tag:theconversation.com,2011:/ca/topics/ross-river-virus-7132/articlesRoss River virus – The Conversation2023-12-04T19:13:29Ztag:theconversation.com,2011:article/2184412023-12-04T19:13:29Z2023-12-04T19:13:29ZWill Japanese encephalitis return this summer? What about other diseases mosquitoes spread?<figure><img src="https://images.theconversation.com/files/562569/original/file-20231129-21-8z7c8x.jpg?ixlib=rb-1.1.0&rect=49%2C518%2C5499%2C2898&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-woman-travel-camping-alone-natural-2122867583">Shutterstock</a></span></figcaption></figure><p>The last two summers have been swarming with mosquitoes thanks to near constant rain and flooding brought on by La Niña. </p>
<p>With <a href="https://www.sydney.edu.au/study/student-life/student-news/2023/11/20/the-bureau-of-meteorology-has-predicted-an-el-nino-this-summer-what-you-need-to-know.html">the return of El Niño</a>, and a hot, dry summer in store, what’s the outlook for Japanese encephalitis and other mosquito-borne diseases?</p>
<h2>First, let’s look back at the last two summers</h2>
<p>The boom in mosquitoes over the last two springs and summers didn’t just bring an <a href="https://theconversation.com/mozzies-are-everywhere-right-now-including-giant-ones-and-those-that-make-us-sick-heres-what-you-need-to-know-194517">increased annoyance of buzzing and bites</a> but also outbreaks of potentially fatal mosquito-borne disease.</p>
<p>The first outbreak of Japanese encephalitis virus was first detected in <a href="https://www.science.org/content/article/how-rains-pigs-and-waterbirds-fueled-shocking-disease-outbreak-australia">southern regions of mainland Australia</a> in February 2022.</p>
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<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 has been detected in mozzies in NSW and Victoria. Here's what you need to know</a>
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<p>This was followed by the return of <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> in early 2023, which turned out to be the biggest outbreak in the southern states <a href="https://pubmed.ncbi.nlm.nih.gov/37860808/">since 1974</a>.</p>
<p>These outbreaks were the result of more than just more mosquitoes. Floodwaters provided <a href="https://www.abc.net.au/news/2023-02-11/record-flooding-in-nsw-triggeres-bird-breeding-bonanza-/101812042">ideal breeding conditions</a> for waterbirds, the key “reservoirs” of these viruses. </p>
<p>Mosquitoes pick up the infection after feeding on the birds and then subsequently <a href="https://theconversation.com/curious-kids-when-we-get-bitten-by-a-mosquito-why-does-it-itch-so-much-93347">spread the viruses</a> to people when they bite.</p>
<h2>What’s different about Japanese encephalitis?</h2>
<p>Outbreaks of Japanese encephalitis virus in temperate regions of Australia in 2022 came as a surprise. There had <a href="https://www.mdpi.com/2414-6366/4/1/38/htm">been activity</a> in northern Australia and the Torres Strait, but it was generally <a href="https://theconversation.com/what-is-japanese-encephalitis-virus-and-how-can-i-avoid-it-when-i-travel-106775">only considered</a> a risk to overseas travellers.</p>
<p>In India, Southeast Asia, and the Western Pacific, Japanese encephalitis is <a href="https://www.who.int/news-room/fact-sheets/detail/japanese-encephalitis">considered</a> one of the most dangerous mosquito-borne diseases, with tens of thousands of cases of severe infection each year. </p>
<p>While the majority of people infected suffer no or very mild symptoms, some will <a href="https://www.health.gov.au/diseases/japanese-encephalitis">experience</a> neck stiffness, fever, headache and, in the most severe cases, permanent neurological complications or death.</p>
<p>However, a vaccine is available that can significantly limit serious illness. </p>
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Read more:
<a href="https://theconversation.com/what-is-japanese-encephalitis-virus-and-how-can-i-avoid-it-when-i-travel-106775">What is Japanese encephalitis virus and how can I avoid it when I travel?</a>
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<p>The <a href="https://theconversation.com/japanese-encephalitis-virus-has-been-detected-in-australian-pigs-can-mozzies-now-spread-it-to-humans-178017">discovery</a> of Japanese encephalitis virus in Australia’s southern states triggered a <a href="https://www.health.gov.au/news/statement-on-the-end-of-japanese-encephalitis-virus-emergency-response">declaration of</a> a “communicable disease incident of national significance”. This was in place from March 2022 through June 2023. A total of 45 people were infected, seven of whom sadly died. </p>
<p>It wasn’t just people who were at risk. The impact on commercial piggeries, which farm pigs for pork production, was <a href="https://www.porkbusiness.com/news/industry/australia-faces-pork-supply-shortages-due-japanese-encephalitis-production-losses">devastating</a> and required urgent strategies to <a href="https://www.farmbiosecurity.com.au/livestock/pigs/controlling-mosquitoes-around-piggeries/">control mosquitoes</a>.</p>
<p>Piggeries weren’t the source of the outbreak, they were the “canaries in the coalmine” – signalling the spread of the virus early on and the need to protect the broader community.</p>
<h2>What caused outbreaks in piggeries?</h2>
<p>Our <a href="https://www.sciencedirect.com/science/article/pii/S2352771423000861?via%3Dihub">research</a> <a href="https://pubmed.ncbi.nlm.nih.gov/19737082/">investigated</a> how different landscapes and weather patterns influence interactions between wildlife, mosquitoes, and outbreaks of Japanese encephalitis virus.</p>
<p>We looked at 62 piggeries where the virus had been detected and some locations where the virus had also been <a href="https://www.health.nsw.gov.au/Infectious/mosquito-borne/Pages/surveillance.aspx">detected in mosquitoes</a>, along with waterbird and feral pig habitats, rainfall and temperature.</p>
<p>Some of the results were unexpected. Piggeries were at highest risk of an outbreak when the number of different waterbird species in their location was “just right”. If there were too few or too many, the risk of an outbreak was reduced. </p>
<p>High rainfall and flooding provided excellent conditions for mosquitoes, with temporary wetlands and flooded areas posing a greater risk than permanent wetlands.</p>
<p>Temporary wetlands may have provided habitat for waterbirds whose normal habitat and movement patterns were disrupted due to the extensive La Niña flooding. </p>
<p>Or perhaps permanent wetlands support a <a href="https://link.springer.com/article/10.1007/s13157-019-01133-2">greater diversity</a> of aquatic life (including animals that eat mosquitoes) that helped keep mosquito numbers lower than temporary waterbodies.</p>
<h2>So what might happen this summer?</h2>
<p>The return of El Niño is expected to bring <a href="https://www.abc.net.au/news/2023-11-16/holder-nsw-el-nino-set-to-peak-as-one-of-the-strongest/103104264">below average rainfall and above average temperatures</a>. But that can be <a href="https://www.abc.net.au/news/2023-12-03/what-happened-to-el-nino/103179568">unpredictable</a>. Wetlands are already drying up. Bushfires have replaced floods.</p>
<p>Mosquito populations are expected to decline sharply. Surveillance programs of state and territory health authorities, such as <a href="https://www.health.nsw.gov.au/environment/pests/vector/Pages/Surveillance-and-monitoring-weekly-reports-season-2023-24.aspx">New South Wales</a> and <a href="https://www.health.vic.gov.au/infectious-diseases/mosquito-surveillance-report">Victoria</a>, are already reporting mosquito populations far lower than previous seasons.</p>
<p>So we may not see as much Japanese encephalitis this season. But that doesn’t mean it will disappear completely. </p>
<p>It doesn’t matter how hot and dry it gets, mosquitoes are resilient and will persist. They’ll seek out the same environments where water remains. So too will waterbirds and feral pigs. </p>
<p>Authorities are also on alert for the return of <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1005070">Ross River virus</a> along the coast. Despite the lower rainfall, the mosquitoes that live in saltwater wetlands will thrive following flooding by high tides, especially “<a href="https://media.bom.gov.au/social/blog/1603/explainer-king-tides/">king tides</a>”.</p>
<p>Combined with extreme weather, even during hot and dry summers, outbreaks of Ross River virus <a href="https://www.sciencedirect.com/science/article/pii/S1326020023000328">can occur</a>.</p>
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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>
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<h2>How can you reduce your chance of getting these viruses?</h2>
<p>To protect yourself and family from mosquito bites and mosquito-borne disease:</p>
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<li><p>keep following the advice of health authorities</p></li>
<li><p>try to avoid bushland and wetland areas in late afternoon and early evening</p></li>
<li><p>cover up with <a href="https://theconversation.com/mozzie-repellent-clothing-might-stop-some-bites-but-youll-still-need-a-cream-or-spray-107266">long-sleeved shirts, long pants</a> and covered shoes</p></li>
<li><p>apply a <a href="https://theconversation.com/mozzies-biting-heres-how-to-choose-a-repellent-and-how-to-use-it-for-the-best-protection-150183">recommended insect repellent</a> </p></li>
<li><p>check your eligibility for a <a href="https://www.health.nsw.gov.au/Infectious/jev/Pages/vaccination.aspx">Japanese encephalitis vaccination</a>.</p></li>
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Read more:
<a href="https://theconversation.com/insect-repellents-work-but-there-are-other-ways-to-beat-mosquitoes-without-getting-sticky-171805">Insect repellents work – but there are other ways to beat mosquitoes without getting sticky</a>
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<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>Michael Walsh has received funding from the Australian Research Council to investigate zoonotic diseases associated with Australian produce and from the Australian Department of Foreign Affairs and Trade to investigate antimicrobial resistance. </span></em></p><p class="fine-print"><em><span>Victoria Brookes 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>This summer is expected to be dry and hot. Here’s what that means for the risk of mosquito-borne diseases.Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of SydneyMichael Walsh, Senior Lecturer of Infectious Disease Epidemiology, University of SydneyVictoria Brookes, Lecturer in Epidemiology and One Health, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1896222022-09-05T20:04:33Z2022-09-05T20:04:33Z5 virus families that could cause the next pandemic, according to the experts<p>The CSIRO has delivered a comprehensive <a href="https://www.csiro.au/pandemic">report</a> on how we should prepare for future pandemics. </p>
<p>The report identifies six key science and technology areas such as faster development of vaccines and onshore vaccine manufacturing to ensure supply, new antivirals and ways of using the medicines we already have, better ways of diagnosing cases early, genome analysis, and data sharing. </p>
<p>It also recommends we learn more about viruses and their hosts across the five most concerning virus families. These causes of disease could fuel the next pandemic. </p>
<p>We asked leading experts about the diseases they can cause and why authorities should prepare well:</p>
<h2>1. Coronaviridae</h2>
<p><strong><em>COVID-19, Middle East respiratory syndrome (MERS), severe acquired respiratory syndrome (SARS)</em></strong></p>
<p>The first human <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7204879/">Coronaviruses</a> (229E and OC43) were found in 1965 and 1967 respectively. They were low-grade pathogens causing only mild cold-like symptoms and gastroenteritis. Initial understanding of this family came from study of related strains that commonly infect livestock or laboratory mice that also caused non-fatal disease. The <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3358201/">HKU-1 strain in 1995</a> again did not demonstrate an ability to generate high levels of disease. As such, coronaviridae were not considered a major concern until severe acquired respiratory syndrome (<a href="https://www.who.int/health-topics/severe-acute-respiratory-syndrome#tab=tab_1">SARS-1</a>) first appeared in 2002 in China.</p>
<p>Coronaviridae have a <a href="https://www.nature.com/articles/s41467-021-22785-x">very long RNA genome</a>, coding up to 30 viral proteins. Only four or five genes make infectious virus particles, but many others support diseases from this family by modifying immune responses. The viruses in this family mutate at a steady low rate, selecting changes in the outer spike to allow virus entry into new host cells.</p>
<p>Coronaviridae viruses are widespread in many ecological niches and common in bat species that make up <a href="https://www.si.edu/spotlight/bats/batfacts">20% of all mammals</a>. Mutations spread in their roosts can spillover into other mammals, such as the <a href="https://link.springer.com/article/10.1007/s11259-020-09781-0">civet cat</a>, then into humans. </p>
<p>Coronaviridae <a href="https://www.cdc.gov/coronavirus/2019-ncov/variants/genomic-surveillance.html">genome surveillance</a> shows an array of previously unknown virus strains circulating in different ecological niches. Climate change threatens intersections of these viral transmission networks. Furthermore, pandemic human spread of SARS-CoV-2 (the virus that causes COVID) has now seeded new transmissions back into other species, such as mink, cats, dogs and white-tailed deer. </p>
<p>Ongoing viral evolution in new animal hosts and also in immune-compromised <a href="https://www.bmj.com/content/376/bmj-2021-069807">HIV patients in under-resourced settings</a>, presents an ongoing source of new variants of concern.</p>
<p><strong>– Damian Purcell</strong></p>
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Read more:
<a href="https://theconversation.com/long-covid-how-researchers-are-zeroing-in-on-the-self-targeted-immune-attacks-that-may-lurk-behind-it-169911">Long COVID: How researchers are zeroing in on the self-targeted immune attacks that may lurk behind it</a>
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<h2>2. Flaviviridae</h2>
<p><strong><em>Dengue fever, Japanese encephalitis, Zika, West Nile fever</em></strong></p>
<p>The flaviviridae family causes several diseases, including dengue, Japanese encephalitis, Zika, West Nile disease and others. These diseases are often not life-threatening, causing fever, sometimes with rash or painful joints. A small proportion of those infected get severe or complicated infection. Japanese encephalitis can cause inflammation of the brain, and Zika virus can cause birth defects.</p>
<p>While all these viruses may be spread by mosquito bites, when it comes to each individual virus, not all mosquitoes bring equal risk. There are <a href="https://www.cdc.gov/zika/prevention/transmission-methods.html#:%7E:text=Zika%20virus%20is%20transmitted%20to,spread%20dengue%20and%20chikungunya%20viruses.">key mosquito species</a> involved in transmission cycles of dengue and Zika virus, such as <em>Aedes aegypti</em> and <em>Aedes albopictus</em>, that may be found in close to where people live. These mosquitoes are found in water-holding containers (such as potted plant saucers, rainwater tanks), water-filled plants, and tree holes. They also like to bite people.</p>
