tag:theconversation.com,2011:/africa/topics/deet-22632/articlesDEET – The Conversation2023-07-10T12:31:42Ztag:theconversation.com,2011:article/2070882023-07-10T12:31:42Z2023-07-10T12:31:42ZNot all repellents are equal – here’s how to avoid mosquito bites this summer<figure><img src="https://images.theconversation.com/files/533800/original/file-20230623-17-1mi6af.jpg?ixlib=rb-1.1.0&rect=6%2C42%2C4019%2C2975&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A group of Anopheles mosquitoes taking a blood meal in an experiment conducted by the New Mexico State University Molecular Vector Physiology Lab. </span> <span class="attribution"><span class="source">Hansen MVP lab</span></span></figcaption></figure><p>Now that summer is in full swing, mosquitoes have come out across the United States. The use of mosquito repellents can protect both your health and sanity this summer.</p>
<p>While mosquitoes leave bothersome, itchy bites on your skin, they can also pose a serious and sometimes deadly risk to your health. When a mosquito bites you, it may transmit harmful pathogens that cause dangerous diseases like <a href="https://www.cdc.gov/parasites/malaria/index.html">malaria</a>, <a href="https://www.cdc.gov/dengue/">dengue fever</a>, <a href="https://www.cdc.gov/zika/">Zika</a> and <a href="https://www.cdc.gov/westnile/">West Nile</a>. </p>
<h2>Avoiding mosquito bites</h2>
<p>Mosquito females bite people to get vital nutrients from our blood. They then use these nutrients <a href="https://doi.org/10.3389/fphys.2014.00103">to make their eggs</a>. One single blood meal can give rise to about 100 mosquito eggs that hatch into wiggling larvae.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/532446/original/file-20230616-17-op8jl0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/532446/original/file-20230616-17-op8jl0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=448&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532446/original/file-20230616-17-op8jl0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=448&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532446/original/file-20230616-17-op8jl0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=448&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532446/original/file-20230616-17-op8jl0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=563&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532446/original/file-20230616-17-op8jl0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=563&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532446/original/file-20230616-17-op8jl0.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"><em>Culex quinquefasciatus larvae</em> Mosquito larvae feed by filtering food from water. Getting rid of standing water can reduce mosquito habitats.</span>
<span class="attribution"><span class="source">Immo Hansen</span></span>
</figcaption>
</figure>
<p>There are several ways to <a href="https://www.cdc.gov/mosquitoes/mosquito-bites/prevent-mosquito-bites.html">avoid getting bitten by mosquitoes</a>, from wearing long, loose clothing and limiting time outside to placing screens over your windows and getting rid of standing water that mosquitoes might use to breed.</p>
<p>However, one of the best ways to protect yourself when you’re going to a place where hungry mosquitoes will be buzzing around is by using <a href="https://doi.org/10.1093/jisesa/iev125">mosquito repellents</a>. </p>
<p>Our team at the <a href="https://nmsu.edu/">New Mexico State University</a> <a href="https://www.hansenmvplab.com/">Molecular Vector Physiology Laboratory</a> has studied different types of mosquito repellents and their efficacy for over a decade. Here’s what you need to know to protect yourself this summer:</p>
<h2>All about repellents</h2>
<p>The use of mosquito repellents goes far back in history, certainly predating written historical accounts. <a href="https://doi.org/10.1201/9781420006650">Some of the oldest records</a> of the use of mosquito repellents date back to early Egyptian and Roman history. During this period, smoke from smudge fires was often used to repel mosquitoes. </p>
<p>Today, we have more options than our ancestors when it comes to choosing what type of mosquito repellent to use – <a href="https://www.nytimes.com/wirecutter/reviews/best-bug-repellent/">sprays and lotions</a>, candles, <a href="https://www.nytimes.com/wirecutter/reviews/mosquito-control-gear/">coils and vaporizers</a>, to name some. </p>
<p>These repellents interfere with a mosquito’s <a href="https://doi.org/10.1016/j.cub.2019.04.004">sense of smell, taste or both</a>. The repellent either blocks or overstimulates these senses. Scientists understand how certain repellents like DEET <a href="https://doi.org/10.1016/j.neuron.2010.07.006">work at the molecular level</a>, but for many of them, it is still unknown why exactly they repel mosquitoes.</p>
<h2>Testing repellents</h2>
<p>We used a variety of <a href="https://www.hansenmvplab.com/services">scientific laboratory experiments and field tests</a> to find out what works. For some products, testing was as simple as putting a volunteer’s treated arm into a cage with 25 mosquitoes and waiting for the first mosquito bite. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/532472/original/file-20230616-19-qwfotj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A researcher's arm covered in a protective sleeve, with part of their skin exposed while mosquitoes fly around." src="https://images.theconversation.com/files/532472/original/file-20230616-19-qwfotj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/532472/original/file-20230616-19-qwfotj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=336&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532472/original/file-20230616-19-qwfotj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=336&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532472/original/file-20230616-19-qwfotj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=336&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532472/original/file-20230616-19-qwfotj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=422&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532472/original/file-20230616-19-qwfotj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=422&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532472/original/file-20230616-19-qwfotj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=422&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Arm-in-cage experimental setup.</span>
<span class="attribution"><span class="source">Keyla R. Salas</span></span>
</figcaption>
</figure>
<p>For others, like citronella candles, we used a <a href="https://www.krwg.org/krwg-news/2022-09-23/research-at-nmsu-looks-at-the-effectiveness-of-mosquito-repellents">slow-speed wind tunnel</a> and put a candle or device between a person and a cage of mosquitoes. Depending on the repellent efficacy of the device, mosquitoes either flew toward the person or away. Another experiment we conducted was the <a href="https://www.youtube.com/watch?v=38gVZgE39K8&t=23s">Y-tube choice assay</a> where mosquitoes chose to fly toward someone’s hand or, if repelled, fly toward the blank or empty option. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/38gVZgE39K8?wmode=transparent&start=23" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">This video from the YouTube channel Veritasium shows our team performing a Y-tube choice assay experiment.</span></figcaption>
