tag:theconversation.com,2011:/ca/topics/mosquito-control-26782/articlesMosquito control – 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/2217382024-01-23T23:50:48Z2024-01-23T23:50:48ZMosquitoes can spread the flesh-eating Buruli ulcer. Here’s how you can protect yourself<figure><img src="https://images.theconversation.com/files/570835/original/file-20240123-15-oolw3x.JPG?ixlib=rb-1.1.0&rect=10%2C395%2C6939%2C2886&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">A/Prof Cameron Webb (NSW Health Pathology)</span></span></figcaption></figure><p>Each year, more and more Victorians become sick with a flesh-eating bacteria known as Buruli ulcer. <a href="https://www.premier.vic.gov.au/take-precautions-against-buruli-ulcer-summer">Last year</a>, 363 people presented with the infection, the highest number since 2004. </p>
<p>But it has been unclear exactly how it spreads, until now. <a href="https://www.nature.com/articles/s41564-023-01553-1">New research</a> shows mosquitoes are infected from biting possums that carry the bacteria. Mozzies spread it to humans through their bite.</p>
<h2>What is Buruli ulcer?</h2>
<p><a href="https://www.betterhealth.vic.gov.au/health/healthyliving/Buruli-ulcer">Buruli ulcer</a>, also known as Bairnsdale ulcer, is a skin infection caused by the bacterium <em>Mycobacterium ulcerans</em>.</p>
<p>It starts off like a small mosquito bite and over many months, slowly develops into an ulcer, with extensive destruction of the underlying tissue.</p>
<p>While often painless initially, the infection can become very serious. If left untreated, the ulcer can continue to enlarge. This is where it gets its “flesh-eating” name. </p>
<p>Thankfully, it’s treatable. A six to eight week course of specific antibiotics is an effective treatment, sometimes supported with surgery to remove the infected tissue.</p>
<h2>Where can you catch it?</h2>
<p>The <a href="https://www.who.int/news-room/fact-sheets/detail/buruli-ulcer-(mycobacterium-ulcerans-infection)">World Health Organization</a> considers Buruli ulcer a neglected tropical skin disease. Cases have been reported across 33 countries, primarily in west and central Africa. </p>
<p>However, since the early 2000s, Buruli ulcer has also been increasingly recorded in coastal Victoria, including suburbs <a href="https://www.theguardian.com/australia-news/2024/jan/18/flesh-eating-buruli-ulcer-cases-victoria-warning-rise-mosquito">around Melbourne</a> and Geelong.</p>
<p>Scientists have long known <a href="https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0002666">Australian native possums</a> were partly responsible for its spread, and suspected <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3375796/">mosquitoes</a> also played a role in the increase in cases. <a href="https://www.nature.com/articles/s41564-023-01553-1">New research</a> confirms this.</p>
<h2>Our efforts to ‘beat Buruli’</h2>
<p>Confirming the role of insects in outbreaks of an infectious disease is <a href="https://www.health.vic.gov.au/infectious-diseases/beating-buruli-in-victoria">achieved</a> by building up corroborating, independent evidence. </p>
<p>In this <a href="https://www.nature.com/articles/s41564-023-01553-1">new research</a>, published in Nature Microbiology, the team (including co-authors Tim Stinear, Stacey Lynch and Peter Mee) conducted extensive surveys across a 350 km² area of Victoria. </p>
<p>We collected mosquitoes and analysed the specimens to determine whether they were carrying the pathogen, and links to infected possums and people. It was like <a href="https://theconversation.com/explainer-what-is-contact-tracing-and-how-does-it-help-limit-the-coronavirus-spread-134228">contact tracing</a> for mosquitoes.</p>
<figure class="align-left ">
<img alt="Dead mosquito specimen in museum collection" src="https://images.theconversation.com/files/570827/original/file-20240123-17-zkh06a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/570827/original/file-20240123-17-zkh06a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570827/original/file-20240123-17-zkh06a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570827/original/file-20240123-17-zkh06a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570827/original/file-20240123-17-zkh06a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570827/original/file-20240123-17-zkh06a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570827/original/file-20240123-17-zkh06a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Aedes notoscriptus was the mosquito identified as carrying the bacteria that caused Buruli ulcer.</span>
<span class="attribution"><span class="source">Cameron Webb (NSW Health Pathology)</span></span>
</figcaption>
</figure>
<p>Molecular testing of the mosquito specimens showed that of the two most abundant mosquito species, only <em>Aedes notoscriptus</em> (a widespread species commonly known as the Australian backyard mosquito) was positive for <em>Mycobacterium ulcerans</em>. </p>
<p>We then used genomic tests to show the bacteria found on these mosquitoes matched the bacteria in possum poo and humans with Buruli ulcer.</p>
<p>We further analysed mosquito specimens that contained blood to show <em>Aedes notoscriptus</em> was feeding on both possums and humans.</p>
<p>To then link everything together, geospatial analysis revealed the areas where human Buruli ulcer cases occur overlap with areas where both mosquitoes and possums that harbour <em>Mycobacterium ulcerans</em> are active.</p>
<h2>Stop its spread by stopping mozzies breeding</h2>
<p>The mosquito in this study primarily responsible for the bacteria’s spread is <em>Aedes notoscriptus</em>, a mosquito that lays its eggs around water in containers in backyard habitats. </p>
<p>Controlling “backyard” mosquitoes is a critical part of reducing the risk of many global mosquito-borne disease, <a href="https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0003713">especially dengue</a> and now Buruli ulcer. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/its-warming-up-and-mozzies-are-coming-heres-how-to-mosquito-proof-your-backyard-212711">It's warming up and mozzies are coming. Here's how to mosquito-proof your backyard</a>
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</em>
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<p>You can reduce places where water collects after rainfall, such as potted plant saucers, blocked gutters and drains, unscreened rainwater tanks, and a wide range of plastic buckets and other containers. These should all be either <a href="https://theconversation.com/you-can-leave-water-out-for-wildlife-without-attracting-mosquitoes-if-you-take-a-few-precautions-128631">emptied at least weekly</a> or, better yet, thrown away or placed under cover.</p>
<figure class="align-center ">
<img alt="A watering can sitting in garden and filled with water" src="https://images.theconversation.com/files/570830/original/file-20240123-27-akrcy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570830/original/file-20240123-27-akrcy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570830/original/file-20240123-27-akrcy.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570830/original/file-20240123-27-akrcy.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570830/original/file-20240123-27-akrcy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570830/original/file-20240123-27-akrcy.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570830/original/file-20240123-27-akrcy.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">Mosquitoes can lay eggs in a wide range of water-filled items in the backyard.</span>
<span class="attribution"><span class="source">Cameron Webb (NSW Health Pathology)</span></span>
</figcaption>
</figure>
<p>There is a role for insecticides too. While residual insecticides applied to surfaces around the house and garden will reduce mosquito populations, <a href="https://theconversation.com/the-battle-against-bugs-its-time-to-end-chemical-warfare-111629">they can also impact</a> other, beneficial, insects. Judicious use of such sprays is recommended. But there are <a href="https://onlinelibrary.wiley.com/doi/10.1111/j.1440-6055.2008.00642.x">ecological safe insecticides</a> that can be applied to water-filled containers (such as ornamental ponds, fountains, stormwater pits and so on).</p>
<p>Recent research also indicates new mosquito-control approaches that use <a href="https://academic.oup.com/jme/article/60/5/1061/7236697">mosquitoes themselves to spread insecticides</a> may soon be available.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/stickers-and-wristbands-arent-a-reliable-way-to-prevent-mosquito-bites-heres-why-220284">Stickers and wristbands aren't a reliable way to prevent mosquito bites. Here's why</a>
</strong>
</em>
</p>
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<h2>How to protect yourself from bites</h2>
<p>The first line of defence will remain personal protection measures against mosquito bites.</p>
<p>Covering up with loose fitted long sleeved shirts, long pants, and covered shoes will provide physical protection from mosquitoes.</p>
<p>Applying topical insect repellent to all exposed areas of skin has been proven to <a href="https://www.jaad.org/article/S0190-9622(18)32824-X/fulltext">provide safe and effective protection</a> from mosquito bites. Repellents should <a href="https://www.phrp.com.au/issues/december-2016-volume-26-issue-5/a-review-of-recommendations-on-the-safe-and-effective-use-of-topical-mosquito-repellents/">include</a> diethytolumide (DEET), <a href="https://www.phrp.com.au/issues/december-2016-volume-26-issue-5/a-review-of-recommendations-on-the-safe-and-effective-use-of-topical-mosquito-repellents/">picaridin</a> or oil of lemon eucalyptus.</p>
<p>While the rise in Buruli ulcer is a significant health concern, <a href="https://theconversation.com/how-can-the-bite-of-a-backyard-mozzie-in-australia-make-you-sick-171601">so too are many other mosquito-borne diseases</a>. The steps to avoid mosquito bites and exposure to <em>Mycobacteriam ulcerans</em> will also protect against viruses such as Ross River, Barmah Forest, Japanese encephalitis, and Murray Valley encephalitis.</p>
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Read more:
<a href="https://theconversation.com/how-can-the-bite-of-a-backyard-mozzie-in-australia-make-you-sick-171601">How can the bite of a backyard mozzie in Australia make you sick?</a>
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<img src="https://counter.theconversation.com/content/221738/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p><p class="fine-print"><em><span>Peter Mee receives funding from the National Health and Medical Research Council.</span></em></p><p class="fine-print"><em><span>Stacey Lynch receives funding from the National Health and Medical Research Council of Australia. The work on this subject was undertaken while employed in a former role at Agriculture Victoria.</span></em></p><p class="fine-print"><em><span>Tim Stinear receives funding from the National Health and Medical Research Council of Australia. </span></em></p>New research shows mosquitoes spread Buruli ulcer. So reducing mosquito populations and avoiding bites is critical.Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of SydneyPeter Mee, Adjunct Associate Lecturer, School of Applied Systems Biology, La Trobe UniversityStacey Lynch, Team Leader- Mammalian infection disease research, CSIROTim Stinear, Professor of Microbiology, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2202842024-01-18T01:00:18Z2024-01-18T01:00:18ZStickers and wristbands aren’t a reliable way to prevent mosquito bites. Here’s why<figure><img src="https://images.theconversation.com/files/569681/original/file-20240116-25-fkx3sy.jpg?ixlib=rb-1.1.0&rect=220%2C137%2C3918%2C3235&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/2-boys-standing-on-green-grass-near-lake-during-daytime-pwCJWny66aI">Meritt Thomas/Unsplash</a></span></figcaption></figure><p>Protecting yourself and family from mosquito bites can be challenging, especially in this hot and humid weather. Protests from young children and fears about topical insect repellents drive some to try alternatives such as wristbands, patches and stickers. </p>
<p>These products are sold online as well as in supermarkets, pharmacies and camping stores. They’re often marketed as providing “natural” protection from mosquitoes.</p>
<p>But unfortunately, they aren’t a reliable way to prevent mosquito bites. Here’s why – and what you can try instead. </p>
<h2>Why is preventing mosquito bites important?</h2>
<p>Mosquitoes can <a href="https://theconversation.com/how-can-the-bite-of-a-backyard-mozzie-in-australia-make-you-sick-171601">spread pathogens that make us sick</a>. <a href="https://theconversation.com/japanese-encephalitis-virus-has-been-detected-in-australian-pigs-can-mozzies-now-spread-it-to-humans-178017">Japanese encephalitis</a> and <a href="https://theconversation.com/murray-valley-encephalitis-has-been-detected-in-mozzies-in-nsw-and-victoria-heres-what-you-need-to-know-197894">Murray Valley encephalitis</a> viruses can have potentially fatal outcomes. While <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1005070">Ross River</a> virus won’t kill you, it can cause potentially debilitating illnesses. </p>
<p>Health authorities <a href="https://www.health.nsw.gov.au/Infectious/mosquito-borne/Pages/default.aspx">recommend</a> preventing mosquito bites by: avoiding areas and times of the day when mosquitoes are most active; covering up with long sleeved shirts, long pants, and covered shoes; and applying a topical insect repellent (a cream, lotion, or spray).</p>
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Read more:
<a href="https://theconversation.com/will-japanese-encephalitis-return-this-summer-what-about-other-diseases-mosquitoes-spread-218441">Will Japanese encephalitis return this summer? What about other diseases mosquitoes spread?</a>
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<h2>I don’t want to put sticky and smelly repellents on my skin!</h2>
<p>While for many people, the “sting” of a <a href="https://www.sciencedirect.com/science/article/pii/S1326020023023567?via%3Dihub">biting mosquitoes is enough to prompt a dose of repellent</a>, others are <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10739303/">reluctant</a>. Some <a href="https://www.liebertpub.com/doi/10.1089/153036603322662156">are deterred</a> by the unpleasant feel or smell of insect repellents. Others believe topical repellents contain chemicals that are dangerous to our health.</p>
<p>However, many studies have shown that, when used as recommended, these products <a href="https://www.sciencedirect.com/science/article/abs/pii/S1080603215004342">are safe to use</a>. All products marketed as mosquito repellents in Australia must be registered by the <a href="https://www.apvma.gov.au/">Australian Pesticides and Veterinary Medicines Authority</a>; a process that provides recommendations for safe use. </p>
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Read more:
<a href="https://theconversation.com/feel-like-youre-a-mozzie-magnet-its-true-mosquitoes-prefer-to-bite-some-people-over-others-128788">Feel like you're a mozzie magnet? It's true – mosquitoes prefer to bite some people over others</a>
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<h2>How do topical repellents work?</h2>
<p>While there remains some uncertainty about how the <a href="https://www.jaad.org/article/S0190-9622(18)32824-X/fulltext">chemicals in topical insect repellents actually work</a>, they appear to either block the sensory organs of mosquitoes that drive them to bite, or overpower the smells of our skin that helps mosquitoes find us. </p>
<p>Diethytolumide (DEET) is a <a href="https://www.phrp.com.au/issues/december-2016-volume-26-issue-5/a-review-of-recommendations-on-the-safe-and-effective-use-of-topical-mosquito-repellents/">widely recommended ingredient</a> in topical repellents. Picaridin and oil of lemon eucalyptus <a href="https://www.phrp.com.au/issues/december-2016-volume-26-issue-5/a-review-of-recommendations-on-the-safe-and-effective-use-of-topical-mosquito-repellents/">are also used</a> and have been shown to be effective and safe.</p>
<h2>How do other products work?</h2>
<p>“Physical” insect-repelling products, such as wristbands, coils and candles, often contain a botanically derived chemical and are often marketed as being an alternative to DEET.</p>
<p>However, studies have shown that devices such as candles <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-3156.2011.02781.x">containing citronella oil</a> provide lower mosquito-bite prevention than topical repellents.</p>
<p>A <a href="https://search.informit.org/doi/abs/10.3316/INFORMIT.227605874334644?casa_token=DEdfTcUX-F0AAAAA%3AwKeVbAzCxFZX2BZj2VvHBqI3Vjv1oKngFHgMteebxGtZVfN5bezrWRbNnBHyoyKViaEG_908OOwCAC4">laboratory study in 2011</a> found wristbands infused with peppermint oil failed to provide full protection from mosquito bites.</p>
<p>Even as topical repellent formulations applied to the skin, these botanically derived products have <a href="https://bioone.org/journals/Journal-of-the-American-Mosquito-Control-Association/volume-25/issue-3/09-0016.1/Are-Commercially-Available-Essential-Oils-from-Australian-Native-Plants-Repellent/10.2987/09-0016.1.short">lower mosquito bite protection</a> than recommended products such as those containing <a href="https://www.phrp.com.au/issues/december-2016-volume-26-issue-5/a-review-of-recommendations-on-the-safe-and-effective-use-of-topical-mosquito-repellents/">DEET, picaridin and oil of lemon eucalyptus</a>.</p>
<p>Wristbands infused with DEET have shown mixed results but may provide some <a href="https://link.springer.com/article/10.1007/s00436-009-1433-x">bite protection</a> or <a href="https://resjournals.onlinelibrary.wiley.com/doi/10.1111/j.1365-2915.1987.tb00331.x">bite reduction</a>. DEET-based wristbands or patches are not currently available in Australia.</p>
<p>There is also a range of mosquito repellent <a href="https://theconversation.com/are-mosquito-coils-good-or-bad-for-our-health-88548">coils, sticks, and other devices</a> that release insecticides (for example, pyrethroids). These chemicals are primarily designed to kill or “knock down” mosquitoes rather than to simply keep them from biting us.</p>
<h2>What about stickers and patches?</h2>
<p>Although insect repellent patches and stickers have been available for many years, there has been a sudden surge in their marketing through social media. But there are very few scientific studies testing their efficacy.</p>
<p>Our current understanding of the way insect repellents work would suggest these small stickers and patches offer little protection from mosquito bites.</p>
<p>At best, they may <a href="https://bioone.org/journals/Journal-of-the-American-Mosquito-Control-Association/volume-22/issue-1/8756-971X(2006)22%5B158:FEONMS%5D2.0.CO;2/FIELD-EVALUATION-OF-NEW-MOUNTAIN-SANDALWOOD-MOSQUITO-STICKSsup-supAND-NEW/10.2987/8756-971X(2006)22%5B158:FEONMS%5D2.0.CO;2.short">reduce some bites</a> in the way mosquito coils containing botanical products work. However, the passive release of chemicals from the patches and stickers is likely to be substantially lower than those from mosquito coils and <a href="https://academic.oup.com/jme/article-abstract/53/2/480/2459702?login=false">other devices actively releasing chemicals</a>.</p>
<p>One <a href="https://doi.org/10.1016/j.actatropica.2012.10.009">study in 2013</a> found a sticker infused with oil of lemon eucalyptus “did not provide significant protection to volunteers”.</p>
<p><a href="https://theconversation.com/mozzie-repellent-clothing-might-stop-some-bites-but-youll-still-need-a-cream-or-spray-107266">Clothing impregnated with insecticides</a>, such as permethrin, will assist in reducing mosquito bites but topical insect repellents are still recommended for exposed areas of skin.</p>
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Read more:
<a href="https://theconversation.com/bzzz-slap-how-to-treat-insect-bites-home-remedies-included-148722">Bzzz, slap! How to treat insect bites (home remedies included)</a>
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<h2>Take care when using these products</h2>
<p>The idea you can apply a sticker or patch to your clothing to protect you from mosquito bites may sound appealing, but these devices provide a false sense of security. There is no evidence they are an equally effective alternative to the topical repellents recommended by health authorities around the world. It <a href="https://theconversation.com/curious-kids-when-we-get-bitten-by-a-mosquito-why-does-it-itch-so-much-93347">only takes one bite</a> from a mosquito to transmit the pathogens that result in serious disease.</p>
<p>It is also worth noting that there are some health warnings and recommendations for their use <a href="https://www.apvma.gov.au/">required by Australian Pesticides and Veterinary Medicines Authority</a>. Some of these products warn against application to the skin (recommending application to clothing only) and to keep products “out of reach of children”. This is a challenge if attached to young children’s clothing.</p>
<p>Similar warnings are associated with most other topical and non-topical mosquito repellents. Always check the labels of these products for safe use recommendations.</p>
<h2>Are there any other practical alternatives?</h2>
<p>Topical insect repellents are safe and effective. Most can be used on children from 12 months of age and pose no health risks. Make sure you apply the repellent as a thin even coat on all exposed areas of skin. </p>
<p>But you don’t need “tropical strength” repellents for short periods of time outdoors; a range of formulations with lower concentrations of repellent will work well for shorter trips outdoors. There are some repellents that don’t smell as strong (for example, children’s formulations, odourless formulations) or formulations that may be more pleasant to use (for example, pump pack sprays).</p>
<p>Finally, you can always cover up. Loose-fitting long-sleeved shirts, long pants, and covered shoes will provide a physical barrier between you and mosquitoes on the hunt for your or your family’s blood this summer.</p><img src="https://counter.theconversation.com/content/220284/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p>It’s hot and humid. With mosquitoes about, applying insect repellent creams, sprays and lotions may not feel good. But how do the alternatives stack up?Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2127112023-09-12T01:50:29Z2023-09-12T01:50:29ZIt’s warming up and mozzies are coming. Here’s how to mosquito-proof your backyard<figure><img src="https://images.theconversation.com/files/547382/original/file-20230911-29-86sa9t.JPG?ixlib=rb-1.1.0&rect=14%2C402%2C4778%2C2737&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">A/Prof Cameron Webb (NSW Health Pathology)</span></span></figcaption></figure><p>The weather is warming up and that means more time in the backyard. It also means more mosquitoes. </p>
<p>Here are five ways you can mosquito-proof your backyard that <a href="https://theconversation.com/the-battle-against-bugs-its-time-to-end-chemical-warfare-111629">don’t rely on spraying insecticides</a>.</p>
<h2>1. Get rid of water</h2>
<p>Mosquitoes need water to complete their life cycles. They <a href="https://theconversation.com/feel-like-youre-a-mozzie-magnet-its-true-mosquitoes-prefer-to-bite-some-people-over-others-128788">need blood</a> – but water and warmth are just as important.</p>
<p>Getting rid of water around your backyard will go a long way to keeping mosquitoes away. Water trapped in blocked roof gutters, drains and tarpaulin covering boats and trailers can be a great home for mosquitoes. </p>
<p>Mosquitoes can exploit the tiniest of water sources too. It may just be the upturned lid of a discarded plastic drink bottle. If it traps water, mosquitoes will find it and lay eggs in it.</p>
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Read more:
<a href="https://theconversation.com/how-can-the-bite-of-a-backyard-mozzie-in-australia-make-you-sick-171601">How can the bite of a backyard mozzie in Australia make you sick?</a>
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<p>Flush out your bird bath once a week to disrupt the mosquito’s life cycle. </p>
<p>If you have a pond, installing a fountain will discourage mosquitoes. If you can’t keep water clean and circulating, consider filling it with sand and gravel to create an interesting garden bed for succulents or other plants.</p>
<p>Mosquitoes will avoid clean and chlorinated swimming pools but will quickly move into “green pools”. If you’re not using your pool, consider <a href="https://www.krg.nsw.gov.au/Environment/Your-local-environment/Wildlife/Living-with-wildlife/Pool-to-pond/How-to-convert-your-pool">converting it to a “pond”</a> so that fish can help keep mosquito numbers down.</p>
<h2>2. Screen up – windows, doors and rainwater tanks</h2>
<p>If you can’t get rid of permanent water, at least stop mosquitoes getting to it (or you).</p>
<p>Ensure <a href="https://www.brisbane.qld.gov.au/clean-and-green/natural-environment-and-water/water/water-smart-homes/rainwater-tanks/using-your-rainwater-tank">rainwater and septic tanks</a> have screens to stop mosquitoes entering.</p>
<p>Screen windows and doors to stop mosquitoes entering the home. There are plenty of flexible screening options for windows, doors and balconies.</p>
<p>If you live in a mosquito-prone area, creating a screened outdoor area (such as a pergola, courtyard, or balcony) will give you the opportunity to spend time outdoors without being hassled by mozzies.</p>
<h2>3. Choose your garden plants carefully</h2>
<p>Some plants <a href="https://bioone.org/journals/Journal-of-the-American-Mosquito-Control-Association/volume-25/issue-3/09-0016.1/Are-Commercially-Available-Essential-Oils-from-Australian-Native-Plants-Repellent/10.2987/09-0016.1.short">contain essential oils and other chemicals</a> that, when extracted and concentrated, provide protection against biting mosquitoes. But there isn’t a lot of evidence that the whole plant will keep mosquitoes away from your garden.</p>
<p>Some types of plants are even marketed as “mozzie blockers” or “mosquito repelling”. But there isn’t <a href="https://www.veranda.com/outdoor-garden/a40592197/do-mosquito-repelling-plants-work/">any evidence of effectiveness</a>. In fact, some of these plants, <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1440-6055.2009.00736.x">such as melaleucas</a>, also happen to be associated with <a href="https://academic.oup.com/jme/article/36/4/515/903838">hot spots of mosquito breeding</a> in coastal Australia.</p>
<p>The plants to <em>avoid</em> around the home are those that help mosquitoes breed, such as <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1440-6055.2008.00641.x">bromeliads</a>, which trap water. </p>
<h2>4. Encourage the animals that eat mosquitoes</h2>
<p>Mosquitoes are food for a range of animals including birds, bats, fish, frogs, lizards, insects, spiders and <a href="https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2656.13965">dragonflies</a>. But don’t expect them to eat enough to keep all mosquitoes away.</p>
<p>Bats are often promoted as a good “biological control” options but studies have shown mosquitoes are <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0077183">more likely to be a snack food</a> for small bats, not an irresistible staple of their diet.</p>
<p>For garden ponds, frogs will eat a few adult mosquitoes but tadpoles of Australian frogs generally <a href="https://bioone.org/journals/journal-of-the-american-mosquito-control-association/volume-21/issue-4/8756-971X(2006)21%5b492%3aTOFCAF%5d2.0.CO%3b2/TADPOLES-OF-FOUR-COMMON-AUSTRALIAN-FROGS-ARE-NOT-EFFECTIVE-PREDATORS/10.2987/8756-971X(2006)21%5B492:TOFCAF%5D2.0.CO;2.short">don’t eat many mosquito “wrigglers”</a>. </p>
<p>Australian native fish <a href="https://pubmed.ncbi.nlm.nih.gov/15532929/">will readily eat mosquitoes</a> and may be useful for backyard ponds.</p>
<p>But not all fish are good. While “mosquitofish” (aka “plague minnow”) is distributed overseas to assist in mosquito control, <a href="https://meridian.allenpress.com/australian-zoologist/article/30/3/316/134508/Does-predation-by-the-fish-Gambusia-holbrooki">it’s a disaster for local wildlife</a> and, <a href="https://www.dpi.nsw.gov.au/fishing/aquatic-biosecurity/pests-diseases/freshwater-pests/finfish-species/gambusia">along with other exotic fish species</a>, should not be released into local waterways.</p>
<p><a href="https://link.springer.com/article/10.1007/s13157-019-01133-2">Healthier habitats promote fewer mosquitoes</a> so the best thing you can do is create habitats for the animals that eat mosquitoes. </p>
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Read more:
<a href="https://theconversation.com/you-can-leave-water-out-for-wildlife-without-attracting-mosquitoes-if-you-take-a-few-precautions-128631">You can leave water out for wildlife without attracting mosquitoes, if you take a few precautions</a>
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<h2>5. Avoid traps and other gadgets</h2>
<p>There are lots of devices purported to catch, kill, or repel mosquitoes from your garden. Some may catch a mosquito or two but they’re not very effective in knocking out big numbers.</p>
<p>“Bug zappers” with bright lights will collect lots of flying insects. It’s just that mosquitoes make up a very small proportion of collections. </p>
<p>Electrocuting devices, again, don’t seem to attract a lot of mosquitoes. </p>