<p>The mosquitoes that spread these viruses are not currently widespread in Australia; they’re generally limited to central and far north Queensland. They are routinely detected through biosecurity surveillance at Australia’s major <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8005993/">airports and seaports</a>. With a rapid return to international travel, movement of people and their belongings may become an ever-increasing pathway of introduction of the diseases and mosquitoes back into Australia.</p>
<p>Different mosquitoes are involved in the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7000427/">transmission</a> of West Nile virus and Japanese encephalitis. These mosquitoes are more likely to be found in wetlands and bushland areas than backyards. They bite people but they also like to <a href="https://theconversation.com/how-australian-wildlife-spread-and-suppress-ross-river-virus-107267">bite the animals</a> most likely to be carrying these viruses. </p>
<p>The <a href="https://theconversation.com/japanese-encephalitis-virus-has-been-detected-in-australian-pigs-can-mozzies-now-spread-it-to-humans-178017">emergence of Japanese encephalitis</a>, a virus spread by mosquitoes between waterbirds, pigs, and people, is a perfect example. Extensive rains and flooding that provide idea conditions for mosquitoes and these animals create a “perfect storm” for disease emergence. </p>
<p><strong>– Cameron Webb & Andrew van den Hurk</strong></p>
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Read more:
<a href="https://theconversation.com/japanese-encephalitis-virus-has-been-detected-in-australian-pigs-can-mozzies-now-spread-it-to-humans-178017">Japanese encephalitis virus has been detected in Australian pigs. Can mozzies now spread it to humans?</a>
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<h2>3. Orthomyxoviridae</h2>
<p><strong><em>Influenza</em></strong></p>
<p>Before COVID-19, influenza was the infection most <a href="https://www.health.gov.au/resources/publications/australian-health-management-plan-for-pandemic-influenza-ahmppi">well-known</a> for causing pandemics.</p>
<p>Influenza virus is subdivided into types (A, B, and rarely C and D). Influenza A is further classified into subtypes based on haemagglutinin (H) and neuraminidase (N) protein variants on the surface of the virus. Currently, the most common influenza strains in humans are A/H1N1 and A/H3N2.</p>
<p><a href="https://www.who.int/news-room/spotlight/influenza-are-we-ready/zoonotic-influenza">Zoonotic infection</a> occurs when influenza strains that primarily affect animals “spill over” to humans. </p>
<p>Major changes in the influenza virus usually result from <a href="https://www.nejm.org/doi/full/10.1056/NEJMp0904572">new combinations</a> of influenza viruses that affect birds, pigs and humans. New strains have the potential to cause pandemics as there is little pre-existing immunity.</p>
<p>Since the beginning of the 20th century, there have been four influenza <a href="https://www.cdc.gov/flu/pandemic-resources/basics/past-pandemics.html">pandemics</a>, in 1918, 1957, 1968, and 2009. In between pandemics, seasonal influenza circulates throughout the world. </p>
<p>Although influenza is not as infectious as many other respiratory infections, the very short incubation period of around 1.4 days means outbreaks can spread quickly.</p>
<p>Vaccines are available to prevent influenza, but are only <a href="https://pubmed.ncbi.nlm.nih.gov/31903487/">partially</a> protective. Antiviral treatments are available, including oseltamivir, zanamivir, peramivir and baloxavir. Oseltamivir <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(14)62449-1/fulltext">decreases</a> the duration of illness by around 24 hours if started early, but whether it reduces the risk of severe influenza and its complications is <a href="https://www.thelancet.com/journals/lanres/article/PIIS2213-2600%2814%2970041-4/fulltext">controversial</a>.</p>
<p><strong>– Allen Cheng</strong> </p>
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Read more:
<a href="https://theconversation.com/my-year-as-victorias-deputy-chief-health-officer-on-the-pandemic-press-conferences-and-our-covid-future-166164">My year as Victoria's deputy chief health officer: on the pandemic, press conferences and our COVID future</a>
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<h2>4. Paramyxoviridae</h2>
<p><strong><em>Nipah virus, Hendra virus</em></strong></p>
<p>Paramyxoviridae are a large group of viruses that affect humans and animals. The most well known are measles and mumps, as well as parainfluenza virus (a common cause of <a href="https://www.rch.org.au/kidsinfo/fact_sheets/Croup/">croup</a> in children). </p>
<p>Globally, <a href="https://www.who.int/news-room/fact-sheets/detail/measles">measles</a> is a dangerous disease for young children, particularly those who are malnourished. Vaccines are highly effective with the measles vaccine alone <a href="https://www.who.int/news/item/12-11-2015-measles-vaccination-has-saved-an-estimated-17-1-million-lives-since-2000">estimated</a> to have saved 17 million lives between 2000 and 2014.</p>
<p>One group of paramyxoviruses is of particular importance for pandemic planning – henipaviruses. This includes Hendra virus, Nipah virus and the new <a href="https://theconversation.com/what-is-this-new-langya-virus-do-we-need-to-be-worried-188577">Langya virus</a> (as well as the fictional MEV-1 in the film <a href="https://www.reuters.com/article/idUS57323549020110913">Contagion</a>). These are all zoonoses (diseases that spill over from animals to humans)</p>
<p>Hendra virus was first <a href="https://onlinelibrary.wiley.com/doi/abs/10.5694/j.1326-5377.1995.tb126050.x">discovered</a> in Queensland in 1994, when it caused the deaths of 14 horses and their horse trainer. Infected flying foxes have since spread the virus to horses in Queensland and northern New South Wales. There have been seven <a href="https://www.outbreak.gov.au/for-vets-and-scientists/hendra-virus">reported</a> human cases of Hendra virus in Australia, including four deaths.</p>
<p>Nipah virus is more <a href="https://www.who.int/news-room/fact-sheets/detail/nipah-virus">significant</a> globally. Infection may be mild, but some people develop encephalitis (inflammation of the brain). Outbreaks frequently occur in Bangladesh, where the first <a href="https://pubmed.ncbi.nlm.nih.gov/10781618/">outbreak</a> was reported in 1998. Significantly, Nipah virus appears to be able to be <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6547369/">transmitted</a> from person-to-person though close contact.</p>
<p><strong>– Allen Cheng</strong></p>
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Read more:
<a href="https://theconversation.com/what-is-this-new-langya-virus-do-we-need-to-be-worried-188577">What is this new Langya virus? Do we need to be worried?</a>
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<h2>5. Togaviridae (alphaviruses)</h2>
<p><strong><em>Chikungunya fever, Ross River fever, Eastern equine encephalitis, Western equine encephalitis, Venezuelan equine encephalitis</em></strong></p>
<p>The most common disease symptoms caused by infection with alphaviruses like chikungunya and Ross River viruses are fever, rash and painful joints.</p>
<p>Like some flaviviruses, <a href="https://www.who.int/news-room/fact-sheets/detail/chikungunya">chikungunya virus</a> is thought to be only spread by <em>Aedes aegypti</em> mosquitoes in Australia. This limits risks, for now, to central and far north Queensland. </p>
<p>Many different mosquitoes play a role in transmission of alphaviruses, including dozens of mosquito species suspected as playing a role in the spread of <a href="http://conditions.health.qld.gov.au/HealthCondition/condition/14/217/120/ross-river-virus">Ross River fever</a>. Many of these mosquitoes <a href="https://theconversation.com/how-can-the-bite-of-a-backyard-mozzie-in-australia-make-you-sick-171601">are commonly found across Australia</a>. </p>
<p>But what role may these local mosquitoes play should diseases such as eastern equine encephalitis or western equine encephalitis make their way to Australia? Given the capacity of our home-grown mosquitoes to spread other alphaviruses, it is reasonable to assume they would be effective at transmitting these as well. That’s why the CSIRO report <a href="https://www.csiro.au/pandemic">notes</a> future pandemic preparation should work alongside Australia’s established biosecurity measures. </p>
<p><strong>– Cameron Webb & Andrew van den Hurk</strong></p>
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Read more:
<a href="https://theconversation.com/how-can-the-bite-of-a-backyard-mozzie-in-australia-make-you-sick-171601">How can the bite of a backyard mozzie in Australia make you sick?</a>
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<p class="fine-print"><em><span>Allen Cheng receives funding from the Australian National Health and Medical Research Council and the Australian government for research, including in influenza. He is Chair of the Advisory Committee for Vaccines and a member of the Australian Technical Advisory Group on Immunisation. </span></em></p><p class="fine-print"><em><span>Andrew van den Hurk has received funding from local, state and federal agencies to study the ecology of mosquito-borne pathogens, and their surveillance and control. He is an employee of the Department of Health, Queensland Government.</span></em></p><p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p><p class="fine-print"><em><span>Damian Purcell consults for Moderna on mRNA vaccine education and receives funding from the National Health and Medical Research Council, and the Victorian Government grants. He is Past Presidents' advisor for the Australasian Virology Society, and Committee member of the RNA Network of Australia.</span></em></p>Authorities have been warned about five virus families that could cause future pandemics. Here are snapshots of the diseases each can cause and why we should be worried.Allen Cheng, Professor in Infectious Diseases Epidemiology, Monash UniversityAndrew van den Hurk, Medical Entomologist, The University of QueenslandCameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of SydneyDamian Purcell, Professor of virology and theme leader for viral infectious diseases, The Peter Doherty Institute for Infection and ImmunityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1850212022-06-21T02:57:04Z2022-06-21T02:57:04ZWhere do all the mosquitoes go in the winter?<figure><img src="https://images.theconversation.com/files/469915/original/file-20220621-17-wrrp6a.jpg?ixlib=rb-1.1.0&rect=77%2C240%2C5044%2C3205&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/iuJgEBVSRIo?utm_source=unsplash&utm_medium=referral&utm_content=creditShareLink">Cameron Webb/NSW Health Pathology</a>, <span class="license">Author provided</span></span></figcaption></figure><p>Summer evenings by the pool, lake or BBQ mean mosquitoes. But what about during winter when we’re mostly indoors? As the weather cools, these bloodsucking pests are rarely seen. </p>
<p>But where do they go?</p>
<h2>Warm, wet conditions suit mosquitoes</h2>
<p>Mosquitoes have complex life cycles that rely on water brought to <a href="https://theconversation.com/hidden-housemates-the-mosquitoes-that-battle-for-our-backyards-59072">wetlands, flood plains, and water-holding containers</a> by seasonal rainfall. Depending on whether we’re experiencing a summer under the influence of <a href="https://theconversation.com/will-the-arrival-of-el-nino-mean-fewer-mosquitoes-this-summer-102496">El Niño</a> or <a href="https://theconversation.com/la-nina-will-give-us-a-wet-summer-thats-great-weather-for-mozzies-147180">La Niña</a>, mosquito populations will change in different ways.</p>
<p>During warmer months, their life cycle lasts about a month. Eggs laid around water hatch and the immature mosquitoes go through four developmental stages. Larvae then change to pupae, from which an adult mosquito emerges, sits briefly on the water surface, and then flies off to buzz and bite and continue the cycle. </p>
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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>Water is crucial but temperature is really important too. Unlike warm-blooded animals, mosquitoes can’t control their own body temperatures. The warmer it is, the more active mosquitoes will be. There’s usually more of them about too.</p>
<p>But once cold weather arrives, their activity slows. They fly less, they don’t bite as often, they reproduce less, and their life cycle takes longer to complete.</p>
<p>Temperature also plays a role in determining the ability of mosquitoes to <a href="https://www.frontiersin.org/articles/10.3389/fmicb.2020.584846/full">spread viruses</a>.</p>
<p>Cold weather isn’t great for mosquitoes but <a href="https://www.annualreviews.org/doi/abs/10.1146/annurev-ento-011613-162023">millions of years of evolution</a> have given them a <a href="https://link.springer.com/article/10.1186/s13071-017-2235-0">few tricks to survive</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/468677/original/file-20220614-21-qmcj4w.jpg?ixlib=rb-1.1.0&rect=0%2C43%2C4883%2C3211&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468677/original/file-20220614-21-qmcj4w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468677/original/file-20220614-21-qmcj4w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468677/original/file-20220614-21-qmcj4w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468677/original/file-20220614-21-qmcj4w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468677/original/file-20220614-21-qmcj4w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468677/original/file-20220614-21-qmcj4w.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">Ponds and puddles may be frozen but that doesn’t mean all mosquitoes have disappeared.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/7UYnlgDyf0o">Tom Keldenich/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Mosquitoes don’t disappear completely</h2>
<p>On a sunny afternoon in winter, you may notice the occasional mosquito buzzing about in your backyard. Not as many as in summer but they’re still around.</p>
<p>Some mosquitoes do disappear. For example, the activity of the pest mosquito <em>Culex annulirostris</em>, thought to play an important role in the <a href="https://theconversation.com/japanese-encephalitis-virus-has-been-detected-in-australian-pigs-can-mozzies-now-spread-it-to-humans-178017">spread of Japanese encephalitis virus</a> in Australia, dramatically declines when temperatures start dropping <a href="https://onlinelibrary.wiley.com/doi/10.1111/j.1442-9993.1980.tb01260.x">below 17.5°C</a>.</p>