</figure>
<h2>Mosquito repellents that don’t work</h2>
<p>Bracelets don’t work. Department stores and pharmacy chains sell hundreds of different varieties of bracelets. They are marketed as “mosquito repellent” bands, wristbands and watches, and their materials can vary from plastic to leather. Even if they are loaded with repellents, they can’t protect your whole body from mosquito bites. </p>
<p>Ultrasonic repellent devices don’t work. These come as electrical plug-ins, free-standing varieties or watchlike accessories that claim to emit a high-frequency sound that deters mosquitoes by mimicking bats. However, in <a href="https://doi.org/10.1111/j.1570-8703.2006.00463.x">scientific studies</a>, ultrasonic repellent devices fail to repel mosquitoes. In fact, when our lab <a href="https://doi.org/10.1093/jisesa/iew117">tested one of these devices</a>, we found a slight increase in mosquito attraction to the wearer. </p>
<p>Dietary supplements – vitamin B, garlic and so on – don’t work. No scientific evidence shows these supplements <a href="https://doi.org/10.1056/NEJMoa011699">protect people from mosquito bites</a>. </p>
<p>Light-based repellents don’t work. These devices come as colored light bulbs, and they don’t attract insects that fly toward white light. This approach works well on <a href="https://doi.org/10.1007/s13355-013-0219-x">moths, beetles and stinkbugs</a>, but not on mosquitoes. </p>
<h2>Mosquito repellents that work</h2>
<p>And here is our ranking of what does work, starting with the best repellent/active ingredient.</p>
<ol>
<li><p>DEET works. DEET, <a href="https://www.epa.gov/insect-repellents/deet">chemical name, N,N-diethyl-meta-toluamide</a>, was developed in the 1950s by the U.S. Army and is a <a href="https://doi.org/10.1081/CLT-120025348">well-established</a> mosquito repellent with a <a href="https://doi.org/10.1016/j.jaad.2007.10.005">long history of use</a>. The higher the percentage, the longer the protection time is – <a href="https://www.hindawi.com/journals/jpr/2015/361021/">up to six hours</a>.</p></li>
<li><p>Picaridin works. This synthetic repellent can protect for <a href="https://link.springer.com/article/10.1007/s00436-006-0450-2">up to six hours at a 20% concentration</a>. This repellent is a <a href="https://www.outdoors.org/resources/amc-outdoors/outdoor-resources/picaridin-vs-deet-which-is-the-best-insect-repellent/">promising alternative</a> for <a href="https://accpjournals.onlinelibrary.wiley.com/doi/full/10.1002/phar.1854">DEET</a>.</p></li>
<li><p>Oil of lemon eucalyptus, or OLE, works. OLE, with the active ingredient PMD, is a plant-based alternative to DEET and picaridin. Its repellent properties can last for <a href="https://academic.oup.com/jinsectscience/article/15/1/140/2583458">up to six hours</a>.</p></li>
<li><p>Other essential oils – some work, some not so much. We applied <a href="https://doi.org/10.1038/s41598-023-28820-9">20 different essential oils</a> in a 10% essential oil lotion mixture to volunteers’ skin. Here’s what we found: </p>
<p>Clove oil works. This oil, with the active ingredient eugenol, can protect from mosquito bites for over 90 minutes at a 10% concentration in lotion. Cinnamon oil works. This oil, with the active ingredients cinnamaldehyde and eugenol, can protect from mosquitoes for over 60 minutes at a 10% concentration in lotion. Geraniol and 2-PEP, or 2-phenylethyl propionate, work for about 60 minutes at a 10% concentration in lotion. Citronella oil works, just not so great. We found citronella oil at a 10% concentration only protected from mosquito bites for about 30 minutes. </p></li>
</ol>
<p><iframe id="vwJXh" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/vwJXh/2/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>If you are planning to mix your own plant-based mosquito repellent this summer, remember that essential oils are <a href="https://www.mdpi.com/2297-8739/10/2/128">complex mixtures of plant-made chemicals</a> that can cause skin irritations at high concentrations.</p>
<p>Based on our study, we recommend using repellents with the active ingredient DEET if you live in or are traveling to regions with a high risk of vector-borne disease transmission. However, plant-based repellents will work just fine to prevent nuisance mosquito bites in low-risk areas, as long as you reapply them as needed.</p><img src="https://counter.theconversation.com/content/207088/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Immo A. Hansen receives funding from the National Institute of Health. </span></em></p><p class="fine-print"><em><span>Hailey A. Luker receives funding from the National Institute of Health.</span></em></p>Two mosquito physiology experts explain which repellents work better than others and how to protect yourself this summer.Immo A. Hansen, Professor of Biology, New Mexico State UniversityHailey A. Luker, Ph.D. Student in Biology, New Mexico State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1946892022-12-07T13:53:51Z2022-12-07T13:53:51ZMosquitoes are not repelled by vitamins and other oral supplements you might take<figure><img src="https://images.theconversation.com/files/499541/original/file-20221207-11795-5gitd3.jpg?ixlib=rb-1.1.0&rect=1077%2C565%2C4913%2C3422&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">It's only wishful thinking that you can ward off mosquitoes from within.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/aedes-aegypti-mosquito-close-up-a-mosquito-sucking-royalty-free-image/831023822">frank600/iStock via Getty Images Plus</a></span></figcaption></figure><p>A longstanding medical myth suggests that taking vitamin B1, also known as thiamine, can make your body repel mosquitoes.</p>
<p>A “<a href="http://doi.org/10.1001/jama.1966.03100160106030">systemic repellent</a>” that makes your whole body unappealing to biting insects certainly sounds good. Even if you correctly reject the <a href="https://doi.org/10.1186/s12936-020-03217-5">misinformation</a> questioning <a href="https://doi.org/10.4269/ajtmh.1998.59.323">safe</a> and <a href="https://doi.org/10.1056/nejm200207043470102">effective</a> <a href="https://www.epa.gov/insect-repellents/deet">repellents</a> like <a href="https://doi.org/10.1186/1756-3305-7-173">DEET</a>, oral repellents would still have the benefit that you wouldn’t need to worry about covering every inch of exposed skin or carrying containers of bug spray whenever you venture into the great outdoors.</p>
<hr>
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<hr>
<p>Along with thiamine, other alleged oral mosquito repellents include <a href="https://doi.org/10.1055/s-0039-3399744">brewer’s yeast</a>, which contains thiamine, and <a href="https://doi.org/10.1001/jama.285.1.39">garlic</a>, the legendary <a href="https://europepmc.org/article/med/7825135">vampire repellent</a>.
