span>
</figcaption>
</figure>
<p>If air treatment does not reduce the risk of illness, why may that be the case? I would argue that there are several reasons air treatment technologies were never going to be the <a href="https://theconversation.com/covid-in-schools-how-ventilation-can-help-to-combat-spread-of-virus-165434">panacea</a> that some were <a href="https://www.gov.uk/government/news/more-support-to-keep-pupils-in-the-classroom">claiming</a>.</p>
<p>First, the risk of transmission of respiratory viruses depends on how close you are to an infected person. Early in the pandemic one group of scientists showed that the risk of infection dropped considerably the further <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31142-9/fulltext#seccestitle10">someone got from an infectious person</a>. </p>
<p>Someone who got within one metre of an infectious person was about five times at greater risk than someone who stayed more than one metre away. It is doubtful that air treatment would affect such close person-to-person transmission.</p>
<p>Second, even if air treatment was effective at preventing infection within a particular indoor space, people move regularly between spaces. Air treatment in your school or workplace will not protect you while on public transport or when gathering in other environments. </p>
<p>Finally, there is the issue of epidemic dynamics of infections that have a short duration of immunity. As I discussed over two years ago, infections like COVID that have a relatively short duration of immunity behave differently than would be predicted by <a href="https://theconversation.com/why-covid-cases-are-now-falling-in-the-uk-and-what-could-happen-next-165123">standard epidemic models</a> because people can be reinfected many times during their life as their immunity wanes. </p>
<p>Infections like COVID are better modelled by the SEIRS (susceptible, exposed, infected, recovered, susceptible) <a href="https://www.nature.com/articles/s41592-020-0856-2">model</a>. In this model, interventions like air filtration or wearing masks become less effective as most infections become reinfections. What then drives infection rates is the rate at which people lose their immunity. </p>
<p>So the balance of real-world evidence is that air treatment technologies do not reduce the risk of becoming ill from a respiratory infection like COVID. There is a little more evidence that increased ventilation may reduce that risk, but the evidence is far from compelling.</p><img src="https://counter.theconversation.com/content/217838/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Hunter consults for the World Health Organization. He receives funding from National Institute for Health Research, the World Health Organization and the European Regional Development Fund.</span></em></p>Air purifiers were meant to save us from COVID. A new systematic review wonders where the evidence for that is.Paul Hunter, Professor of Medicine, University of East AngliaLicensed as Creative Commons – attribution, no derivatives.