<p>Devices that <a href="https://theconversation.com/the-buzz-from-your-smartphone-wont-stop-mosquito-bites-92611">emit high frequency sounds</a> won’t help either. </p>
<p>The best devices are typically those that are baited with carbon dioxide. These are a mainstay of state and territory <a href="https://www.health.nsw.gov.au/Infectious/mosquito-borne/Pages/surveillance.aspx">mosquito and arbovirus surveillance programs</a>. For a mosquito, the C0₂ tricks them into thinking the trap is a warm-blooded animal. The only problem is these can be expensive to run and don’t seem quite as effective for mosquito control <a href="https://bioone.org/journals/journal-of-the-american-mosquito-control-association/volume-22/issue-3/8756-971X(2006)22%5b490%3aTATTFA%5d2.0.CO%3b2/Traps-and-Trapping-Techniques-for-Adult-Mosquito-Control/10.2987/8756-971X(2006)22%5B490:TATTFA%5D2.0.CO;2.short">unless used in large numbers</a>. </p>
<h2>Yes, you’ll still need repellent</h2>
<p>Perhaps the best way to avoid mosquito bites is to pick an insect repellent <a href="https://www.phrp.com.au/issues/december-2016-volume-26-issue-5/a-review-of-recommendations-on-the-safe-and-effective-use-of-topical-mosquito-repellents/">recommended by health authorities</a> and <a href="https://theconversation.com/mozzies-biting-heres-how-to-choose-a-repellent-and-how-to-use-it-for-the-best-protection-150183">apply it</a> to ensure all exposed areas of skin are covered. These products and safe, affordable and effective.</p>
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Read more:
<a href="https://theconversation.com/mozzies-biting-heres-how-to-choose-a-repellent-and-how-to-use-it-for-the-best-protection-150183">Mozzies biting? Here's how to choose a repellent (and how to use it for the best protection)</a>
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<img src="https://counter.theconversation.com/content/212711/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p>Warm weather has arrived and that means our annual battle against mosquitoes is back on. Here are five ways to mosquito-proof your backyard that don’t rely on spraying insecticides.Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1978942023-01-17T05:07:23Z2023-01-17T05:07:23ZMurray Valley encephalitis has been detected in mozzies in NSW and Victoria. Here’s what you need to know<p>Where there’s water, you’ll find mosquitoes – including some that transmit viruses that can make us seriously ill. </p>
<p>Authorities have been on alert after an outbreak of Japanese encephalitis last summer which resulted in <a href="https://www.health.gov.au/health-alerts/japanese-encephalitis-virus-jev/japanese-encephalitis-virus-jev?language=en">45 human cases and seven deaths</a>. Favourable conditions for mosquitoes <a href="https://theconversation.com/a-wet-spring-and-summer-means-more-mosquitoes-but-now-weve-got-japanese-encephalitis-virus-to-worry-about-too-191510">continued</a>. </p>
<p>Now, we’ve seen the return of another pathogen to southeastern Australia: Murray Valley encephalitis virus. Mosquitoes carrying the virus have been detected in <a href="https://www.health.nsw.gov.au/news/Pages/20230111_00.aspx">New South Wales</a> and northern <a href="https://www.health.vic.gov.au/health-alerts/murray-valley-encephalitis-virus-detected-in-victoria">Victoria</a>.</p>
<p>While Murray Valley encephalitis is endemic in Northern Australia, meaning it is always present in mosquitoes, it’s not often detected in southeastern Australia. No human cases have yet been reported in the southern states, but past outbreaks after floods show we need to be cautious.</p>
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Read more:
<a href="https://theconversation.com/how-to-mozzie-proof-your-property-after-a-flood-and-cut-your-risk-of-mosquito-borne-disease-178299">How to mozzie-proof your property after a flood and cut your risk of mosquito-borne disease</a>
</strong>
</em>
</p>
<hr>
<h2>What is Murray Valley encephalitis virus?</h2>
<p><a href="https://www.health.nsw.gov.au/Infectious/factsheets/Pages/murray-valley-encephalitis.aspx">Murray Valley encephalitis virus</a> is a member of the <a href="https://theconversation.com/5-virus-families-that-could-cause-the-next-pandemic-according-to-the-experts-189622">Flavivirus family</a>, which includes Japanese encephalitis, <a href="https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue">dengue</a>, <a href="https://www.who.int/news-room/fact-sheets/detail/yellow-fever">yellow fever</a> and <a href="https://www.cdc.gov/westnile/index.html">West Nile</a> viruses. </p>
<p>Murray Valley encephalitis causes similar symptoms to <a href="https://www.health.nsw.gov.au/Infectious/factsheets/Pages/japanese_encephalitis.aspx">Japanese encephalitis</a> virus. <a href="https://theconversation.com/japanese-encephalitis-virus-can-cause-deadly-brain-swelling-but-in-less-than-1-of-cases-178985">Encephalitis</a> means inflammation, or swelling, of the brain.</p>
<p>Only a small proportion of people infected, <a href="https://www.mja.com.au/journal/2012/196/5/murray-valley-encephalitis-review-clinical-features-diagnosis-and-treatment">perhaps as few as one in 1,000</a>, will develop symptoms. These include fever, headache and vomiting, as well as neurological problems resulting in confusion, dizziness, or loss of consciousness.</p>
<p>The disease, like that caused by Japanese encephalitis virus, is fatal in <a href="https://www.mja.com.au/journal/2012/196/5/murray-valley-encephalitis-review-clinical-features-diagnosis-and-treatment">up to 30%</a> of those who get symptoms. </p>
<p>People who survive may have permanent neurological complications that require life-long medical care. Only <a href="https://www.mja.com.au/journal/2012/196/5/murray-valley-encephalitis-review-clinical-features-diagnosis-and-treatment">around 40%</a> of those experiencing severe symptoms recover completely.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-wet-spring-and-summer-means-more-mosquitoes-but-now-weve-got-japanese-encephalitis-virus-to-worry-about-too-191510">A wet spring and summer means more mosquitoes but now we've got Japanese encephalitis virus to worry about too</a>
</strong>
</em>
</p>
<hr>
<h2>How does it spread?</h2>
<p>Waterbirds such as herons and egrets are the <a href="https://www.liebertpub.com/doi/abs/10.1089/vbz.2008.0040">natural hosts</a> of the virus. Mosquitoes pick up the virus as they feed on the blood of birds, and then pass it on to people when the mosquitoes bite again.</p>
<p>The key mosquito <a href="https://onlinelibrary.wiley.com/doi/abs/10.1038/icb.1984.61">driving spread of the virus</a> is <em>Culex annulirostris</em>. It thrives in freshwater habitats and <a href="https://europepmc.org/article/med/1474387">travels many kilometres</a> from local wetlands.</p>
<p>The virus circulates between mosquitoes and waterbirds during the wet season in <a href="https://www.healthywa.wa.gov.au/Articles/J_M/Murray-Valley-encephalitis-and-Kunjin-viruses">northern Australia</a>, particularly in the <a href="https://pubmed.ncbi.nlm.nih.gov/14628944/">Kimberley region</a>. </p>
<p>After flooding, the virus makes its way into southeastern Australia from northern regions of the country. <a href="https://www.dcceew.gov.au/water/cewo/media-release/waterbird-resurgence-murray-darling-basin">Waterbirds travel to newly flooded areas</a> for favourable feeding and breeding conditions. </p>
<p>With flooding continuing in southeastern Australia, as well as <a href="https://www.abc.net.au/news/2023-01-14/bom-warning-forecast-weather-flooding-rainfall-north-central-qld/101855568">Queensland</a> and <a href="https://theconversation.com/disastrous-floods-in-wa-why-were-we-not-prepared-197407">Western Australia</a>, mosquito numbers are expected to remain high in many regions of Australia for months ahead. More mosquitoes and more waterbirds increase the likelihood of infection in people.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/504686/original/file-20230116-20-ma9aul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/504686/original/file-20230116-20-ma9aul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504686/original/file-20230116-20-ma9aul.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504686/original/file-20230116-20-ma9aul.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504686/original/file-20230116-20-ma9aul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504686/original/file-20230116-20-ma9aul.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504686/original/file-20230116-20-ma9aul.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 Nankeen Night Heron is a host of Murray Valley encephalitis virus.</span>
<span class="attribution"><span class="source">Paul Balfe/Flickr</span></span>
</figcaption>
</figure>
<h2>What happened in past outbreaks?</h2>
<p>The virus was first isolated in 1951 from patients who died from encephalitis in the Murray Valley. The outbreak included <a href="https://link.springer.com/article/10.1007/BF01321074">45 reported cases, including 19 deaths</a>.</p>
<p>But that wasn’t the first or last outbreak. There is evidence the virus was causing human disease in the early 1900s and at the time was known as “<a href="https://www.sciencedirect.com/science/article/pii/037811359500074K">Australian X disease</a>”.</p>
<p>The most significant outbreak occurred in 1974 with <a href="https://link.springer.com/article/10.1007/BF01321074">58 cases reported including 13 fatalities</a>. Seasonal agricultural workers became <a href="https://trove.nla.gov.au/newspaper/article/110760785?searchTerm=Murray%20valley%20encephalitis%20virus">reluctant to travel</a> to the regions impacted by the virus.</p>
<p>The virus didn’t disappear after 1974. It has been sporadically detected in humans, mosquitoes, or other animals, most commonly in <a href="https://academic.oup.com/trstmh/article/111/6/248/4554990#113640420">northern</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/11950201/">central</a> Australia.</p>
<p>The largest outbreak since 1974 in southeastern Australia was in 2011, with a total of <a href="https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0002656">17 cases reported including three deaths</a>. </p>
<p>The major trigger for previous outbreaks has always been above average rainfall.</p>
<h2>What can we do about it?</h2>
<p><a href="https://www.health.nsw.gov.au/infectious/jev/pages/vaccination.aspx">Unlike Japanese encephalitis</a>, there is no vaccine for Murray Valley encephalitis. </p>
<p>Preventing mosquito bites is critical to stop infection. The <a href="https://theconversation.com/mozzies-biting-heres-how-to-choose-a-repellent-and-how-to-use-it-for-the-best-protection-150183">steps you take to stop mosquito bites</a> every other summer will reduce the spread of Murray Valley encephalitis virus too.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/mozzies-biting-heres-how-to-choose-a-repellent-and-how-to-use-it-for-the-best-protection-150183">Mozzies biting? Here's how to choose a repellent (and how to use it for the best protection)</a>
</strong>
</em>
</p>
<hr>
<p>Those spending lots of time outdoors face the greatest risk. To <a href="https://www.health.nsw.gov.au/Infectious/mosquito-borne/Pages/bite-prevention.aspx">reduce mosquito bites</a>:</p>
<ul>
<li><p>avoid outdoor activity at dusk and during evening near wetlands or bushland areas where mosquitoes are active</p></li>
<li><p>cover up with light coloured, loose-fitting, long-sleeved shirts with long pants and covered shoes</p></li>
<li><p>use topical insect repellents containing diethytoluamide, picaridin, or oil of lemon eucalyptus. These formulations will provide the longest-lasting protection against mosquito bites if applied to all exposed areas of skin</p></li>
<li><p>use insect screens and nets around the home on windows and doors, and while camping</p></li>
<li><p>use “knockdown” insect sprays and plug-in repellent devices indoors or in sheltered outdoor areas.</p></li>
</ul>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/hSag2Nx4DHs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">You can reduce your risk of Murray Valley encephalitis in the same way you’d protect yourself from other diseases spread by mosquitoes.</span></figcaption>
</figure>
<p>The risk of Murray Valley encephalitis virus will remain for months ahead. It’s not until the colder weather of autumn arrives that mosquito populations will decline and with them the risks of disease.</p>
<p>Perhaps the <a href="https://www.theguardian.com/australia-news/2023/jan/04/australia-could-swing-from-three-years-of-la-nina-to-hot-and-dry-el-nino-in-2023">return of El Niño dominated weather patterns</a> in coming years, with less rainfall and fewer favourable breeding spots for mosquitoes and waterbirds, the virus will disappear from southeastern Australia. But for how long?</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/feel-like-youre-a-mozzie-magnet-its-true-mosquitoes-prefer-to-bite-some-people-over-others-128788">Feel like you're a mozzie magnet? It's true – mosquitoes prefer to bite some people over others</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/197894/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p>Murray Valley encephalitis has been detected in south-eastern Australia. No human cases have yet been reported, but past outbreaks after floods show we need to be cautious.Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1915102022-10-06T19:04:24Z2022-10-06T19:04:24ZA wet spring and summer means more mosquitoes but now we’ve got Japanese encephalitis virus to worry about too<figure><img src="https://images.theconversation.com/files/487660/original/file-20221003-3041-m8qey8.jpg?ixlib=rb-1.1.0&rect=1617%2C432%2C2154%2C1757&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/XgNJasHTQH0">Kevin LEE/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Mosquitoes are a problem every summer. But the recent arrival of the mosquito-borne Japanese encephalitis virus in eastern Australia brings more significant concerns. </p>
<p>There are <a href="https://www.publish.csiro.au/book/6391/">hundreds of different mosquito species</a> in Australia but only a dozen or so pose a public health threat. Activity of these mosquitoes shifts from season to season with differences in rainfall and temperature. </p>
<p>A changing climate and extreme wet weather events can boost mosquito numbers and <a href="https://www.phrp.com.au/issues/december-2020-volume-30-issue-4/bushfires-covid-19-and-mosquito-borne-disease/">bring additional threats</a>. </p>
<p>So how can we reduce the risk of contracting diseases that spread via mosquitoes, including Japanese encephalitis?</p>
<h2>First, some mozzie basics</h2>
<p>Mosquitoes need stagnant water to complete their life cycle. Immature mosquitoes hatch from eggs and complete their development underwater until they turn into pupae, before emerging as adult mosquitoes. </p>
<p>Female mosquitoes need blood before laying eggs. They seek blood from a wide range of animals and, as well as sucking up blood, they can also pick up a virus. That virus can then be passed on to another animal, or person, when they need another hit of blood.</p>
<p>Mozzies make you sick by <a href="https://theconversation.com/curious-kids-when-we-get-bitten-by-a-mosquito-why-does-it-itch-so-much-93347">injecting a cocktail</a> of saliva and virus when they bite. The “mozzie spit” may leave you with an itching red lump as well as a dose of a potentially deadly disease.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/5-virus-families-that-could-cause-the-next-pandemic-according-to-the-experts-189622">5 virus families that could cause the next pandemic, according to the experts</a>
</strong>
</em>
</p>
<hr>
<h2>What diseases can mosquitoes transmit?</h2>
<p>Australia has always battled with mosquito-borne diseases. Ross River virus infects <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1005070">thousands of people every year</a>. Extreme weather events appear to be <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/1753-6405.13283">increasing the number of cases</a> around our cities and growing coastal communities.</p>
<p>Murray Valley encephalitis virus is <a href="https://theconversation.com/explainer-what-is-murray-valley-encephalitis-virus-112212">incredibly rare</a> but can be fatal. Significant outbreaks have been <a href="https://onlinelibrary.wiley.com/doi/10.5694/mja11.11026">closely associated with flooding</a> throughout the Murray-Darling Basin region.</p>
<p>Mosquito-borne diseases pose a threat to more than just people. Horses can suffer severe symptoms following infection with <a href="https://www.sciencedirect.com/science/article/pii/S0737080620302343">Ross River virus</a> or <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/avj.12018">Kunjin virus</a>. </p>
<p>There are also concerns about <a href="https://www.dpi.nsw.gov.au/animals-and-livestock/beef-cattle/health-and-disease/viral-diseases/bovine-ephemeral-fever">Bovine ephemeral fever</a> and <a href="https://animalhealthaustralia.com.au/lumpy-skin-disease/">lumpy skin disease</a> in cattle. </p>
<p>Even in our backyard, our dogs can be affected by <a href="https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-016-1821-x">parasites spread by mosquito bites</a>.</p>
<figure class="align-center ">
<img alt="Dog holds ball in its mouth" src="https://images.theconversation.com/files/488224/original/file-20221005-22-a6z6ag.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/488224/original/file-20221005-22-a6z6ag.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=394&fit=crop&dpr=1 600w, https://images.theconversation.com/files/488224/original/file-20221005-22-a6z6ag.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=394&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/488224/original/file-20221005-22-a6z6ag.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=394&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/488224/original/file-20221005-22-a6z6ag.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=495&fit=crop&dpr=1 754w, https://images.theconversation.com/files/488224/original/file-20221005-22-a6z6ag.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=495&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/488224/original/file-20221005-22-a6z6ag.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">
<figcaption>
<span class="caption">Dogs can also get sick from mosquito bites.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/GFFoVUqcO4k">Tadeusz Lakota/AAP</a></span>
</figcaption>
</figure>
<h2>What about Japanese encephalitis virus?</h2>
<p>The discovery of mosquito-borne <a href="https://theconversation.com/japanese-encephalitis-virus-has-been-detected-in-australian-pigs-can-mozzies-now-spread-it-to-humans-178017">Japanese encephalitis virus last summer</a> changed the landscape of mosquito-borne disease in Australia.</p>
<p>The <a href="https://www.health.nsw.gov.au/Infectious/factsheets/Pages/japanese_encephalitis.aspx">illness</a> can be mild, with common symptoms of fever, joint pain and a rash. In severe cases people also experience headache, neck stiffness, confusion, seizures, and sometimes coma and death. Fewer than 1% of those infected will develop a <a href="https://theconversation.com/japanese-encephalitis-virus-can-cause-deadly-brain-swelling-but-in-less-than-1-of-cases-178985">severe brain infection</a>, encephalitis, which may be fatal. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/japanese-encephalitis-virus-has-been-detected-in-australian-pigs-can-mozzies-now-spread-it-to-humans-178017">Japanese encephalitis virus has been detected in Australian pigs. Can mozzies now spread it to humans?</a>
</strong>
</em>
</p>
<hr>
<p>Japanese encephalitis virus is a significant health concern across <a href="https://www.who.int/news-room/fact-sheets/detail/japanese-encephalitis">Southeast Asia and the Western Pacific</a>. The virus circulates between <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/tbed.14656">mosquitoes and waterbirds</a> but <a href="https://academic.oup.com/ije/advance-article/doi/10.1093/ije/dyac050/6556297">pigs can be hosts</a> too.</p>
<p>The virus was first detected in <a href="https://animalhealthaustralia.com.au/japanese-encephalitis-outbreak/">commercial piggeries where reproductive losses had been observed</a> and Australia declared it a “communicable disease incident of national significance” in March. </p>
<p>The virus has been detected in humans, pigs (both in commercial piggeries and feral populations) and mosquitoes across South Australia, Victoria, New South Wales, Queensland and Northern Territory. There have been <a href="https://www.health.gov.au/health-alerts/japanese-encephalitis-virus-jev/about">40 cases of human disease</a>, including six deaths. </p>
<p>A <a href="https://www.abc.net.au/news/2022-09-14/japanese-encephalitis-vaccines-expanded-nsw-health-study/101440020">recent study</a> of five regional communities in southern NSW suggests almost 9% of the human population had been exposed to the virus last summer.</p>
<h2>What might happen this summer?</h2>
<p>We’re expecting another wet summer thanks to a <a href="http://www.bom.gov.au/climate/enso/outlook/">third consecutive season influenced by La Niña</a>. Flooding has <a href="https://www.abc.net.au/news/2022-10-03/flooded-inland-nsw-preparing-for-more-rain/101496958">already started</a>.</p>
<p>More rain doesn’t just mean more mosquitoes: it means better conditions for waterbird breeding too. More water, more birds, and more mosquitoes sets the scene for potentially more activity of Japanese encephalitis and other mosquito-borne diseases. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/la-nina-will-give-us-a-wet-summer-thats-great-weather-for-mozzies-147180">La Niña will give us a wet summer. That's great weather for mozzies</a>
</strong>
</em>
</p>
<hr>
<p>The mosquito species of greatest concern is <em>Culex annulirostris</em>. This mosquito is the one most likely to be driving transmission of the virus among animals, as well as <a href="https://www.mdpi.com/1999-4915/14/6/1208">spillover to the human population</a>. </p>
<p>This species is closely associated with freshwater habitats. With extensive flooding across many regions, there will be plenty of suitable habitat available throughout the coming summer.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/487668/original/file-20221003-3041-5kbchw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/487668/original/file-20221003-3041-5kbchw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/487668/original/file-20221003-3041-5kbchw.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/487668/original/file-20221003-3041-5kbchw.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/487668/original/file-20221003-3041-5kbchw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/487668/original/file-20221003-3041-5kbchw.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/487668/original/file-20221003-3041-5kbchw.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">Mosquitoes belonging to the genus Culex are thought to play the most important role in Japanese encephalitis virus transmission.</span>
<span class="attribution"><span class="source">Cameron Webb/NSW Health Pathology</span></span>
</figcaption>
</figure>
<h2>So how can we reduce the risk?</h2>
<p>While authorities are investigating ways to control mosquito populations such as spraying insecticides <a href="https://www.farmbiosecurity.com.au/livestock/pigs/controlling-mosquitoes-around-piggeries/">especially around piggeries</a> and other high-risk locations, insecticides alone won’t eliminate the risk of Japanese encephalitis virus this season. Other strategies are required.</p>
<p>A <a href="https://www.health.gov.au/health-alerts/japanese-encephalitis-virus-jev/vaccines">safe and effective vaccine is available</a> and authorities are developing strategies to ensure “at risk” communities and individuals have <a href="https://www.health.nsw.gov.au/news/Pages/20220914_01.aspx">access to it</a>. </p>
<p>But there simply isn’t enough vaccine available globally to vaccinate everyone at risk in Australia.</p>
<p>Surveillance will provide an early warning of elevated risks. Authorities will <a href="https://www.health.gov.au/ministers/the-hon-greg-hunt-mp/media/69-million-for-japanese-encephalitis-virus-jev-response">track and test</a> mosquito populations for the presence of virus, as will various networks of animal surveillance. If detected, authorities can strategically respond through enhanced surveillance, control, or education programs.</p>
<p>Many of the <a href="https://theconversation.com/insect-repellents-work-but-there-are-other-ways-to-beat-mosquitoes-without-getting-sticky-171805">ways we reduce mosquito bites during summer months</a> to allow us to enjoy time outdoors, whether it is in the backyard of bush, will also protect against the mosquitoes carrying these viruses.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-mozzie-proof-your-property-after-a-flood-and-cut-your-risk-of-mosquito-borne-disease-178299">How to mozzie-proof your property after a flood and cut your risk of mosquito-borne disease</a>
</strong>
</em>
</p>
<hr>
<p>Covering up with loose fitting long sleeves, long pants, and covered shoes will create a barrier to mosquito bites. </p>
<p>Applying topical insect repellents, especially formulations containing diethyltoluamide, picaridin, or oil of lemon eucalyptus, will provide <a href="https://www.phrp.com.au/issues/december-2016-volume-26-issue-5/a-review-of-recommendations-on-the-safe-and-effective-use-of-topical-mosquito-repellents/">safe and effective</a> long-lasting protection against biting mosquitoes. </p>
<p>Preventing mosquito bites is the best way to protect yourself and your family from mosquito-borne diseases.</p><img src="https://counter.theconversation.com/content/191510/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p>Mozzies can make you sick by injecting a cocktail of saliva and virus when they bite. Ross River virus has long been a risk but now we’re also contending with the more serious Japanese encephalitis.Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1843082022-06-07T20:03:18Z2022-06-07T20:03:18ZThis mosquito species from Papua New Guinea was lost for 90 years – until a photographer snapped a picture of it in Australia<figure><img src="https://images.theconversation.com/files/467098/original/file-20220606-14-nd13n.JPG?ixlib=rb-1.1.0&rect=0%2C698%2C4943%2C2747&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Tracking mosquitoes in our backyards, such as Aedes notoscriptus, helps authorities work out future health risks.</span> <span class="attribution"><span class="source">Cameron Webb (NSW Health Pathology)</span>, <span class="license">Author provided</span></span></figcaption></figure><p>There are already plenty of mosquitoes in Australia. They bring pest and public health risks to many parts of the country. </p>
<p>Now a new species of mosquito, <em>Aedes shehzadae</em>, has been discovered 90 years after the first (and only other observation) of it in Papua New Guinea – and it’s thanks to citizen science.</p>
<h2>Mosquitoes and their health threats</h2>
<p>Mosquitoes are simple creatures, but they pose complex health risks. The recent widespread arrival of Japanese encephalitis virus, which caused dozens of cases of <a href="https://www.health.gov.au/health-alerts/japanese-encephalitis-virus-jev/about">disease</a> and five deaths, is a reminder of the threat mosquitoes pose in Australia. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/japanese-encephalitis-virus-has-been-detected-in-australian-pigs-can-mozzies-now-spread-it-to-humans-178017">Japanese encephalitis virus has been detected in Australian pigs. Can mozzies now spread it to humans?</a>
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<p>To address this threat, there are mosquito and mosquito-borne pathogen <a href="https://theconversation.com/the-worst-year-for-mosquitoes-ever-heres-how-we-find-out-68433">surveillance programs</a> in states and territories around the country. Our borders are checked by the <a href="https://www.awe.gov.au/biosecurity-trade/import/arrival/pests">Department of Agriculture Water and Environment</a> for the arrival of invasive mosquitoes with international travellers, their belongings, or freight. </p>
<p>These programs collect valuable information on local and invasive mosquitoes. But they can’t be everywhere – which is where <a href="https://www.nature.com/articles/s41467-017-00914-9">citizen science</a> can step in.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/467095/original/file-20220606-24-tpqupv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/467095/original/file-20220606-24-tpqupv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/467095/original/file-20220606-24-tpqupv.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/467095/original/file-20220606-24-tpqupv.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/467095/original/file-20220606-24-tpqupv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/467095/original/file-20220606-24-tpqupv.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/467095/original/file-20220606-24-tpqupv.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">Water-filled potted plant saucers and other containers in the backyard can be a perfect place to find mosquitoes.</span>
<span class="attribution"><span class="source">Cameron Webb (NSW Health Pathology/University of Sydney)</span></span>
</figcaption>
</figure>
<p>We can learn more about mosquitoes, and their spread across the country, with the help of volunteer “<a href="https://citizenscience.org.au/">citizen scientists</a>”.