<p><a href="https://onlinelibrary.wiley.com/doi/10.1111/aen.12021">Studies in Sydney</a> have shown some mosquitoes, such as <em>Culex annulirostris</em>, disappear. Others, such as <em>Culex quinquefasciatus</em> and <em>Culex molestus</em>, remain active throughout the winter. You just may not notice them (unless they enter your home to buzz about your ears). </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/469917/original/file-20220621-17-k6jyri.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/469917/original/file-20220621-17-k6jyri.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/469917/original/file-20220621-17-k6jyri.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/469917/original/file-20220621-17-k6jyri.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/469917/original/file-20220621-17-k6jyri.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/469917/original/file-20220621-17-k6jyri.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/469917/original/file-20220621-17-k6jyri.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">Some mosquitoes, such as the common Aedes notoscriptus, may occasionally be seen buzzing about in winter.</span>
<span class="attribution"><span class="source">Cameron Webb/NSW Health Pathology</span></span>
</figcaption>
</figure>
<h2>Mosquitoes can disappear into diapause</h2>
<p>We’re familiar with the idea of mammals hibernating through winter but mosquitoes, like many other insects, can enter a phase of inactivity called <a href="https://onlinelibrary.wiley.com/doi/10.1111/eea.12753">diapause</a>. </p>
<p>Once cold weather arrives, adult mosquitoes find hiding places such as tree hollows and animal burrows, within the cracks and crevices of bushland environments, or in garages, basements or other structures around our homes, suburbs and cities. These mosquitoes may only live a few weeks during summer but going into diapause allows them to survive many months through winter.</p>
<p>Mosquitoes can also be found in frozen bodies of water, whether it is a bucket of water in your backyard or a near freezing wetland. For example, there is a group of mosquitoes that belong to the genus <em>Coquillettidia</em> whose <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/jvec.12338">larvae attach</a> to the submerged parts of aquatic plants and can survive the cold winter temperatures. Their development dramatically slows and they’ll stay in the water until spring arrives.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/469888/original/file-20220621-11-eny4r6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/469888/original/file-20220621-11-eny4r6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/469888/original/file-20220621-11-eny4r6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/469888/original/file-20220621-11-eny4r6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/469888/original/file-20220621-11-eny4r6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/469888/original/file-20220621-11-eny4r6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/469888/original/file-20220621-11-eny4r6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/469888/original/file-20220621-11-eny4r6.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">By going into ‘diapause’ adults can survive in places like tree hollows for the cold months.</span>
<span class="attribution"><a class="source" href="https://images.unsplash.com/photo-1625635756778-218152037ccc?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=1770&q=80">Unsplash/Pat Whelan</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
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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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<h2>All their eggs in one winter basket</h2>
<p>Some mosquitoes make it through the winter thanks to their eggs. Mosquito eggs can be incredibly resilient. They survive being dried out in hot and salty coastal wetlands during summer but also frozen in snow-covered creeks in winter.</p>
<p>In coastal regions of Australia, eggs of the saltmarsh mosquito (<em>Aedes vigilax</em>), sit perfectly safely on soil. Once the weather warms and tides bring in water to the wetlands, these eggs will be ready to hatch.</p>
<p>There is also a special mosquito in Australia known as the “snow melt mosquito” (<em>Aedes nivalis</em>) whose <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1440-6055.1996.tb01371.x">eggs survive under snow</a> and hatch once that snow melts and fills ponds, creeks and wetlands throughout alpine regions.</p>
<h2>Does it matter where mosquitoes go in the winter?</h2>
<p>It also isn’t just the mosquitoes that survive the cold months. Viruses, such as <a href="https://theconversation.com/japanese-encephalitis-virus-can-cause-deadly-brain-swelling-but-in-less-than-1-of-cases-178985">Japanese encephalitis virus</a> or <a href="https://theconversation.com/explainer-what-is-ross-river-virus-24630">Ross River virus</a>, can survive from <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2631767/">summer to summer</a> in mosquito eggs, immature stages, or diapausing adults.</p>
<p>Knowing the seasonal spread of mosquitoes helps health authorities design surveillance and control programs. It may help understand how <a href="https://entomologytoday.org/2022/05/24/snow-covered-tires-help-invasive-mosquitoes-survive-cold-winters/">invasive mosquitoes survive</a> conditions in Australia outside their native ranges by <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0211167">hiding out from the cold</a>, such as in rainwater tanks. </p>
<p>Even mosquitoes typically found in tropical locations can even <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.13480">adapt to cooler climates</a>.</p>
<p>This knowledge may even expose the chilly chink in mosquito’s armour that we can use to better control mosquito populations and reduce the risks of disease outbreaks.</p><img src="https://counter.theconversation.com/content/185021/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>Mosquitoes are commonplace in summer but where do they go once the weather cools? They don’t completely disappear but find fascinating ways to survive the winter.Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1718052022-01-31T05:39:31Z2022-01-31T05:39:31ZInsect repellents work – but there are other ways to beat mosquitoes without getting sticky<figure><img src="https://images.theconversation.com/files/443310/original/file-20220131-15248-1b08evd.jpg?ixlib=rb-1.1.0&rect=8%2C0%2C5982%2C3997&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/dad-son-use-mosquito-spray-insect-1081091330">Shutterstock</a></span></figcaption></figure><p>Summer can be hot and sticky. And insect repellent creams, lotions, and sprays can make it stickier. </p>
<p>Stopping mosquito bites is key to avoiding itchy bumps and mosquito-borne disease. Thankfully, there are several methods can you try – and some things to avoid – for a mozzie bite-free summer.</p>
<h2>Topical insect repellents are safe and effective</h2>
<p>Insect repellents are a safe, effective, and affordable way to <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/">prevent mosquito bites</a>. </p>
<p>They are <a href="https://www.frontiersin.org/articles/10.3389/fpubh.2019.00054/full">promoted by health authorities in Australia</a> as the best way to avoid mosquito bites.</p>
<p>Products sold in Australia must be approved for sale by the <a href="https://apvma.gov.au/">Australian Pesticides and Veterinary Medicines Authority</a> (APVMA) which checks products for safety and effectiveness. If applied as recommended – a thin and even coat over all exposed areas of skin – insect repellents can prevent mosquito bites. How long bite protection lasts varies with the strength of the formulation but research has shown it can <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1753-6405.2009.00435.x">last for many hours</a>.</p>
<p>But insect repellents aren’t always the perfect solution. Despite being <a href="https://academic.oup.com/jtm/article/17/3/182/1804104?login=true">recommended by health authorities and experts</a> around the world and many studies demonstrating registered repellents cause <a href="https://www.sciencedirect.com/science/article/pii/S1080603215004342">minimal adverse reactions</a>, there remains a perception they can pose a <a href="https://www.health.harvard.edu/blog/be-vigilant-about-bug-spray-2020080720702">health risk</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/28171823/">contaminate</a> the natural environment or they’re unpleasant to use.</p>
<p>In Australia, not much has changed with regard to the active ingredients used in repellent formulations but the cosmetic constituents have greatly improved, making them more pleasant to use. </p>
<p>For those who find insect repellents a challenge, there are alternatives to creams, lotions and sprays. </p>
<h2>Insecticide sprays ✅</h2>
<p>Insecticides can help <a href="https://academic.oup.com/ee/article/49/2/435/5709893?login=true">knock down or repel</a> buzzing and biting mosquitoes. But, be warned, these products aren’t specific to mosquitoes so using them too frequently will <a href="https://theconversation.com/the-battle-against-bugs-its-time-to-end-chemical-warfare-111629">reduce the beneficial insects</a> around your home.</p>
<h2>Mosquito coils and other devices ✅</h2>
<p>Mosquito coils have been a mainstay of the Australian summer. They will certainly <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">assist in reducing bites</a> in sheltered areas and those with insecticides will work best. </p>
<p>But never burn them inside, especially not beside the bed at night. The smoke you inhale <a href="https://theconversation.com/are-mosquito-coils-good-or-bad-for-our-health-88548">can be bad for your health</a>.</p>
<p>A range of <a href="https://parasitesandvectors.biomedcentral.com/articles/10.1186/1756-3305-5-287">alternative devices</a> work like “smoke free” mosquito coils. These devices are either battery or plug in powered and rely on heating an insecticide treated pad or reservoir of oil to release product that knocks out or repels mosquitoes. These can be a useful option indoors and can even be paired with a timer to work for only a few hours during the evening.</p>
<p>Portable devices are that can be clipped to your belt when out and about. It’s important to remember that as soon as you’re outside, especially in windy conditions or close to wetland or bushland areas, these products become less effective. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/443312/original/file-20220131-19-1ntd0v3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="mosquito coil" src="https://images.theconversation.com/files/443312/original/file-20220131-19-1ntd0v3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/443312/original/file-20220131-19-1ntd0v3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443312/original/file-20220131-19-1ntd0v3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443312/original/file-20220131-19-1ntd0v3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443312/original/file-20220131-19-1ntd0v3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443312/original/file-20220131-19-1ntd0v3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443312/original/file-20220131-19-1ntd0v3.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">Never use smoking coils inside.</span>
<span class="attribution"><a class="source" href="https://image.shutterstock.com/image-photo/mosquito-repellent-600w-626047901.jpg">Shutterstock</a></span>
</figcaption>
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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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<h2>Dress for success ✅</h2>
<p>Probably the best alternative to putting repellents on your skin is to cover up. This is always tricky when it is hot and humid but the physical barrier clothing provides may be the best option in areas where mosquito activity is high.</p>
<p>Long sleeved shirts, long pants, and covered shoes are <a href="https://www.health.nsw.gov.au/Infectious/factsheets/Pages/mosquito.aspx">key</a> to this approach. </p>
<p>Protection against mosquito bites can be improved by <a href="https://theconversation.com/mozzie-repellent-clothing-might-stop-some-bites-but-youll-still-need-a-cream-or-spray-107266">applying an insecticide to clothing</a>. For <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0152805">extra protection</a>, clothing can be treated with the insecticide permethrin – the same insecticide used to treat bed nets in countries prone to malaria. Always use as directed and do not apply directly to the skin.</p>
<h2>Wrist bands and sound emitting devices ❌</h2>
<p>For those wanting to avoid topical repellents, the coloured wrist bands sold in many pharmacies and supermarkets may seem an desirable option. Unfortunately, there is <a href="https://search.informit.org/doi/abs/10.3316/INFORMIT.227605874334644">no scientific evidence</a> these devices, irrespective of the active ingredients they contain, can provide whole body protection against mosquitoes.</p>
<p>Mosquitoes don’t seem put off by sound either. For decades small sound-emitting devices have been sold, and <a href="https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD005434.pub2/full">repeatedly shown to be ineffective</a>. “Mosquito repellent” smart phone apps <a href="https://theconversation.com/the-buzz-from-your-smartphone-wont-stop-mosquito-bites-92611">don’t work either</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/439998/original/file-20220110-23-13op6fi.jpg?ixlib=rb-1.1.0&rect=36%2C72%2C3989%2C2921&q=45&auto=format&w=1000&fit=clip"><img alt="girl runs in sprinkler outside" src="https://images.theconversation.com/files/439998/original/file-20220110-23-13op6fi.jpg?ixlib=rb-1.1.0&rect=36%2C72%2C3989%2C2921&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/439998/original/file-20220110-23-13op6fi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/439998/original/file-20220110-23-13op6fi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/439998/original/file-20220110-23-13op6fi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/439998/original/file-20220110-23-13op6fi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/439998/original/file-20220110-23-13op6fi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/439998/original/file-20220110-23-13op6fi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Summer fun is quickly ruined by mosquito bites.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/FRsGNnM4Z18">Elena Rabkina/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Changing your diet ❌</h2>
<p>It would be wonderful if there was a pill we could take to prevent us being bitten by mosquitoes. It would overcome the challenges of getting you to apply sticky and unusual smelling solutions throughout summer. Problem is, such a thing doesn’t exist. There is <a href="https://theconversation.com/what-can-i-eat-to-stop-mosquitoes-biting-me-87178">no scientific evidence</a> anything you can eat or drink will prevent mosquitoes biting you.</p>
<p>You can still enjoy your gin and tonic, bananas, or vegemite on toast – just don’t expect the mosquitoes to stop biting!</p>
<hr>
<p>
<em>
<strong>
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>
</strong>
</em>
</p>
<hr>
<h2>The final word (give repellents a chance)</h2>
<p>It is important to remember mosquitoes are <a href="https://theconversation.com/how-can-the-bite-of-a-backyard-mozzie-in-australia-make-you-sick-171601">more than just a nuisance</a>. Viruses spread by mosquitoes in Australia can cause debilitating disease. There are few treatments available for these illnesses, so prevention is vital.</p>