If oral repellents sound too good to be true, it’s because they are. </p>
<p><a href="https://scholar.google.com/citations?user=TSIGUnYAAAAJ&hl=en&oi=ao">As a professor of entomology</a> in Taiwan, where the mosquito-transmitted Dengue virus is endemic, I was curious what science really says about food-based repellents. After a very deep dive into the literature and reading practically every paper ever written on the subject, I compiled this knowledge into the first <a href="https://doi.org/10.1017/S0007485321001176">systematic review</a> of the subject.</p>
<p>The scientific consensus is, unequivocally, that oral repellents don’t exist. Despite <a href="https://doi.org/10.5281/zenodo.7403167">extensive searches</a>, no <a href="http://doi.org/10.1371/journal.pntd.0006247">food, supplement</a>, <a href="https://doi.org/10.4269/ajtmh.1968.17.461">medication, or condition</a> has ever been proven to make people repellent. People with vitamin B1 deficiency don’t attract more mosquitoes, either. </p>
<p>So where did the myth that mosquitoes hate vitamins come from, and why is it so hard to exterminate?</p>
<h2>Making of a myth</h2>
<p>In 1943, Minnesota pediatrician <a href="https://doi.org/10.5281/zenodo.7313319">W. Ray Shannon</a> gave 10 patients varying doses of thiamine, which had only <a href="https://doi.org/10.1159/000343109">first been synthesized</a> seven years prior. They reported back that it relieved itching and prevented further mosquito bites. In 1945, California pediatrician <a href="https://doi.org/10.5281/zenodo.7403108">Howard Eder</a> claimed 10 milligram doses could protect people from fleas. In Europe in the 1950s, physician <a href="https://doi.org/10.5281/zenodo.7403124">Dieter Müting</a> claimed that daily 200 milligram doses kept him bite-free while vacationing in Finland, and hypothesized a breakdown product of thiamine was expelled through the skin.</p>
<p>These findings drew rapid attention, and almost immediate repudiation. The U.S. Naval Medical Research Institute <a href="https://doi.org/10.1126/science.100.2590.147.a">tried to replicate Shannon’s findings, but failed</a>. By 1949, Californians using thiamine to repel fleas from dogs were reporting it as “<a href="https://doi.org/10.1001/archderm.1949.01530070124012">completely worthless</a>.” Controlled studies from <a href="https://pubmed.ncbi.nlm.nih.gov/13568728/">Switzerland</a> to <a href="https://pubmed.ncbi.nlm.nih.gov/4733214/">Liberia</a> repeatedly failed to find any effects at any dose. The first <a href="https://doi.org/10.5281/zenodo.7403142">clinical trial</a> in 1969 concluded definitively that “vitamin B1 is not a systemic mosquito repellent in man,” and <a href="https://doi.org/10.2987/8756-971X(2005)21%5B213:TVBAAH%5D2.0.CO;2">all controlled studies since</a> suggest the same for thiamine, <a href="https://pubmed.ncbi.nlm.nih.gov/6885593/">brewer’s yeast</a>, <a href="https://doi.org/10.1111/j.0269-283X.2005.00544.x">garlic</a>, and <a href="https://doi.org/10.1024/0040-5930.62.11.713">other</a> <a href="https://doi.org/10.1093/pch/19.6.326">alternatives</a>. </p>
<p>The evidence was so overwhelming that, in 1985, the <a href="https://doi.org/10.1016/B978-0-323-54696-6.00006-9">U.S. Food and Drug Administration declared</a> all oral insect repellents are “<a href="https://tile.loc.gov/storage-services/service/ll/fedreg/fr050/fr050116/fr050116.pdf#page=140">not generally recognized as safe and effective and are misbranded</a>,” making labeling supplements as repellents technically fraud.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/499542/original/file-20221207-27-o3hgzd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="foods including egg, lentils, nuts and a " src="https://images.theconversation.com/files/499542/original/file-20221207-27-o3hgzd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/499542/original/file-20221207-27-o3hgzd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/499542/original/file-20221207-27-o3hgzd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/499542/original/file-20221207-27-o3hgzd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/499542/original/file-20221207-27-o3hgzd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/499542/original/file-20221207-27-o3hgzd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/499542/original/file-20221207-27-o3hgzd.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">Along with being in poultry and pork, B1 is found in many whole grains and legumes.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/products-and-ingredients-containing-vitamin-b1-and-royalty-free-image/668509672">ratmaner/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<h2>Medical mechanisms aren’t there</h2>
<p>Scientists know much more about both mosquitoes and vitamins today than ever before.</p>
<p>Vitamin B1 <a href="https://www.ncbi.nlm.nih.gov/books/NBK482360/">does not break down in the body</a> and has <a href="https://doi.org/10.1021/bi401618y">no known effect on skin</a>. The body strongly regulates it, absorbing little ingested thiamine after the first 5 milligrams and <a href="https://doi.org/10.1177/0884533611426149">quickly excreting any excess</a> via urine, so it <a href="https://doi.org/10.1177/0885066616659429">does not build up</a>. Overdose is almost impossible.</p>
<p>As in humans, thiamine is an <a href="https://doi.org/10.1093/aesa/70.4.541">essential nutrient</a> <a href="https://doi.org/10.1093/aesa/52.1.26">for mosquitoes</a>. There is no reason they would fear it or try to avoid it. Nor is there evidence that they can smell it.</p>
<p>The best sources of thiamine are <a href="https://doi.org/10.3390/nu12092810">whole grains, beans, pork, poultry and eggs</a>. If eating a carnitas burrito won’t make you repel mosquitoes, then neither should a pill.</p>
<p>What explains the early reports, then? Along with shoddy experimental design, many used anecdotal patient reports of fewer bite symptoms as a proxy for reduced biting, which is not a good way to get an accurate picture of what’s going on.</p>
<p>Mosquito bites are followed by <a href="https://doi.org/10.1111/j.1346-8138.1989.tb01251.x">two reactions</a>: an immediate reaction that starts fast and lasts hours and a delayed reaction lasting days. The presence and intensity of these reactions depends not on the mosquito, but on your own immune system’s familiarity with that particular species’ saliva. With age and continued exposure, the body goes from no reaction, to delayed reaction only, to both, to immediate reaction only, and eventually no reaction.</p>