Individuals or groups can participate in projects such as <a href="https://metrosouth.health.qld.gov.au/zika-mozzie-seeker">Zika Mozzie Seeker</a> or <a href="https://mozziemonitors.com/">Mozzie Monitors</a>. Mozzie Monitors has expanded in recent years to become the only national program, primarily focused around the annual <a href="https://www.unisa.edu.au/media-centre/Releases/2022/mozzie-monitors-kicks-off-monster-mosquito-season/">Mozzie Month</a>. </p>
<p>Citizen scientists can also upload photographs of mosquitoes to online platforms such as <a href="https://www.inaturalist.org/">iNaturalist</a>, which provides opportunities to observe the insects in nature. An analysis of more than 2,000 mosquito observations <a href="https://www.mdpi.com/1660-4601/19/10/6337/htm">uploaded to iNaturalist</a> revealed an astonishing 57 species observed across Australia. </p>
<p>And one of the most remarkable observations uploaded to iNaturalist in recent years has been a mysterious and distinctive mosquito, <em>Aedes shehzadae</em>. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-naming-all-our-mozzies-is-important-for-fighting-disease-92379">Why naming all our mozzies is important for fighting disease</a>
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</em>
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<h2>A discovery 90 years in the making</h2>
<p><em>Aedes shehzadae</em> was first captured in Australia by photographer John Lenagan in 2021, while on the lookout for moths in the Kutini-Payamu National Park (Iron Range) in Queensland’s Cape York. </p>
<p>The photo kicked off a cascade of investigations into mosquito collections held in research institutes and museums across Australia. They even stretched as far as the Natural History Museum in London.</p>
<p>We and our colleagues have detailed the circumstances around this unique discovery in this month’s edition of the <a href="https://bioone.org/journals/journal-of-vector-ecology/volume-47/issue-1/1081-1710-47.1.133/First-record-of-the-mosquito-Aedes-Downsiomyia-shehzadae-Diptera/10.52707/1081-1710-47.1.133.short">Journal of Vector Ecology</a>.</p>
<p>Lenagan’s photo wasn’t just the first time <em>Aedes shehzadae</em> was observed in Australia – it was also only the second time this mosquito had ever been formally recorded. The discovery may have gone unnoticed, had the photograph not been uploaded to <a href="https://www.inaturalist.org/taxa/1360797-Aedes-shehzadae">iNaturalist</a> and sparked interest.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/467387/original/file-20220607-14-wv15lw.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up shot of a mosquito." src="https://images.theconversation.com/files/467387/original/file-20220607-14-wv15lw.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/467387/original/file-20220607-14-wv15lw.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=539&fit=crop&dpr=1 600w, https://images.theconversation.com/files/467387/original/file-20220607-14-wv15lw.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=539&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/467387/original/file-20220607-14-wv15lw.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=539&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/467387/original/file-20220607-14-wv15lw.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=678&fit=crop&dpr=1 754w, https://images.theconversation.com/files/467387/original/file-20220607-14-wv15lw.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=678&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/467387/original/file-20220607-14-wv15lw.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=678&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 first time a live specimen of <em>Aedes shehzadae</em> was observed in Australia, about 90 years after first being collected in the mountains of Papua New Guinea.</span>
<span class="attribution"><span class="source">John Lenagan/iNaturalist</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The only other specimen of this mosquito was collected in Papua New Guinea in 1934, almost 90 years ago. It was collected by a remarkable unpaid entomologist named <a href="https://www.nhm.ac.uk/discover/lucy-evelyn-cheesman.html">Lucy Evelyn Cheesman</a>, and stored in the Natural History Museum, until being <a href="https://apps.dtic.mil/sti/pdfs/ADA117969.pdf">formally described</a> in 1972 by the Malaria Institute of Pakistan entomologist M. Qutubiddin (first name unconfirmed). He named the mosquito after his daughter. </p>
<p><a href="https://womenyoushouldknow.net/lucy-evelyn-cheesman-entomologist/">Cheesman</a> was a tenacious naturalist who collected around 70,000 specimens of insects, plants, and other animals for the Natural History Museum – many during expeditions to the South West Pacific.</p>
<p>We don’t know much about <em>Aedes shehzadae</em>. We’re not even sure whether it’s a new arrival in Australia, or if it had simply not been observed before. In all likelihood it won’t pose a significant threat to our backyards. </p>
<p>But that can’t be said for other exotic and invasive mosquitoes knocking on our door. Mosquitoes such as <em>Aedes albopictus</em>, or the “tiger mosquito”, could be <a href="https://theconversation.com/new-mosquito-threats-shift-risks-from-our-swamps-to-our-suburbs-56350">a game-changer</a> for mosquito-borne disease in Australia.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/stowaway-mozzies-enter-australia-from-asian-holiday-spots-and-theyre-resistant-to-insecticides-113999">Stowaway mozzies enter Australia from Asian holiday spots – and they're resistant to insecticides</a>
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<h2>Community assistance</h2>
<p>Much has been said about the potential for citizen science to help health authorities identify exotic and invasive mosquitoes. This <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.13767">has been the case in Europe</a>. And these programs may well be <a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969719353410?via%3Dihub">instrumental</a> in tracking newly arrived mosquitoes that have hitched a ride with travellers or freight to the backyards and bushland of Australia.</p>
<p>We’re used to female mosquitoes biting us <a href="https://theconversation.com/feel-like-youre-a-mozzie-magnet-its-true-mosquitoes-prefer-to-bite-some-people-over-others-128788">for blood</a>, but we’re less aware of the flowers they visit to help pollination. We also don’t know a lot about the animals that eat mosquitoes, so perhaps some photographs of them caught in spider webs would be useful too.</p>
<p>There’s no doubt participants in citizen science projects can contribute to our understanding of native and invasive species distribution in meaningful ways. If <em>Aedes shehzadae</em> is anything to go by, anyone with a camera and some curiosity can be the discoverer of a new species, or new mosquito arrival.</p><img src="https://counter.theconversation.com/content/184308/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p><p class="fine-print"><em><span>Craig Williams receives funding from the NH&MRC through the HEAL (Healthy Environments and Lives) project, and is a member of the National Arbovirus and Malaria Advisory Committee for the Commonwealth Department of Health. </span></em></p><p class="fine-print"><em><span>Larissa Braz Sousa works for University of South Australia. She received funding from the Australian Technology Network (ATN-LATAM) Research Scholarship during her PhD research. She is also a co-founder of the not-for-profit Ferox australis.
</span></em></p><p class="fine-print"><em><span>Marlene Walter receives a scholarship funded by Melbourne Water.</span></em></p>Tracking mosquitoes is essential to understanding their pest and public health risks. You can help too – here’s how.Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of SydneyCraig Williams, Professor and Dean of Programs (Pharmacy and Biomedical Sciences), University of South AustraliaLarissa Braz Sousa, PhD candidate on citizen science and public health, University of South AustraliaMarlene Walter, Masters of Research Student, Walter and Eliza Hall InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1780172022-03-01T01:43:46Z2022-03-01T01:43:46ZJapanese encephalitis virus has been detected in Australian pigs. Can mozzies now spread it to humans?<figure><img src="https://images.theconversation.com/files/448916/original/file-20220228-25-1k030kd.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5431%2C3604&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/b-zyMn_e_R4?utm_source=unsplash&utm_medium=referral&utm_content=creditShareLink">Pascal Debrunner/Unsplash</a></span></figcaption></figure><p>With our summer dominated by wet weather and booming mosquito populations, health authorities have been alert to the threat of mosquito-borne disease.</p>
<p>One such disease is Japanese encephalitis virus, which has been detected for the first time in southeastern Australia. It has been found in pigs at pig farms in <a href="https://www.abc.net.au/news/2022-02-28/warning-about-mosquito-borne-viruses-in-sa-after-death/100866726">Victoria, New South Wales and Queensland</a>, indicating the virus is likely circulating in the local mosquito populations, which could infect humans. </p>
<p>Ongoing <a href="https://theconversation.com/like-rivers-in-the-sky-the-weather-system-bringing-floods-to-queensland-will-become-more-likely-under-climate-change-176711">rain and flooding</a> ensures suitable conditions for mosquitoes will persist well into Autumn.</p>
<h2>What is Japanese encephalitis virus?</h2>
<p>Japanese encephalitis virus is part of the flavivirus family, closely related to West Nile, Zika, Murray Valley encephalitis, dengue and yellow fever. </p>
<p>An estimated <a href="https://www.who.int/news-room/fact-sheets/detail/japanese-encephalitis">68,000 cases of encephalitis</a> occur annually across Southeast Asia and Western Pacific regions.</p>
<p>The virus is maintained in a cycle between mosquitoes and waterbirds. Pigs are also an important host, especially where pigs, mosquitoes, waterbirds, and water bodies all occur together.</p>
<p>Outbreaks are more likely to occur during the wet season.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/la-nina-will-give-us-a-wet-summer-thats-great-weather-for-mozzies-147180">La Niña will give us a wet summer. That's great weather for mozzies</a>
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<h2>How serious is Japanese encephalitis?</h2>
<p>Most infected people have mild illness or no symptoms at all. Symptoms of fever, joint pain, and rash are common but severe cases also experience headache, neck stiffness, confusion, seizures, and sometimes coma and death. </p>
<p><a href="https://www.mdpi.com/2414-6366/4/1/38/htm">Less than 1%</a> of those infected will develop a severe brain infection, encephalitis, which may be fatal. </p>
<p>The disease is particularly problematic in children, with survivors often left with significant brain injuries.</p>
<p>To confirm infection, cerebrospinal fluid (that surrounds the brain and spinal cord) and blood are tested by specialised public health laboratory.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/448918/original/file-20220228-19-a4dvsm.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/448918/original/file-20220228-19-a4dvsm.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/448918/original/file-20220228-19-a4dvsm.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/448918/original/file-20220228-19-a4dvsm.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/448918/original/file-20220228-19-a4dvsm.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/448918/original/file-20220228-19-a4dvsm.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/448918/original/file-20220228-19-a4dvsm.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">Culex annulirostris is the most likely mosquito to be transmitting Japanese encephalitis virus in Australia and is widespread and abundant after flooding.</span>
<span class="attribution"><span class="source">Cameron Webb/NSW Health Pathology</span></span>
</figcaption>
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<h2>Why has Japanese encephalitis virus appeared in Australia?</h2>
<p>Outbreaks of Japanese encephalitis virus have occurred in countries neighbouring Australia’s north, including Papua New Guinea and <a href="https://www.news.com.au/travel/travel-updates/warnings/australians-warned-about-travelling-to-bali-amid-spike-in-japanese-encephalitis-cases/news-story/e255ca32f524bcbdae9d1ee1f7e3a429">Indonesia</a>.</p>
<p><a href="https://www.mdpi.com/2414-6366/4/1/38/htm">Concern has often been raised</a> about the potential introduction and spread of the virus onto the Australian mainland, given the high populations of mosquitoes, wild pigs and waterbirds in the north. </p>
<p>During outbreaks of Japanese encephalitis virus in <a href="https://onlinelibrary.wiley.com/doi/abs/10.5694/j.1326-5377.1996.tb124960.x">Torres Strait during the 1990s</a>, the <a href="https://www1.health.gov.au/internet/main/publishing.nsf/Content/cda-pubs-cdi-1998-cdi2205-cdi2205d.htm">virus even spread to the Cape York Peninsula</a>. But the virus didn’t take hold and the last definitive evidence of activity on the mainland <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6473502/">was in 2004</a>.</p>
<p>Now the virus is back. A new incursion occurred in early 2021, <a href="https://nt.gov.au/wellbeing/health-conditions-treatments/viral/japanese-encephalitis">when a human case was diagnosed in the Northern Territory</a>. </p>
<p>Now there is evidence of Japanese encephalitis virus in pigs in multiple pig farms in New South Wales, Victoria and Queensland. And there is a risk of transmission to humans. </p>
<h2>How did the virus make its way south?</h2>
<p>Investigations are underway to work out how much virus is in the region and assess the ongoing risk to human and animal health. But we will never definitively know how (or when) the virus managed to move south.</p>
<p>It could be linked to overlapping transmission cycles fuelled by favourable weather conditions that bring water to flood plains, wetlands, and other habitats shared by mosquitoes and waterbirds. Or it could be due to migration of infected birds or mosquitoes. </p>
<p>There is little doubt the La Nina-dominated weather patterns that impacted southeastern Australia over the <a href="https://theconversation.com/back-so-soon-la-nina-heres-why-were-copping-two-soggy-summers-in-a-row-173684">past two years</a> played a role.</p>
<p>The spread of mosquito-borne viruses, such as <a href="https://theconversation.com/explainer-what-is-murray-valley-encephalitis-virus-112212">Murray Valley encephalitis virus</a>, from northern Australia to southeastern Australia has been documented before. We just never expected Japanese encephalitis virus to take this pathway too.</p>
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<img alt="" src="https://images.theconversation.com/files/448913/original/file-20220228-3997-a97p0c.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/448913/original/file-20220228-3997-a97p0c.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/448913/original/file-20220228-3997-a97p0c.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/448913/original/file-20220228-3997-a97p0c.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/448913/original/file-20220228-3997-a97p0c.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/448913/original/file-20220228-3997-a97p0c.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/448913/original/file-20220228-3997-a97p0c.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">La Nina has brought above average rainfall to much of Australia and flooding has provided ideal conditions for local mosquitoes.</span>
<span class="attribution"><span class="source">Cameron Webb/NSW Health Pathology</span></span>
</figcaption>
</figure>
<h2>How can you avoid catching Japanese encephalitis virus?</h2>
<p>A <a href="https://immunisationhandbook.health.gov.au/vaccine-preventable-diseases/japanese-encephalitis">vaccine is available to protect against Japanese encephalitis virus</a>. This has been demonstrated as an effective way to prevent disease outbreaks. </p>
<p>Some Australians have been vaccinated but it <a href="https://theconversation.com/what-is-japanese-encephalitis-virus-and-how-can-i-avoid-it-when-i-travel-106775">hasn’t been a routine part of international travel</a>, even to <a href="https://www.abc.net.au/news/2017-06-21/australian-man-dies-after-returning-from-thailand/8639620">countries where the risk is high</a>.</p>
<p>Consideration could be given to vaccinating at-risk groups in Australia.</p>
<p>Reducing further transmission of the virus to people will rely on the use of insecticides around high-risk locations, such as piggeries where infections have been identified, and the use of personal protection measures against mosquito bites.</p>
<p>Fortunately, the steps we routinely take to avoid mosquitoes bites during the Australian summer will work just as well against the mosquitoes likely to be carrying the virus. People just need to be more vigilant to protect themselves and family against mosquito bites. </p>
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<strong>
Read more:
<a href="https://theconversation.com/mozzies-biting-heres-how-to-choose-a-repellent-and-how-to-use-it-for-the-best-protection-150183">Mozzies biting? Here's how to choose a repellent (and how to use it for the best protection)</a>
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<p>Health authorities are recommending a number of steps to avoid mosquito bites. Minimimse time outdoors when mosquitoes are most active, especially dawn and dusk. Wear a long sleeved shirt, long pants and covered shoes. Apply a topical insect repellent containing Diethyltolumide, picaridin, or oil of lemon eucalyptus. </p>
<p>The weather has clearly contributed to this outbreak but it may also assist ending it. The onset of cooler weather in autumn will slow mosquito population growth and once winter arrives, most of the mosquitoes across southern regions of Australia will disappear. At least for a few months.</p><img src="https://counter.theconversation.com/content/178017/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p><p class="fine-print"><em><span>Andrew van den Hurk has received funding from local, state and federal agencies to study the ecology of mosquito-borne pathogens, and their surveillance and control. He is an employee of the Department of Health, Queensland Government.</span></em></p><p class="fine-print"><em><span>Dominic Dwyer 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 mosquito-borne Japanese encephalitis virus has been detected for the first time in southeastern Australia, in pigs at a pig farm. So what threat does it pose to human health?Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of SydneyAndrew van den Hurk, Medical Entomologist, The University of QueenslandDominic Dwyer, Director of Public Health Pathology, NSW Health Pathology, Westmead Hospital and University of Sydney, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1397102020-06-03T12:16:09Z2020-06-03T12:16:09ZGenetically modified mosquitoes could be released in Florida and Texas beginning this summer – silver bullet or jumping the gun?<figure><img src="https://images.theconversation.com/files/338916/original/file-20200601-95032-uv3cee.jpg?ixlib=rb-1.1.0&rect=18%2C37%2C4078%2C2480&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">In 2018 scientists of the Miami-Dade County Mosquito Control tested a new way to suppress mosquito populations carrying the Zika virus. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/dr-bill-petrie-director-of-miami-dade-county-mosquito-news-photo/916186362?adppopup=true">RHONA WISE/AFP via Getty Images</a></span></figcaption></figure><p>This summer, for the first time, genetically modified mosquitoes could be released in the U.S. </p>
<p>On May 1, 2020, the company Oxitec received an <a href="https://content.govdelivery.com/accounts/USAEPAOPPT/bulletins/2896a76">experimental use permit</a> from the U.S. Environmental Protection Agency to release <a href="https://beta.regulations.gov/document/EPA-HQ-OPP-2019-0274-0353">millions of GM mosquitoes</a> (labeled by Oxitec as OX5034) every week over the next two years in Florida and Texas. Females of this mosquito species, <em>Aedes aegypti</em>, transmit dengue, chikungunya, yellow fever and Zika viruses. When these lab-bred GM males are released and mate with wild females, their female offspring die. Continual, large-scale releases of these OX5034 GM males should eventually cause the temporary collapse of a wild population. </p>
<p>However, as vector biologists, geneticists, policy experts and bioethicists, we are concerned that current government oversight and scientific evaluation of GM mosquitoes do not ensure their responsible deployment. </p>
<h2>Genetic engineering for disease control</h2>
<p>Coral reefs that can withstand rising sea temperatures, <a href="https://theconversation.com/new-genetically-engineered-american-chestnut-will-help-restore-the-decimated-iconic-tree-52191">American chestnut trees</a> that can survive blight and <a href="https://doi.org/10.1016/j.pt.2018.02.003">mosquitoes that can’t spread disease</a> are examples of how genetic engineering may transform the natural world. </p>
<p>Genetic engineering offers an unprecedented opportunity for humans to reshape the fundamental structure of the biological world. Yet, as new advances in <a href="https://doi.org/10.1038/s41586-018-0692-z">genetic decoding</a> and <a href="https://doi.org/10.1073/pnas.1805874115">gene editing</a> emerge with speed and enthusiasm, the ecological systems they could alter remain enormously complex and understudied. </p>
<p>Recently, no group of organisms has received more attention for genetic modification than mosquitoes – to <a href="https://dx.doi.org/10.1371%2Fjournal.pntd.0003864">yield inviable offspring</a> or make them <a href="https://doi.org/10.1371/journal.ppat.1002458">unsuitable for disease transmission</a>. These strategies hold considerable potential benefits for the hundreds of millions of people impacted by <a href="https://www.who.int/neglected_diseases/vector_ecology/mosquito-borne-diseases/en/">mosquito-borne diseases</a> each year. </p>
<p>Although the EPA approved the permit for Oxitec, state approval is still required. A previously planned release in the Florida Keys of an earlier version of Oxitec’s GM mosquito (OX513) was <a href="https://www.wlrn.org/post/gmo-mosquito-application-withdrawn-another-way#stream/0">withdrawn in 2018</a> after <a href="https://www.wlrn.org/post/gmo-mosquito-application-withdrawn-another-way#stream/0">a referendum in 2016</a> indicated significant opposition from local residents. Oxitec has field-trialed their GM mosquitoes in <a href="https://doi.org/10.1080/23299460.2017.1326257">Brazil</a>, the Cayman Islands, Malaysia and Panama. </p>
<p>The <a href="https://beta.regulations.gov/document/EPA-HQ-OPP-2019-0274-0355">public forum</a> on Oxitec’s recent permit application garnered 31,174 comments opposing release and 56 in support. The EPA considered these during their review process. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/338910/original/file-20200601-95036-uhkqxr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/338910/original/file-20200601-95036-uhkqxr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/338910/original/file-20200601-95036-uhkqxr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/338910/original/file-20200601-95036-uhkqxr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/338910/original/file-20200601-95036-uhkqxr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/338910/original/file-20200601-95036-uhkqxr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/338910/original/file-20200601-95036-uhkqxr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/338910/original/file-20200601-95036-uhkqxr.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">In 2016, technicians from the Oxitec laboratory located in Campinas, Brazil, released genetically modified mosquitoes <em>Aedes egypti</em> to combat the Zika virus.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/biologist-works-with-genetically-modified-mosquitoes-on-news-photo/509588568?adppopup=true">Victor Moriyama / Getty Images</a></span>
</figcaption>
</figure>
<h2>Time to reassess risk assessment?</h2>
<p>However, it is difficult to <a href="https://beta.regulations.gov/document/EPA-HQ-OPP-2019-0274-0359">assess how EPA regulators</a> weighed and considered public comments and how much of the <a href="https://doi.org/10.1093/biosci/biz009">evidence used in final risk determinations</a> was provided solely by the technology developers. </p>
<p>The closed nature of this risk assessment process is concerning to us. </p>
<p>There is a potential bias and conflict of interest when experimental trials and assessments of ecological risk lack <a href="https://doi.org/10.1080/23299460.2017.1326257">political accountability</a> and are performed by, or in close collaboration with, the technology developers. </p>
<p>This scenario becomes more troubling with a <a href="https://www.biospace.com/article/releases/intrexon-scores-oxitec-in-160-million-stock-cash-deal-/">for-profit technology company</a> when cost- and risk-benefit analyses comparing GM mosquitoes to other approaches <a href="https://www.regulations.gov/docket?D=EPA-HQ-OPP-2019-0274">aren’t being conducted</a>. </p>
<p>Another concern is that <a href="https://apps.who.int/iris/handle/10665/271990">risk assessments</a> tend to focus on only a narrow set of biological parameters – such as the potential for the GM mosquito to transmit disease or the potential of the mosquitoes’ new proteins to trigger an allergic response in people – and neglect other important <a href="https://www.econexus.info/publication/release-gm-mosquito-aedes-aegypti-ox513a">biological</a>, <a href="https://dx.doi.org/10.1371%2Fjournal.pntd.0006501">ethical</a> and <a href="https://doi.org/10.1080/00139157.2017.1350011">social</a> considerations. </p>
<p>To address these shortcomings, the Institute for Sustainability, Energy and Environment at University of Illinois Urbana-Champaign convened a “<a href="https://sustainability.illinois.edu/outreach/critical-conversations/critical-conversation-spring-2019/">Critical Conversation</a>” on GM mosquitoes. The discussion involved 35 participants from academic, government and nonprofit organizations from around the world with expertise in mosquito biology, community engagement and risk assessment. </p>
<p>A primary takeaway from this conversation was an urgent need to make regulatory procedures more transparent, comprehensive and protected from biases and conflicts of interest. In short, we believe it is time to reassess risk assessment for GM mosquitoes. Here are some of the key elements we recommend.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/338919/original/file-20200601-95024-hn134f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/338919/original/file-20200601-95024-hn134f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/338919/original/file-20200601-95024-hn134f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/338919/original/file-20200601-95024-hn134f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/338919/original/file-20200601-95024-hn134f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/338919/original/file-20200601-95024-hn134f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/338919/original/file-20200601-95024-hn134f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/338919/original/file-20200601-95024-hn134f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The mosquito spray OFF! was handed out for free at the Zika Virus Town Hall Meeting at Waverly Condominiums in 2016.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/woman-looking-at-the-free-mosquito-spray-off-being-given-news-photo/917609734?adppopup=true">Jeffrey Greenberg/Universal Images Group via Getty Images</a></span>
</figcaption>
</figure>
<h2>Steps to make risk assessment more open and comprehensive</h2>
<p>First, an official, government-funded registry for GM organisms specifically designed to reproduce in the wild and intended for release in the U.S. would make risk assessments more transparent and accountable. Similar to the U.S. <a href="https://clinicaltrials.gov/">database that lists all human clinical trials</a>, this field trial registry would require all technology developers to disclose intentions to release, information on their GM strategy, scale and location of release and intentions for data collection.</p>
<p>This registry could be presented in a way that protects intellectual property rights, just as therapies entering clinical trials are patent-protected in their registry. The GM organism registry would be updated in real time and made fully available to the public. </p>
<p>Second, a broader set of risks needs to be assessed and an evidence base needs to be generated by third-party researchers. Because each GM mosquito is released into a unique environment, risk assessments and experiments prior to and during trial releases should address local effects on the ecosystem and food webs. They should also probe the disease transmission potential of the mosquito’s wild counterparts and <a href="https://doi.org/10.1560/IJEE.56.3-4.353">ecological competitors</a>, examine evolutionary pressures on disease agents in the mosquito community and <a href="https://doi.org/10.1126/science.aaz5392">track the gene flow</a> between GM and wild mosquitoes. </p>
<p>To identify and assess risks, a commitment of funding is necessary. The U.S. <a href="https://www.epa.gov/research-grants/assessment-tools-biotechnology-products">EPA’s recent announcement</a> that it would improve general risk assessment analysis for biotechnology products is a good start. But regulatory and funding support for an external advisory committee to review assessments for GM organisms released in the wild is also needed; <a href="https://doi.org/10.1126/science.aat4612">diverse expertise and local community representation</a> would secure a more fair and comprehensive assessment. </p>
<p>Furthermore, independent researchers and advisers could help guide what data are collected during trials to reduce uncertainty and inform future large-scale releases and risk assessments.</p>
<p>The objective to reduce or even eliminate mosquito-borne disease is laudable. GM mosquitoes could prove to be an important tool in alleviating global health burdens. However, to ensure their success, we believe that regulatory frameworks for open, comprehensive and participatory decision-making are urgently needed. </p>
<p><em>This article was updated to correct the date that Oxitec withdrew its OX513 trial application to 2018.</em></p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p><img src="https://counter.theconversation.com/content/139710/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brian Allan receives funding from the Institute for Sustainability, Energy and Environment. </span></em></p><p class="fine-print"><em><span>Jennifer Kuzma receives funding from the U.S. Department of Agriculture, Walton Family Foundation and National Science Foundation.. </span></em></p><p class="fine-print"><em><span>Natalie Kofler receives funding from the University of Illinois Institute for Sustainability, Energy and the Environment. She is an advisor for the Scientific Citizenship Initiative at Harvard Medical School and founder of Editing Nature. </span></em></p><p class="fine-print"><em><span>Chris Stone and Holly Tuten do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Release of GM mosquitoes in Florida is imminent. But a multidisciplinary team of scientists believe that more studies are needed first. They encourage a publicly accessible registry for GM organisms.Brian Allan, Associate Professor of Entomology, University of Illinois at Urbana-ChampaignChris Stone, Medical Entomologist, University of Illinois at Urbana-ChampaignHolly Tuten, Vector Ecologist, University of Illinois at Urbana-ChampaignJennifer Kuzma, Goodnight-NCGSK Distinguished Professor, North Carolina State UniversityNatalie Kofler, Scientific Citizenship Initiative Advisor and Center for Bioethics Lecturer, Harvard UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1287882020-02-10T19:12:06Z2020-02-10T19:12:06ZFeel like you’re a mozzie magnet? It’s true – mosquitoes prefer to bite some people over others<figure><img src="https://images.theconversation.com/files/314314/original/file-20200209-27557-1pkfocg.jpg?ixlib=rb-1.1.0&rect=36%2C27%2C5925%2C3953&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/3skLpaOBlMw">Photo by Eric Nopanen on Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>It’s always you, isn’t it? The person busy swatting away buzzing backyard mosquitoes or nursing an arm full of itchy red lumps after a weekend camping trip.</p>
<p>You’re not imagining it – mosquitoes really are attracted to some people more than others. </p>
<h2>Why do mosquitoes need blood?</h2>
<p>Only female mosquitoes bite. They do it for the nutrition contained in blood, which helps develop their eggs. </p>
<p>Mosquitoes don’t just get blood from people. They’re actually far more likely to get it from biting animals, <a href="https://theconversation.com/how-australian-wildlife-spread-and-suppress-ross-river-virus-107267">birds</a>, <a href="https://www.abc.net.au/news/2016-08-18/australian-geographic-nature-photographer-of-the-year-winners/7753248">frogs</a> and reptiles. They even <a href="https://www.nature.com/articles/s42003-018-0096-5">bite earthworms</a>.</p>
<p>But some mosquitoes specifically target people. One of the worst culprits is the <em>Aedes aegypti</em> species, which spreads <a href="https://www.cdc.gov/dengue/index.html">dengue</a> and <a href="https://www.cdc.gov/yellowfever/">yellow fever</a> viruses. </p>
<p>Another that prefers humans are the <em>Anopheles</em> mosquitoes, responsible for spreading the parasites that cause <a href="https://www.who.int/malaria/en/">malaria</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-when-we-get-bitten-by-a-mosquito-why-does-it-itch-so-much-93347">Curious Kids: When we get bitten by a mosquito, why does it itch so much?</a>
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</em>
</p>
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<h2>How do mosquitoes find us?</h2>
<p>Most mosquitoes will get their blood from whatever is around and don’t necessarily care if they’re biting one person or another. </p>
<p>Although it’s our blood they’re after, there is no strong indicator they prefer a particular blood type over another. Some studies have <a href="https://academic.oup.com/jme/article/41/4/796/885285">suggested they prefer people with type O blood</a> but that’s unlikely to be the case for all types of mosquitoes. </p>
<p>Whether we’re picked out of a crowd may come down to heavy breathing and skin smell.</p>