<p>You may not like applying insect repellent, but it is probably the best strategy we’ve got. Just as we’ve developed the habit of using sunscreen on a regular basis, we need to get into the swing of smearing or spraying on some insect repellent during the warmer months too.</p><img src="https://counter.theconversation.com/content/171805/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>Summer is no fun when mosquitoes are biting. Insect repellent creams, sprays, and lotions are safe and effective but there are alternatives. Here’s what works and what doesn’t!Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1716012021-11-16T03:23:26Z2021-11-16T03:23:26ZHow can the bite of a backyard mozzie in Australia make you sick?<figure><img src="https://images.theconversation.com/files/431764/original/file-20211113-17238-7fqadt.jpg?ixlib=rb-1.1.0&rect=30%2C30%2C3023%2C2128&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Cameron Webb/NSW Health Pathology</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Mosquitoes will be loving the wet weather that’s hit the east coast of Australia over the last week. </p>
<p>Mosquito populations naturally increase in spring, especially when there is plenty of water left around to complete their breeding cycle. So it’s a good time to start thinking about where water might be collecting around your backyard. </p>
<p>The bites of backyard mozzies aren’t just annoying – they can also make us sick. So what pathogens, or bugs, can mosquitoes transmit to humans? And how do they do it?</p>
<h2>What types of mosquito are found in our backyard?</h2>
<p>Hundreds of mosquitoes are found across the country but only a few regularly breed in our backyards. The larvae of these mosquitoes were originally found in natural water-filled receptacles like tree holes. </p>
<p>Now they’re commonly found in water-holding containers around our homes such as bird baths, damaged rainwater tanks, potted plant saucers and roof gutters. Neglected swimming pools can be a great place for mosquitoes too.</p>
<p>The most common of these mosquitoes is <em>Aedes notoscriptus</em>. It’s likely every Australian has been bitten by this “home grown” mosquito at least once. As well as being found in every corner of the country, it has also found its way to <a href="https://www.tepapa.govt.nz/discover-collections/rread-watch-play/science/mosquito-facts/which-new-zealand-mosquitoes-bite">New Zealand</a> and <a href="https://entomologytoday.org/2021/11/09/invasive-species-spread-aedes-notoscriptus-mosquito-southern-california/">North America</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/431837/original/file-20211114-38712-17dympe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/431837/original/file-20211114-38712-17dympe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/431837/original/file-20211114-38712-17dympe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/431837/original/file-20211114-38712-17dympe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/431837/original/file-20211114-38712-17dympe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/431837/original/file-20211114-38712-17dympe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/431837/original/file-20211114-38712-17dympe.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 common backyard mosquito, Aedes notoscriptus.</span>
<span class="attribution"><span class="source">Cameron Webb</span></span>
</figcaption>
</figure>
<p><a href="https://theconversation.com/zika-aedes-aegypti-mosquitoes-love-biting-humans-and-thats-why-they-spread-viruses-so-well-54238"><em>Aedes aegypti</em></a> is also found in Australia. This mozzie is widespread in tropical regions of the world and loves water-filled containers around the home. </p>
<p><em>Aedes aegypti</em> is currently only found in central and far north Queensland, but it has a habit of <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/jvec.12379">popping up elsewhere</a> if given the chance. </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>What diseases are a risk in our backyards?</h2>
<p>Like most mosquitoes, these backyard <a href="https://theconversation.com/curious-kids-when-we-get-bitten-by-a-mosquito-why-does-it-itch-so-much-93347">mozzies need blood</a>. When they bite, there is a chance that can spread the pathogens that make us sick. </p>
<p>But it isn’t just that they bite that determines if we’ll get sick. The mosquitoes need to pick up the pathogen first and that typically means they have to <a href="https://theconversation.com/how-australian-wildlife-spread-and-suppress-ross-river-virus-107267">bite an animal</a> or a person who has the pathogen circulating in their blood.</p>
<p>Dengue is the most significant mosquito-borne viral disease globally. In Australia, we’re fortunate <a href="https://theconversation.com/after-decades-away-dengue-returns-to-central-queensland-117821">very few local cases are reported</a>. </p>
<p>The mosquito that spreads dengue viruses is <em>Aedes aegypti</em>. As it isn’t widespread in Australia, <a href="https://theconversation.com/common-australian-mosquitoes-cant-spread-zika-65163">the risks are limited to parts of Queensland</a> and transmission only occurs when these viruses are introduced by an infected traveller. </p>
<p>These regions in Queensland have been the focus of innovative mosquito management programs that have minimised public health risks by <a href="https://www.csiro.au/en/news/news-releases/2021/landmark-trial-eliminates-pest-mosquito">reducing mosquito populations</a> or their <a href="https://www.worldmosquitoprogram.org/en/global-progress/australia/cairns-and-surrounds">capacity to spread viruses</a>.</p>
<p><a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1005070">Ross River</a> and <a href="https://www.health.nsw.gov.au/Infectious/factsheets/Pages/Barmah_Forest_virus_infection.aspx">Barmah Forest</a> viruses are responsible for most mosquito-borne disease notifications in Australia. More than 5,000 cases are reported each year across the country, mostly in Queensland and New South Wales. </p>
<p>Outbreaks of Ross River virus have become more common, including <a href="https://wwwnc.cdc.gov/eid/article/25/12/18-1810_article">around metropolitan areas</a>.</p>
<p>In the cities, suburbs and towns of Australia, <em>Aedes notoscriptus</em> may well be playing an important role in spreading these viruses. There is still lots to learn about these mosquitoes, their biology, and risk to human health.</p>
<hr>
<p>
<em>
<strong>
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>
</strong>
</em>
</p>
<hr>
<h2>New research highlights how much we have to learn</h2>
<p>Newly <a href="https://academic.oup.com/ve/article/7/2/veab082/6371231?searchresult=1">published research</a> from investigators in Queensland has identified a diverse range of viruses found within <em>Aedes notoscriptus</em> collected throughout the suburbs of Brisbane. </p>
<p>After testing more than 6,600 mosquitoes, the researchers identified a number of viruses, including those of potential human health concern. The results suggest these backyard mosquitoes may pose much more than a nuisance disrupting our time in the backyard.</p>
<p>The researchers also discovered a diverse range of lesser known “insect-specific” viruses. These viruses only infect mosquitoes and they’re not spread to people or animals. </p>
<p>Interestingly, related “insect-specific” viruses are being used to develop <a href="https://www.science.org/doi/10.1126/scitranslmed.aax7888?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed">diagnostic tests and vaccines</a> to combat the viruses that make humans sick. This highlights the importance of identifying viruses in wild mosquito populations. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/431838/original/file-20211114-60121-10m5679.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/431838/original/file-20211114-60121-10m5679.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/431838/original/file-20211114-60121-10m5679.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/431838/original/file-20211114-60121-10m5679.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/431838/original/file-20211114-60121-10m5679.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/431838/original/file-20211114-60121-10m5679.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/431838/original/file-20211114-60121-10m5679.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 left in even the smallest of quantity can be home to mosquitoes.</span>
<span class="attribution"><span class="source">Cameron Webb/NSW Health Pathology</span></span>
</figcaption>
</figure>
<h2>What can you do about backyard mosquitoes?</h2>
<p>There are plenty of ways you can reduce the numbers of mosquitoes in your backyard. You don’t need to <a href="https://theconversation.com/five-reasons-not-to-spray-the-bugs-in-your-garden-this-summer-85673">rely on insecticides</a>. You can still <a href="https://theconversation.com/you-can-leave-water-out-for-wildlife-without-attracting-mosquitoes-if-you-take-a-few-precautions-128631">leave water out for pets and wildlife</a>.</p>
<p>Routinely tip out, throw away, or cover up any water-holding containers. This includes discarded tyres, buckets, and bottles. Neglected children’s toys have lots of nooks and crannies that catch water too and can be a great place for mosquitoes. </p>
<p>Ensure your roof gutters, and other drains around the home, are regularly cleaned and your rainwater tank should be correctly installed and screened, too.</p>
<hr>
<p>
<em>
<strong>
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>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/171601/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>Backyard mosquitoes can be more than just annoying pests. Their bites can spread the pathogens that make us sick.Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of SydneyAndrew van den Hurk, Medical Entomologist, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1111732019-02-07T05:53:22Z2019-02-07T05:53:22ZAfter the floods come the mosquitoes – but the disease risk is more difficult to predict<p>We’re often warned to avoid mosquito bites after major flooding events. With more water around, there are likely to be more mosquitoes. </p>
<p>As flood waters recede around Townsville and clean-up efforts continue, the local population will be faced with this prospect over the coming weeks.</p>
<p>But whether a greater number of mosquitoes is likely to lead to an outbreak of mosquito-borne disease is tricky to predict. It depends on a number of factors, including the fate of other wildlife following a disaster of this kind.</p>
<h2>Mozzies need water</h2>
<p>Mosquitoes lay their eggs in and around water bodies. In the initial stages, baby mosquitoes (or “wrigglers”) need the water to complete their development. During the warmer months, it doesn’t take much longer than a week before they are grown and fly off looking for blood. </p>
<p>So the more water, the more mosquito eggs are laid, and the more mosquitoes end up buzzing about. </p>
<p>But outbreaks of disease carried by mosquitoes are dependent on more than just their presence. Mosquitoes rarely emerge from wetlands infected with pathogens. They typically need to pick them up from <a href="https://theconversation.com/how-australian-wildlife-spread-and-suppress-ross-river-virus-107267">biting local wildlife</a>, such as birds or mammals, before they can spread disease to people.</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>
</strong>
</em>
</p>
<hr>
<h2>Mosquitoes and extreme weather events</h2>
<p>Historically, major inland flooding events have triggered <a href="https://cameronwebb.wordpress.com/2016/10/06/do-outbreaks-of-mosquito-borne-disease-always-follow-floods/">significant outbreaks of mosquito-borne disease</a> in Australia. These <a href="https://academic.oup.com/trstmh/article/111/6/248/4554990">outbreaks</a> have included epidemics of the potentially fatal Murray Valley encephalitis virus. In recent decades, Ross River virus has more commonly been the culprit.</p>
<p>A focal point of the current floods is the Ross River, which runs through Townsville. The <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1005070">Ross River virus</a> was first identified from mosquitoes collected along this waterway. The disease it causes, known as Ross River fever, is diagnosed in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC89008/">around 5,000 Australians every year</a>. The disease isn’t fatal but it can be seriously debilitating.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/257600/original/file-20190206-174883-18eppdz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/257600/original/file-20190206-174883-18eppdz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/257600/original/file-20190206-174883-18eppdz.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/257600/original/file-20190206-174883-18eppdz.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/257600/original/file-20190206-174883-18eppdz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/257600/original/file-20190206-174883-18eppdz.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/257600/original/file-20190206-174883-18eppdz.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">Following substantial rainfall, mosquito populations can dramatically increase. Carbon dioxide baited light traps are used by local authorities to monitor changes in mosquito populations.</span>
<span class="attribution"><span class="source">Cameron Webb (NSW Health Pathology)</span></span>
</figcaption>
</figure>
<p>In recent years, major outbreaks of Ross River virus have occurred throughout the country. Above average rainfall is likely a driving factor as it boosts both the abundance and diversity of local mosquitoes.</p>
<p>Flooding across Victoria over the 2016-2017 summer produced <a href="https://www.abc.net.au/news/2017-02-09/ross-river-virus-cases-spike-victoria-nsw/8255280">exceptional increases in mosquitoes</a> and resulted in the state’s largest outbreak of Ross River virus. There were almost <a href="http://www9.health.gov.au/cda/source/cda-index.cfm">1,700 cases</a> of Ross River virus disease reported there in 2017 compared to an average of around 300 cases annually over the previous 20 years.</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>
</strong>
</em>
</p>
<hr>
<p>Despite plagues of mosquitoes taking advantage of flood waters, outbreaks of disease don’t always follow. </p>
<p>Flooding resulting from hurricanes in North America has been associated with increased mosquito populations. After Hurricane Katrina hit Louisiana and Mississippi in 2005, there was <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2828079/">no evidence</a> of increased mosquito-borne disease. The impact of wind and rain is likely to have adversely impacted local mosquitoes and wildlife, subsequently reducing disease outbreak risk.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/257643/original/file-20190207-174873-x72kvj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/257643/original/file-20190207-174873-x72kvj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/257643/original/file-20190207-174873-x72kvj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/257643/original/file-20190207-174873-x72kvj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/257643/original/file-20190207-174873-x72kvj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/257643/original/file-20190207-174873-x72kvj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/257643/original/file-20190207-174873-x72kvj.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">Applying insect repellent is worthwhile even if the risk of mosquito-borne disease isn’t known.</span>