<p>What Shannon and others thought was repellency could have been <a href="https://doi.org/10.3109/07853899409147906">desensitization</a>: The patients were still getting bitten, they just stopped showing symptoms.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/499543/original/file-20221207-27-w8izk8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="woman with backpack in woods sprays her arm" src="https://images.theconversation.com/files/499543/original/file-20221207-27-w8izk8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/499543/original/file-20221207-27-w8izk8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/499543/original/file-20221207-27-w8izk8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/499543/original/file-20221207-27-w8izk8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/499543/original/file-20221207-27-w8izk8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/499543/original/file-20221207-27-w8izk8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/499543/original/file-20221207-27-w8izk8.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">Applying a safe and effective insect repellent to your skin is a proven way to ward off mosquitoes and their bites.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/woman-applies-mosquito-spray-to-her-hands-during-royalty-free-image/1404334863">SimpleImages/Moment via Getty Images</a></span>
</figcaption>
</figure>
<h2>So, what’s the problem?</h2>
<p>Despite the scientific consensus, a 2020 survey of pharmacists in <a href="https://doi.org/10.3390/pharmacy8020094">Australia</a> found that 27% were still recommending thiamine as a repellent to patients traveling abroad: an unacceptable recommendation. Besides wasting money, people relying on vitamins as protection against mosquitoes can still get bitten, potentially putting them at risk of <a href="https://doi.org/10.1001/jama.296.18.2234">diseases</a> like <a href="https://doi.org/10.1155/2003/158926">West Nile</a> and <a href="https://doi.org/10.2310/7060.2000.00074">malaria</a>.</p>
<p>To get around the American ban and widely agreed-upon scientific consensus on oral repellents, some unscrupulous dealers are making thiamine patches or even injections. Unfortunately, while thiamine is safe if swallowed, it <a href="https://doi.org/10.1016/j.alit.2022.01.004">can</a> <a href="https://doi.org/10.1016/S0196-0644(89)80215-X">cause</a> <a href="https://doi.org/10.1016/S0091-6749(95)70111-7">severe</a> <a href="https://doi.org/10.1001/jama.1941.72820340003008a">allergic</a> <a href="https://doi.org/10.1001/archderm.1950.01530120149018">reactions</a> when taken by other routes. <a href="https://doi.org/10.1016/j.actatropica.2012.10.009">These products</a> are thus not only <a href="https://doi.org/10.1093/jisesa/iev125">worthless</a>, but also potentially dangerous.</p>
<p>Not every problem can be solved with food. Long sleeves and <a href="https://doi.org/10.7326/0003-4819-128-11-199806010-00013">bug spray</a> <a href="http://doi.org/10.1056/NEJMoa011699">containing DEET</a>, <a href="http://npic.orst.edu/ingred/picaridin.html">picaridin</a> or <a href="https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients">other proven repellents</a> are still your best defense against biting pests.</p><img src="https://counter.theconversation.com/content/194689/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matan Shelomi does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A medical myth persists that the B vitamin thiamine is a systemic insect repellent that wards off mosquitoes when taken orally. But scientists have disproven this mistaken belief again and again.Matan Shelomi, Associate Professor of Entomology, National Taiwan UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1574172021-04-11T11:47:52Z2021-04-11T11:47:52ZFact or fiction: Debunking 4 common myths about ticks<figure><img src="https://images.theconversation.com/files/392979/original/file-20210331-15-usvm4c.jpg?ixlib=rb-1.1.0&rect=156%2C0%2C2455%2C1742&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">With warm weather comes tick season.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Blooming flowers, chirping birds and long-awaited rays of sunshine: The first signs of spring are often greeted with joy. But soon comes the realization that with warm weather comes ticks.</p>
<p>With the climate warming, diseases caused by ticks are <a href="https://doi.org/10.1111/j.1365-2664.2012.02112.x">predicted to spread further into Canada</a>. Infected ticks are transported by <a href="https://doi.org/10.1289/ehp.0901389">different host species that are expanding their ranges northward</a>. For example, white-footed mice, a major tick host, are <a href="https://doi.org/10.1371/journal.pone.0080724">shifting their ranges northward up to 15 kilometres per year</a>.</p>
<p>For researchers like me who study ticks, the spring represents the start of fieldwork. We visit different locations in search of our bloodsucking friends. It also provides us with an opportunity to talk about ticks with people who are enjoying the outdoors.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/390737/original/file-20210321-21-14zy2f0.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Adult female blacklegged tick, adult female bird tick, rabbit tick larva, and adult female dog tick taken under a dissecting microscope." src="https://images.theconversation.com/files/390737/original/file-20210321-21-14zy2f0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/390737/original/file-20210321-21-14zy2f0.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=136&fit=crop&dpr=1 600w, https://images.theconversation.com/files/390737/original/file-20210321-21-14zy2f0.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=136&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/390737/original/file-20210321-21-14zy2f0.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=136&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/390737/original/file-20210321-21-14zy2f0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=170&fit=crop&dpr=1 754w, https://images.theconversation.com/files/390737/original/file-20210321-21-14zy2f0.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=170&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/390737/original/file-20210321-21-14zy2f0.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=170&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Common tick species in Canada. From left to right: blacklegged tick (Ixodes scapularis), bird tick (Ixodes auritulus), rabbit tick (Haemaphysalis leporispalustris) and dog tick (Dermacentor variabilis).</span>
</figcaption>
</figure>
<p>Through these interactions, I began to realize how much anxiety is caused by the <a href="https://doi.org/10.1371/journal.pone.0201924">increased presence of ticks in Canada</a> and by the myths about ticks that have come with them. Here are some of the most common myths about ticks that I would like to debunk:</p>
<h2>Myth: Ticks are only seasonally active in forests</h2>
<p>Many people think that ticks can only survive in forests from the spring to fall, but this is no longer true.</p>