<p>When they need blood, mosquitoes can pick up on the <a href="https://www.cambridge.org/core/journals/bulletin-of-entomological-research/article/role-of-carbon-dioxide-in-hostfinding-by-mosquitoes-diptera-culicidae-a-review/2506B86EF63852B2D02EC3FCEE1E3B8B">carbon dioxide</a> we exhale. Around the world, carbon dioxide is one of the most common “baits” used to attract and collect mosquitoes. If you’re exhaling greater volumes of carbon dioxide, you’re probably an easier target for mosquitoes.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-worst-year-for-mosquitoes-ever-heres-how-we-find-out-68433">The worst year for mosquitoes ever? Here's how we find out</a>
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<p>When the mosquito gets closer, she is <a href="https://www.sciencedirect.com/science/article/pii/S2214574517300342">responding to a range of stimuli</a>. </p>
<p>Perhaps it’s <a href="https://www.sciencedirect.com/science/article/abs/pii/S1471492210002618">body heat and sweat</a>: exercise that increases body temperature and perspiration can attract mosquitoes.</p>
<p>Perhaps it’s body size: studies indicate <a href="https://academic.oup.com/trstmh/article/96/2/113/1909983">pregnant women are more likely to be bitten</a> by mosquitoes.</p>
<p>How hairy are you? Mosquitoes may have a tough job finding a path through to your skin if there is an abundance of body hair.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/mozzie-repellent-clothing-might-stop-some-bites-but-youll-still-need-a-cream-or-spray-107266">Mozzie repellent clothing might stop some bites but you'll still need a cream or spray</a>
</strong>
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</p>
<hr>
<p>More than anything else, though, it’s about the smell of your skin. Hundreds of chemicals are sweated out or emitted by our body’s bacteria. The <a href="https://www.sciencedirect.com/science/article/pii/S2214574517300536">cocktail of smells they create</a> will either attract or deter mosquitoes.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/314338/original/file-20200209-27533-15totfp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/314338/original/file-20200209-27533-15totfp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/314338/original/file-20200209-27533-15totfp.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/314338/original/file-20200209-27533-15totfp.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/314338/original/file-20200209-27533-15totfp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/314338/original/file-20200209-27533-15totfp.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/314338/original/file-20200209-27533-15totfp.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 saltmarsh mosquito is one of the biggest nuisance-biting pests in Australia.</span>
<span class="attribution"><span class="source">Dr Cameron Webb</span></span>
</figcaption>
</figure>
<h2>It’s not just who they bite but where</h2>
<p>Mosquitoes could also have a preference for different parts of the body. </p>
<p>One study showed mosquitoes are more attracted to hands and feet <a href="https://www.nature.com/articles/srep27141">than armpits</a>, but that just turned out to be because of deodorant residues. </p>
<p>Mosquitoes may also be more attracted to our feet: studies have shown cheese sharing similar bacteria to that <a href="https://www.ncbi.nlm.nih.gov/pubmed/15275226">found between our toes</a> attracts mosquitoes!</p>
<h2>Who is to blame for this misery?</h2>
<p>It’s not your diet. There is no evidence that what you eat or drink will prevent mosquito bites. Some food or drink may subtly change how many mosquitoes are likely to bite you but it won’t make that much difference. </p>
<p><a href="https://www.mdpi.com/2075-4450/9/4/129">Eating bananas</a> or <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2832015/">drinking beer</a> has been shown to marginally increase the attraction of mosquitoes but the results aren’t enough to suggest any dietary change will reduce your mosquito bites. That’s why our supermarket shelves aren’t full of “mozzie repellent” pills.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-can-i-eat-to-stop-mosquitoes-biting-me-87178">What can I eat to stop mosquitoes biting me?</a>
</strong>
</em>
</p>
<hr>
<p>Your irresistibility to mosquitoes may not be your fault. Blame your parents. Studies have shown the chemicals responsible for the “<a href="https://europepmc.org/article/med/2230769">skin smell</a>” that attracts mosquitoes has <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4406498/">a high level of heritability</a> when twins are exposed to biting mosquitoes. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/314337/original/file-20200209-27529-g7jtju.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/314337/original/file-20200209-27529-g7jtju.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/314337/original/file-20200209-27529-g7jtju.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/314337/original/file-20200209-27529-g7jtju.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/314337/original/file-20200209-27529-g7jtju.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/314337/original/file-20200209-27529-g7jtju.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/314337/original/file-20200209-27529-g7jtju.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">Whether you’re a mosquito magnet or not, topical insect repellents are the best way to stop mozzie bites.</span>
<span class="attribution"><span class="source">Dr Cameron Webb</span></span>
</figcaption>
</figure>
<h2>What can you do about it?</h2>
<p>We have to be careful about generalisations. There are thousands of types of mosquitoes around the world and all will have a different preference for what or who to bite. And the attraction of individuals and the scenario that plays out in one part of the world may be much different in another.</p>
<p>Remember, it only takes one mosquito bite to transmit a pathogen that could make you sick. So whether you’re a mosquito magnet or feeling a little invisible because you’re not bitten so often, don’t be complacent and <a href="https://theconversation.com/the-best-and-worst-ways-to-beat-mosquito-bites-70274">use insect repellents</a>.</p><img src="https://counter.theconversation.com/content/128788/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology and University of Sydney, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on the biology of medically important insects. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management as well as risk assessment of a wide range of arthropod pests of public health importance.</span></em></p>Feel like mosquitoes are picking you out of a crowd when looking for someone to bite? It may come down to the smell of your skin and how heavily you breathe.Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1286312020-01-14T02:07:00Z2020-01-14T02:07:00ZYou can leave water out for wildlife without attracting mosquitoes, if you take a few precautions<figure><img src="https://images.theconversation.com/files/306456/original/file-20191211-95165-1u1iphc.jpg?ixlib=rb-1.1.0&rect=30%2C24%2C3965%2C2637&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Leaving water out for wildlife is important during droughts and bushfires but if it's not changed regularly it can be a breeding ground for mosquitoes.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/wodjamiff/5792023476/in/photolist-9PPCMJ-cRxS4u-DYqZ4B-c6jixA-PXyAH1-tqTNEg-9fjx4t-AS4Ge5-dykVLg-ypeT4g-9fxCnR-5TxJB8-ykyu69-dsTVf7-7Envj7-dsUN34-Agkffv-dsWg8K-dsWeoQ-rZqYL-AiHcde-stSNEY-pe6VhK-9fAMmL-tqTHMv-9m8de-7nWW83-buC8qY-dsTxm3-dsWR6o-dsW5Tc-9fAK6W-dsTBAE-toyerJ-7FZ6mg-dsUgVH-dsWN1M-dsVDx4-dsTAVC-dsWG3E-dsU4kp-7nTu4p-dsTBxL-dsVpcr-zXgAeS-dsV9Ks-dsTrZg-z5rK52-su4udz-A1bkJu">Roger Smith/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>Australia is in for a long, hot summer. The recent bushfires have been devastating for communities and wildlife. Drought is also impacting many regions. </p>
<p>Understandably, people want to leave water out for thirsty birds and animals.</p>
<p>Health authorities generally warn against collecting and storing water in backyards as one measure to protect against mosquito bites and mosquito-borne diseases caused by, for example, <a href="https://theconversation.com/explainer-what-is-dengue-fever-8571">dengue</a> and <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1005070">Ross River</a> viruses. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-australian-wildlife-spread-and-suppress-ross-river-virus-107267">How Australian wildlife spread and suppress Ross River virus</a>
</strong>
</em>
</p>
<hr>
<p>But it’s possible to leave water out for wildlife – and save water for your garden – without supplying a breeding ground for mosquitoes, if you take a few precautions. </p>
<h2>For some mozzies, any water will do</h2>
<p>Mosquitoes often look for wetlands and ponds to lay their eggs. But sometimes, anything that holds water – a bucket, bird bath, drain or rainwater tank – will do.</p>
<p>When the immature stages of mosquitoes hatch out of those eggs, they wriggle about in the water for a week or so before emerging to fly off in search of blood.</p>
<p>While there are many mosquitoes found in wetlands and bushland areas, <em>Aedes notoscriptus</em> and <em>Culex quinquefasciatus</em> are the mosquitoes most commonly found in our backyards and have been shown to transmit pathogens that cause mosquito-borne disease. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/308556/original/file-20200106-11896-1udnelr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/308556/original/file-20200106-11896-1udnelr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308556/original/file-20200106-11896-1udnelr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308556/original/file-20200106-11896-1udnelr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308556/original/file-20200106-11896-1udnelr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308556/original/file-20200106-11896-1udnelr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308556/original/file-20200106-11896-1udnelr.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 Australian backyard mosquito (Aedes notoscriptus) is quick to take advantage of water-filled containers around the home.</span>
<span class="attribution"><span class="source">Cameron Webb (NSW Health Pathology)</span></span>
</figcaption>
</figure>
<p>In central and north Queensland, mosquitoes such as <em>Aedes aegypti</em> can bring <a href="https://theconversation.com/after-decades-away-dengue-returns-to-central-queensland-117821">more serious health threats</a>, such as dengue, to some towns.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/after-decades-away-dengue-returns-to-central-queensland-117821">After decades away, dengue returns to central Queensland</a>
</strong>
</em>
</p>
<hr>
<p>Mosquitoes can also impact our quality of life through bites as well as the nuisance of simply buzzing about our bedrooms and backyards. </p>
<p>So how can you stop mozzies making a home in your backyard?</p>
<h2>Empty water containers once a week</h2>
<p>Mosquitoes need access to standing water for about a week or so. Reduce the number of water-filled containers available or how long that water is available to mosquitoes.</p>
<p>Emptying a water-filled container once a week will stop the immature mosquitoes from completing their development and emerging as adults. </p>
<p>If you’re <a href="http://www.birdsinbackyards.net/content/article/How-you-can-help-birds-after-fires">leaving water out for pets or wildlife</a>, use smaller volume containers that will allow for easy emptying once a week. You can tip any remaining water into the garden, as mosquito larvae won’t survive if they’re “stranded” on soil.</p>
<p>For larger or heavier items, such as bird baths, flushing them out once a week with the hose will knock out most of the wrigglers and stop the mosquitoes completing their life cycle.</p>
<h2>Make sure garden water doesn’t slosh about</h2>
<p>Be careful with self-watering planter boxes. These often have a reservoir of water in their base and, while it may seem like a water-wise idea, these can turn into tiny mozzie hotels!</p>
<p>A simple trick to keep water available to plants, but not mosquitoes, is to fill your potted plant saucers with sand. The sand traps and stores some moisture but there is no water sloshing about for mosquitoes.</p>
<p>If you’re collecting water from showers, baths, or washing machines (commonly known as <a href="http://www.sydneywater.com.au/sw/your-home/using-water-wisely/greywater-reuse/index.htm">grey water</a>), use it immediately on the garden, don’t store it outside in buckets or other containers. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-drought-is-affecting-water-supply-in-australias-capital-cities-127909">How drought is affecting water supply in Australia’s capital cities</a>
</strong>
</em>
</p>
<hr>
<h2>Gutters, ponds, tanks and pools</h2>
<p>Make sure your <a href="https://www.ajtmh.org/content/journals/10.4269/ajtmh.2002.67.244">roof gutters</a> and drains are free of leaves and other debris that will trap water and provide opportunities for mosquitoes.</p>
<p>Ensure rainwater tanks (and other large water-storage containers) are appropriately screened to prevent access by mosquitoes.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/308562/original/file-20200106-11900-1g8g9j5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/308562/original/file-20200106-11900-1g8g9j5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308562/original/file-20200106-11900-1g8g9j5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308562/original/file-20200106-11900-1g8g9j5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308562/original/file-20200106-11900-1g8g9j5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308562/original/file-20200106-11900-1g8g9j5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308562/original/file-20200106-11900-1g8g9j5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Rainwater tanks can be a useful way to conserve water in our cities but they can also be a source of mosquitoes.</span>
<span class="attribution"><span class="source">Cameron Webb (NSW Health Pathology)</span></span>
</figcaption>
</figure>
<p>A well maintained swimming pool won’t be a source of mosquitoes. But if it’s turning “green”, through neglect <a href="http://www.kmc.nsw.gov.au/Current_projects_priorities/Key_priorities/Environment_and_Sustainability/Pool_to_Pond">and not intent</a>, it may become a problem. Mosquitoes don’t like the chlorine or salt treatments typically used for swimming pools but when there is a build up of leaves and other detritus, as well as algae, the mosquitoes will move in.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/as-heat-strikes-heres-one-way-to-help-fight-disease-carrying-and-nuisance-mosquitoes-128466">As heat strikes, here's one way to help fight disease-carrying and nuisance mosquitoes</a>
</strong>
</em>
</p>
<hr>
<p>For backyard ponds, introducing native fish can help keep mosquito numbers down. </p>
<p>But if you want your pond to be a home for frogs, avoid fish as they may eat the tadpoles. Instead, try to encourage other wildlife that may help keep mosquito numbers down by creating habitats for <a href="https://theconversation.com/dont-like-spiders-here-are-10-reasons-to-change-your-mind-126433">spiders</a> and other predatory insects, reptiles, frogs, birds, and bats.</p>
<p>Avoiding <a href="https://theconversation.com/the-battle-against-bugs-its-time-to-end-chemical-warfare-111629">excessive use of insecticides</a> around the backyard will help encourage and protect that wildlife too.</p>
<h2>Mozzies can still come</h2>
<p>There isn’t much that can be done about those mosquitoes flying in from over the back fences from local bushland or wetland areas. </p>
<p>Mosquitoes are generally most active at dusk and dawn so keep that in mind when planning time outdoors. But when mosquito populations are peaking, they’ll be active almost all day long.</p>
<p>Applying an insect repellent can be a <a href="https://theconversation.com/the-best-and-worst-ways-to-beat-mosquito-bites-70274">safe and effective way to stop those bites</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-best-and-worst-ways-to-beat-mosquito-bites-70274">The best (and worst) ways to beat mosquito bites</a>
</strong>
</em>
</p>
<hr>
<p>Covering up with long pants, long-sleeved shirt and shoes will provide a physical barrier to mosquitoes. If you’re spending a lot of time outdoors, perhaps even consider <a href="https://theconversation.com/mozzie-repellent-clothing-might-stop-some-bites-but-youll-still-need-a-cream-or-spray-107266">treating your clothing with insecticide</a> to add that extra little bit of protection. </p>
<p>Make sure insect screens are installed, and in good condition, on windows and doors. Mosquitoes outdoors can be bad; you don’t want them inside as well.</p><img src="https://counter.theconversation.com/content/128631/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology and University of Sydney, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on the biology of medically important insects. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management as well as risk assessment of a wide range of arthropod pests of public health importance.</span></em></p>Temperatures are soaring and bushfires are decimating Australia’s wildlife. So how can we avoid creating a breeding ground for mosquitoes when putting water out for thirsty birds and animals?Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1284662019-12-10T19:02:56Z2019-12-10T19:02:56ZAs heat strikes, here’s one way to help fight disease-carrying and nuisance mosquitoes<figure><img src="https://images.theconversation.com/files/305857/original/file-20191209-90588-z0hh9p.jpg?ixlib=rb-1.1.0&rect=10%2C5%2C3446%2C2308&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Although yellow fever does not currently exist in Australia, the species Aedes aegypti - which can transmit the disease - is found widely across northern Queensland. The virus remains a global health concern, but citizen scientists could help prevent its spread.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/dfataustralianaid/10703811283/in/photolist-hiRQbp-o2C5Ea-5teKrM-prufsH-9JrLwy-pQqpF-nL5DfG-77JZRZ-cpUoNL-9tkBLk-5jxMyp-7iZSB-r9ZY2X-cg2SEh-5teJBV-cpUp4u-5pBMJ8-5pBMJp-rrmyFd-5pBMJ4-4XfWfe-b29TGT-Bm2uxJ-a4SkT1-edLmUv-3WkCVT-8uLqtp-c21i5A-emM5p-6qrVrt-NrjrV-xc69Yg-8uPuEu-8uLqBa-a5XbDu-87nf2R-nEXatf-CHguk-nVU9DN-aq412c-fH3CgY-xtKBz-g4wDM-d8VGcm-9AVAYW-foZPD-fnviLL-wgXh5-bvXznE-Xm4f">Simon Kutcher/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Mosquito-borne disease is a concern for health authorities around Australia. Each year, thousands fall ill to <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1005070">Ross River virus disease</a> caused by mosquito bites.</p>
<p>Tracking mosquito populations can help us respond to these threats, and new research suggests citizen scientists may be the key to doing this more effectively.</p>
<p>Health authorities coordinate the surveillance of <a href="https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-018-2901-x?optIn=false">mosquitoes and their pathogens</a>. These surveillance data help improve the understanding of mosquito-borne disease outbreaks.</p>
<p>They also help guide <a href="https://ww2.health.wa.gov.au/Articles/F_I/Fight-the-Bite-campaign">public education campaigns</a>, and assist in mosquito control efforts, <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1440-6055.2008.00642.x">often through the application of insecticides</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-worst-year-for-mosquitoes-ever-heres-how-we-find-out-68433">The worst year for mosquitoes ever? Here's how we find out</a>
</strong>
</em>
</p>
<hr>
<p>However, there aren’t enough resources to set mosquito traps everywhere. It can also be tricky getting specimens from the field to the lab for testing. This is where <a href="https://theconversation.com/explainer-what-is-citizen-science-16487">citizen science</a> is important.</p>
<p>This public-led movement involves volunteers gathering scientific data for programs coordinated by professional scientists, simply through <a href="https://www.environment.nsw.gov.au/research-and-publications/your-research/citizen-science/digital-projects/coastsnap">taking photos</a> or <a href="https://www.frogid.net.au/">recording sounds</a> on their smartphones.</p>
<p>In this way, sightings of <a href="https://www.theguardian.com/environment/2018/aug/06/the-golden-age-of-citizen-science-and-how-it-is-reshaping-the-world">animals and plants</a> can be reported. Citizen scientists can even help in experimental design, data analysis and distribution of research results.</p>
<h2>Getting bu-zzzz-y tracking mosquitoes</h2>
<p>One program called <a href="https://hehp.wordpress.com/category/mozzie-monitors/">Mozzie Monitors</a>, <a href="https://www.unisa.edu.au/sansominstitute/mosquito/">launched in June</a> last year, is shedding light on how citizen science can address critical resource shortages in mosquito surveillance efforts. </p>
<p>Our research published last week in <a href="https://www.sciencedirect.com/science/article/pii/S0048969719353410">Science and the Total Environment</a> reveals how the program’s use of smartphone e-entomology (“e” stands for electronic) is enabling the low-cost upscaling of mosquito surveillance.</p>
<p>The program involves <a href="https://www.abc.net.au/btn/newsbreak/mozzie-monitors-help-researchers/11221072">recruiting volunteers</a> to set up cheap and simple mosquito traps in their backyards, and use their smartphones to send back data on the caught mosquitoes. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/305733/original/file-20191208-90618-1ltddkg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/305733/original/file-20191208-90618-1ltddkg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/305733/original/file-20191208-90618-1ltddkg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/305733/original/file-20191208-90618-1ltddkg.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/305733/original/file-20191208-90618-1ltddkg.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/305733/original/file-20191208-90618-1ltddkg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/305733/original/file-20191208-90618-1ltddkg.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/305733/original/file-20191208-90618-1ltddkg.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">Mozzie Monitors volunteers used a simple BG-GAT trap to catch mosquitoes.</span>
<span class="attribution"><span class="source">Cameron Webb/NSW Health Pathology</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>A <a href="https://chuffed.org/project/mozzie-monitors">crowd-funding campaign</a> attracted donations from over 150 people to help launch the program, from which 126 people became actively involved in data collection. </p>
<p>Each participant was provided with an easy-to-use <a href="https://eu.biogents.com/bg-gat-for-homeowners/">Biogents BG-GAT (Gravid Aedes Trap)</a> and asked to email the research group with photos of collected mosquitoes. Scientists were then able to use these photos to identify and count the different species collected. This approach is called e-entomology. </p>
<p>The volunteers sent more than 10,000 photos of mosquitoes to scientists. From these, 15 different species were identified, ranging from <em>Aedes notoscriptus</em> (the common Australian backyard mosquito) to <em>Aedes camptorhynchus</em>, a mosquito flying into suburbs from nearby coastal wetlands.</p>
<p>The number of mosquitoes changed throughout the year in response to changing temperatures. Unsurprisingly, they hit their peak during summer.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/hidden-housemates-the-mosquitoes-that-battle-for-our-backyards-59072">Hidden housemates: the mosquitoes that battle for our backyards</a>
</strong>
</em>
</p>
<hr>
<h2>The value of citizen science data</h2>
<p>The Mozzie Monitors program marks the first time formal mosquito trapping has been combined with citizen science.</p>
<p>A key research question for us was: do the data collected by citizen scientists align with data collected in formal mosquito surveillance programs?</p>
<p>To test this, the data collected by Mozzie Monitors volunteers were compared to data collected from a professional program monitoring mosquitoes around urban wetlands. Mosquitoes <a href="https://entomologytoday.org/2019/04/11/mosquito-management-key-urban-wetlands/">associated with these wetlands</a> can pose pest and public health risks. </p>
<p>The citizen scientists contributed more than four times the amount of data than professional monitoring efforts. This included locally important species known to spread Ross River virus. </p>
<p>In terms of the number and diversity of mosquitoes collected, citizen science proved just as reliable as a professional program.</p>
<h2>Other victories</h2>
<p>There has been growing interest in the <a href="https://www.nature.com/articles/s41467-017-00914-9">potential of citizen science to assist the surveillance of mosquitoes</a> associated with nuisance-biting and disease risks. </p>
<p>In Brisbane, the Metro South Public Health Unit’s <a href="https://metrosouth.health.qld.gov.au/zika-mozzie-seeker">Zika Mozzie Seeker</a> program has sought to detect the arrival of exotic mosquitoes that may increase the risk of potentially serious diseases caused by the dengue, <a href="https://www.who.int/news-room/fact-sheets/detail/chikungunya">chikungunya</a>, or Zika viruses. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/new-mosquito-threats-shift-risks-from-our-swamps-to-our-suburbs-56350">New mosquito threats shift risks from our swamps to our suburbs</a>
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</em>
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<p>In Spain last year, citizen scientists using the <a href="https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-019-3317-y">Mosquito Alert</a> app for smartphones detected the arrival of an invasive mosquito, <em>Aedes japonicus</em>, before local authorities could.</p>
<h2>Where to now?</h2>
<p>The citizen science movement is growing across the world, promoting life-long learning among citizens. </p>
<p>It’s important communities continue to be made aware of their potential role in wildlife surveillance efforts. </p>
<p>By engaging the public in Mozzie Monitors, we’ve been able to integrate citizen science with a professional programs to boost mosquito surveillance. </p>
<p>Now, more mosquitoes can be trapped in more locations, giving health authorities a clearer picture of potential health risks. This also increases our chances of detecting invasive species that are a biosecurity threat.</p>
<p>Apart from monitoring mosquitoes, the Mozzie Monitors program is educating communities about mosquito diversity in their own backyards, and helping raise awareness of local disease risk. </p>
<p>As mosquitoes were identified during the trial, results were <a href="https://public.tableau.com/profile/mozzie.monitors#!/vizhome/MosquitoesinSouthAustralia-GoogleSheets_0/MosquitoesinSouthAustralia">made available on the research group website</a>. Citizen scientists were updated monthly on the distribution and frequency of mosquitoes in and around their suburbs. This encouraged many participants to identify mosquitoes they collected themselves.</p>
<p>The program’s next trial has already started in South Australia, and <a href="https://hehp.wordpress.com/2019/11/22/call-for-citizen-scientists-in-sa/">everyone is welcome to get involved</a>.</p><img src="https://counter.theconversation.com/content/128466/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology and University of Sydney, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on the biology of medically important insects. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management as well as risk assessment of a wide range of arthropod pests of public health importance.</span></em></p><p class="fine-print"><em><span>Craig Williams receives funding from the University of South Australia, the Western Australian Department of Health and the South Australian Department of Health. </span></em></p><p class="fine-print"><em><span>Larissa Braz Sousa receives funding from the Australian Technology Network (ATN-LATAM) Research Scholarship. </span></em></p><p class="fine-print"><em><span>Seamus Doherty receives funding from the University of South Australia, Ian Gould Experimental Science Scholarship. </span></em></p><p class="fine-print"><em><span>Stephen Rober Fricker receives funding from the from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management. </span></em></p>Nuisance-biting and mosquito-borne disease are ongoing concerns for health authorities. But an effective citizen science program is now showing how all of us can help beat the bite of mozzies.Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of SydneyCraig Williams, Associate Professor in Biology, University of South AustraliaLarissa Braz Sousa, PhD candidate on citizen science and public health, University of South AustraliaSeamus Doherty, Biologist, University of South AustraliaStephen Robert Fricker, Manager of Vector Surveillance, University of South AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1246452019-11-18T14:27:12Z2019-11-18T14:27:12ZCollaboration pushes frontiers of anti-malaria drug regimes<figure><img src="https://images.theconversation.com/files/301954/original/file-20191115-66932-1v635m2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Africa is home to 92% of malaria cases and 93% of malaria deaths. </span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>More than <a href="https://www.who.int/malaria/media/world-malaria-report-2018/en/#Global%20and%20regional%20malaria%20burden,%20in%20numbers">200 million</a> people around the world suffered from malaria in 2017. Over 400,000 died. The vast majority – around 90% – were in Africa, where many are all too familiar with the devastating impact of the disease. Young children and pregnant women are the most vulnerable.</p>
<p>Protective measures can help significantly to reduce the burden. This includes spraying with insecticides and using mosquito nets. But 100% coverage using these methods is impossible. Until the disease is eradicated, availability of effective treatments is critical. </p>
<p>This is why drugs are critical to managing the disease. But even here new challenges are beginning to emerge. For example, in <a href="https://www.theguardian.com/world/2019/jul/23/drug-resistant-malaria-parasites-spreading-aggressively-across-south-east-asia">South East Asia</a>, drug resistance to current first-line treatment has become a cause for concern. It threatens progress made in recent years against malaria. The only way to overcome this threat is to discover new agents against malaria that are safe, effective and affordable. </p>
<p>A collaborative effort between the <a href="http://www.h3d.uct.ac.za/">University of Cape Town’s drug discovery and development centre</a> and the Swiss-based non-profit organisation <a href="https://www.mmv.org/">Medicines for Malaria Venture</a> has spent the past ten years working this. The project is supported by the South African Medical Research Council and the country’s Department of Science and Innovation. The aim is to discover and develop medicines to help tackle the burden of the disease in endemic countries and support malaria eradication. </p>
<p>The collaboration is also contributing to the development of sustainable research capacity in African countries.</p>
<p>The joint projects arising from this collaboration embrace multidisciplinary activities. One example involves screening activities to identify exciting new chemical starting points. Another is to optimise new compounds through the drug discovery pipeline and deliver candidate compounds that can be researched further in clinical studies. </p>
<h2>From aid to partnerships</h2>
<p>During the 1980s and 1990s anti-malarial efforts were largely conducted under the umbrella of development aid. In addition, health services faced cuts under programmes imposed by international institutions, such as the World Bank and International Monetary Fund. </p>
<p>Since then, there have been significant shifts in financing these efforts. Partnerships between research organisations from the global north and south have been critical to supporting evidence-based sustainable research. These partnerships include the <a href="https://www.ukri.org/research/global-challenges-research-fund/">Global Challenges Research Fund</a> and the <a href="http://www.data4sdgs.org/">Global Partnership for Sustainable Development Data</a>.</p>
<p>The biggest breakthrough in anti-malaria drug treatment was the discovery and extraction of artemisinin from its plant source by Chinese scientist <a href="https://www.nobelprize.org/prizes/medicine/2015/tu/facts/">Youyou Tu</a>. </p>
<p>Artemisin’s effect on the management of malaria cannot be overstated. It rapidly reduces parasitemia and fever. Millions of lives have been saved since its introduction in the 1970s and subsequent wider implementation. It remains the cornerstone malaria treatment.</p>
<p>But the emergence of drug-resistant malaria threatens to reverse this progress. To really consider malaria eradication new medicines are needed that can block transmission, protect against malaria and target the dormant forms of the disease that lead to relapse. </p>
<p>The partnership we’re involved in is a continuation of efforts to find new breakthroughs to meet these needs. </p>
<p>In the past decade this collaboration has delivered:</p>
<ul>
<li><p>A clinical drug candidate – <a href="https://www.medicalbrief.co.za/archives/uct-researcher-leads-discovery-new-anti-malaria-drug-candidate/">MMV048</a>. This is currently in Phase IIa clinical trials in Ethiopia to test the ability of the molecule to cure patients of malaria. This is the first malaria drug candidate to have been researched by an African-led team;</p></li>
<li><p>A second pre-clinical candidate – <a href="https://www.ncbi.nlm.nih.gov/pubmed/29941635">UCT943</a> – as a backup to MMV048. This is important because drug development is risky. Having an alternative candidate allows for more shots on goal; </p></li>
<li><p>Investigation of 10 novel chemical series;</p></li>
<li><p>Peer-reviewed publications and training and development of scientists in Africa.</p></li>
</ul>
<h2>Next steps</h2>
<p>The collaboration aims to discover and develop new medicines to treat the symptoms of infection caused by the two main species of malaria parasite (<em>Plasmodium falciparum</em> and <em>Plasmodium vivax</em>). In this way, there would be medicines available to cure most cases of malaria – even those that may be resistant to existing therapies. </p>
<p>We are also conducting research to identify medicines that could offer protection and block transmission of the infection by killing transmissible forms of the parasite. By blocking transmission, we would be able to bring the overall burden of malaria down and make more progress towards malaria eradication.</p>
<p>Malaria is not the only infectious disease threatening the African continent.