<span class="attribution"><span class="source">From shutterstock.com</span></span>
</figcaption>
</figure>
<p><a href="https://academic.oup.com/jme/article/51/6/1097/861519">Australian studies</a> suggest there’s not always an association between flooding and Ross River virus outbreaks. Outbreaks can be triggered by flooding, but this is not always the case. Where and when the flooding occurs probably plays a major role in determining the likelihood of an outbreak.</p>
<p>The <a href="https://www.tandfonline.com/doi/abs/10.1080/23737867.2017.1359697">difficulty in predicting</a> outbreaks of Ross River virus disease is that there can be <a href="https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-018-2776-x">complex biological, environmental and climatic drivers</a> at work. Conditions may be conducive for large mosquito populations, but if the extreme weather events have displaced (or decimated) local wildlife populations, there may be a decreased chance of outbreak. </p>
<p>This may be why historically significant outbreaks of mosquito-borne disease have occurred in inland regions. Water can persist in these regions for longer than coastal areas. This provides opportunities not only for multiple mosquito generations, but also for increasing <a href="https://www.sciencedirect.com/science/article/pii/S0006320701002683">populations of water birds</a>. These birds can be important <a href="https://www.liebertpub.com/doi/abs/10.1089/vbz.2008.0040">carriers of pathogens</a> such as the Murray Valley encephalitis virus.</p>
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Read more:
<a href="https://theconversation.com/giant-mosquitoes-flourish-in-floodwaters-that-hurricanes-leave-behind-104350">Giant mosquitoes flourish in floodwaters that hurricanes leave behind</a>
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<p>In coastal regions like Townsville, where the main concern would be Ross River virus, flood waters may displace the wildlife that carry the virus, such as kangaroos and wallabies. For that reason, the flood waters may actually reduce the initial risk of outbreak.</p>
<h2>Protect yourself</h2>
<p>There is <a href="https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-018-2733-8">still much to learn</a> about the ecology of wildlife and their role in driving outbreaks of disease. And with a fear of <a href="https://www.abc.net.au/news/2019-02-06/could-climate-change-make-australia-uninsurable/10783490">more frequent and severe extreme weather events</a> in the future, it’s an important area of research.</p>
<p>Although it remains difficult to predict the likelihood of a disease outbreak, there are steps that can be taken to avoid mosquito bites. This will be useful even if just to reduce the nuisance of sustaining bites.</p>
<p>Cover up with long-sleeved shirts and long pants for a physical barrier against mosquito bites and use topical insect repellents containing <a href="https://theconversation.com/chemical-or-natural-whats-the-best-way-to-repel-mozzies-36879">DEET, picaridin, or oil of lemon eucalyptus</a>. Be sure to apply an even coat on all exposed areas of skin for the longest lasting protection.</p><img src="https://counter.theconversation.com/content/111173/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.</span></em></p>The more water, the more mosquito eggs are laid, and the more mosquitoes end up buzzing about. But to spread disease to people, they first need to bite infected wildlife.Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of SydneyLicensed 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>
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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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<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>
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<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">
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<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>
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<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>
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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>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">
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<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>
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<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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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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<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/424022015-08-19T03:22:11Z2015-08-19T03:22:11ZHow a new test is revolutionising what we know about viruses in our midst<figure><img src="https://images.theconversation.com/files/90839/original/image-20150805-22496-1gics2b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Detecting viruses in wild-caught mosquitoes provides intimate detail of disease transmission cycles.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/publichealthuw/19529872674/in/photolist-vKMGJE-wqjd6c-wGNVTe-wHiuUp-wqcmdu-wqc1oN-vKMGwL-wqcm9m-wHivc8-wHiv9T-wqjcz2-wG6Bh5-wqckNb-wqjcx8-wqc1fm-wEuk8S-wqc1dY-vKWg54-wGNVQD-vKMGns-wHiv8v-wGNW5X-2vVkpu-qJWvom-hg5nvz-wqjd3r-vKMGZQ-wqjcsZ-wEuk3G-wG6Bp9-vKWfYx-vKMGAy-wHiuzr-onja7R-onz3iG-8bgE3t-ftJaP5-fuj1Gy-FDNvY-8haqb5-54K4y5-8h7byc-8h7bxi-aZXeqk-fhpwyd-8EVHkB-rFQjYy-8gU4fa-f5ZKB-584D1k">University of Washington SPH/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Mosquitoes’ role in the spread of disease make them perhaps one of the most reviled insects in the world. But it also makes them more studied than most of their brethren. Now, a new technique for collecting mosquito saliva from the field has made monitoring mosquitoes both more sensitive and inexpensive.</p>
<p>Mosquito-borne disease remains an intractable problem both in Australia and globally. The seasonal curse of <a href="http://cmr.asm.org/content/14/4/909.short">Ross River fever</a> is well known to Australians, as is <a href="http://www.biomedcentral.com/content/pdf/1756-3305-7-379.pdf">dengue</a>, which is readily acquired when holidaying in Southeast Asia or even tropical northern Queensland. </p>
<p>Public health warnings and mosquito control remain central to the control of such diseases. But our ability to predict disease outbreaks is hampered by laborious mosquito trapping, underdeveloped forecasting models and unreliable human blood testing. </p>
<h2>Good spit</h2>
<p>Detecting viruses in wild-caught mosquitoes provides intimate detail of disease transmission cycles, helping us understand the complexities of disease ecology and providing new avenues for predicting and controlling outbreaks. Such virus hunting traditionally involved cumbersome mass collections of mosquitoes shipped live to faraway labs where they were ground up and analysed by scientists to search for traces of viruses. </p>
<p>What’s more, all this effort only showed that a mosquito in that “haystack” was carrying the virus; it couldn’t show whether it was capable of infecting someone with that virus. This, of course, is an important distinction since many mosquitoes can pick up a virus but not pass it on.</p>
<p>But an elegant new technology is helping to improve field detection of viruses, reduce cost and identify only mosquitoes capable of infecting someone with the virus. </p>
<p>A few years ago, <a href="http://www.pnas.org/content/107/25/11255.short">Queensland scientists discovered</a> that if trapped mosquitoes could be convinced to spit onto a specially coated card that preserves virus genes (made from DNA and RNA), then the viruses they carry could be more easily detected. </p>
<p>The spat-on cards are processed in a lab where the genes are “amplified” using a process that uses enzymes to probe the cards for virus genes. These genes are then copied, analysed and identified. This is how the concept of the mosquito “spit test” was born.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/90842/original/image-20150805-22488-1ak2s3p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/90842/original/image-20150805-22488-1ak2s3p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/90842/original/image-20150805-22488-1ak2s3p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/90842/original/image-20150805-22488-1ak2s3p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/90842/original/image-20150805-22488-1ak2s3p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/90842/original/image-20150805-22488-1ak2s3p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/90842/original/image-20150805-22488-1ak2s3p.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">
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<span class="caption">How do you get mosquitoes to spit on a card? Easy. Just coat it with honey.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/jason-riedy/16037303758/in/photolist-qranFd-6TMT1D-6E2z8i-CcPuv-7gTqzK-feqspn-2rfBz9-nJ9epV-81EBzR-eqQC6u-hotMJ5-6ZtgtR-a3SSh4-abckV9-65uHZk-7DToxm-aNKMLF-56Qd3K-9DPg6i-dbkD2m-7YwMbg-r6jKrj-4JMsmv-cQoLed-7gyJkP-a5b4w7-cXTumd-bz6AkW-vfqcME-5ayCeu-g8NVi5-5ocU9G-n2VvW-4YTkB1-YeDAs-CcP5D-8MyuKE-s3KBaG-4951yv-o2LCSy-6E2yf2-a7ypHU-jq9DFa-7PqSWm-awea63-rtgBK1-68hSMD-5V75sU-8MyuxW-omNZvj">Jason Riedy/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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</figure>
<p>But how do you get a mosquito to give a saliva sample? Easy. Just coat the card in honey and the mosquito will happily spit while getting a sugar fix. Only mosquitoes with virus in their saliva (rather than in their gut) are detected, thus identifying only the most dangerous (infectious-disease-carrying) mosquitoes. </p>
<p>Thousands of mosquitoes can spit on a single card, meaning much less time and money spent in the lab. And there’s no need for expensive shipments of live mosquitoes. What’s more, the cards can be shipped without refrigeration, making surveillance in remote areas far more effective. </p>
<h2>Understanding viral ecology</h2>
<p>Initial field trials <a href="http://online.liebertpub.com/doi/abs/10.1089/vbz.2013.1373">in Queensland and then the Northern Territory</a> showed viruses could be collected in the field. The idea is now being rolled out in <a href="http://medent.usyd.edu.au/arbovirus/results/virusisolates.htm">New South Wales</a>, Western Australia and South Australia. </p>
<p>In 2014, an existing mosquito surveillance <a href="http://www.unisa.edu.au/Global/Health/Sansom/Documents/SAMIR%20Virus%20detection%20info%20Mar%202014.pdf">trapping program</a> in South Australia was modified to retrofit mosquito traps with “honey cards”. When traps were picked up from the field, mosquitoes inside could be seen feeding on the cards. The traps were kept in the lab for a few more days, making sure every mosquito had a chance to provide a saliva sample.</p>
<p>Three virus types (Ross River, Barmah Forest, Stratford) were <a href="http://online.liebertpub.com/doi/abs/10.1089/vbz.2014.1759">detected 18 times</a> in the Adelaide region and in River Murray towns, in a year with very little human disease and only moderate mosquito numbers. Sometimes virus was detected in traps with only a small number of mosquitoes present. </p>
<p>This research showed there was perhaps more virus circulating in urban areas than we first realised, and that our understanding of what leads to large disease outbreaks is poorly developed. What we still don’t know is how much virus circulation is “normal”. And how much virus we need to find before sounding the alarm. </p>
<p>Honey cards collecting mosquito spit have the potential to change our perspective on mosquito-borne disease transmission and open up new avenues for enhanced surveillance strategies. Other mosquito-borne viruses such as <a href="http://www.health.gov.au/internet/main/Publishing.nsf/Content/cdi3702f">chikungunya</a> and <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4055592/">zika</a> are now threatening Australia, but our surveillance of them is poorly developed. </p>
<p>Using mosquito spit tests could enable early detection of these viruses. And this could help safeguard us from incursions of diseases not yet transmitted here.</p><img src="https://counter.theconversation.com/content/42402/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Craig Williams receives funding from SA Health, various local governments in SA, and the Adelaide and Mt Lofty Ranges Natural Resource Management Board. Craig is a member of the National Arbovirus and Malaria Advisory Committee for the Department of Health and Ageing.</span></em></p><p class="fine-print"><em><span>Emily Johnston Flies receives funding from The Royal Society of South Australia and the University of South Australia.</span></em></p>We monitor mosquitoes to help predict and control virus outbreaks. And a new technique for collecting mosquito saliva from the field has made the process both more sensitive and inexpensive.Craig Williams, Associate professor in Biology, University of South AustraliaEmily J Flies, PhD student in Disease Ecology, University of South AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/434712015-07-21T20:16:03Z2015-07-21T20:16:03ZA tale of three mosquitoes: how a warming world could spread disease<figure><img src="https://images.theconversation.com/files/89176/original/image-20150721-24286-ftzot.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Will climate change cause mosquito-borne diseases to spread?</span> <span class="attribution"><span class="source">Steve Doggett</span>, <span class="license">Author provided</span></span></figcaption></figure><p><em>Changing wildlife: this article is <a href="https://theconversation.com/au/topics/changing-wildlife">part of a series</a> looking at how key species such as bees, insects and fish respond to environmental change, and what this means for the rest of the planet.</em></p>
<p>As the world warms, animals and plants will shift their ranges to keep pace with their favoured climate. While the changing distributions of species can tell us how climate change is affecting the natural world, it may also have a direct impact on us. </p>
<p>One good example is the disease carried by insects.</p>
<p>Those small, familiar flies called mosquitoes are responsible for much human suffering around the globe because of their ability to transmit diseases.</p>
<p>Mosquitoes transmit a number of viruses, such as <a href="http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Dengue_fever">Dengue</a>, <a href="http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Ross_River_disease">Ross River Virus</a>, <a href="http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Murray_Valley_encephalitis">Murray Valley Encephalitis Virus</a> and the local variant of the West Nile Virus known as <a href="http://www.health.nsw.gov.au/Infectious/factsheets/Pages/Kunjin_virus.aspx">Kunjin</a>. </p>
<p>Could climate change cause these diseases to spread? While this an extremely important health question, the answer is <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1440-6055.2008.00677.x/abstract">far from simple</a>. </p>