<p>With the expanding ranges of their hosts, ticks are appearing in <a href="https://www.toronto.ca/community-people/health-wellness-care/health-programs-advice/lyme-disease/blacklegged-tick-surveillance-results/">greater numbers close to city centres like Toronto</a> <a href="https://www.cbc.ca/news/canada/montreal/lyme-disease-cases-on-the-rise-in-quebec-1.5355796">and Montréal</a>. Ticks are even being found in people’s backyards due to the annual reproduction of nearby populations. Unfortunately, some of these ticks have also tested positive for <a href="https://www.canada.ca/en/public-health/services/diseases/lyme-disease/causes-lyme-disease.html"><em>Borrelia burgdorferi</em>, the bacteria that cause Lyme disease</a>.</p>
<h2>Myth: Ticks can jump</h2>
<p>How do ticks find their way onto people? Many people described having ticks jumping on them from trees, but ticks can’t jump. Instead, they patiently sit on low vegetation or crawl around the ground, <a href="https://entomologytoday.org/2018/01/16/up-close-look-tiny-sensory-pits-ticks-use-smell/">sensing a host’s carbon dioxide and heat</a>.</p>
<p>Ticks search for their next meal when <a href="https://ticktalkcanada.com/seasonality-of-ticks/">temperatures are above 4°C</a>. During the winter, people think that ticks are inactive or dead because of the cold. However, if <a href="https://ticktalkcanada.com/seasonality-of-ticks/">temperatures rise above freezing for several days, ticks can emerge from their dormancy</a>, leaving us and our pets at risk.</p>
<h2>Myths about how to remove ticks</h2>
<p>Fact: Painless ticks need to be removed with tweezers.</p>
<p>Last summer, I was doing a tick check after being outdoors. I inspected every part of my body for ticks especially in crevices and anywhere covered by hair and, to my horror, I found a tick. I was shocked that I hadn’t felt its bite, but you likely won’t feel it either.</p>
<p>Ticks have developed a critical tool to discreetly attach to their host: their saliva. We don’t react to their bites because ticks make sure we don’t know they’re there. Their <a href="https://doi.org/10.3389/fcimb.2017.00281">saliva contains multiple components</a> that trick our bodies into blocking pain and itching, as well as stopping any defensive immune responses.</p>
<p>When a tick is attached, it should be removed quickly. I’ve heard of many removal methods including lit matches, different household items (for example, essential oils, petroleum jelly, soap or rubbing alcohol), or squeezing with your fingers. You are more likely to contract a disease using these methods because a <a href="https://www.aafp.org/afp/2002/0815/p643.html">tick can regurgitate its content</a> — like bacteria and viruses — into you before dying.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/390738/original/file-20210321-13-pvh7ka.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Infographic of how to remove a tick with the tweezers located near the head of the tick. There is an arrow pointed straight upwards from the back of the tick." src="https://images.theconversation.com/files/390738/original/file-20210321-13-pvh7ka.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/390738/original/file-20210321-13-pvh7ka.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=253&fit=crop&dpr=1 600w, https://images.theconversation.com/files/390738/original/file-20210321-13-pvh7ka.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=253&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/390738/original/file-20210321-13-pvh7ka.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=253&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/390738/original/file-20210321-13-pvh7ka.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=318&fit=crop&dpr=1 754w, https://images.theconversation.com/files/390738/original/file-20210321-13-pvh7ka.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=318&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/390738/original/file-20210321-13-pvh7ka.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=318&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">How to properly remove an attached tick. First, locate the head of the tick close to the skin with fine-tipped tweezers. Then, pull the tick straight upward with even force.</span>
<span class="attribution"><span class="source">Pixabay</span></span>
</figcaption>
</figure>
<p><a href="https://www.canada.ca/en/public-health/services/diseases/lyme-disease/removing-submitting-ticks-testing.html"><strong>Fine-tipped tweezers are the only efficient and safe way to remove a tick</strong></a>. Use the tweezers to grab the head close to the skin and lift straight upwards with steady even pressure. Parts of the tick’s head or mouth may remain, but they are unable to transmit any disease without the body.</p>
<h2>Myth: All ticks are infected with Lyme disease</h2>
<p>People often panic thinking they will immediately get infected with Lyme disease if they’re bitten by a tick. In Canada, some ticks may not be infected at all, while others <a href="https://www.canada.ca/en/public-health/services/reports-publications/canada-communicable-disease-report-ccdr/monthly-issue/2019-45/issue-4-april-4-2019/article-2-increased-risk-tick-borne-diseases-climate-change.html">can carry a variety of less prevalent diseases besides Lyme disease</a>, which is the most common.</p>
<p>For example, blacklegged ticks can also transmit babesiosis and Powassan virus. Dog ticks are well-known carriers of Rocky Mountain spotted fever and tularemia. Both kinds of ticks can also pass on anaplasmosis and ehrlichiosis.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/393672/original/file-20210406-21-1m224ui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A bullseye-shaped rash on a woman's upper arm" src="https://images.theconversation.com/files/393672/original/file-20210406-21-1m224ui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/393672/original/file-20210406-21-1m224ui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=893&fit=crop&dpr=1 600w, https://images.theconversation.com/files/393672/original/file-20210406-21-1m224ui.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=893&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/393672/original/file-20210406-21-1m224ui.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=893&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/393672/original/file-20210406-21-1m224ui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1122&fit=crop&dpr=1 754w, https://images.theconversation.com/files/393672/original/file-20210406-21-1m224ui.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1122&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/393672/original/file-20210406-21-1m224ui.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1122&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 characteristic bullseye-shaped rash associated with Lyme disease doesn’t appear with every case.</span>
<span class="attribution"><span class="source">(CDC/James Gathany)</span></span>
</figcaption>
</figure>
<p>If a tick is infected, the time it takes for a disease to be transmitted varies. Usually Lyme disease requires more than 24 hours for transmission, but studies have shown that <a href="https://doi.org/10.2147/IJGM.S73791">this could happen in less than 16 hours</a>. Some diseases like <a href="https://www.health.ny.gov/diseases/communicable/powassan/fact_sheet.htm">Powassan virus are transmitted very quickly, in less than 15 minutes</a>.</p>