Work is being done to replicate the success in malaria research to address other diseases such as tuberculosis and antibiotic-resistant microbial diseases. </p>
<p><em>Dr Timothy Wells, Chief Scientific Officer at Medicines for Malaria Venture, co-authored this article.</em></p><img src="https://counter.theconversation.com/content/124645/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kelly Chibale receives funding from Medicines for Malaria Venture (Switzerland), South African Technology Innovation Agency (TIA), Department of Science and Innovation (DSI) and Strategic Innovation Partnerships unit of the South African Medical Research Council.</span></em></p><p class="fine-print"><em><span>Richard Gordon runs the grant funding at the SAMRC and did consult for MMV 2011 – 2017/8. He is an extraordinary professor at NWU and sits on several Ministerial advisory committees.</span></em></p>The aim is to discover, develop and facilitate delivery of anti-malarial medicines to help tackle the burden of malaria in endemic countries and support malaria eradication.Kelly Chibale, Professor of Organic Chemistry, University of Cape TownRichard Gordon, Executive Director of the Grants, Innovation and Product Development Unit, South African Medical Research CouncilLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1180292019-06-03T13:07:52Z2019-06-03T13:07:52ZFeeding mosquitoes sugar makes them less likely to bite – but don’t go leaving out sugary treats just yet<figure><img src="https://images.theconversation.com/files/277632/original/file-20190603-69075-1v8v743.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2600%2C1728&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/asian-tiger-mosquito-aedes-albopictus-extreme-297163811?src=52B-JjdRxO4abHQqrU8rig-1-39">InsectWorld/Shutterstock</a></span></figcaption></figure><p>The teasing temptation of a sugary treat can often get the better of us. But don’t worry, we’re not the only ones. The saccharine substance that our sweet tooth finds so hard to resist is also powerfully seductive to mosquitoes. And according to <a href="https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3000238">new research</a>, in helping to keep the pests away from our blood-rich body parts, sugar may for once be good for our health. </p>
<p>But don’t start mixing up any sugar water just yet – or you might end up doing as much harm as good.</p>
<p>We’ve long understood that sugar is an important energy source for mosquitoes. In fact, it’s actually <a href="https://www.annualreviews.org/doi/abs/10.1146/annurev.en.40.010195.002303">better</a> than blood in terms of fuelling flight and basic survival processes. Only female mosquitoes feed on blood, as it provides essential nutrients needed to make their eggs.</p>
<p>Of course, this thirst for blood generates a terrible disease burden <a href="https://www.who.int/vector-control/en/">globally</a>, often in the countries least well equipped to cope. Amid the hundreds of scientists across the world working to reduce the menace of mosquitoes, one promising avenue is investigating how their desires for sugar and blood interact.</p>
<p>The new research, published in Plos Biology, set about investigating exactly this. It focused on the Asian tiger mosquito (<em>Aedes albopictus</em>), an invasive species that has infiltrated every continent, closely associates with humans, and is very difficult to suppress, making it a particularly dangerous <a href="https://ecdc.europa.eu/en/disease-vectors/facts/mosquito-factsheets/aedes-albopictus">transmitter</a> of diseases such as dengue fever, yellow fever, and Zika virus.</p>
<p>The research team <a href="https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3000238">found</a> that feeding young tiger mosquitoes sugar solutions caused a physiological response similar to that after feeding on blood. Importantly, it then delayed their search for the red velvet blood of a human host.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/277677/original/file-20190603-69071-10ut0oi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/277677/original/file-20190603-69071-10ut0oi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/277677/original/file-20190603-69071-10ut0oi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/277677/original/file-20190603-69071-10ut0oi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/277677/original/file-20190603-69071-10ut0oi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/277677/original/file-20190603-69071-10ut0oi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/277677/original/file-20190603-69071-10ut0oi.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">Making mosquito eggs is thirsty work.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/close-dried-mosquito-eggs-hatch-isolated-135540473?src=PC3YTZKEq_UwaG86Udmi1Q-1-31">7th Son Studio/Shutterstock</a></span>
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<p>Interestingly, the researchers found that feeding on sugar caused levels of a protein called vitellogenin to rise in the mosquitoes. Vitellogenin is an important component in the production of the egg yolk that provides nutrients to unborn mosquito offspring. Normally, vitellogenin is produced when receptors detect specific nutrients that mosquitoes gather from blood meals.</p>
<p>Using gene interference experiments, researchers were able to identify a specific gene associated with vitellogenin that when knocked out, restored the mosquitoes’ attraction to humans. This is exciting, as it highlights potential for this gene to be targeted as a way of reducing host seeking behaviour, and in turn, the transmission of deadly diseases that affect millions.</p>
<h2>Work still to do</h2>
<p>This research is a significant breakthrough in understanding the physiological mechanisms that influence mosquito feeding behaviour. However, there is still a great deal of work left to do. As the authors themselves are aware of, feeding sugar to mosquitoes cannot alone be used as a control method in the real world.</p>
<p>There are many reasons for this, but the most important is that the effects of sugar on mosquito behaviour can vary significantly, even within just this one species. For example, while the reduction in human attraction held true for young adult mosquitoes, when older females were fed sugar they remained highly attracted to humans, and displayed increased nutrient reserves. This is not a desirable outcome. Physical condition, how well the mosquito fed as larva, whether it has mated, and whether it has previously laid eggs may also influence the effect of sugar on <a href="https://academic.oup.com/jme/article-abstract/33/4/608/2221578">feeding behaviour</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/277675/original/file-20190603-69055-p0vn98.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/277675/original/file-20190603-69055-p0vn98.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/277675/original/file-20190603-69055-p0vn98.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/277675/original/file-20190603-69055-p0vn98.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/277675/original/file-20190603-69055-p0vn98.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/277675/original/file-20190603-69055-p0vn98.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/277675/original/file-20190603-69055-p0vn98.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Feeding the Anopheles mosquito sugar isn’t a good idea.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/mosquito-feeding-anopheles-gambiae-transmits-malaria-242818555?src=hdgjv1lZNiAvbTslnN-gFQ-1-52">Everett Historical/Shutterstock</a></span>
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<p>Things get even more complex when other mosquito species are taken into account. For example, high vitellogenin levels <a href="https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1000434">weaken</a> the immune system of the African malarial mosquito (<em>Anopheles gambiae</em>), thereby making it more likely to contract and pass on malaria. Raised vitellogenin is therefore clearly not always a good thing.</p>
<p>Leaving sugar out for mosquitoes may put off younger mosquitoes from biting you, but it will make older mosquitoes stronger, and could weaken the defences of other mosquito species. We may, however, be able to genetically modify or treat tiger mosquitoes with <a href="https://www.pnas.org/content/105/50/19631.short">hormones</a> that raise vitellogenin levels in the absence of sugar, eliminating this trade off. Given that in most cases mosquitoes pick up disease pathogens during their first meal, such control methods could substantially delay the first blood meal of mosquitos, making them infectious for a shorter period of time.</p>
<p>Of course, at this early stage it is difficult to estimate how effective control measures that alter vitellogenin might be. Importantly, there is still a long way to go before any single answer will be created for mosquitoes, so continue to follow the best <a href="https://www.bug-off.org/">current advice</a> when travelling.</p><img src="https://counter.theconversation.com/content/118029/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Richard Halfpenny 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>Mosquitoes love sugar – so much so that can delay their search for our blood. Now, their sweet tooth may have revealed an important genetic weapon against the spread of mosquito-borne disease.Richard Halfpenny, Lecturer in Biological Sciences, Staffordshire UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1178212019-05-29T07:26:05Z2019-05-29T07:26:05ZAfter decades away, dengue returns to central Queensland<figure><img src="https://images.theconversation.com/files/276933/original/file-20190529-126243-7lgesy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Australia's dengue cases are usually limited to far north Queensland.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/dad-son-use-mosquito-sprayspraying-insect-1081091330">Shutterstock</a></span></figcaption></figure><p>The Queensland city of Rockhampton was free of dengue for decades. Now, a case of one of the most serious mosquito-borne diseases has authorities scratching their heads. </p>
<p>Over the past decade, dengue infections have tended to be isolated events in which international travellers have returned home with the disease. But the recent case <a href="https://www.brisbanetimes.com.au/national/queensland/full-outbreak-response-first-rockhampton-dengue-fever-case-in-decades-20190524-p51qop.html">seems to have been locally acquired</a>, raising concerns that there could be more infected mosquitoes in the central Queensland town, or that other people may have been exposed to the bites of an infected mosquito. </p>
<h2>What is dengue fever?</h2>
<p>The illness known as <a href="http://conditions.health.qld.gov.au/HealthCondition/condition/14/217/284/Dengue">dengue fever</a> typically includes symptoms such as rash, fever, headache, joint pain, vomiting, diarrhoea, and abdominal pain. Symptoms can last for around a week or so. Four types of <a href="https://theconversation.com/explainer-what-is-dengue-fever-8571">dengue virus</a> cause the illness and they are spread by mosquito bites.</p>
<p>Once infected, people become immune to that specific dengue virus. However, they can still get sick from the other dengue viruses. Being infected by multiple dengue viruses can increase the risk of more severe symptoms, and even death.</p>
<p>Hundreds of millions of people are infected each year. It is estimated that <a href="https://www.who.int/denguecontrol/en/">40% of the world’s population is at risk</a> given the regions where the virus, and the mosquitoes that spread it, are active. This includes parts of Australia.</p>
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Read more:
<a href="https://theconversation.com/explainer-what-are-antibodies-and-why-are-viruses-like-dengue-worse-the-second-time-68227">Explainer: what are antibodies and why are viruses like dengue worse the second time?</a>
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<p>The last <a href="http://microbiology.publish.csiro.au/?paper=MA18027">significant outbreak</a> in Australia occurred in far north Queensland in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3712959/">2009</a>, when more than 900 people were infected by local mosquitoes. </p>
<p>Only a handful of locally acquired cases have been reported around Cairns and Townsville in the past decade. All these cases have two things in common: the <a href="https://theconversation.com/stowaway-mozzies-enter-australia-from-asian-holiday-spots-and-theyre-resistant-to-insecticides-113999">arrival of infected travellers</a> and the presence of the “right” mosquitoes. </p>
<p>The dengue virus isn’t spread from person to person. A mosquito needs to bite an infected person, become infected, and then it may transmit the virus to a second person as they bite. If more people are infected, more mosquitoes can pick up the virus as they bite and, subsequently, the outbreak can spread further. </p>
<h2>Why are mosquitoes important?</h2>
<p>Australia has <a href="https://www.publish.csiro.au/book/6391/">hundreds of different types of mosquitoes</a>. Dozens can spread local pathogens, such as <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1005070">Ross River virus</a>, but just one is capable of spreading exotic viruses such as dengue and Zika: <em>Aedes aegypti</em>. </p>
<p><em>Aedes aegypti</em> <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0211167">breeds in water-holding containers</a> around the home. It is one of the most invasive mosquitoes globally and is easily moved about by people through international travel. While these days the mosquito stows away in planes, historically it was just as readily moved about in water-filled barrels on sailing ships. </p>
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<img alt="" src="https://images.theconversation.com/files/276722/original/file-20190528-92796-8vl534.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/276722/original/file-20190528-92796-8vl534.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/276722/original/file-20190528-92796-8vl534.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/276722/original/file-20190528-92796-8vl534.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/276722/original/file-20190528-92796-8vl534.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/276722/original/file-20190528-92796-8vl534.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/276722/original/file-20190528-92796-8vl534.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Aedes aegypti is the mosquito primarily responsible for the spread of dengue viruses.</span>
<span class="attribution"><span class="source">By James Gathany - PHIL, CDC, Public Domain</span></span>
</figcaption>
</figure>
<p>The spread of <em>Aedes aegypti</em> through Australia is the driving force in determining the nation’s future outbreak risk. </p>
<p>The mosquito was <a href="https://onlinelibrary.wiley.com/doi/full/10.5694/j.1326-5377.2009.tb02393.x">once widespread in coastal Australia</a> but since the 1950s, it become limited to central and far north Queensland. We don’t really know why – <a href="https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0005848">there are many possible reasons for the retreat</a>, but the important thing now is they don’t return to temperate regions of the country. </p>
<p>Authorities <a href="http://www.phrp.com.au/issues/december-2016-volume-26-issue-5/exotic-mosquito-threats-require-strategic-surveillance-and-response-planning/">must be vigilant</a> to monitor their spread and, where they’re currently found, building capacity to respond should cases of dengue be identified. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/is-climate-change-to-blame-for-outbreaks-of-mosquito-borne-disease-39176">Is climate change to blame for outbreaks of mosquito-borne disease?</a>
</strong>
</em>
</p>
<hr>
<h2>What happened in Rockhampton?</h2>
<p>Last week, for the first time in decades, a <a href="https://www.health.qld.gov.au/clinical-practice/guidelines-procedures/diseases-infection/diseases/mosquito-borne/dengue/dengue-outbreaks">locally acquired case of dengue</a> was detected in Rockhampton, in central Queensland. The disease was found in someone who hasn’t travelled outside the region, which suggests they’ve been bitten locally by an infected mosquito. </p>
<p>This has prompted a <a href="https://www.abc.net.au/news/2019-05-24/first-locally-acquired-case-of-dengue-fever-in-central-qld/11144996">full outbreak response</a> to protect the community from any additional infected mosquitoes.</p>
<p>While the risk of dengue around central Queensland is considered lower than around Cairns or Townsville, authorities are <a href="https://www.health.qld.gov.au/clinical-practice/guidelines-procedures/diseases-infection/diseases/mosquito-borne/resources">well prepared to respond</a>, with a variety of techniques including <a href="https://www.abc.net.au/radio/programs/am/dengue-fever-in-rockhampton-signals-shift/11149410">house-to-house mosquito surveillance and mosquito control</a> to minimise the spread.</p>
<p>These approaches have been successful around Cairns and Townsville for many years and have helped avoid substantial outbreaks.</p>
<p>The coordinated response of local authorities, combined with the onset of cooler weather that will slow down mosquitoes, greatly reduces any risk of more cases occurring.</p>
<h2>What can we do about dengue in the future?</h2>
<p>Outbreaks of dengue remain a risk in areas with <em>Aedes aegypti</em> mosquitoes. There are also other mosquitoes, such as <em>Aedes albopictus</em> (the Asian tiger mosquito), that aren’t <a href="https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0005286">currently found on mainland Australia</a> but may further increase risks should they arrive. Authorities need to be prepared to respond to the introductions of these mosquitoes. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-we-kept-disease-spreading-asian-tiger-mozzies-away-from-the-australian-mainland-72873">How we kept disease-spreading Asian Tiger mozzies away from the Australian mainland</a>
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</p>
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<p>While <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1440-6055.2008.00677.x">a changing climate may play a role in increasing the risk</a>, increasing international travel, which represents pathways of introduction of “dengue mosquitoes” into new regions of Australia, may be of greater concern. </p>
<p>There is more that can be done, both locally and internationally. Researchers are working to develop a <a href="https://www.cdc.gov/dengue/prevention/dengue-vaccine.html">vaccine</a> that protects against all four strains of dengue virus. </p>
<p>Others are tackling the mosquitoes themselves. <a href="https://theconversation.com/pitting-mozzies-against-mozzies-to-stop-the-spread-of-disease-67447">Australian scientists</a> have played a crucial role in using the <em>Wolbachia</em> bacteria, <a href="https://www.nature.com/articles/nature10356">which spreads among <em>Aedes aegypti</em> and blocks transmission of dengue</a>, to control the disease. </p>
<p>The objective is to raise the prevalence of the <em>Wolbachia</em> infections among local mosquitoes to a level that greatly reduces the likelihood of local dengue transmission. </p>
<p>Field studies <a href="https://www.abc.net.au/news/2016-10-27/zika-eliminate-dengue-project-to-expand-after-qld-success/7969038">have been successful in far north Queensland</a> and may explain why so few local cases of dengue have been reported in recent years.</p>
<p>While future strategies may rely on emerging technologies and vaccines, simple measures such as <a href="https://theconversation.com/hidden-housemates-the-mosquitoes-that-battle-for-our-backyards-59072">minimising water-filled containers around our homes</a> will reduce the number of mosquitoes and their potential to transmit disease.</p><img src="https://counter.theconversation.com/content/117821/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology and University of Sydney, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on the biology of medically important insects. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management as well as risk assessment of a wide range of arthropod pests of public health importance.</span></em></p>Mosquito-borne dengue virus returned to central Queensland after being absent for decades. But while most Australian cases involve travellers, this one is locally acquired.Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1122122019-02-25T19:09:03Z2019-02-25T19:09:03ZExplainer: what is Murray Valley encephalitis virus?<p>Western Australian health authorities recently <a href="https://ww2.health.wa.gov.au/Media-releases/2019/Murray-Valley-encephalitis-warning-for-Kimberley">issued warnings</a> about Murray Valley encephalitis, a serious disease that can spread by the bite of an infected mosquito and cause inflammation of the brain.</p>
<p>Thankfully, no human cases have been reported this wet season. The virus that causes the disease was detected in chickens in the Kimberley region. These “sentinel chickens” act as an early warning system for potential disease outbreaks.</p>
<h2>What is Murray Valley encephalitis virus?</h2>
<p>Murray Valley encephalitis virus is named after the Murray Valley in southeastern Australia. The virus was first isolated from patients who died from encephalitis during an outbreak there in 1951.</p>
<p>The virus is a member of the Flavivirus family and is closely related to <a href="https://theconversation.com/what-is-japanese-encephalitis-virus-and-how-can-i-avoid-it-when-i-travel-106775">Japanese encephalitis virus</a>, a major cause of encephalitis in Asia. </p>
<p>Murray Valley encephalitis virus is found in northern Australia circulating between mosquitoes, especially <em>Culex annulirostris</em>, and water birds. Occasionally the virus spreads to southern regions, as mosquitoes come into contact with infected birds that have migrated from northern regions.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/after-the-floods-come-the-mosquitoes-but-the-disease-risk-is-more-difficult-to-predict-111173">After the floods come the mosquitoes – but the disease risk is more difficult to predict</a>
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</p>
<hr>
<h2>How serious is the illness?</h2>
<p>After being transmitted by an infected mosquito, the virus incubates for around two weeks. </p>
<p>Most people infected don’t develop symptoms. But, if you’re unlucky, you could develop <a href="https://www.mja.com.au/journal/2012/196/5/murray-valley-encephalitis-review-clinical-features-diagnosis-and-treatment">symptoms</a> ranging from fever and headache to paralysis, encephalitis and coma. </p>
<p>Around 40% of people who develop symptoms won’t fully recover and about 25% die. Generally, one or two human cases are reported in Australia per year.</p>
<p>Since the 1950s, there have been <a href="https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0002656">sporadic outbreaks</a> of Murray Valley encephalitis, most notably in 1974 and 2011. The 1974 outbreak was Australia-wide, resulting in 58 cases and 12 deaths. </p>
<p>It’s likely the virus has been causing disease since at least the early 1900s when epidemics of encephalitis were attributed to a mysterious illness called <a href="https://www.sciencedirect.com/science/article/pii/037811359500074K">Australian X disease</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/260097/original/file-20190221-148517-1h3kl53.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/260097/original/file-20190221-148517-1h3kl53.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/260097/original/file-20190221-148517-1h3kl53.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/260097/original/file-20190221-148517-1h3kl53.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/260097/original/file-20190221-148517-1h3kl53.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/260097/original/file-20190221-148517-1h3kl53.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/260097/original/file-20190221-148517-1h3kl53.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Traditional monitoring of mosquito-borne diseases relies on the collection of mosquitoes using specially designed traps baited with carbon dioxide.</span>
<span class="attribution"><span class="source">Cameron Webb</span></span>
</figcaption>
</figure>
<h2>Early warning system</h2>
<p>Given the severity of Murray Valley encephalitis, health authorities rely on <a href="https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-018-2901-x">early warning systems</a> to guide their responses. </p>
<p>One of the most valuable surveillance tools to date have been chooks because the virus circulates between birds and mosquitoes. Flocks of chickens are placed in areas with past evidence of virus circulation and where mosquitoes are buzzing about.</p>
<p>Chickens are highly susceptible to infection so blood samples are routinely taken and analysed to determine evidence of virus infection. If a chicken tests positive, the virus has been active in an area.</p>
<p>The good news is that even if the chickens have been bitten, they don’t get sick.</p>
<p>Mosquitoes can also be collected in the field using <a href="https://theconversation.com/the-worst-year-for-mosquitoes-ever-heres-how-we-find-out-68433">a variety of traps</a>. Captured mosquitoes are counted, grouped by species and tested to see if they’re carrying the virus. </p>
<p>This method is very sensitive: it can identify as little as one infected mosquito in a group of 1,000. But processing is labour-intensive. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-australian-wildlife-spread-and-suppress-ross-river-virus-107267">How Australian wildlife spread and suppress Ross River virus</a>
</strong>
</em>
</p>
<hr>
<h2>How can technology help track the virus?</h2>
<p>Novel approaches are allowing scientists to more effectively detect viruses in mosquito populations. </p>
<p>Mosquitoes feed on more than just blood. They also need a sugar fix from time to time, usually plant nectar. When they feed on sugary substances, <a href="https://academic.oup.com/jme/article-abstract/44/5/845/973141?redirectedFrom=fulltext">they eject small amounts of virus in their saliva</a>. </p>
<p>This led researchers to develop traps that contain <a href="https://www.pnas.org/content/107/25/11255">special cards coated in honey</a>. When the mosquitoes feed on the cards, they spit out virus, which specific tests can then detect. </p>
<p>We are also investigating whether <a href="https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0006771">mosquito poo</a> could be used to enhance the sugar-based surveillance system. Mosquitoes spit only tiny amounts of virus, whereas they poo a lot (300 times more than they spit). </p>
<p>This mosquito poo can contain a treasure trove of genetic material, <a href="https://www.nature.com/articles/srep24885">including viruses</a>. But we’re still working out the best way to collect the poo. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/260136/original/file-20190221-195883-zv7d4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/260136/original/file-20190221-195883-zv7d4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=386&fit=crop&dpr=1 600w, https://images.theconversation.com/files/260136/original/file-20190221-195883-zv7d4a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=386&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/260136/original/file-20190221-195883-zv7d4a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=386&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/260136/original/file-20190221-195883-zv7d4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=485&fit=crop&dpr=1 754w, https://images.theconversation.com/files/260136/original/file-20190221-195883-zv7d4a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=485&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/260136/original/file-20190221-195883-zv7d4a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=485&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Mosquito poo, shown here after mosquitoes have fed on coloured honey, can be used to detect viruses like Murray Valley encephalitis.</span>
<span class="attribution"><span class="source">Dagmar Meyer</span></span>
</figcaption>
</figure>
<h2>Staying safe from Murray Valley encephalitis</h2>
<p>There is no vaccine or specific treatment for the virus. Avoiding mosquito bites is the only way to protect yourself from the virus. You can do this by:</p>
<ul>
<li><p>wearing protective clothing when outdoors</p></li>
<li><p>avoiding being outdoors when the mosquitoes that transmit the virus are most active (dawn and dusk)</p></li>
<li><p>using <a href="https://theconversation.com/the-best-and-worst-ways-to-beat-mosquito-bites-70274">repellents</a>, mosquito coils, insect screens and mosquito nets</p></li>
<li><p>following public health advisories for your area.</p></li>
</ul>
<p>The virus is very rare and your chances of contracting the disease are extremely low, but not being bitten is the best defence.</p><img src="https://counter.theconversation.com/content/112212/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ana Ramírez is supported by a doctoral scholarship granted by the Australian Institute of Tropical Health and Medicine, James Cook University. </span></em></p><p class="fine-print"><em><span>Andrew van den Hurk has received funding from local, state and federal agencies to study the ecology of mosquito-borne pathogens, and their surveillance and control. He is an employee of the Department of Health, Queensland Government.</span></em></p><p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology and University of Sydney, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on the biology of medically important insects. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p><p class="fine-print"><em><span>Scott Ritchie receives funding from the National Health and Medical Research Council, Menzies HOT NORTH Programme, and Verily Life Sciences to study the ecology of mosquitoes and how to trap them.</span></em></p>Murray Valley encephalitis virus is a rare but potentially fatal mosquito-borne virus. Here’s what you need to know about it.Ana Ramírez, PhD candidate, James Cook UniversityAndrew van den Hurk, Medical Entomologist, The University of QueenslandCameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of SydneyScott Ritchie, Professorial Research Fellow, James Cook UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1072672019-01-14T19:10:34Z2019-01-14T19:10:34ZHow Australian wildlife spread and suppress Ross River virus<figure><img src="https://images.theconversation.com/files/252173/original/file-20181230-47292-1isykoi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mozzies feed on many native species, including the Nankeen Night Heron.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/foto-graffie/8622685489/in/photolist-e8XvZc">Janis Otto/flikr</a></span></figcaption></figure><p>Ross River virus is Australia’s most common mosquito-borne disease. It infects <a href="https://cmr.asm.org/content/14/4/909.short">around 4,000 people a year</a> and, despite being named after a river in North Queensland, is found in all states and territories, including Tasmania. </p>