<h2>Complicated life cycle</h2>
<p>The life cycle of mosquitoes and its viral parasites is particularly complicated. </p>
<p>Only adult females consume blood, and the immature stages (larvae) live in fresh or brackish water, filtering out small organic particles.</p>
<p>The virus undergoes certain parts of its lifecycle inside particular mosquito organs, but also requires other organs in the vertebrate host to complete its life cycle. And to get into a vertebrate, such as us, it relies on a hungry blood-sucking insect. </p>
<p>These viruses always have other hosts besides humans, which may include native and domestic animals. The pathway that these viruses take to infect humans is often via our domestic animals, which are also bitten by the same mosquitoes that feed on us.</p>
<p>In addition, rates of virus transmission to humans is also affected by the human built environment, and also human behaviour.</p>
<p>Because mosquitoes breed in water, changes in rainfall patterns are likely to change the distribution and abundance of mosquitoes, and therefore could affect disease transmission. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/89180/original/image-20150721-24301-ntpj8z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/89180/original/image-20150721-24301-ntpj8z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/89180/original/image-20150721-24301-ntpj8z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=359&fit=crop&dpr=1 600w, https://images.theconversation.com/files/89180/original/image-20150721-24301-ntpj8z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=359&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/89180/original/image-20150721-24301-ntpj8z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=359&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/89180/original/image-20150721-24301-ntpj8z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=451&fit=crop&dpr=1 754w, https://images.theconversation.com/files/89180/original/image-20150721-24301-ntpj8z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=451&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/89180/original/image-20150721-24301-ntpj8z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=451&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 larvae of Aedes notoscriptus, which carries the Barmah Forest and Ross River viruses.</span>
<span class="attribution"><span class="source">Stephen Doggett</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Australian climate is characterised by its variability, however we have experienced a general trend towards increased <a href="http://www.csiro.au/en/Research/OandA/Areas/Assessing-our-climate/State-of-the-Climate/2014-SoC-Report">spring and summer monsoonal rain</a> across northern Australia, and <a href="http://www.csiro.au/en/Research/OandA/Areas/Assessing-our-climate/State-of-the-Climate/2014-SoC-Report">decreased late autumn and winter rainfall in the south</a>.</p>
<h2>Flooding rains</h2>
<p>Kunjin virus is mainly transmitted by a small mosquito called <em>Culex annulirostris</em>, the common banded mosquito, in Australia. We are lucky because human infection rarely causes disease, even though Kunjin and the common-banded mosquito are widespread in Australia. </p>
<p>Kunjin’s close relative, the US strain of West Nile Virus is much more virulent, causing more human disease. These viruses are well known for their ability to mutate quickly, so they are always keeping medical authorities on their toes. </p>
<p>Higher than average rainfall and flooding in eastern Australia in the second half of 2010 and 2011 provided ideal conditions for breeding common banded mosquitoes, and in 2011 <a href="http://rstb.royalsocietypublishing.org/content/370/1665/20130561">a dangerous strain of Kunjin appeared</a> that caused acute encephalitis (swelling of the brain) in horses. This disease has only been detected in one human, however this mosquito feeds on both humans and horses. </p>
<p>This new virulent strain of Kunjin also appeared in new areas east of the Great Dividing Range, suggesting other unknown changes in transmission. </p>
<p>As temperatures increase, mosquito activity will begin earlier in the season and reach higher levels of abundance sooner, and maintain higher populations longer. These factors will all probably tend to increase the rate of transmission of Kunjin to both humans and animals.</p>
<h2>Drying out</h2>
<p>While flooding may have helped spread Kunjin, drought may have helped another mosquito-borne virus. </p>
<p>It would be simple to assume that drought would reduce mosquito populations by reducing the larval habitat (water), and thereby reduce the incidence of mosquito-borne disease in Australia. </p>
<p>However, this is not necessarily the case. Another Australian mosquito, <em>Aedes notoscriptus</em>, the striped mosquito, is responsible for transmitting Ross River and Barmah Forest Virus in Australia. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/89101/original/image-20150721-12546-rlynlw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/89101/original/image-20150721-12546-rlynlw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/89101/original/image-20150721-12546-rlynlw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/89101/original/image-20150721-12546-rlynlw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/89101/original/image-20150721-12546-rlynlw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/89101/original/image-20150721-12546-rlynlw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=525&fit=crop&dpr=1 754w, https://images.theconversation.com/files/89101/original/image-20150721-12546-rlynlw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=525&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/89101/original/image-20150721-12546-rlynlw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=525&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 will breed wherever there is standing water.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/cyborgsuzy/1456536366/">Suzanne Phillips/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>The striped mosquito is unusual in comparison to its cousins because it breeds in small containers of water, such as tree holes in natural environments. The main carrier of Dengue in Australia, <em>Aedes aegypti</em>, shares this habit.</p>
<p>These small container habitats abound in Australia’s urban backyard, with water features, water and food bowls for pets, and various toys providing such breeding places. </p>
<p>With the drought, Australians became much more water wise, and installed various water storage devices in their gardens, ranging from buckets left out in a storm, to professionally installed rain tanks. All these are potential habitat for the striped mosquito to breed. </p>
<p>In this case drought has caused an <a href="http://inthealth.oxfordjournals.org/content/5/4/251">increase in the abundance</a> of a mosquito virus carrier because of a change in human behaviour. </p>
<h2>The return of Dengue?</h2>
<p>Dengue fever is transmitted in Australia by the mosquito <em>Aedes aegypti</em>. The mosquito is restricted to Queensland, and Dengue fever transmission is restricted to coastal northern Queensland.</p>
<p>Recent modelling predicts that moderate climate change would extend the Dengue risk zone to Brisbane, exposing much larger human populations to risk.</p>
<p>However, <a href="https://www.mja.com.au/journal/2009/190/5/dengue-and-climate-change-australia-predictions-future-should-incorporate">before the 1930s</a>, Dengue fever transmission was known south almost to Sydney, and <em>Aedes aegypti</em> was known throughout mainland Australia except the deserts. </p>
<p>Both the mosquito, and the disease, have retreated to Queensland since then, and we don’t know why. What is clear is that we don’t really understand what controls the distribution of <em>Aedes aegypti</em> or Dengue in Australia, but given the contraction of the disease in historical time, it is unlikely that a warming climate will produce a simple response in the insect or the disease.</p>
<p>Australian insects will be affected by climate change, but simple predictions based on increasing average temperatures and changing rainfall patterns miss the important effects of complex biological interactions. </p>
<p>In addition, we are only just beginning to use models that are sophisticated enough to consider how insects might evolve under changing climate. </p>
<p>Investing in a deeper understanding of these complex biological webs, and their outcomes for human society, will result in great returns. Our predictions of the future state of Australian plants and animals will become more accurate and we will also improve human health and manage our biodiversity more sustainably into the future.</p><img src="https://counter.theconversation.com/content/43471/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Yeates receives funding from CSIRO, The Schlinger Foundation, The Australian Biological Resources Study and the US National Science Foundation.</span></em></p>Could climate change cause mosquito-borne diseases to spread? While this an extremely important health question, the answer is far from simple.David Yeates, Director of the Australian National Insect Collection, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/391762015-04-02T23:05:44Z2015-04-02T23:05:44ZIs climate change to blame for outbreaks of mosquito-borne disease?<figure><img src="https://images.theconversation.com/files/76860/original/image-20150402-31268-1wwzjri.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A changing climate may contribute to more mosquito-borne disease, but it doesn't guarantee it.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/13105441@N04/1368626064">john dunstan/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>The east coast of Australia is currently experiencing one of its worst outbreaks of mosquito-borne disease in years. Mosquitoes have plagued the summer and now there’s a <a href="http://www.couriermail.com.au/news/queensland/queenslands-worst-ross-river-virus-outbreak-in-almost-20-years-hits-brisbane/story-fnn8dlfs-1227261900933">dramatic increase</a> in disease caused by Ross River virus, spread by the bite of mosquitoes.</p>
<p>Mosquitoes need blood and, unfortunately, they often bite people to get it – <a href="https://theconversation.com/health-check-why-mosquitoes-seem-to-bite-some-people-more-36425">some more than others</a>. </p>
<p>Pathogens spread by mosquitoes already kill <a href="https://theconversation.com/when-it-comes-to-natures-public-enemy-number-one-the-mosquito-is-a-modern-monster-39214">more than a million people a year</a> across the world, mostly in tropical regions. The increased <a href="http://www.biomedcentral.com/1471-2334/14/167">risk of mosquito-borne disease</a> in a warmer, wetter world is a concern for health authorities internationally. </p>
<p>But more mosquitoes doesn’t guarantee more mosquito-borne disease. If it isn’t the “right” mosquito, there won’t be outbreaks of dengue or malaria. </p>
<p>And while a changing climate may contribute to more mosquito-borne disease, it doesn’t guarantee it: human movement around the world is likely to play just as an important a role.</p>
<h2>Not all mozzies are equal</h2>
<p>Mosquitoes aren’t like dirty syringes spreading infected blood. They’re diverse and complex creatures that have a special relationship with the parasites and viruses they can spread.</p>
<p>Very few of the thousands of mosquitoes found on earth are able to spread <a href="https://theconversation.com/explainer-what-is-dengue-fever-8571">dengue</a> or <a href="https://theconversation.com/explainer-the-chikungunya-virus-and-its-risk-to-australia-16968">chikungunya</a> viruses. A different group are involved in the spread of <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3990373/">West Nile virus</a> and <a href="http://www.cdc.gov/japaneseencephalitis/">Japanese encephalitis virus</a>, while a different type of mosquito altogether is involved in <a href="http://www.who.int/topics/malaria/en/">spreading malaria</a> parasites. </p>
<h2>Human movement</h2>
<p>A recent article in the journal <a href="http://www.thelancet.com/journals/laninf/article/PIIS1473-3099%2815%2970091-5/abstract">Lancet Infectious Diseases</a> reviews the factors contributing to future increases in mosquito-borne disease risk in the United Kingdom. While the authors identify increased temperatures as potentially providing suitable conditions for mosquitoes that spread pathogens, climate change alone wasn’t enough. </p>
<p>The mosquitoes that can spread dengue and chikungunya viruses, particularly the Asian Tiger Mosquito (<em>Aedes albopictus</em>), need to get there in the first place and, most likely, that is with people and their belongings. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/76043/original/image-20150325-12293-1880cs9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/76043/original/image-20150325-12293-1880cs9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=386&fit=crop&dpr=1 600w, https://images.theconversation.com/files/76043/original/image-20150325-12293-1880cs9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=386&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/76043/original/image-20150325-12293-1880cs9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=386&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/76043/original/image-20150325-12293-1880cs9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=485&fit=crop&dpr=1 754w, https://images.theconversation.com/files/76043/original/image-20150325-12293-1880cs9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=485&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/76043/original/image-20150325-12293-1880cs9.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 Asian Tiger Mosquito.</span>
<span class="attribution"><span class="source">SteveDoggett</span></span>
</figcaption>
</figure>
<p>It isn’t only the UK that is at risk. Until recently, chikungunya virus was unknown from the Americas but within a year of it being introduced into the Caribbean, it had spread to both North America and South America and is <a href="http://www.cdc.gov/chikungunya/geo/">suspected to have infected</a> over 1.2 million people.</p>
<p>As the researchers highlight, even the way authorities respond to the threats of climatic change, such as the construction or rehabilitation of wetlands <a href="http://www.nature.com/nclimate/journal/v3/n10/abs/nclimate1944.html">to create a buffer</a> against increasingly frequent storms and sea level rise, may further increase risk. Mosquitoes that spread West Nile virus could move into these wetlands.</p>
<h2>Hitching a ride to Australia</h2>
<p>The Asian Tiger Mosquito poses a significant threat to Australia. It was discovered in the <a href="http://www.bioone.org/doi/abs/10.2987/8756-971X%282006%2922%5B358:DOAWIO%5D2.0.CO%3B2">Torres Strait in 2005</a>, having thought to have hitchhiked on <a href="http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0002361">fishing boats from Indonesia</a>. Its a question of when, not if, this mosquito will make its way to mainland Australia.</p>
<p>The mosquito has already hitchhiked to Europe and North America with eggs attached to used tyres and lucky bamboo. Movement of people, not shifts in climate is the biggest risk. </p>