<p>Lyme disease is well known for its bullseye rash, but this symptom might only be present in <a href="https://www.cdc.gov/lyme/signs_symptoms/index.html">70 to 80 per cent of infected people</a>. Other <a href="https://www.canada.ca/en/public-health/services/diseases/lyme-disease/health-professionals-lyme-disease.html">variations of the rash</a> can include blistering, uniform or crusted skin lesions or a blue-purple colour. As the bacteria spread through the blood, these rashes may <a href="https://www.aad.org/public/diseases/a-z/lyme-disease-signs">appear in other areas of the body</a> far from the bite site.</p>
<p>Rather than relying on the presence of a rash, the most accurate way to detect disease is to check for several early symptoms after a tick bite. Symptoms like <a href="https://www.canada.ca/en/public-health/services/diseases/lyme-disease/symptoms-lyme-disease.html">fever, joint pain, muscle aches, fatigue and headaches usually start to appear in three to 30 days</a>.</p>
<h2>Prevention, and when to see a doctor</h2>
<p>If a tick has been attached for more than 24 hours, a visit to the doctor is recommended, especially in high-risk regions for Lyme disease. <a href="https://www.canada.ca/en/public-health/services/diseases/lyme-disease/treatment-lyme-disease.html">People treated with the appropriate antibiotics</a> as either a preventive measure or with the onset of disease symptoms usually recover rapidly and completely.</p>
<p>Tick bites might be worrisome, but need not cause panic. <a href="https://www.canada.ca/en/public-health/services/diseases/lyme-disease/prevention-lyme-disease.html">Prevention remains the best protection against ticks</a>. Insect repellents like DEET or Natrapel, long-sleeved shirts and pants and full-body tick checks on ourselves and our pets can help prevent tick exposure while still letting us to enjoy the outdoors.</p><img src="https://counter.theconversation.com/content/157417/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kirsten Crandall receives funding from the Natural Sciences and Engineering Research Council. </span></em></p>There is plenty of misinformation circulating about ticks and the diseases they may carry. Here are four myths debunked, along with tick facts to keep people safe when exploring the outdoors.Kirsten Crandall, Ph.D. Cotutelle candidate, Department of Biology, McGill UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1501832020-12-24T21:25:35Z2020-12-24T21:25:35ZMozzies biting? Here’s how to choose a repellent (and how to use it for the best protection)<figure><img src="https://images.theconversation.com/files/373012/original/file-20201204-23-67p3hy.jpg?ixlib=rb-1.1.0&rect=53%2C0%2C6000%2C3997&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Mosquitoes are an inevitable part of the Australian summer. And this year, with COVID a consideration, we might be spending more time outdoors than usual.</p>
<p>Supermarkets and pharmacies are stocked with a wide range of insect repellents including aerosols, creams, gels, sprays, roll-ons and wipes. There are even wristbands, fabric sprays, coils, sticks, plug-in devices and smartphone apps.</p>
<p>But not all products that purport to protect us from mosquito bites are equal.</p>
<p>So, how do you choose and use a repellent to best protect you and your family from mosquito bites?</p>
<h2>The key ingredients</h2>
<p>Health authorities <a href="https://www.frontiersin.org/articles/10.3389/fpubh.2019.00054/full">around Australia</a> recommend using insect repellents that you apply directly to exposed skin to prevent mosquito bites and reduce the risk of <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1005070">mosquito-borne diseases</a>. </p>
<p>All insect repellents sold in Australia must be registered with the Australian Pesticides and Veterinary Medicines Authority (<a href="https://apvma.gov.au/">APVMA</a>), which checks that products are safe and effective. </p>
<p>Despite the wide range of formulations available, there are only a small number of active ingredients registered for use. So any insect repellent on the shelves in Australia will contain at least one of these ingredients. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/371638/original/file-20201126-21-stabyq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/371638/original/file-20201126-21-stabyq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/371638/original/file-20201126-21-stabyq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/371638/original/file-20201126-21-stabyq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/371638/original/file-20201126-21-stabyq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/371638/original/file-20201126-21-stabyq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/371638/original/file-20201126-21-stabyq.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">Spending more time outdoors means a greater chance of mosquito bites.</span>
<span class="attribution"><span class="source">David Todd McCarty/Unsplash</span></span>
</figcaption>
</figure>
<p><strong>Diethyltoumide</strong> (DEET) is one of the <a href="https://www.phrp.com.au/wp-content/uploads/2016/12/PHRPDec16-Mosquito-031Dec16.pdf">most widely used and recommended</a> repellents across the world. It <a href="https://academic.oup.com/jme/article/41/3/414/917125">effectively prevents mosquito bites</a> and has repeatedly been shown to have <a href="https://malariajournal.biomedcentral.com/articles/10.1186/s12936-020-03217-5">minimal adverse side effects</a> if used as directed. </p>
<p>DEET formulations in Australia are available in a range of concentrations, as low as 10% through to “heavy duty” or “tropical strength” products that may be as high as 80%.</p>
<p><strong>Picaridin</strong> is a common ingredient in local mosquito repellent formulations and <a href="https://academic.oup.com/jme/article/41/3/414/917125">effectively reduces mosquito bites</a>. Like DEET, it has been <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0172566">assessed as safe to use</a>. Most formulations in Australia have concentrations of less than 20%.</p>
<p><strong>Oil of lemon eucalyptus</strong> is increasingly common in mosquito repellents. The chemical, p-menthane-3,8-diol, is derived from the leaves of the lemon-scented gum <a href="https://bioone.org/journals/journal-of-the-american-mosquito-control-association/volume-22/issue-3/8756-971X(2006)22%5B507:PARBMR%5D2.0.CO;2/PMD-a-Registered-Botanical-Mosquito-Repellent-with-Deet-Like-Efficacy/10.2987/8756-971X(2006)22%5B507:PARBMR%5D2.0.CO;2.full"><em>Corymbia citriodora</em></a>. </p>