<p>While the disease isn’t fatal, it can cause debilitating joint pain, swelling and fatigue lasting weeks or even months. It can leave sufferers unable to work or look after children, and is estimated to <a href="https://experts.griffith.edu.au/publication/n7ed6560d90fce1d2a6f7c69459320c1d">cost the economy A$2.7 to A$5.6 million each year</a>.</p>
<p>There is no treatment or vaccine for Ross River virus; the only way to prevent is to avoid mosquito bites.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-what-is-ross-river-virus-24630">Explainer: what is Ross River virus?</a>
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</em>
</p>
<hr>
<p>Mosquitoes pick up the disease-causing pathogen by feeding on an infected animal. The typical transmission cycle involves mosquitoes moving the virus between native animals but occasionally, an infected mosquito will bite a person. If this occurs, the mosquito can spread Ross River virus to the person.</p>
<h2>Animal hosts</h2>
<p>Ross River virus has been found in a range of animals, including rats, <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1751-0813.2002.tb12057.x">dogs</a>, <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1751-0813.1987.tb16129.x">horses</a>, <a href="https://www.ajtmh.org/content/journals/10.4269/ajtmh.2001.65.777">possums</a>, flying foxes, bats and birds. But marsupials – kangaroos and wallabies in particular – are <a href="https://www.liebertpub.com/doi/abs/10.1089/vbz.2014.1617">generally better</a> than other animals at amplifying the virus under experimental infection and are therefore thought to be “reservoir hosts”. </p>
<p>The <a href="https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-018-2733-8">virus circulates</a> in the blood of kangaroos and wallabies for longer than other animals, and at higher concentrations. It’s then much more likely to be picked up by a blood-feeding mosquito. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/246392/original/file-20181120-161615-1fs0exl.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/246392/original/file-20181120-161615-1fs0exl.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/246392/original/file-20181120-161615-1fs0exl.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/246392/original/file-20181120-161615-1fs0exl.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/246392/original/file-20181120-161615-1fs0exl.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/246392/original/file-20181120-161615-1fs0exl.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/246392/original/file-20181120-161615-1fs0exl.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Kangaroos are a common sight around Australia’s coastal wetlands.</span>
<span class="attribution"><span class="source">Dr Cameron Webb (NSW Health Pathology)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Dead-end hosts</h2>
<p>When we think of animals and disease we often try to identify which species are good at transmitting the virus to mosquitoes (the reservoir hosts). But more recently, researchers have started to focus on species that get bitten by mosquitoes but <em>don’t</em> transmit the virus. </p>
<p>These species, known as dead-end hosts, may be important for reducing transmission of the virus. </p>
<p>With Ross River virus, research suggests birds that get Ross River virus from a mosquito cannot transmit the virus to another mosquito. If this is true, having an abundance of birds in and around our urban environments may reduce the transmission of Ross River virus to animals, mosquitoes and humans in cities.</p>
<h2>Other reservoir hosts?</h2>
<p>Even in areas with a high rates of Ross River virus in humans, we don’t always find an abundance of kangaroos and wallabies. So there must be other factors – or animals yet to be identified as reservoirs or dead-end hosts – playing an important role in transmission.</p>
<p>Ross River virus is prevalent in the Pacific Islands, for instance, where there aren’t any kangaroos and wallabies. One study of blood donors in <a href="https://www.sciencedirect.com/science/article/pii/S1201971215001393">French Polynesia</a> found that 42.4% of people tested had previously been exposed to the virus. The rates are even higher in <a href="https://www.sciencedirect.com/science/article/pii/S1201971217300449">American Samoa</a>, where 63% of people had been exposed.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-worst-year-for-mosquitoes-ever-heres-how-we-find-out-68433">The worst year for mosquitoes ever? Here's how we find out</a>
</strong>
</em>
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<hr>
<p>It’s unclear if the virus has recently started circulating in these islands, or if it’s been circulating there longer, and what animals have been acting as hosts.</p>
<h2>What about people?</h2>
<p>Mosquitoes can transmit some viruses, such as <a href="https://theconversation.com/explainer-what-is-dengue-fever-8571">dengue</a> and <a href="https://theconversation.com/does-zika-virus-pose-a-threat-to-australia-53557">Zika</a> between people quite easily. </p>
<p>But the chances of a mosquito picking up Ross River virus when biting an infected human is low, though not impossible. The virus circulates in our blood at lower concentrations and for shorter periods of time compared with marsupials. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/251836/original/file-20181220-103643-1jgbbmv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/251836/original/file-20181220-103643-1jgbbmv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/251836/original/file-20181220-103643-1jgbbmv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/251836/original/file-20181220-103643-1jgbbmv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/251836/original/file-20181220-103643-1jgbbmv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/251836/original/file-20181220-103643-1jgbbmv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/251836/original/file-20181220-103643-1jgbbmv.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">Stop mozzies biting with insect repellents.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/dad-son-use-mosquito-sprayspraying-insect-1081091330?src=TZjDKAkFmWuc_NZLfG7P9Q-1-5">Elizaveta Galitckaia/Shutterstock</a></span>
</figcaption>
</figure>
<p>If humans are infected with Ross River virus, around 30% will develop <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/ross-river-virus-disease">symptoms</a> of joint pain and fatigue (and sometimes a rash) three to 11 days after exposure, while some may not experience any symptoms until three weeks after exposure. </p>
<p>To reduce your risk of contracting Ross River virus, take care to cover up when you’re outdoors at sunset and wear repellent when you’re in outdoor environments where mosquitoes and wildlife may be frequently mixing. </p>
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<strong>
Read more:
<a href="https://theconversation.com/mozzie-repellent-clothing-might-stop-some-bites-but-youll-still-need-a-cream-or-spray-107266">Mozzie repellent clothing might stop some bites but you'll still need a cream or spray</a>
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</em>
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<img src="https://counter.theconversation.com/content/107267/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eloise Stephenson is supported through an Australian Government Research Training Program Scholarship.</span></em></p><p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology and University of Sydney, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p><p class="fine-print"><em><span>Emily Johnston Flies has received funding from The Royal Society of South Australia and the University of South Australia (during her PhD) and her salary is currently funded through an ARC Laureate Fellowship (awarded to Prof Barry Brook) at University of Tasmania.</span></em></p>Thousands of Australians contract Ross River virus each year. Mozzies can infect us with their bites, but only after they’ve bitten an infected animal host.Eloise Skinner, PhD Candidate, Griffith UniversityCameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of SydneyEmily J Flies, Postdoctoral Research Fellow (U.Tasmania), University of TasmaniaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/926112018-03-07T19:25:00Z2018-03-07T19:25:00ZThe buzz from your smartphone won’t stop mosquito bites<p>Forget a peaceful night’s sleep. The whine of a lone mosquito circling your bedroom can be incredibly frustrating. They’re not just the <a href="http://www.who.int/mediacentre/factsheets/fs094/en/">deadliest animals on the planet</a>, they could be the most annoying!</p>
<p>Often various products or apps claim special sounds can stop mosquitos from buzzing. But the science doesn’t back up these claims. And tuning into mosquitoes’ murmurings might even help us prevent disease.</p>
<h2>Why do mosquitoes make that sound?</h2>
<p>All mosquitoes make sound. The mosquitoes you hear are usually the ones a little less decisive about biting. Those more ready to bite will come in, land, suck your blood and fly off before you’ve noticed them. </p>
<p>Those occasionally annoying tones produced by mosquitoes come from the <a href="https://www.sciencenews.org/article/mosquito-flight-unlike-any-other-insect">beating of their wings</a>. The sounds can be wide-ranging and vary between males and females. Each mosquito has its own musical “fingerprint” but its not just the noisy by-product of flight, the tones produced by mosquitoes can be used for communication. Romantic communication.</p>
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Read more:
<a href="https://theconversation.com/what-can-i-eat-to-stop-mosquitoes-biting-me-87178">What can I eat to stop mosquitoes biting me?</a>
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<p>Male and female mosquitoes of some species have been documented responding to the wing beat frequencies of each other in a “<a href="https://www.sciencedirect.com/science/article/pii/S0960982209009816">mating duet</a>”. In a phenomenon known as “harmonic convergence” the mosquitoes change the frequency of their wing beats in response to each other. This <a href="https://www.sciencedirect.com/science/article/pii/S0960982206016368">helps identify potential mates</a> and make an <a href="http://science.sciencemag.org/content/323/5917/1077">assessment of the quality</a> of the potential mate based on the quality of their “song”.</p>
<p>This romantic sing-along has been reported in a range of mosquitoes involved in the transmission of <a href="http://science.sciencemag.org/content/323/5917/1077">dengue</a> and <a href="https://www.sciencedirect.com/science/article/pii/S0960982209020557">malaria</a> pathogens. So an understanding of how mosquitoes make and respond to sound could provide better mosquito surveillance or control strategies.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/208739/original/file-20180303-65522-1f8ega5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/208739/original/file-20180303-65522-1f8ega5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/208739/original/file-20180303-65522-1f8ega5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/208739/original/file-20180303-65522-1f8ega5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/208739/original/file-20180303-65522-1f8ega5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/208739/original/file-20180303-65522-1f8ega5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/208739/original/file-20180303-65522-1f8ega5.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">This is the mosquito buzzing in your ear, the brown house mosquito (Culex quinquefasciatus) most commonly comes inside and will buzz about your bedroom at night.</span>
<span class="attribution"><span class="source">Stephen Doggett (NSW Health Pathology)</span></span>
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</figure>
<p><audio preload="metadata" controls="controls" data-duration="131" data-image="" data-title="Sounds of the Brown House Mosquito (_Culex quinquefasciatus_)" data-size="2111946" data-source="Cameron Webb" data-source-url="https://soundcloud.com/seaworthy/culex-quinquefasciatus" data-license="Author provided (no reuse)" data-license-url="">
<source src="https://cdn.theconversation.com/audio/1073/cameronwebb-mosquitoesounds-culexquinquefasciatus-feb2018.mp3" type="audio/mpeg">
</audio>
<div class="audio-player-caption">
Sounds of the Brown House Mosquito (<em>Culex quinquefasciatus</em>)
<span class="attribution"><a class="source" rel="nofollow" href="https://soundcloud.com/seaworthy/culex-quinquefasciatus">Cameron Webb</a>, <span class="license">Author provided (no reuse)</span><span class="download"><span>2.01 MB</span> <a target="_blank" href="https://cdn.theconversation.com/audio/1073/cameronwebb-mosquitoesounds-culexquinquefasciatus-feb2018.mp3">(download)</a></span></span>
</div></p>
<h2>Sounds to keep mosquitoes away</h2>
<p>There is a long history of entrepreneurs marketing various sound-producing gadgets to repel mosquitoes. The sounds broadcast typically covered a range of frequencies, some even the sounds of mosquito predators (such as the wing beat frequencies of dragonflies). There was <a href="http://www.bbc.com/news/magazine-20669080">little scientific evidence</a> they worked.</p>
<p>There are now dozens of “mosquito repellent” apps available online for your smartphone. The sounds may now be available with a swipe of the finger, rather than a flick of a switch, but the general sale pitch remains the same, silence the mosquito bites with sound.</p>
<p>It’s all wishful thinking. There is no evidence sound emitting devices can stop mosquitoes biting. A review of field testing showed <a href="http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD005434.pub2/full">no protection was provided</a>. Similarly, laboratory studies <a href="http://europepmc.org/abstract/med/2906666">failed to show any bite prevention</a>.</p>
<p>Studies have even demonstrated these sound-emitting devices actually increase mosquito bites by the <a href="https://www.sciencedirect.com/science/article/pii/S0001706X12003452">Asian Tiger Mosquito</a> and <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1948-7134.2010.00061.x/full">Yellow Fever mosquito</a>.</p>
<p>There’s no reason to think smartphone apps are <a href="http://www.independent.co.uk/travel/news-and-advice/can-you-repel-mosquitoes-with-an-app-a6981121.html">going to perform any better</a> than any of the other gimmicks that have come and gone from supermarket shelves over the decades. If they cannot stop mosquito bites, they won’t <a href="http://www.scielo.br/scielo.php?pid=S1519-566X2001000300030&script=sci_arttext">prevent mosquito-borne disease</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/208782/original/file-20180304-65516-tl91zz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/208782/original/file-20180304-65516-tl91zz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=373&fit=crop&dpr=1 600w, https://images.theconversation.com/files/208782/original/file-20180304-65516-tl91zz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=373&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/208782/original/file-20180304-65516-tl91zz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=373&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/208782/original/file-20180304-65516-tl91zz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=469&fit=crop&dpr=1 754w, https://images.theconversation.com/files/208782/original/file-20180304-65516-tl91zz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=469&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/208782/original/file-20180304-65516-tl91zz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=469&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">There are dozens of apps available for your smartphone but there is little evidence they provide any genuine protection from biting mosquitoes.</span>
<span class="attribution"><span class="source">Cameron Webb (NSW Health Pathology)</span></span>
</figcaption>
</figure>
<h2>Calling all mosquitoes!</h2>
<p>Sound may not be helping stop mosquito bites but it could still be useful in managing mosquito-borne disease outbreaks.</p>
<p>Mosquito traps used by scientists and health authorities around the world focus on <a href="https://theconversation.com/the-worst-year-for-mosquitoes-ever-heres-how-we-find-out-68433">attracting female mosquitoes</a> as they search for blood or a place to lay eggs. There’s generally not been much interest in males.</p>
<p>Exploiting the attraction of male mosquitoes to the sounds of females is being tested in new surveillance technologies. Baiting mosquito traps with sound devices replicating the flight tone of female <em>Aedes aegypti</em> mosquitoes collected <a href="https://phys.org/news/2015-10-male-mosquitoes-lured-female-wing-beats.html">approximately twice as many male mosquitoes</a> compared to traps without sound. </p>
<p>Female mosquitoes didn’t respond to sound but when biosecurity surveillance relies on picking up as many mosquitoes as possible, the additional male mosquitoes collected increases the likelihood of detecting the arrival of exotic mosquitoes.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/new-mosquito-threats-shift-risks-from-our-swamps-to-our-suburbs-56350">New mosquito threats shift risks from our swamps to our suburbs</a>
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</em>
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<p>The “acoustic fingerprint” of mosquitoes may be also be key to new mosquito traps that not only catch the mosquitoes, but <a href="https://medium.com/the-physics-arxiv-blog/entomologists-have-never-been-able-to-identify-flying-insects-automatically-until-now-ee4d93067443">can identify them too</a>. Studies have investigated how wing beat frequencies can be used to identify the mosquito species and <a href="https://www.sciencedirect.com/science/article/pii/S0168169915002471">even tell if they’re male or female</a>.</p>
<p>There is little doubt <a href="https://news.microsoft.com/transform/videos/technology-turns-mosquitoes-into-allies-instead-of-enemies-in-the-fight-against-deadly-viruses/#sm.000006ip5r949vdw2rexdyfudjj3x">traps of this nature</a> will play a critical role in providing an early warning of future mosquito-borne disease outbreaks.</p>
<p>For now though, if it’s the buzz of bedroom mosquitoes keeping you awake, there are some easy solutions. Screening your windows will keep them out. Using insecticides will help but are not always necessary.</p>
<p>Switch on a ceiling or oscillating fan and the breeze will blow away the carbon dioxide you’re exhaling that’s attracting the mosquitoes. It will also make it just a little harder for the mosquito to circle your bed and buzz in your ears!</p><img src="https://counter.theconversation.com/content/92611/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p>The sounds of mosquitoes may be annoying to many but tuning into their musical whines could help design new mosquito traps. Just don’t expect sounds from your smartphone to protect you from bites!Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, South Western Sydney Local Health DistrictLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/914192018-02-25T07:34:53Z2018-02-25T07:34:53ZHow we pinned down what attracts mosquitos that carry dengue fever<figure><img src="https://images.theconversation.com/files/206221/original/file-20180213-44639-paf95e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Flickr/AFPMB</span></span></figcaption></figure><p>Kenya has seen a rapid <a href="http://www.who.int/csr/don/09-august-2016-chikungunya-kenya/en/">increase</a> in <a href="https://theconversation.com/delhi-has-been-hit-by-a-chikungunya-epidemic-what-is-this-disease-65592">chikungunya</a> and <a href="https://theconversation.com/explainer-what-is-dengue-fever-8571">dengue viruses</a> outbreaks since 2016. Both are mosquito-borne viral infections that lead to debilitating joint and muscle pain.</p>
<p>The two sister diseases are transmitted by the <a href="https://www.ncbi.nlm.nih.gov/pubmed/5301574">Aedes aegypti</a> – a black mosquito with white spots that only bites during the day. The viruses are <a href="http://www.who.int/mediacentre/factsheets/fs327/en/">spread</a> by the female mosquito when she searches for blood as a source of protein and iron which she needs to <a href="https://www.cabdirect.org/cabdirect/abstract/19900596879">form mosquito eggs</a>. </p>
<p>The outbreaks in Kenya have been in areas normally associated with the diseases, such as the coastal city of Mombasa, as well as new areas such as the North Eastern part of the country. </p>
<p>Compared with the large amount of research that’s been done on the vectors that carry malaria, not many studies have been done on those that spread dengue and chikungunya. The main reason for this is that malaria continues to kill one million people each year while dengue and chikungunya claim less than <a href="http://www.eliminatedengue.com/our-research/dengue-fever">25 000 lives a year</a>.</p>
<p>As a result only a limited number of methods have been developed to manage the Aedes aegypti.</p>
<p>We wanted to understand what attracts the black mosquito to its hosts. To do this, we compared commercially available bait traps that contained bait made from natural body odours to see which were more attractive to mosquitoes in their natural environments. Our <a href="https://www.ncbi.nlm.nih.gov/pubmed/25246030">study</a> found that body odour lured the mosquitoes better. We went further and narrowed the attraction down to <a href="https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-015-0866-6">four groups of chemical compounds</a> in body odour. </p>
<p>Our findings provide the first evidence of how chemical compounds found in body odour can be used to develop effective bait traps to control dengue and chikungunya. </p>
<h2>Finding the perfect host</h2>
<p>Studies have shown that the <a href="https://www.ncbi.nlm.nih.gov/pubmed/1983456">lure of carbon dioxide</a> in the human breathe help mosquitoes detect a host. Several additional pieces of research have gone further, showing that mosquitoes are attracted to several different stimuli including physical, visual and olfactory. Physical cues include heat and moisture while visual stimuli include light, colour and form.</p>
<p>One study, for example showed that <a href="https://www.ncbi.nlm.nih.gov/pubmed/2230769">mosquitoes were attracted</a> to objects that had been heated and covered in body odour. In another, researchers established that a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3162918/">combination</a> of heat, moisture and body odour was even more <a href="https://www.nature.com/scientificamerican/journal/v233/n1/pdf/scientificamerican0775-104.pdf">potent</a>. </p>
<p>And in yet <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4983048/">another study</a>, where light traps were baited with carbon dioxide, researchers were able to establish that one of the three mosquitoes that spread malaria – the anopheles gambiae mosquito – bites their hosts at night.</p>
<h2>All about the smell</h2>
<p>Efforts to understand what attracts the Aedes aegypti mosquitoes has been researched in ernest over the past 12 years. </p>
<p>The challenge with many previous studies is that most were conducted on samples in laboratories and not in the field. We set about conducting our tests in the field. In addition, we wanted to test the entire body odour and not just the breathe. </p>
<p>We did two studies. In the first, we used samples of body odour from used socks and worn t-shirts in bait traps in the field. When we compared them to the commercial versions of the traps, we found that the mosquitoes were more attracted to the body odour traps. </p>
<p>Once we established this, we then analysed the body odour and identified most potent chemical compounds. These were from four major chemical groups: the aldehydes, fatty acids, ketones and alcohols. </p>
<p>Aldehydes and fatty acids dominate human odour profiles. But each person has a unique chemical compound profile, with different ratios of the four groups of compounds. This means that different people offer different levels of attractiveness to a mosquito. </p>
<p>The chemical compound profile also changes at different points of the body of an individual. This makes certain parts of the body more or less attractive to the mosquito. </p>
<p>Our second study took these compounds into baited traps. We found that when the compounds were combined with carbon dioxide, they sharpened the body odours that mosquitoes were able to pick up using their antennae.</p>
<p>Our results suggest that there are additional chemical compound candidates that could be commercialised to attract mosquitoes, particularly Aedes aegypti. </p>
<h2>Trap bait</h2>
<p>Ultimately, our findings could lead to a technology made from compounds that come from human body odours to lure and kill mosquitoes that spread the dengue and chikungunya viruses. </p>
<p>For now our next steps are to identify the other compounds in body odour that could also attract mosquitoes. Once these are identified they will need to be tested to see if they are also capable of being used as super bait for mosquitoes.</p><img src="https://counter.theconversation.com/content/91419/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eunice Anyango Owino is a medical entomologist and works as a lecturer at the University of Nairobi. Funding for the reported findings was from the Swedish International Development Cooperation Agency, SIDA and the research was based at the Behavioural and Chemical Ecology Unit, icipe. </span></em></p>In the future, traps for mosquito that spread the dengue and chikungunya virus could be made from the carbon dioxide in human breathe as well as body odour.Eunice Anyango Owino, Medical Entomologist at the School of Biological Sciences, University of NairobiLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/916492018-02-14T19:06:25Z2018-02-14T19:06:25ZHow the new mozzie emoji can create buzz to battle mosquito-borne disease<figure><img src="https://images.theconversation.com/files/205930/original/file-20180212-58315-co93r9.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Set to land in mid 2018, the new mosquito emoji will give people a new way to talk about mozzies. </span> <span class="attribution"><span class="source">Cameron Webb </span>, <span class="license">Author provided</span></span></figcaption></figure><p>Mosquitoes are coming. The <a href="http://blog.unicode.org/2018/02/unicode-emoji-110-characters-now-final.html">Unicode Consortium</a> has just announced that alongside your smiling face – or perhaps crying face – emoji you’ll soon be able to add a mosquito. </p>
<p>The <a href="http://www.unicode.org/emoji/charts-11.0/emoji-released.html#x1f99f">mosquito emoji</a> will join the rabble of emoji wildlife including butterflies, bees, whales and rabbits. </p>
<p>We see a strong case that the addition of the much maligned mozzie to your emoji toolbox could help health authorities battle the health risks associated with these bloodsucking pests. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-i-use-emoji-in-research-and-teaching-75399">Why I use emoji in research and teaching</a>
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<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/206087/original/file-20180212-58352-kkry57.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/206087/original/file-20180212-58352-kkry57.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/206087/original/file-20180212-58352-kkry57.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/206087/original/file-20180212-58352-kkry57.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/206087/original/file-20180212-58352-kkry57.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/206087/original/file-20180212-58352-kkry57.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/206087/original/file-20180212-58352-kkry57.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">It may be small but it could make all the difference in battling mosquito-borne disease outbreaks.</span>
<span class="attribution"><span class="source">https://emojipedia.org/mosquito/</span></span>
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</figure>
<p>Given it is the <a href="https://www.gatesnotes.com/Health/Most-Lethal-Animal-Mosquito-Week">most dangerous animal on the planet</a>, the mosquito is more than deserving of an emoji. But will it make a difference to the way the science behind mosquito research is communicated? Could it influence how the community engages with public health messages of local authorities? Will more people wear insect repellent because of the mosquito emoji? </p>
<p>We won’t know for sure until the mozzie is released.</p>
<h2>Where did the mosquito emoji idea come from?</h2>
<p>A staggering <a href="http://www.adweek.com/digital/facebook-world-emoji-day-stats-the-emoji-movie-stickers/">sixty million emoji</a> are shared on Facebook each day!</p>
<p>We’ve needed a mosquito emoji for a while now (although the blood filled syringe has been a useful substitute). While heavily promoted last year by the <a href="https://ccp.jhu.edu/">Johns Hopkins Center for Communication Programs</a> and the <a href="https://www.gatesfoundation.org/">Bill & Melinda Gates Foundation</a>, it was one of us, an Australian virologist, who played a critical role in the emoji’s development by <a href="http://www.unicode.org/L2/L2017/17295-mosquito-emoji.pdf">submitting the original proposal</a> in June 2016.</p>