<p>Should it reach one of our major cities, <a href="http://onlinelibrary.wiley.com/doi/10.1111/aec.12105/abstract">there is little doubt</a> that mosquito could become a <a href="http://jme.oxfordjournals.org/content/early/2015/03/05/jme.tjv004">persistent summer pest</a> and <a href="http://jme.oxfordjournals.org/content/51/3/661">possible public health threat</a>. The way we respond to water shortages in our cities, <a href="http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0000429">by increasing water storage around our homes</a>, may set the scene for this mozzie to move in.</p>
<h2>Aussie mozzie risks</h2>
<p>Exotic mosquitoes and viruses are a concern but there are still plenty of ways a local mosquito bite can make you sick. </p>
<p><a href="https://theconversation.com/explainer-what-is-ross-river-virus-24630">Ross River virus</a> is the most commonly reported local mosquito-borne disease. Every year about 5,000 fall ill due to this virus. While not fatal, it can cause fever, rash, headache, joint pain and fatigue that may last a few weeks or many months. It can be seriously debilitating. </p>
<p>By the end of March, New South Wales and Queensland will have <a href="http://www9.health.gov.au/cda/source/rpt_4.cfm">recorded over 4,700 cases</a> of Ross River virus disease. Those figures already exceed the total number of cases reported in each of the previous three to five years. This may be the biggest outbreak of mosquito-borne disease along the east coast of Australia since the mid-1990s.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/76862/original/image-20150402-31316-1prg481.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/76862/original/image-20150402-31316-1prg481.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/76862/original/image-20150402-31316-1prg481.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/76862/original/image-20150402-31316-1prg481.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/76862/original/image-20150402-31316-1prg481.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/76862/original/image-20150402-31316-1prg481.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/76862/original/image-20150402-31316-1prg481.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">Kangaroos and wallabies also carry the Ross River virus.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/thorstenrinne/4492591283">Thorsten Rinne/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>Australia has had <a href="https://www.mja.com.au/journal/2009/190/5/dengue-and-climate-change-australia-predictions-future-should-incorporate">major outbreaks of dengue in the past</a>. But the only mosquito in Australia able to spread the virus is restricted to far north Queensland. It is <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1440-6055.2008.00677.x/full">unlikely to spread</a> to southern cities beyond Brisbane based on temperature change alone.</p>
<p><a href="http://www.health.nsw.gov.au/Infectious/factsheets/Pages/barmah-forest-virus.aspx">Barmah Forest</a>, <a href="https://www.mja.com.au/journal/2012/196/5/murray-valley-encephalitis-review-clinical-features-diagnosis-and-treatment?">Murray Valley encephalitis</a> and <a href="http://www.health.nsw.gov.au/Infectious/factsheets/Pages/Kunjin_virus.aspx">Kunjin</a> viruses are all also spread by mosquitoes in Australia too, although they’re generally far less common that Ross River virus.</p>
<h2>Could the current outbreak be linked to a changing climate?</h2>
<p>Thanks to the <a href="http://www.bom.gov.au/climate/current/statements/scs50.pdf">warmest spring on record</a> and substantial rainfall associated with <a href="http://www.abc.net.au/science/articles/2015/03/25/4201439.htm">tropical cyclones</a>, conditions have been perfect for mosquitoes. If these climatic events become more common, there is little doubt we’ll continue to see outbreaks of Ross River virus disease and other mosquito-borne diseases.</p>
<p>However, outbreaks of Ross River virus are determined by more than mosquitoes. Wildlife play an important role too, as <a href="http://online.liebertpub.com/doi/abs/10.1089/vbz.2014.1617">kangaroos and wallabies that carry the virus</a> are increasingly found close to residential areas. </p>
<p>So understanding and predicting outbreaks requires <a href="http://online.liebertpub.com/doi/abs/10.1089/vbz.2012.1284">an understanding</a> of wetlands and wildlife, as well as climate and mosquitoes. The way we <a href="https://theconversation.com/using-urban-planning-to-reduce-mosquito-borne-disease-8430">guide urban development</a> will also be important.</p>
<p>The current outbreak, however, may provide a glimpse of what lays ahead. With warmer weather, we may see an extension of the “mosquito season” each year. Aside from the risks to public health extending well into autumn (or possibly arriving earlier in summer), there is the increased economic burden on local authorities needing to <a href="http://www.couriermail.com.au/news/queensland/brisbane-city-councils-air-and-land-assault-to-beat-mosquito-plague/story-fnn8dlfs-1227193706970">expand mosquito control</a> and <a href="http://www.theleader.com.au/story/2025003/more-mosquitoes-on-the-way/">disease surveillance programs</a>.</p>
<p>There are still gaps in our understanding of the relationship between climate, mosquitoes and disease. But the current outbreak of Ross River virus disease should serve as a reminder that in the future, more of our “home grown” mosquito-borne disease, and not necessarily the spread of “tropical” disease such as dengue and chikungunya, could be our primary concern.</p><img src="https://counter.theconversation.com/content/39176/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology 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 east coast of Australia is currently experiencing one of its worst outbreaks of mosquito-borne disease in years.Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/368792015-02-18T19:04:57Z2015-02-18T19:04:57ZChemical or natural: what’s the best way to repel mozzies?<figure><img src="https://images.theconversation.com/files/71579/original/image-20150210-24697-40blv0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">For exposed skin, there really isn’t an alternative to topical insect repellents.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-200078597/stock-photo-the-feet-of-a-young-woman-lying-in-the-grass-in-a-park-on-a-summer-day.html?src=K_rIbDulJr-32dgHidI0WQ-2-24&ws=1">LoloStock/Flickr</a></span></figcaption></figure><p>Mosquitoes need blood to survive. And what better place to get a good meal than a slow, <a>tasty human</a>.</p>
<p>Mosquitoes aren’t just annoying. Every year around 5,000 Australians get sick following a mosquito bite. Most commonly the infection is <a href="https://theconversation.com/explainer-what-is-ross-river-virus-24630">Ross River virus</a> but there is annual activity of <a href="http://www.abc.net.au/health/library/stories/2015/02/05/4174461.htm">dengue viruses in north Queensland</a> and there are occasional cases of the rare, but potentially fatal, <a href="https://www.mja.com.au/journal/2012/196/5/murray-valley-encephalitis-review-clinical-features-diagnosis-and-treatment">Murray Valley encephalitis virus</a>.</p>
<p>Spraying insecticides may kill some mosquitoes around our backyards but it won’t completely protect us from mozzie bites. </p>
<p>Tipping out, throwing away or covering up any water-holding containers around the backyard will take away opportunities for them to breed in our backyards. But there isn’t much you can do if they’re flying in from nearby wetlands.</p>
<p>Mosquitoes aren’t going anywhere. They’re a natural part of our environment and they’re increasingly finding a <a href="https://theconversation.com/aussie-mozzie-found-in-urban-california-31784">home within our cities</a>. We’re going to have to learn to live with them, and take on the challenge to avoid their bites.</p>
<h2>The first line of defence</h2>
<p>Avoiding wetlands or bushland at dawn and dusk will ensure you’re missing the time and place where mosquitoes are most active. </p>
<p>Wearing light-coloured long-sleeved shirts and pants won’t repel mosquitoes but you’ll attract fewer to you. Those that do land will be less likely to bite through if clothing is loose-fitting. You can also consider <a href="http://onlinelibrary.wiley.com/doi/10.1111/mve.12068/full">treating the clothing with insecticide</a> for added protection.</p>
<p>For exposed skin, there really isn’t an alternative to topical insect repellents. There is nothing you can eat or drink that will prevent mosquito bites so you’ll need to pick out your favourite repellent formulation.</p>
<p>Any product for sale in Australia purporting to repel mosquitoes must be registered with the <a href="http://apvma.gov.au/">Australian Pesticides and Veterinary Medicines Authority</a>. The label on your repellent will tell you what the ingredients are in each formulation. But not all repellents are equal. </p>
<h2>Chemical repellents</h2>
<p>The <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1708-8305.2010.00402.x/full">most effective</a> topical repellents are those that contain either <a href="https://theconversation.com/aussies-vs-mozzies-a-users-guide-to-repellents-10964">DEET or picaridin</a>. These two products have repeatedly been shown to protect against bites and, despite the common misconception, have shown to be <a href="http://www.sciencedirect.com/science/article/pii/S0273230008000494">safe to use</a>, including on children over the age of three months.</p>
<p>While there is still <a href="https://theconversation.com/sniffing-out-new-repellents-why-mozzies-cant-stand-the-deet-33457">some debate</a> about whether products such as DEET and picaridin actively repel or simply confuse mosquitoes looking for blood, there is no doubt that when applied to exposed skin, they stop biting by mosquitoes.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/71570/original/image-20150210-24682-125de89.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/71570/original/image-20150210-24682-125de89.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=448&fit=crop&dpr=1 600w, https://images.theconversation.com/files/71570/original/image-20150210-24682-125de89.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=448&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/71570/original/image-20150210-24682-125de89.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=448&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/71570/original/image-20150210-24682-125de89.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=563&fit=crop&dpr=1 754w, https://images.theconversation.com/files/71570/original/image-20150210-24682-125de89.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=563&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/71570/original/image-20150210-24682-125de89.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=563&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">If you need several hours of protection, opt for a high-dose or ‘tropical strength’ repellent.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/aquilaonline/3157213356">Aquila/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>It is, however, important to understand what the “strength” of a formulation tells you about how well it will repel mosquitoes.</p>
<p>Let’s take DEET as an example. The “strength” of the repellent (the concentration of DEET in the commercial formulation) will determine for how long mozzies are prevented from biting. This means that for short periods, say around two hours, a “low dose” repellent will stop just as many mosquitoes from biting as a “high dose” (often called tropical strength) repellent. </p>
<p>But while that “low dose” repellent may stop working after a few hours, the “high dose” repellent will provide protection for many, many hours. The same equation applies to picaridin-based repellents.</p>
<p>In Australia, the highest-dose repellent contains 80% DEET and laboratory studies <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1753-6405.2009.00435.x/abstract">have demonstrated over ten hours protection</a> from biting mosquitoes.</p>
<p>But if you’re only going to be outside for a short period, there is really no need to use a “high dose” formulation. </p>
<h2>Botanical repellents</h2>
<p>Extracts from many different plants have been purported to repel mosquitoes. In many cultures, smouldering aromatic leaves have been used to repel mosquitoes with some success. But what about plant-based topical repellents? </p>
<p>Some of the most widely available “botanical” repellents contain one or a blend of citronella, tea-tree, eucalyptus, lavender or catmint oils. Essential oils from <a href="http://www.bioone.org/doi/abs/10.2987/09-0016.1?journalCode=moco">Australian native plants</a> are also popular. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/71571/original/image-20150210-24660-vak188.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/71571/original/image-20150210-24660-vak188.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=426&fit=crop&dpr=1 600w, https://images.theconversation.com/files/71571/original/image-20150210-24660-vak188.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=426&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/71571/original/image-20150210-24660-vak188.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=426&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/71571/original/image-20150210-24660-vak188.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=535&fit=crop&dpr=1 754w, https://images.theconversation.com/files/71571/original/image-20150210-24660-vak188.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=535&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/71571/original/image-20150210-24660-vak188.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=535&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Citronella burners may help reduce the number of biting mozzies but they won’t provide complete protection.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/emiliano-iko/4748043421">i k o/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>But <a href="http://www.nejm.org/doi/full/10.1056/NEJMoa011699">rarely</a> do these repellents provide the same duration of protection as DEET or picaridin-based repellents. </p>
<p>If you’re only outside for a short time, this may not be a problem. If you’re heading out for a bush walk, picnic near local wetlands or a stint of gardening in the late afternoon, you’ll need to reapply “botanical” formulations <a href="http://www.crcpress.com/product/isbn/9781466553552">three to four times as frequently</a> as low dose DEET-based repellents.</p>
<p>It’s also important to remember that although these “botanical” repellents are often perceived to be safer to use, there are plenty of examples of <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1365-4632.2012.05654.x/full">adverse skin reactions</a> resulting from the over application of essential oils to skin. </p>
<p>Even registered botanical products are generally not advised for use on children under 12 months of age.</p>
<p>There are plenty of mosquito coils and sticks available that contain plant-based repellents such as citronella. While these <a href="http://www.bioone.org/doi/abs/10.2987/8756-971X%282006%2922%5B158:FEONMS%5D2.0.CO;2">help reduce</a> the number of biting mosquitoes, they won’t provide the complete protection that a topical DEET-based repellent will.</p>