<p>This ingredient is a byproduct of the distillation process, not an essential oil extracted from the leaves of the plant. This is important, as this product is a much more effective repellent than <a href="https://bioone.org/journals/journal-of-the-american-mosquito-control-association/volume-25/issue-3/09-0016.1/Are-Commercially-Available-Essential-Oils-from-Australian-Native-Plants-Repellent/10.2987/09-0016.1.full">essential oils</a> (we’ll get to these alternatives shortly). </p>
<p>Formulations containing oil of lemon eucalyptus <a href="https://meridian.allenpress.com/jamca/article/35/3/186/438795">provide comparable protection</a> to DEET-based repellents.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/la-nina-will-give-us-a-wet-summer-thats-great-weather-for-mozzies-147180">La Niña will give us a wet summer. That's great weather for mozzies</a>
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</em>
</p>
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<p>The active ingredient in the repellent will be listed on the packaging, along with the concentration.</p>
<p>Any insect repellent that contains these products should provide protection against biting mosquitoes. But the stronger the formulation, the longer the protection will last. </p>
<p>If you’re only outside for a couple of hours, say, in the backyard, there’s really no need for a high-concentration formulation. But if you’re going for a long bushwalk or fishing trip, pick a high-concentration product (regardless of the active ingredient).</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/374589/original/file-20201213-17-1bll6b0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/374589/original/file-20201213-17-1bll6b0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/374589/original/file-20201213-17-1bll6b0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/374589/original/file-20201213-17-1bll6b0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/374589/original/file-20201213-17-1bll6b0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/374589/original/file-20201213-17-1bll6b0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/374589/original/file-20201213-17-1bll6b0.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">Mosquitoes are one of the most common insect pests in Australia.</span>
<span class="attribution"><span class="source">A/Prof Cameron Webb (NSW Health Pathology)</span></span>
</figcaption>
</figure>
<h2>How you use it matters too</h2>
<p>A dab here and there, or spraying repellent into the air around you, as you might a perfume, won’t provide much protection. </p>
<p>These products need to be applied thinly and evenly to all exposed areas of skin. Think of repellents as camouflaging us from mosquitoes on the lookout for blood.</p>
<p>While an aerosol or pump spray may allow for application direct from the container, you’ll need to rub creams, roll-ons and gels into your skin.</p>
<p>That doesn’t necessarily mean one is better than the other. But when choosing a formulation, think about which one you feel you’ll be able to apply thoroughly most easily.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/feel-like-youre-a-mozzie-magnet-its-true-mosquitoes-prefer-to-bite-some-people-over-others-128788">Feel like you're a mozzie magnet? It's true – mosquitoes prefer to bite some people over others</a>
</strong>
</em>
</p>
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<h2>What about ‘natural’ alternatives?</h2>
<p>Some “natural” formulations that contain tea tree oil and other plant-based active ingredients have APVMA registration. Products sold at local markets or online may not be registered.</p>
<p>Notably, products that contain plant-based repellents <a href="https://theconversation.com/chemical-or-natural-whats-the-best-way-to-repel-mozzies-36879">generally don’t provide long-lasting protection</a> from mosquito bites. </p>
<p>If you prefer to use products <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1440-6055.2009.00736.x">containing tea-tree oil</a> or other botanical repellents, you need to be prepared to reapply much more frequently than with DEET, picaridin or oil of lemon eucalyptus formulations.</p>
<p>And avoid making up your own insect repellents from essential oils. Without the checks in place associated with APVMA-registered repellents, there may be a greater risk of <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1440-0960.2007.00341.x">adverse skin reactions</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/371421/original/file-20201126-15-jjc31k.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/371421/original/file-20201126-15-jjc31k.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/371421/original/file-20201126-15-jjc31k.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/371421/original/file-20201126-15-jjc31k.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/371421/original/file-20201126-15-jjc31k.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/371421/original/file-20201126-15-jjc31k.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/371421/original/file-20201126-15-jjc31k.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">Mosquito repellents come in a range of formulations.</span>
<span class="attribution"><span class="source">A/Prof Cameron Webb (NSW Health Pathology)</span></span>
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</figure>
<h2>Can anything else help?</h2>
<p>There’s no evidence mosquito-repellent <a href="https://theconversation.com/health-check-do-wrist-bands-work-to-repel-mozzies-50186">wristbands</a> or <a href="https://theconversation.com/the-buzz-from-your-smartphone-wont-stop-mosquito-bites-92611">smartphone apps</a> will protect you from mosquito bites.</p>
<p>A range of <a href="https://bioone.org/journals/journal-of-the-american-mosquito-control-association/volume-24/issue-1/8756-971X(2008)24%5B154:AOEOCT%5D2.0.CO;2/Ability-of-Essential-Oil-Candles-to-Repel-Biting-Insects-in/10.2987/8756-971X(2008)24%5B154:AOEOCT%5D2.0.CO;2.short">candles</a>, <a href="https://www.sciencedirect.com/science/article/abs/pii/S1226861519302791">coils</a>, <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">sticks</a>, <a href="https://meridian.allenpress.com/jamca/article/36/2/120/446434">plug-in and fan devices</a> and <a href="https://theconversation.com/mozzie-repellent-clothing-might-stop-some-bites-but-youll-still-need-a-cream-or-spray-107266">insecticide-treated</a> clothing offer varying assistance in reducing mosquito bites. But unfortunately, none of these provides complete protection and are always best combined with topical mosquito repellents.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-can-i-eat-to-stop-mosquitoes-biting-me-87178">What can I eat to stop mosquitoes biting me?</a>
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</em>
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<p>Some people perceive so-called “chemical” repellents as <a href="https://malariajournal.biomedcentral.com/articles/10.1186/s12936-020-03217-5">posing a risk to our health</a>. But, in most instances, they can be safely applied to anyone over 12 months of age. (For babies, it’s best to provide physical protection, such as covering the stroller with a mosquito net.)</p>