<p>The idea arose during the Zika virus epidemic in South America, when the mosquito-borne infection was triggering <a href="https://theconversation.com/does-zika-virus-pose-a-threat-to-australia-53557">many questions and few answers</a>. While the emoji doesn’t represent a specific mosquito species, it captures the distinctive shape of a mosquito. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/205925/original/file-20180212-58335-6mpo22.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/205925/original/file-20180212-58335-6mpo22.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=405&fit=crop&dpr=1 600w, https://images.theconversation.com/files/205925/original/file-20180212-58335-6mpo22.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=405&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/205925/original/file-20180212-58335-6mpo22.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=405&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/205925/original/file-20180212-58335-6mpo22.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=510&fit=crop&dpr=1 754w, https://images.theconversation.com/files/205925/original/file-20180212-58335-6mpo22.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=510&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/205925/original/file-20180212-58335-6mpo22.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=510&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Time spent outdoors may be the perfect opportunity to employ the mozzie emoji.</span>
<span class="attribution"><span class="source">jiulliano</span></span>
</figcaption>
</figure>
<h2>How might a mozzie emoji make a difference?</h2>
<p>The mozzie emoji will give health professionals and academics a more relatable way to communicate health risks and new research using social media. </p>
<p>Surveillance programs across the world routinely <a href="https://theconversation.com/the-worst-year-for-mosquitoes-ever-heres-how-we-find-out-68433">monitor mosquitoes</a>. Local health authorities could simply tweet a string of mozzie emoji to indicate the relative mosquito risk or identify that there is a risk. Adding in the new <a href="https://www.unicode.org/L2/L2017/17113-science-emoji.pdf">microbe emoji</a> (currently in the form of a generic green microscopic shape) could even indicate the presence of mosquito-borne viruses such as <a href="https://theconversation.com/explainer-what-are-antibodies-and-why-are-viruses-like-dengue-worse-the-second-time-68227">dengue virus</a>, <a href="https://theconversation.com/explainer-west-nile-virus-outbreak-in-the-united-states-8935">West Nile virus</a> or <a href="https://theconversation.com/explainer-what-is-ross-river-virus-24630">Ross River virus</a>.</p>
<p>Emoji could remind us to tip out, drain or cover backyard water-holding containers <a href="https://theconversation.com/hidden-housemates-the-mosquitoes-that-battle-for-our-backyards-59072">that may be a source of mosquitoes</a> following rain. Weather monitoring services or health authorities could simply add the mosquito emoji in alerts featuring a string of storm clouds and water droplets. </p>
<p>More than likely, it’ll be used by the public to punctuate those summer tweets complaining of bites and bumps following backyard BBQs. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-best-and-worst-ways-to-beat-mosquito-bites-70274">The best (and worst) ways to beat mosquito bites</a>
</strong>
</em>
</p>
<hr>
<h2>Social media is changing public health</h2>
<p>Social media will continue to play a role in <a href="http://www.phrp.com.au/issues/december-2017-volume-27-issue-5/live-and-trending-the-next-step-for-public-health-campaigns/">public health campaigns</a>. Whether <a href="http://www.couriermail.com.au/news/queensland/nutritionists-warn-conflicting-eating-advice-from-social-media-creates-dangerously-unhealthy-diets/news-story/c84145728a2963d1e91b0f9b8f1e9fc4">promoting better nutrition</a>, <a href="https://www.asc.upenn.edu/news-events/news/social-networks-can-motivate-people-exercise-more-penn-study-finds">encouraging exercise</a> or <a href="http://www.smh.com.au/national/health/how-twitter-more-accurately-maps-vaccination-coverage-than-census-data-20170511-gw299i.html">addressing concerns over vaccine coverage</a>, Twitter, Facebook, Instagram, and whatever platform comes next will remain important for the communication tool kits of local health authorities.</p>
<p>Smartphones have already been identified as tools for surveillance of <a href="https://www.sciencedirect.com/science/article/pii/S0001706X13002714">mosquito-borne disease outbreaks</a>. </p>
<p>The addition of a mosquito emoji, together with concise public health messaging, may increase the chances a message hits home, maybe even changing behaviour and reducing the risk of bites.</p>
<h2>Simple communication works</h2>
<p>The usefulness of emoji as a communication tool has been shown in several fields of research. Emoji can accurately express <a href="https://www.sciencedirect.com/science/article/pii/S0950329316301781">emotional associations with commercial products</a>, reflect <a href="https://newsnetwork.mayoclinic.org/discussion/physical-activity-data-emojis-on-apple-watch-correlated-with-patient-reported-outcomes/">state of mind in cancer patients</a> and aid <a href="http://www.abc.net.au/news/2017-10-04/sydney-childrens-hospital-using-emojis-to-interact-with-patients/9011782">communication with sick young patients</a>. </p>
<p>Applying these examples to the mozzie emoji, we predict it may aid citizen science – for example, if the community can signal how bad nuisance-biting mosquitoes are in their area. Perhaps this mobile surveillance network could help pick up the introduction of exotic mosquitoes such as the Asian Tiger Mosquito, a species often first detected because of reports by the community. Measuring a rise in mozzie emoji use may <a href="http://datafication.com.au/feel-the-pulse-of-the-nation/">identify regions</a> under attack by mosquitoes.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/new-mosquito-threats-shift-risks-from-our-swamps-to-our-suburbs-56350">New mosquito threats shift risks from our swamps to our suburbs</a>
</strong>
</em>
</p>
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<p>Big corporations have already identified the usefulness of emoji, and fork out serious cash for <a href="http://www.adweek.com/digital/these-4-brands-are-embracing-twitter-emoji-craze-167979/">hashtag-customized emoji</a>. If branded emoji work for commercial enterprises, why not for public health and why not a mosquito? A simple image may provide a critical reminder to put on insect repellent, sleep under a bed net or get appropriately vaccinated for mosquito-borne diseases such as <a href="http://www.who.int/mediacentre/factsheets/fs386/en/">Japanese encephalitis</a> or <a href="http://www.who.int/mediacentre/factsheets/fs100/en/">Yellow Fever</a>.</p>
<p>It is increasingly difficult to escape our social media streams, and emoji use shows no sign of waning. Health authorities should embrace these tiny visual prompts to better engage the community with key health messages. </p>
<p>The mozzie emoji may pave the way for more medically important arthropods: perhaps the tick, flea, lice and bed bug emoji will be on their way soon. Perhaps even viruses and bacteria.</p>
<p>From the middle of 2018, we look forward to watching the creative ways researchers, health workers and the general public incorporate the mosquito emoji into their communications.</p><img src="https://counter.theconversation.com/content/91649/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p><p class="fine-print"><em><span>Ian M. Mackay has received funding from NHMRC and ARC. </span></em></p>The mozzies are coming! A mosquito emoji will be available on your devices in mid 2018, providing a new angle for communicating the science and health implications of these very dangerous insects.Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of SydneyIan M. Mackay, Adjunct assistant professor, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/885482017-12-18T19:14:09Z2017-12-18T19:14:09ZAre mosquito coils good or bad for our health?<figure><img src="https://images.theconversation.com/files/197852/original/file-20171205-22977-u98sru.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some experts have likened burning a mosquito coil in a closed room to smoking 100 cigarettes. </span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/w/index.php?curid=41527545">By trini, CC BY 2.1 jp</a></span></figcaption></figure><p>The sight and smell of smouldering mosquito coils is a mainstay of summer. But is all that smoke really keeping away the swarms of mosquitoes, and is breathing in the smoke worse than mosquito bites for our health?</p>
<p>The burning of aromatic plant material to keep away swarms of mosquitoes is an integral part of many cultural traditions around the world. But it wasn’t until the early 1900s that the distinctively shaped mosquito coil was born, thanks to Japanese entrepreneurs Eiichiro and Yuki Ueyama and their <a href="https://www.japantimes.co.jp/news/2013/07/15/reference/mosquito-coils/">katori senk</a> (mosquito-killing incense).</p>
<p>While traditional coils and sticks were made from a pyrethrum paste, modern mosquito coils mostly contain either pyrethroid insecticides or plant-derived substances such as citronella. They’re cheap, portable and generally effective at reducing mosquito bites, but do they actually reduce the risks of mosquito-borne disease?</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-best-and-worst-ways-to-beat-mosquito-bites-70274">The best (and worst) ways to beat mosquito bites</a>
</strong>
</em>
</p>
<hr>
<h2>How do they work?</h2>
<p>Mosquito coils contain a mix of substances. Along with the products that deter mosquito biting, there are also products that hold the coil together and enable it to smoulder slowly.</p>
<p>Mosquito coils work in one of two ways. Those that contain insecticides will kill (or at least “knock down”) mosquitoes, while those that contain aromatic substances (such as citronella) will repel mosquitoes or reduce the likelihood they’ll bite.</p>
<p>Mosquito coils and their role in killing or repelling mosquitoes has been well studied. Despite differences between the chemical constituents of products and the ways in which they are tested, they will generally <a href="https://parasitesandvectors.biomedcentral.com/articles/10.1186/1756-3305-5-287">reduce the ability of mosquitoes to bite people</a>.</p>
<p>The problem is, less nuisance-biting by mosquitoes is good but when there is a risk of disease, you need to stop all mosquito bites. Are mosquito coils doing enough?</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-do-wrist-bands-work-to-repel-mozzies-50186">Health Check: do wrist bands work to repel mozzies?</a>
</strong>
</em>
</p>
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<h2>Preventing bites and disease</h2>
<p>Mosquito-borne pathogens kill more than half a million people a year and make hundreds of thousands of people sick. Malaria is the worst of these, with recent reports from the <a href="http://www.who.int/malaria/publications/world-malaria-report-2017/en/">World Health Organisation</a> suggesting the steady improvements in the burden of disease are slowing, and the situation may even be getting worse. </p>
<p><a href="https://theconversation.com/explainer-what-is-dengue-fever-8571">Dengue</a> continues to have wide ranging impacts. Australia has also seen record-breaking epidemics of <a href="http://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1005070">Ross River virus disease</a> in recent years.</p>
<p>To prevent public health risk associated with mosquitoes, most people have to rely on “covering up” with long-sleeved shirts and long pants, sleeping under bed nets, <a href="http://www.phrp.com.au/issues/december-2016-volume-26-issue-5/a-review-of-recommendations-on-the-safe-and-effective-use-of-topical-mosquito-repellents/">applying topical insect repellents</a> or burning mosquito coils.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/197880/original/file-20171205-31128-1udv2f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/197880/original/file-20171205-31128-1udv2f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/197880/original/file-20171205-31128-1udv2f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/197880/original/file-20171205-31128-1udv2f7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/197880/original/file-20171205-31128-1udv2f7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/197880/original/file-20171205-31128-1udv2f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/197880/original/file-20171205-31128-1udv2f7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/197880/original/file-20171205-31128-1udv2f7.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">No links have been found between mosquito coils and lung cancer.</span>
<span class="attribution"><span class="source">from www.shutterstock.com</span></span>
</figcaption>
</figure>
<p>While there is <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1708-8305.2010.00402.x/full">general consensus</a> among experts that mosquito coils may be useful in preventing mosquito-borne disease, proving mosquito-borne disease prevention is missing. <a href="https://academic.oup.com/jtm/article/11/2/92/1803449">A review of 15 previously published studies</a> showed there’s no evidence burning insecticide-containing mosquito coils prevented malaria. <a href="http://www.ajtmh.org/content/journals/10.4269/ajtmh.2006.74.692#html_fulltext">Similar studies</a> indicated there was no strong evidence that routine burning of mosquito coils prevented dengue risk, either.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sniffing-out-new-repellents-why-mozzies-cant-stand-the-deet-33457">Sniffing out new repellents: why mozzies can't stand the DEET</a>
</strong>
</em>
</p>
<hr>
<h2>Health concerns</h2>
<p>There’s growing concern about the adverse health impacts associated with the burning of mosquito coils and sticks indoors. The <a href="https://www.ncbi.nlm.nih.gov/pubmed/16180929/">insecticide products</a> used are generally considered safe, but it’s the particulate matter produced from a smouldering mosquito coil that poses the greatest risk. Is it correct to conclude “<a href="http://www.thehindu.com/sci-tech/health/mosquito-coils-incense-sticks-contain-carcinogens-says-expert/article6686633.ece">burning one mosquito coil in a closed room amounts to smoking roughly 100 cigarettes</a>” as some have claimed?</p>
<p>The link between smoking cigarettes and poor health outcomes is clear. What about mosquito coil smoke, especially if there’s almost daily exposure, as there is in some countries?</p>
<p>One study estimated the particulate matter produced from burning one mosquito coil was <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1241646/">equivalent to burning 75-137 cigarettes</a>. This amount of exposure <a href="http://journals.sagepub.com/doi/abs/10.1177/1420326X9400300510?journalCode=ibea">poses a health risk</a>, but there is a lack of clear evidence that the long-term exposure to mosquito coil smoke increases the risk of more serious health impacts such as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4771599/">lung cancer</a>. In the face of this uncertainty, the key message should be to avoid prolonged exposure, especially in enclosed spaces.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/chemical-or-natural-whats-the-best-way-to-repel-mozzies-36879">Chemical or natural: what's the best way to repel mozzies?</a>
</strong>
</em>
</p>
<hr>
<h2>Balancing risks</h2>
<p>In Australia, all products that purport to kill or repel mosquitoes must be registered by the <a href="https://apvma.gov.au/">Australian Pesticides and Veterinary Medicines Authority</a>. Check the packaging for a registration number. There are dozens of variations on “mosquito coils”, including sticks, coils, candles and a variety of “smokeless”, plug-in devices. Fortunately, some of the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1241643/">more dangerous chemicals found in mosquito coils</a> are not used in products produced and sold locally in Australia.</p>
<p>There’s enough evidence to show that when used outdoors, burning a mosquito coil will assist in reducing mosquito bites, but should be used judiciously. Using them <a href="https://theconversation.com/the-best-and-worst-ways-to-beat-mosquito-bites-70274">in combination with topical insect repellents</a> probably provides the best protection. Their use in closed rooms is best avoided – “smokeless” devices are worth considering as an alternative.</p>
<p>Recently, consumer products have been made available in Australia that contain the insecticide <a href="https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-017-2219-0">Metofluthrin</a>, an insecticide shown to hold great potential for managing mosquito-borne disease. Products of this nature are better suited to indoor use than mosquito coils so may be important in controlling outbreaks of disease.</p>
<p>They also may help knock off that one stray mosquito in the bedroom whose annoying buzz is keeping you awake at night.</p><img src="https://counter.theconversation.com/content/88548/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p>Mosquito coils can help beat the bite of mosquitoes are most effective outdoors, and best avoided in closed, indoor settings.Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/802692017-07-16T19:56:40Z2017-07-16T19:56:40ZMozzies are evolving to beat insecticides – except in Australia<figure><img src="https://images.theconversation.com/files/178024/original/file-20170713-9462-16t5ncj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mosquitoes are the main vectors for dengue and zika. Insecticides are our best weapon against them. </span> <span class="attribution"><span class="source">Anja Jonsson/Flickr</span></span></figcaption></figure><p>Chemical pesticides have been used for many years to control insect populations and remain the most important method of managing diseases carried by pests, including mosquitoes. However, insects have fought back by evolving resistance to many pesticides. <a href="https://www.pesticideresistance.org/">There are now thousands of instances of evolved resistance</a>, which make some chemical classes completely ineffective.</p>
<p>The <em>Aedes</em> mosquito, largely responsible for the spread of viruses like dengue and zika, has globally developed <a href="http://unifeb.edu.br/uploads/arquivos/revista-cientifica/Toxicidade_aguda_de_inseticidas_e_espalhante_usados_no_controle_de_vetores.pdf">resistance to commonly used chemicals, including pyrethroids</a>. Pyrethroids are the most used insecticides in the world, which includes the control of dengue outbreaks and quarantine breaches at air and sea ports.</p>
<p>In Asia and the Americas, pyrethroid resistance in <em>Aedes</em> mosquitoes is now <a href="http://journal.tropika.net/scielo.php?script=sci_arttext&pid=s2078-86062010000100003&lng=en">widespread</a>. In Australia, our mosquitoes have not developed these defences and pyrethroids are still very effective.</p>
<p>The difference lies in our stringent and careful protocols for chemical use. As the global community fights zika and other mosquito-borne diseases, there are lessons to be learned from Australia’s success. </p>
<h2>Developing resistance</h2>
<p>Mosquitoes usually become resistant to pyrethroids through the <a href="http://www.mdpi.com/2075-4450/7/4/60">mutation of a sodium channel gene</a> that controls the movement of ions across cell membranes. Mutations in a single gene are enough to make mosquitoes almost completely resistant to the level of pyrethroids used in insecticides. </p>
<p>The mutations first arises in a population by chance, and are rare. However, they rapidly spread as resistant females breed. The more times a mosquito population is exposed to the same chemical, the more the natural selection process favours their impervious offspring.</p>
<p>Eventually, when many individuals in a population carry the resistance mutation, the chemical becomes ineffective. This can <a href="https://www.mosquitonets.com/blog/the-practice-of-fogging/">happen where insecticide “fogging” is common practice</a>. Overseas, fogging is sometimes undertaken across entire neighbourhoods, several times a month, <a href="http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0004551">despite concerns about its effectiveness</a> as well as <a href="http://www.todayonline.com/voices/widespread-fogging-may-do-more-harm-good">its environmental and health impacts</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/178025/original/file-20170713-10278-1tiyfhp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/178025/original/file-20170713-10278-1tiyfhp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=389&fit=crop&dpr=1 600w, https://images.theconversation.com/files/178025/original/file-20170713-10278-1tiyfhp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=389&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/178025/original/file-20170713-10278-1tiyfhp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=389&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/178025/original/file-20170713-10278-1tiyfhp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=489&fit=crop&dpr=1 754w, https://images.theconversation.com/files/178025/original/file-20170713-10278-1tiyfhp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=489&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/178025/original/file-20170713-10278-1tiyfhp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=489&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A pest exterminator carries out insecticide fogging in an apartment block in Singapore.</span>
<span class="attribution"><a class="source" href="http://one.aap.com.au/#/search/mosquitoes?q=%7B%22pageSize%22:25,%22pageNumber%22:2%7D">EPA, Wallace Woon/AAP</a></span>
</figcaption>
</figure>
<p>Once resistance develops, it can spread to non-resistant mosquito populations in other areas. Pest species, including mosquitoes, are often highly mobile because they fly or are carried passively (in vehicles, ships and planes) at any stage of their life cycle. Their mobility means mutations spread quickly, crossing borders and possibly seas. </p>
<h2>We can still control Australian mosquitoes</h2>
<p>Despite this, Australian populations of <em>Aedes</em> mosquitoes remain susceptible to pyrethroids. <em>Aedes aegypti</em> (the yellow fever mosquito) is the main disease-carrying mosquito in Australia. Its population is restricted to urban areas of northern Queensland, where dengue can occur. </p>
<p>Recent research found that <a href="https://academic.oup.com/jme/article-abstract/doi/10.1093/jme/tjx145/3964514/Pyrethroid-Susceptibility-Has-Been-Maintained-in?redirectedFrom=fulltext">all Australian populations of this species are still vulnerable to pyrethroids</a>. None of the hundreds of mosquitoes tested had any mutations in the sodium channel gene, despite the high incidence of such mutations in <a href="https://www.ncbi.nlm.nih.gov/pubmed/26463408">mosquito populations of South-East Asia</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/178027/original/file-20170713-19645-sqvtig.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/178027/original/file-20170713-19645-sqvtig.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/178027/original/file-20170713-19645-sqvtig.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/178027/original/file-20170713-19645-sqvtig.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/178027/original/file-20170713-19645-sqvtig.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=507&fit=crop&dpr=1 754w, https://images.theconversation.com/files/178027/original/file-20170713-19645-sqvtig.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=507&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/178027/original/file-20170713-19645-sqvtig.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=507&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A female <em>Aedes aegypti</em> mosquito during a feed.</span>
<span class="attribution"><a class="source" href="https://phil.cdc.gov/phil/details.asp?pid=9178">James Gathany, CDC Prof Frank Hadley Collins/Wikimedia</a></span>
</figcaption>
</figure>
<p>We believe these mosquitoes remain vulnerable to pyrethroids because in Australia pressure to select for resistance has been low. </p>
<p>Australia does not carry out routine fogging. If <a href="https://www.health.qld.gov.au/__data/assets/pdf_file/0022/444433/dengue-mgt-plan.pdf">dengue is detected in an area</a>, pyrethoids are used in highly regimented and limited fashion. Spraying is restricted to the insides of premises within selected house blocks, and then only for a short period. </p>
<p>Importantly, water-filled artificial containers, which can serve as a habitat for larvae, are treated with insect growth regulators, which do not select for the pyrethroid resistance mutations. </p>
<h2>Exporting resistance</h2>
<p>With chemical resistance growing around the world, it is more urgent than ever that we co-ordinate action to control and reduce risk of resistance. Unfortunately, no global guidelines exist to minimise the evolution of resistance in mosquitoes. </p>
<p>Adopting <a href="http://www.irac-online.org/about/resistance/management/">pesticide resistance management strategies</a> has proven to be effective against other pests – for example, the <a href="https://www.daf.qld.gov.au/plants/field-crops-and-pastures/broadacre-field-crops/integrated-pest-management/a-z-insect-pest-list/helicoverpa/insecticide-resistance">corn earworm</a> (<em>Helicoverpa armigera</em>). Guidelines include rotating different class of pesticides to deny pests the chance to develop resistance, and investing in non-chemical options such as natural predators of target pests.</p>
<p>Resistance management strategies are particularly critical for new pesticides that have different <a href="http://www.irac-online.org/modes-of-action/">modes of attack</a>, such as preventing juvenile insects from moulting, or attacking various chemical receptors. </p>
<p>To prolong the effectiveness of pesticides, we must develop these strategies before resistance begins to develop. North Queensland may be an example to the rest of the world on the best path forward.</p><img src="https://counter.theconversation.com/content/80269/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ary Hoffmann receives funding from the National Health and Medical Research Council, the Australian Research Council,
the Wellcome Trust, and the Grains Research and Development Corporation. </span></em></p><p class="fine-print"><em><span>Nancy Margaret Endersby-Harshman receives funding from the National Health and Medical Research Council. </span></em></p><p class="fine-print"><em><span>Scott Ritchie receives funding from the National Health and Medical Research Council, US Dept. of Defence, and USAid.</span></em></p>Australian mosquitoes, unlike their Asian and American counterparts, can still be controlled by insecticides like pyrethroids. What lessons are there for managing pesticide resistance in insects?Ary Hoffmann, Professor, School of BioSciences and Bio21 Institute, The University of MelbourneNancy Margaret Endersby-Harshman, Research fellow, The University of MelbourneScott Ritchie, Professorial Research Fellow, James Cook UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/775412017-05-23T03:48:21Z2017-05-23T03:48:21ZInfecting mosquitoes with bacteria so they can’t infect us with viruses like Zika and dengue<figure><img src="https://images.theconversation.com/files/170203/original/file-20170519-12250-7w6chd.jpg?ixlib=rb-1.1.0&rect=267%2C0%2C3640%2C2450&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Tiny bug, major disease spreader.</span> <span class="attribution"><a class="source" href="https://pixnio.com/science/microscopy-images/insects/anopheles-gambiae-mosquito/of-the-approximately-430-anopheles-species-only-30-40-transmit-malaria-in-nature">Dr. Paul Howell, USCDCP</a></span></figcaption></figure><p>Mosquitoes and their itchy bites are more than just an annoyance. They transmit dangerous viruses with deadly consequences – making them the <a href="https://www.gatesnotes.com/Health/Most-Lethal-Animal-Mosquito-Week">most lethal animal on Earth</a>. It’s the <em>Aedes aegypti</em> and <em>Aedes albopictus</em> mosquito species that are behind outbreaks of <a href="https://www.cdc.gov/dengue/">dengue virus</a>, <a href="https://www.cdc.gov/zika/">Zika virus</a>, <a href="https://www.cdc.gov/yellowfever/">yellow fever virus</a> and <a href="https://www.cdc.gov/chikungunya/index.html">Chikungunya virus</a>, responsible for over <a href="https://www.cdc.gov/ncezid/dvbd/">100 million human cases</a> around the world annually. And they’re <a href="https://dx.doi.org/10.7554/eLife.08347">expanding their habitat</a> around the world as the <a href="https://doi.org/10.1371/journal.pone.0060874">global climate warms</a>, bringing them into contact with more potential victims who have <a href="https://doi.org/10.1128/JVI.00252-16">less immunity and increased susceptibility</a> to these mosquito-transmitted viruses.</p>
<p>A vaccine can provide the recipient with immunity to one or two of these viruses at a time. But there’s another way to tackle these diseases: by going after the insects. Targeting the mosquito population as a whole or their ability to transmit disease takes aim at all these viruses at the same time.</p>
<p>As the U.S. enters another mosquito season, mosquito control districts in <a href="http://keysmosquito.org/2017/03/03/fkmcd-to-test-wolbachia-mosquitoes-in-mid-april/">Florida</a> and <a href="https://cmad.maps.arcgis.com/apps/MapJournal/index.html?appid=f90115bcf15943928fc82a79af89d71e">California</a> are preparing <a href="http://www.cnn.com/2017/04/20/health/florida-mosquito-wolbachia-trial-zika/">new strategies to combat mosquitoes</a> and the viruses they transmit. They’re trying out one of two new mosquito management methods made possible by a bacterium called <em>Wolbachia pipientis</em>. </p>
<h2>A bacterium that’s our enemy’s enemy</h2>
<p><em>Wolbachia</em> are bacteria naturally found in insects throughout the world. They live inside a host organism’s cells. From there, <em>Wolbachia</em> are able to manipulate their host in many ways – things like <a href="https://doi.org/10.1126/science.1209609">increasing the number of eggs</a> a host lays or even <a href="https://doi.org/10.1038/nrmicro1969">changing the host’s sex</a> from male to female by manipulating its hormones.</p>