<h2>It’s not just what you choose but how you use</h2>
<p>It doesn’t matter what type of repellent you choose, unless there is a complete application to all exposed skin, you won’t be completely protected. Mosquitoes are highly skilled at finding the smallest chinks in your repellent armour.</p>
<p>Spraying repellent on clothes or giving a dab “here and there” won’t provide protection. You need to apply it like you would sunscreen but probably not quite so much. A thin cover is enough for short periods of protection. </p>
<p>Obviously, reapplication is required after swimming or sweating.</p>
<h2>What about those wrist bands?</h2>
<p>In the middle of a hot and humid summer afternoon, rubbing a somewhat sticky substance over your skin is far from appealing. It’s little wonder that there is great interest in wrist bands and patches that purport to protect against mosquito bites.</p>
<p>But they only work for <a href="https://cameronwebb.wordpress.com/2013/11/25/do-mosquito-repellent-wrist-bands-work/">a few millimetres</a> either side of the band. <a href="http://www.entsocnsw.org.au/images/stories/media/40%20webb%20and%20russell%20wrist%20bands.pdf">Laboratory testing</a> of wrist bands containing an essential oil indicated that while there was a reduction in the number of mosquitoes attempting to bite close to the band, there was little protection on the upper arm. They don’t provide “whole body” protection against biting mosquitoes and aren’t <a href="http://www.nejm.org/doi/full/10.1056/NEJMoa011699">an effective alternative</a> to topical repellents.</p>
<p>Botanical products and wristbands are marketed as “safer”, “more natural” or “more convenient to use”. But users may be inadvertently putting themselves at risk of mosquito-borne disease. DEET- or picaridin-based repellent formulations provide the best protection. </p>
<p><em><strong>Further reading:</strong> <a href="https://theconversation.com/health-check-why-mosquitoes-seem-to-bite-some-people-more-36425">Health Check: why mosquitoes seem to bite some people more</a></em></p><img src="https://counter.theconversation.com/content/36879/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology 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.</span></em></p>Mosquitoes need blood to survive. And what better place to get a good meal than a slow, tasty human. Mosquitoes aren’t just annoying. Every year around 5,000 Australians get sick following a mosquito bite…Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/246302014-03-24T19:14:25Z2014-03-24T19:14:25ZExplainer: what is Ross River virus?<figure><img src="https://images.theconversation.com/files/44529/original/pnnp2wzb-1395632840.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The saltmarsh mosquito, Aedes vigilax, transmits Ross River virus in many coastal regions of Australia.</span> <span class="attribution"><span class="source">Mr Stephen Doggett (Medical Entomology, Pathology West - ICPMR Westmead)</span></span></figcaption></figure><p>Ross River virus infection is the most commonly reported mosquito-borne disease in Australia, with <a href="http://cmr.asm.org/content/14/4/909.short">more than 4,000 cases</a> of illness are reported every year. </p>
<p>Activity has been recorded from every state and territory in the country. And while Ross River virus generally considered a disease of rural regions, it is increasingly active at our urban fringes.</p>
<h2>Symptoms</h2>
<p>Ross River virus is not fatal but it can be debilitating. The symptoms typically include “<a href="http://www.health.nsw.gov.au/Infectious/factsheets/Pages/Ross-River-Fever.aspx">flu-like symptoms</a>” such as fever, chills, headache, muscle and joint pain and a general feeling of fatigue. </p>
<p>The symptoms develop a week or so after being bitten by an infected mosquito. But while they typically last less than two weeks, there are cases where fatigue, muscle and joint pain persist for many months. </p>
<p>Ross River virus is a <a href="http://www.health.gov.au/casedefinitions">notifiable disease</a>, so infection can only be confirmed through a blood test. For this reason – and because the severity and duration of symptoms can be highly variable – it is strongly suspected that many cases go unreported and that the official statistics are a dramatic underestimate of the total number of infections each year.</p>
<p>There are no specific treatments or vaccines, so preventing mosquito bites is critical in avoiding disease.</p>
<p>It’s <a href="http://www.ajtmh.org/content/72/6/792.short">difficult to predict outbreaks</a> and governments don’t have the capacity to undertake broad-scale mosquito control in all regions, so health authorities generally focus their efforts on raising awareness and issuing warnings, based on information from local <a href="http://medent.usyd.edu.au/arbovirus/">surveillance programs</a>.</p>
<h2>Transmission</h2>
<p>There are more than <a href="http://www.annualreviews.org/doi/abs/10.1146/annurev.ento.47.091201.145100">40 mosquito species</a> that may play a role in transmitting the virus. This is a problem because the mosquitoes transmitting the virus during outbreaks may vary from region to region, making it difficult to track. </p>
<p>It is also a problem because the environmental drivers of mosquito abundance will change from region to region. This means that in some locations, the risks of an outbreak may be triggered by rainfall while in others, it is the tidal flooding of coastal wetlands.</p>
<p>While it is not surprising that outbreaks generally occur when mosquito populations are high, abundant mosquito populations and wetlands <a href="http://online.liebertpub.com/doi/abs/10.1089/vbz.2007.0152">don’t guarantee</a> an outbreak will occur. </p>
<p>Mosquitoes generally don’t hatch out of the wetlands infected with Ross River virus, they must bite an infected animal first. The most important reservoirs for Ross River virus are macropods (kangaroos and wallabies).</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/44384/original/ch3zgzq6-1395306184.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/44384/original/ch3zgzq6-1395306184.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/44384/original/ch3zgzq6-1395306184.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/44384/original/ch3zgzq6-1395306184.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/44384/original/ch3zgzq6-1395306184.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/44384/original/ch3zgzq6-1395306184.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/44384/original/ch3zgzq6-1395306184.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 and wallabies are critical in determining the risks of Ross River virus.</span>
<span class="attribution"><span class="source">Dr Cameron Webb (University of Sydney and Pathology West)</span></span>
</figcaption>
</figure>
<p>There have been Ross River virus cases from most of our major metropolitan centres. In many urban fringe areas, newly constructed wetlands are <a href="https://theconversation.com/using-urban-planning-to-reduce-mosquito-borne-disease-8430">increasing the abundance</a> of local mosquito populations, while the control of foxes and feral cats has led to an increase in populations of wallabies. </p>
<p>Wallabies using the bushland corridors along our rivers and estuaries therefore may be increasing the risks of Ross River virus. This potential has been illustrated by the recent <a href="http://www.health.nsw.gov.au/news/Pages/20140221_0.aspx">public health warnings</a> issued due to the detection of Ross River virus in <a href="http://www.theleader.com.au/story/2025003/more-mosquitoes-on-the-way/">mosquitoes collected along the Georges River</a> in southern Sydney where wallabies are common within Georges River National Park.</p>
<h2>Prevention</h2>
<p>It’s important to protect yourself from mosquito bites with protective clothing or <a href="https://theconversation.com/aussies-vs-mozzies-a-users-guide-to-repellents-10964">topical insect repellents</a> when you’re around wetland and bushland areas, particularly at dawn and dusk when mosquitoes are most active. </p>
<p>Remember, even though mosquito populations are falling, autumn is actually the peak period of virus activity. You may not be swamped by mozzies but you should still take precautions to avoid bites.</p><img src="https://counter.theconversation.com/content/24630/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology have been engaged by a range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology.</span></em></p>Ross River virus infection is the most commonly reported mosquito-borne disease in Australia, with more than 4,000 cases of illness are reported every year. Activity has been recorded from every state…Cameron Webb, Clinical Lecturer and Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/169682013-09-17T04:43:16Z2013-09-17T04:43:16ZExplainer: the chikungunya virus and its risk to Australia<figure><img src="https://images.theconversation.com/files/31378/original/26jmqdbc-1379304185.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A primary carrier of the Chikungunya virus, the Asian tiger mosquito (_Aedes albopictus_) could easily hop to mainland Australia from Torres Strait islands.</span> <span class="attribution"><span class="source">Camponotus Vagus</span></span></figcaption></figure><p>Chikungunya is a virus transmitted to people by mosquitoes; it usually causes a non-fatal but debilitating illness. </p>
<p>Despite thousands of people being infected each year in Africa, Asia and Melanesia, chikungunya is not currently transmitted within Australia. The virus hasn’t had time and the opportunity to colonise Australia – yet.</p>
<p>Few Australians have immunity to the virus, leading to concerns that, should it become established here, there could be a very large outbreak.</p>
<h2>A short history</h2>
<p>Chikungunya was first identified in Africa. It’s closely related to the Ross River virus, which affects around 4,000 Australians each year, and causes similar symptoms of joint pain, fever, headache, conjunctivitis, and rash. </p>
<p>Whereas Ross River virus is maintained in animals such as kangaroos, chikungunya only persists in humans and other primates, and is circulated by mosquito bites. The dengue mosquito (<em>Aedes aegypti</em>), and the Asian tiger mosquito (<em>Aedes albopictus</em>) are its primary carriers.</p>
<p>The naming of chikungunya comes from a Tanzanian Makonde word meaning “to bend up”, in reference to the stooped posture of sufferers. A full recovery can be expected after a week or two, although some cases can be chronic and debilitating, incurring significant <a href="http://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0001197">social, economic and direct medical costs</a>. </p>
<p>In large epidemics, chikungunya infection has led to some fatalities.</p>
<p>As far as we know, Australians first started catching chikungunya overseas in 1989. A major upswing in imported cases from 2008 was related to major epidemics in Africa and India; <a href="http://www.plospathogens.org/article/info%3Adoi%2F10.1371%2Fjournal.ppat.0030201">the virus had mutated</a> to become more infectious and cause more severe disease.</p>
<p>There were 168 cases of chikungunya notified in Australia between 2002 and 2012, with the majority of infections acquired by travellers in Malaysia, Indonesia, and India. Of course, the number of cases we know about may be just the tip of the iceberg of the actual number of people carrying the virus. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/31379/original/6d6v6jmm-1379304522.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/31379/original/6d6v6jmm-1379304522.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/31379/original/6d6v6jmm-1379304522.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/31379/original/6d6v6jmm-1379304522.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/31379/original/6d6v6jmm-1379304522.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=507&fit=crop&dpr=1 754w, https://images.theconversation.com/files/31379/original/6d6v6jmm-1379304522.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=507&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/31379/original/6d6v6jmm-1379304522.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">The dengue mosquito (<em>Aedes aegypti</em>) is also a primary carrier of the chikungunya virus.</span>
<span class="attribution"><span class="source">Sanofi Pasteur/Flickr</span></span>
</figcaption>
</figure>
<p>Of those carrying the virus, only some will get sick; of those who get sick, only some will see a doctor, and only some doctors will think to order a blood test for chikungunya.</p>
<h2>Danger to Australia</h2>
<p>So how likely is it that chikungunya could become established in Australia with transmission by local mosquitoes? Given the lack of general awareness of it, the lack of immunity among Australians, and our very poor understanding of just how much chikungunya is entering the country each year, the answer is unclear. </p>
<p>We have only the barest understanding of what parts of Australia are likely to have the right kind of environmental conditions to enable chikungunya transmission to occur. </p>
<p>Queensland remains the most likely place for chikungunya to become established, given that dengue mosquitoes (which can transmit the virus) are already there. But, in the last few years, <a href="http://online.liebertpub.com/doi/abs/10.1089/vbz.2009.0106">studies of native Australian mosquitoes</a> by Queensland scientists have shown local mozzies may be able to do the job in the right circumstances. </p>
<p>There’s also a risk that Asian tiger mosquitoes may colonise the Australian mainland from their springboard on the Torres Strait islands, where we know they have been since 2004 (when a survey on Masig Island located a small number of them). </p>
<p>From recent genetic evidence and historical records, these invasive critters are thought to have hitchhiked from East Timor and Papua New Guinea.</p>
<p>This is a cold-adapted mosquito that could work its way south into the major cities. As a carrier of dengue and chikungunya, the arrival of the Asian tiger mosquito could be a game-changer (or barbecue-stopper, if you like) – Australia would become home to two efficient chikungunya spreaders (vectors) well-adapted to city life.</p>
<p>Greater awareness of exotic diseases such as chikungunya could stimulate better surveillance. Coupled with some peer-reviewed risk analysis, we could be halfway to developing a national strategy for minimising the risk of chikungunya becoming established in Australia.</p><img src="https://counter.theconversation.com/content/16968/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Craig Williams is affiliated with the National Centre for Epidemiology and Population Health at the Australian National University in Canberra, and is a member of the National Arbovirus and Malaria Advisory Committee for the Commonwealth's Department of Health and Ageing.</span></em></p>Chikungunya is a virus transmitted to people by mosquitoes; it usually causes a non-fatal but debilitating illness. Despite thousands of people being infected each year in Africa, Asia and Melanesia, chikungunya…Craig Williams, Dean: Research Education and Senior Lecturer in Biological Sciences, University of South AustraliaLicensed as Creative Commons – attribution, no derivatives.