<p>Researchers discovered in 2008 that <em>Wolbachia</em> in fruit flies <a href="https://dx.doi.org/10.1126/science.1162418">protect their hosts from fruit fly viruses</a>. That realization got them wondering: Could <em>Wolbachia</em> also protect <em>Aedes aegypti</em> mosquitoes from viruses that cause human diseases?</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/170430/original/file-20170522-7361-cycavo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/170430/original/file-20170522-7361-cycavo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/170430/original/file-20170522-7361-cycavo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/170430/original/file-20170522-7361-cycavo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/170430/original/file-20170522-7361-cycavo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/170430/original/file-20170522-7361-cycavo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/170430/original/file-20170522-7361-cycavo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/170430/original/file-20170522-7361-cycavo.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"><em>Wolbachia</em> bacteria, indicated in red, are distributed throughout the infected mosquitoes.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/pennstatelive/12589512185">Penn State</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p><em>Aedes aegypti</em> mosquitoes don’t naturally carry <em>Wolbachia</em>. But consistent with the fruit fly studies, when researchers infected <em>Aedes aegypti</em> in the lab, the viruses they carry <a href="http://dx.doi.org/10.1016/j.cell.2009.11.042">replicated less</a>. Fewer of the infectious bits of the disease-carrying virus inside the mosquito meant disease transmission was limited – they were less likely to be passed on when mosquitoes fed on their prey.</p>
<p>Researchers in <a href="http://vectorbiologygroup.com/">Australia</a>, the <a href="http://people.bu.edu/hfrydman/">United States</a> and elsewhere are currently investigating the reasons why <em>Wolbachia</em> limit viruses. Some hypothesize <em>Wolbachia</em> improves the <a href="https://doi.org/10.1371/journal.ppat.1002548">mosquitoes’ immunity to the virus</a>, while other research, including my own, suggests <em>Wolbachia</em> <a href="https://doi.org/10.1128/JVI.00339-17">steals key nutrients</a> the virus needs. Both may be true.</p>
<p>The real need to employ this strategy now is motivating field trials to release <em>Wolbachia</em>-infected mosquitoes in several regions of the world. </p>
<h2>Vector competency: The female approach</h2>
<p>Only female mosquitoes bite and transmit viruses. Thus, the most powerful approach to reducing virus spread is limiting viruses in the female mosquito.</p>
<p><em>Wolbachia</em> bacteria are transmitted from mother to offspring. If you introduce <em>Wolbachia</em>-infected female mosquitoes to a population, all offspring will have <em>Wolbachia</em> – and therefore be less likely to transmit disease-causing viruses.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/170427/original/file-20170522-7372-1d6t4ca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/170427/original/file-20170522-7372-1d6t4ca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/170427/original/file-20170522-7372-1d6t4ca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/170427/original/file-20170522-7372-1d6t4ca.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/170427/original/file-20170522-7372-1d6t4ca.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/170427/original/file-20170522-7372-1d6t4ca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/170427/original/file-20170522-7372-1d6t4ca.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/170427/original/file-20170522-7372-1d6t4ca.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Researchers in Vietnam working with <em>Wolbachia</em>-infected mosquito pupae.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Vietnam-Dengue-Blocking-Mosquito/199b148f9cf54dfa822d6ff0e6ff119f/14/0">AP Photo/Na Son Nguyen</a></span>
</figcaption>
</figure>
<p>This strategy is used by the <a href="http://www.eliminatedengue.com/program">Eliminate Dengue</a> program, a nonprofit collaboration employing seven research institutes around the world. In test areas, Eliminate Dengue has successfully incorporated <em>Wolbachia</em> into mosquito populations.</p>
<p>In this context, an interesting aspect of <em>Aedes aegypti</em> behavior is their tendency not to travel far. In fact, a highway is a sufficient barrier to <a href="https://doi.org/10.1371/journal.pntd.0000634">prevent mosquito spread</a>. When researchers set up a release site in one city or town, they don’t see their mosquitoes travel to other areas.</p>
<p>This allows for controlled studies, as well as the release of these mosquitoes only where it’s been approved. The limited spread and isolated sites used were important factors in the <a href="https://www.epa.gov/pesticides/epa-grants-extension-experimental-use-permit-wolbachia-mosquito">decision to allow mosquito releases in the United States</a>.</p>
<p>Eliminate Dengue is not yet active in the U.S. Instead, the U.S. is taking a different approach, looking to male rather than female mosquitoes.</p>
<h2>Population control: The male approach</h2>
<p><a href="http://mosquitomate.com/?v=3.0">MosquitoMate</a> is a company developed out of the University of Kentucky in Lexington by medical entomologist Stephen Dobson. Partnering with the <a href="http://keysmosquito.org/">Florida Keys Mosquito Control District</a>, they started the <a href="http://keysmosquito.org/2017/04/18/fkmcd-releases-wolbachia-mosquitoes-on-stock-island/">release of 40,000 <em>Wolbachia</em>-infected</a> <a href="http://fkmcd.maps.arcgis.com/apps/MapJournal/index.html?appid=d8c2b636e93b40b4b940e6042ef286c6">male mosquitoes per week this spring</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/170426/original/file-20170522-7358-lhsm36.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/170426/original/file-20170522-7358-lhsm36.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/170426/original/file-20170522-7358-lhsm36.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/170426/original/file-20170522-7358-lhsm36.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/170426/original/file-20170522-7358-lhsm36.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/170426/original/file-20170522-7358-lhsm36.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/170426/original/file-20170522-7358-lhsm36.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/170426/original/file-20170522-7358-lhsm36.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A Florida Keys Mosquito Control District research entomologist releasing <em>Wolbachia</em>-infected male mosquitoes in Key West, Florida, in April.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Modified-Mosquitoes/0ef1eb60fb234e628c7ce2c3fe5a9522/1/0">Beth Ranson/Florida Keys Mosquito Control District via AP</a></span>
</figcaption>
</figure>
<p>The strategy relies on a phenomenon called <a href="https://doi.org/10.1073/pnas.0403853101">cytoplasmic incompatibility (CI)</a> to reduce mosquito populations. CI occurs when a male mosquito infected with <em>Wolbachia</em> mates with an uninfected female. Because <em>Wolbachia</em> is transmitted through the female egg, the offspring will be <em>Wolbachia</em>-free. But <em>Wolbachia</em> has already altered the father’s sperm DNA in a way that allows offspring to survive only if the fertilized egg has <em>Wolbachia</em>. Since the infected males will come in contact only with the naturally occurring <em>Wolbachia</em>-free population, their offspring will die during embryonic development – the eggs won’t hatch. </p>
<p>And unfortunately for the mosquitoes, females store sperm inside them to continuously fertilize their eggs. This means that the female mosquito’s first mate will be the father of all her offspring. So even if a female just mates again, once she’s partnered with a <em>Wolbachia</em>-infected male, all her offspring will not be viable.</p>
<p>The Florida Keys Mosquito District is not limiting its attack to <a href="http://keysmosquito.org/control-methods/">just one approach</a>. Beyond <em>Wolbachia</em> and more traditional strategies, they’re also partnering with <a href="http://www.oxitec.com">Oxitec</a>, a genetic engineering company. Like MosquitoMate, Oxitec also releases male mosquitoes. But, in place of <em>Wolbachia</em>, Oxitec genetically modifies its mosquito to <a href="http://www.oxitec.com/our-solution/technology/">contain a self-limiting gene that causes offspring to die</a>.</p>
<p>The goal remains the same: Release males into the environment that will mate with females and cause all offspring to die, eventually leading to a mosquito population crash.</p>
<h2>Male and female strategies share one goal</h2>
<p>Each <em>Wolbachia</em> mosquito strategy has its strengths: The female approach is broad-reaching and should directly decrease disease transmission. The male strategy effectively lowers the local mosquito population, without releasing female nuisance mosquitoes.</p>
<p>The male release strategies are an important “right-now” fix, but they’ll require an annual, costly release because male mosquitoes – with either MosquitoMate’s <em>Wolbachia</em> or Oxitec’s self-limiting gene – cannot pass on to the next generation their crucial trait. When these males are not being released, fertile wild males will mate with females and the population will rebound.</p>
<p>Eliminate Dengue’s female release strategy is sustainable long-term, but it takes extensive monitoring to ensure the initial establishment of mosquitoes. While MosquitoMate and Oxitec do not disclose their costs, Eliminate Dengue hopes to make their system affordable at a cost of <a href="https://dx.doi.org/10.1038/533450a">approximately US$1 per person</a>.</p>
<p>Some members of the public have <a href="https://dx.doi.org/10.1126/science.aal0350">advocated against these kinds of mosquito release programs</a>, particularly when the mosquitoes have been genetically modified, as with Oxitec’s transgenic insects. While the United States Department of Agriculture received <a href="https://dx.doi.org/10.1038/533450a">2,600 responses to the Oxitec plan, only one response</a> was filed regarding MosquitoMate’s non-GMO strategy.</p>
<p>In the U.S., mosquito control districts are taking a cautious approach. They’re first trying the two nonpermanent male strategies in small areas. The Florida Keys will be <a href="http://keysmosquito.org/2017/03/03/fkmcd-to-test-wolbachia-mosquitoes-in-mid-april/">evaluating mosquitoes on their Stock Island release site for 12 weeks</a>. We should know how effective male <em>Wolbachia</em>-infected mosquitoes are at reducing populations by late summer.</p><img src="https://counter.theconversation.com/content/77541/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michaela Schultz 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>Several sites in the US are releasing bacteria-infected mosquitoes as a way to fight mosquito-borne viruses that threaten people. What’s the science – and how well will it work?Michaela Schultz, Graduate Student in Biology, Boston UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/728732017-02-21T04:07:52Z2017-02-21T04:07:52ZHow we kept disease-spreading Asian Tiger mozzies away from the Australian mainland<figure><img src="https://images.theconversation.com/files/156888/original/image-20170215-19589-vra0gc.jpg?ixlib=rb-1.1.0&rect=24%2C218%2C1251%2C731&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mosquito control in the Torres Strait can be tough but it provides protection of the mainland from invading exotic mosquitoes.</span> <span class="attribution"><span class="source">medical entomology, tropical public health services cairns </span>, <span class="license">Author provided</span></span></figcaption></figure><p>Spring floods and summer heatwaves. There is nothing mosquitoes love more than <a href="https://theconversation.com/the-worst-year-for-mosquitoes-ever-heres-how-we-find-out-68433">warm weather and water</a>. In many regions of Australia, these extreme conditions can increase the risk of mosquito-borne disease. </p>
<p>Outbreaks of <a href="http://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1005070">Ross River virus</a> in some parts of the country have been as record-breaking as the heatwaves. The virus has even started encroaching on suburban <a href="http://www.dailytelegraph.com.au/newslocal/the-express/more-mosquitoes-along-georges-river-raising-virus-risk/news-story/9b66a897ae5b572e60a7c9cf78a5ad67">Sydney</a> and <a href="http://www.abc.net.au/news/2017-02-09/ross-river-virus-detected-in-melbourne-possibly-for-first-time/8256310">Melbourne</a>.</p>
<p>While increasing climate variability and extreme weather events may <a href="https://theconversation.com/is-climate-change-to-blame-for-outbreaks-of-mosquito-borne-disease-39176">heighten the risks of home-grown mosquito-borne disease</a>, the real game changer will be the arrival of new mosquitoes to Australian backyards. The Asian tiger mosquito, <em>Aedes albopictus</em>, is the type of greatest concern.</p>
<h2>Why worry about the Asian tiger mosquito?</h2>
<p>This mosquito has already invaded most continents, bringing with it outbreaks of mosquito-borne disease. But it’s not just the risk of disease that’s a concern. This mosquito is also one of the most important pest mosquito species on the planet because they bite relentlessly during the day. In a <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0089221">recent study of over 120 people in the US</a>, almost 60% claimed the Asian Tiger Mosquito prevented them enjoying time outside. </p>
<p>Having adapted to <a href="https://theconversation.com/new-mosquito-threats-shift-risks-from-our-swamps-to-our-suburbs-56350">life around our homes</a>, the mosquito lays its eggs in water-holding containers rather than wetlands. It’s <a href="http://onlinelibrary.wiley.com/doi/10.1111/aec.12105/full">not just restricted to tropical regions</a> and is just as much at home in cooler climates. </p>
<p>So the tiger mosquito <a href="https://theconversation.com/hidden-housemates-the-mosquitoes-that-battle-for-our-backyards-59072">could become a common feature of life in major metropolitan regions</a> of Brisbane, Sydney, Melbourne, Adelaide or Perth. Once it’s here, the risk of outbreaks of <a href="http://theconversation.com/explainer-what-is-dengue-fever-8571">dengue</a>, <a href="http://theconversation.com/explainer-the-chikungunya-virus-and-its-risk-to-australia-16968">chikungunya</a> and <a href="http://theconversation.com/does-zika-virus-pose-a-threat-to-australia-53557">Zika</a> viruses will increase as, at the moment, <a href="https://theconversation.com/common-australian-mosquitoes-cant-spread-zika-65163">the common mosquitoes in our cities cannot transmit these pathogens</a>. But the tiger mosquito can.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/156890/original/image-20170215-19589-2nb3ns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/156890/original/image-20170215-19589-2nb3ns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=386&fit=crop&dpr=1 600w, https://images.theconversation.com/files/156890/original/image-20170215-19589-2nb3ns.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=386&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/156890/original/image-20170215-19589-2nb3ns.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=386&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/156890/original/image-20170215-19589-2nb3ns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=485&fit=crop&dpr=1 754w, https://images.theconversation.com/files/156890/original/image-20170215-19589-2nb3ns.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=485&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/156890/original/image-20170215-19589-2nb3ns.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=485&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The invasive pest, Aedes albopictus, commonly known as the Asian Tiger Mosquito.</span>
<span class="attribution"><span class="source">Stephen Doggett/NSW Health Pathology</span></span>
</figcaption>
</figure>
<h2>A serious pest on our doorstep</h2>
<p>This mosquito has been spread around the world with the movement of humans and their belongings. Although it has been detected many times at our border, it hasn’t become established on mainland Australia. However, more than a decade ago, the mosquito was discovered on <a href="http://www.sciencedirect.com/science/article/pii/S2352771415300161">islands in the Torres Strait</a> and, given the invasive nature of this mosquito, authorities were concerned this would just be a stepping stone to the suburbs of our major metropolitan regions.</p>
<p>Between 2005 and 2008, a <a href="http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0005286">government-funded eradication program</a> attacked the mosquito on many fronts. Teams were dispatched from Cairns into the Torres Strait for weeks at a time to assess and respond to the detection of the mosquito. </p>
<p>The teams searched water-filled containers looking for mosquito wrigglers every day. Genetic analysis of specimens was also undertaken to ensure there was no confusion between the detection of <em>Aedes albopictus</em> and other local mosquito species.</p>
<p>Insecticides were applied to water-filled containers and other habitats, while rubbish and other potential habitats (such as discarded containers or tyres) were removed, destroyed or placed under cover and out of reach of mosquitoes. Unfortunately, eradicating a mosquito isn’t easy. The job was made more difficult due to suspected re-introductions into the region by boat traffic and the continual accumulation of rubbish that the mosquito loves.</p>
<p>More worrisome was that the mosquito invaded both Horn Island and Thursday Island, which are the major transport hubs between Torres Strait and the mainland. If the mosquito became established there, the chance of them hitching a ride into Queensland would increase.</p>
<h2>Strategic shifts on mosquito control efforts required</h2>
<p>In response, authorities took the fight to where the mosquitoes were hiding out. Well-shaded leaf litter under thick vegetation that provided protection from wind and sunshine was a perfect place for mosquitoes to rest. It was also the perfect place to target control efforts.</p>
<p>In an approach known as “harbourage spraying”, insecticides were applied to these mosquito resting spots. The insecticides offered residual control, in much the same way surface sprays used in our kitchen keep cockroaches at bay. Once mosquitoes went looking for these hiding places, they were exposed to the insecticide and died.</p>
<p>Supporting the control efforts was a strategic surveillance program, tracking the presence of this mosquito at key locations. The mosquito control proved so successful that there was a steady decline in the detection of the mosquito, to the point that it is now undetectable in up to 90% of surveys on Horn and Thursday Islands.</p>
<p>This success is great news on two fronts. Firstly, it has undoubtedly reduced the risk this mosquito will make it to mainland Australia. Testimony to the effectiveness of the program is there has never been an established population of <em>Aedes albopictus</em> detected on the mainland in the more than ten years since its first detection in the Torres Strait.</p>
<p>Secondly, the experience gained from the <em>Aedes albopictus</em> eradication program provides a framework for practical management of this species during disease outbreaks, both within Australia or internationally. When outbreaks of dengue, chikungunya or Zika viruses occur, the approaches shown to be effective in suppressing populations in the Torres Strait can be employed to reduce the burden of disease. These approaches may not work against the “wetland” mosquitoes spreading Ross River virus, but they look to be perfect for “backyard” mosquitoes such as <em>Aedes albopictus</em>.</p>
<p>At a time when <a href="http://theconversation.com/pitting-mozzies-against-mozzies-to-stop-the-spread-of-disease-67447">emerging technologies</a> are expected to radically change the way we control mosquito populations, the lessons from Torres Strait are a reminder there will never be a “one size fits all” approach. Strategic and flexible approaches will provide the best outcomes in the battle against mosquito-borne disease.</p><img src="https://counter.theconversation.com/content/72873/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p><p class="fine-print"><em><span>Andrew van den Hurk is an employee of the Department of Health, Queensland Government and a member of the Aedes albopictus Eradication Program Technical Advisory Group. </span></em></p><p class="fine-print"><em><span>Scott Ritchie receives funding from the National Health and Medical Research Council. He is an employee of James Cook University and the Australian Institute of Tropical Health and Medicine where he works on a wide range of mosquito related projects, and is the chair of the Aedes albopictus Eradication Program.</span></em></p>A new study shows how Australian authorities are battling the invasive Asian tiger mosquito in Torres Strait, reducing risks of mosquito-borne disease outbreaks.Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of SydneyAndrew van den Hurk, Medical Entomologist, The University of QueenslandScott Ritchie, Professorial Research Fellow, James Cook UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/680252016-11-02T09:17:15Z2016-11-02T09:17:15ZScientists turn one pathogen against another in fight against dengue and Zika<figure><img src="https://images.theconversation.com/files/144110/original/image-20161101-11456-2s4w5m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Aedes_aegypti.jpg">Muhammad Mahdi Karim</a></span></figcaption></figure><p>Mosquitoes have been described as the most dangerous animals in the world due to their role in spreading diseases such as <a href="http://www.who.int/features/factfiles/malaria/en/">malaria</a>, <a href="http://www.who.int/mediacentre/factsheets/fs117/en/">dengue</a>, <a href="http://www.who.int/mediacentre/factsheets/fs327/en/">chikugunya</a> and <a href="http://www.who.int/mediacentre/factsheets/fs100/en/">yellow fever</a>. Hundreds of millions of people are infected every year, leading to <a href="http://www.who.int/features/factfiles/malaria/en/">many hundreds of thousands of deaths</a>.</p>
<p>One of the biggest concerns this year has been the rapid spread of <a href="http://www.who.int/mediacentre/factsheets/zika/en/">Zika</a>, another virus in the same family as dengue and the yellow fever viruses. There is no vaccine available that is able to protect people from Zika infection at present, and no known cure. So the challenge is to prevent the means of infection: the bite of the mosquito, <em>Aedes aegypti</em>.</p>
<p>Unlike other species of mosquito that transmit the malaria parasite, <em>Aedes</em> mosquitoes bite during the day, which means sleeping under a net offers little protection. Insecticides have been effective but resistance develops rapidly, and public health programmes that target and remove mosquito breeding sites are expected to be difficult to sustain. This has led to a sophisticated new approach that uses one species of parasite to prevent the spread of another.</p>
<h2>Bacteria vs virus</h2>
<p>The parasites in question belong to a group of bacteria called <a href="http://www.eliminatedengue.com/our-research/wolbachia">Wolbachia</a>. These naturally infect a great number of insect species, in which they inhabit tissues including the insect’s ovaries. From here they infect the developing eggs, and so are passed on to the next generation. Although it’s only female insects that can pass the bacteria on to their offspring, the bacteria can reduce the reproductive capability of both male and female hosts. Depending upon the species of Wolbachia, this can lead to sterility, or to swing the sex ratio of offspring in favour of females – which in turn means Wolbachia will spread more rapidly through the insect population through successive generations of infected eggs.</p>
<p>However, Wolbachia infection is not all bad news for insects: there is evidence that Wolbachia also prevents other pathogens from developing in host insects. </p>
<p>For several years, an Australian research group led by <a href="https://www.monash.edu/science/schools/biological-sciences/staff2/oneill">Scott O’Neill</a> has taken advantage of this as a strategy to control the spread of dengue viruses. But in order to use Wolbachia to prevent other pathogens from infecting <em>Aedes</em> mosquitoes, first they had to overcome a big hurdle because <em>Aedes</em> are not naturally infected with Wolbachia. </p>
<p>Using very fine needles, they were able to inject Wolbachia from other insects into newly laid <em>Aedes</em> eggs. The bacteria survived inside the mosquitoes that hatched from the eggs, and began to spread naturally through further generations of their lab mosquito colony. When those mosquitoes infected with Wolbachia were subsequently infected with dengue, the dengue virus was not able to replicate and spread to the mosquito’s salivary glands – and so the mosquitoes could not transmit dengue.</p>
<p><a href="http://www.cell.com/cell/abstract/S0092-8674(09)01500-1?_returnURL=http%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867409015001%3Fshowall%3Dtrue">Subsequent research</a> has demonstrated that the same technique using Wolbachia also reduces the ability of <em>Aedes</em> mosquitoes to transmit the viruses that cause yellow fever, chikungunya and Zika – and there is some evidence that it can inhibit transmission of the malaria parasite in other mosquito species. The mechanism by which Wolbachia infection does this is not clear, but it’s likely that it involves a change to the mosquito’s immune system.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/144107/original/image-20161101-15814-3cic7w.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/144107/original/image-20161101-15814-3cic7w.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/144107/original/image-20161101-15814-3cic7w.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=246&fit=crop&dpr=1 600w, https://images.theconversation.com/files/144107/original/image-20161101-15814-3cic7w.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=246&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/144107/original/image-20161101-15814-3cic7w.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=246&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/144107/original/image-20161101-15814-3cic7w.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=309&fit=crop&dpr=1 754w, https://images.theconversation.com/files/144107/original/image-20161101-15814-3cic7w.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=309&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/144107/original/image-20161101-15814-3cic7w.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=309&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Map showing the global distribution of the <em>Aedes aegypti</em> mosquito which spreads dengue and other diseases.</span>
<span class="attribution"><a class="source" href="https://elifesciences.org/content/4/e08347">Moritz UG Kraemer/eLife</a></span>
</figcaption>
</figure>
<h2>Weaponising mosquitoes</h2>
<p>Unlike the viruses, Wolbachia bacteria are too big to pass through the mosquito’s salivary duct when she bites a human, so there’s no chance that Wolbachia-infected mosquitoes can spread Wolbachia to humans – indeed, Wolbachia is not dangerous to humans. Stringent independent risk assessments have concluded that these mosquitoes were of negligible risk to humans or the environment, so trial releases of these mosquitoes have now taken place in Australia. By breeding with wild <em>Aedes</em>, the infected mosquitoes have rapidly spread Wolbachia throughout the population. The <a href="http://www.eliminatedengue.com/program">Eliminate Dengue</a> project has now also released mosquitoes in Indonesia, Vietnam, Colombia and Brazil.</p>
<p>In Brazil, <a href="http://www.eliminatedengue.com/progress/index/article/739">the positive results</a> from two pilot releases of Wolbachia-carrying mosquitoes have led to plans to expand the programme across the Rio de Janeiro and Niterói regions and monitor the effects on mosquito-borne viral infections. Facilities there are capable of producing 10m Wolbachia-infected <em>Aedes</em> eggs for release every week.</p>
<p>In the US, the <a href="http://mosquitomate.com/science-research/">Mosquito Mate</a> project is using a similar technique but instead aims to reduce the number of biting mosquitoes in an area rather than preventing the spread of disease. Using a different species of Wolbachia that causes sterility in the Asian tiger mosquito (<em>Aedes albopictus</em>), the project has released Wolbachia-carrying male mosquitoes which mate with wild females. As no fertile eggs result, the mosquito population declines. However, unlike the Eliminate Dengue strategy, this approach requires continual releases of mosquitoes because this strain of Wolbachia cannot spread naturally within the mosquito population. </p>
<p>Because Wolbachia-carrying mosquitoes are regarded as biopesticides, Mosquito Mate quickly got regulatory approval by the US Environmental Protection Agency. This is in contrast to the experience of firms such as <a href="http://www.oxitec.com/">Oxitec</a> which use genetically modified male mosquitoes that are sterile.</p>
<p>It may take several years to determine whether either of these strategies actually reduces or even eliminates the spread of mosquito-borne viral diseases – but if successful the implications for the millions affected by these diseases worldwide are enormous.</p><img src="https://counter.theconversation.com/content/68025/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hilary Hurd 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>There’s a new weapon against mosquitoes that spreads diseases such as dengue and yellow fever – more mosquitoes.Hilary Hurd, Emeritus Professor of Parasitology, Keele UniversityLicensed as Creative Commons – attribution, no derivatives.