<p>It’s also often said these traditional repellents are unpleasant to use. But even though the active ingredients haven’t changed much, the cosmetic constituents of insect repellents have greatly improved in recent years.</p>
<p>To get you through summer, choose a repellent formulation registered with APVMA. Pick whichever one you find easiest to spread over the skin to provide complete cover. And always check the instructions on the label.</p><img src="https://counter.theconversation.com/content/150183/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Associate Professor Cameron Webb and the Department of Medical Entomology, NSW Health Pathology, have been engaged by a wide range of insecticide manufacturers to provide testing of products and provide expert advice on, specifically, mosquito biology. Cameron has also received funding from local, state, federal and international agencies to undertake research into mosquito-borne disease surveillance and management strategies.</span></em></p>Summer is here, and so are the mozzies. So what do you need to consider when you’re picking a mosquito repellent?Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/871782018-01-04T20:32:07Z2018-01-04T20:32:07ZWhat can I eat to stop mosquitoes biting me?<figure><img src="https://images.theconversation.com/files/194253/original/file-20171113-29389-12nppci.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Could the menu for your upcoming backyard party help keep the pesky mosquitoes away?</span> <span class="attribution"><a class="source" href="https://static.pexels.com/photos/545058/pexels-photo-545058.jpeg">From Pexels</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>The warm weather is beckoning us into the backyard but pesky bloodsuckers are waiting. Insect repellents are <a href="https://theconversation.com/the-best-and-worst-ways-to-beat-mosquito-bites-70274">safe and effective</a> but many people are reluctant to rub what they perceive to be smelly or sticky on their skin. Wouldn’t it be great if there was something you could eat or drink to protect yourself from mosquito bites?</p>
<p>There are plenty of “mozzie busting” gadgets and gimmicks marketed as alternatives to topical formulations. From <a href="https://theconversation.com/health-check-do-wrist-bands-work-to-repel-mozzies-50186">wrist bands to smartphone apps</a>, the range of products reflects the demand among the public for these products. Unfortunately, <a href="https://academic.oup.com/jinsectscience/article/2996380/Efficacy">few of these provide effective protection</a>.</p>
<p>We know <a href="https://theconversation.com/health-check-why-mosquitoes-seem-to-bite-some-people-more-36425">some people are more likely to be bitten by mosquitoes than others</a>, with the <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0028991">bacteria on our skin</a> playing a crucial role in our attractiveness to mosquitoes. Studies indicate <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0122716">our parents are mostly to blame</a>, not our diets.</p>
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<strong>
Read more:
<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>
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<p>Many myths surround the food and drink that may keep mosquitoes at bay but, when it comes to the science behind these theories, it all becomes a bit too hard to swallow.</p>
<h2>Cheers to mosquito-borne disease</h2>
<p>Love a <a href="http://www.slate.com/articles/health_and_science/foreigners/2013/08/gin_and_tonic_kept_the_british_empire_healthy_the_drink_s_quinine_powder.html">gin and tonic</a>? There was once a time you could sip your way out of a malaria-induced fever. It was more about the tonic than the gin. A key ingredient in tonic water is quinine. Derived from the bark of a cinchona tree, quinine had been identified as a <a href="http://journals.sagepub.com/doi/abs/10.1177/0141076816681421">treatment for malaria</a> in the 1960s and although it’s currently not recommended as a first-line treatment, historically it was critically important in battling the parasites that cause malaria. </p>
<p>It’s important to note that while it’s thought to be toxic to the parasites, there was no evidence it actually stopped mosquito bites. Also, modern tonic water <a href="https://en.wikipedia.org/wiki/Tonic_water">hardly contains any quinine</a>.</p>
<p>Booze and mosquito bites may actually make a good match. Studies in Africa have demonstrated <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0009546">drinking beer can make you more attractive to mosquitoes</a>. After downing a few glasses of beer, volunteers were found to attract more mosquitoes than those drinking just water. </p>
<p>Why? It didn’t seem to be due to body temperature or the amount of carbon dioxide exhaled. Perhaps mosquitoes are evolving to bite drunk people less able to swat the bloodsuckers away?</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/194252/original/file-20171113-29358-zai5dk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/194252/original/file-20171113-29358-zai5dk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/194252/original/file-20171113-29358-zai5dk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/194252/original/file-20171113-29358-zai5dk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/194252/original/file-20171113-29358-zai5dk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/194252/original/file-20171113-29358-zai5dk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/194252/original/file-20171113-29358-zai5dk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The ‘Aussie Backyard Mozzie’, Aedes notoscriptus, taking a bloodmeal.</span>
<span class="attribution"><span class="source">Stephen Doggett (NSW Health Pathology)</span></span>
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</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-best-and-worst-ways-to-beat-mosquito-bites-70274">The best (and worst) ways to beat mosquito bites</a>
</strong>
</em>
</p>
<hr>
<h2>Snacking your way to a bite-free summer?</h2>
<p>One of the most commonly suggested foods to eat to avoid mosquito bites is the humble banana. Problem is, it seems as many people think eating bananas will make you more attractive to mosquitoes than not! There <a href="http://www.mosquitoreviews.com/bananas.html">isn’t the science to support either claim,</a> but it’s unlikely eating bananas would substantially change the way mosquitoes pick you out from a crowd.</p>
<p>If garlic can keep mythic blood suckers away, what about those buzzing about in real life? Nope. Our breath may smell a bit after a garlic-rich meal but a <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.0269-283X.2005.00544.x/full">study has shown it does nothing</a> to lessen our attractiveness to mosquitoes. It may actually make us <a href="https://www.ncbi.nlm.nih.gov/pubmed/7825135">more attractive to vampires, according to science</a>!</p>
<h2>Beating bloodsuckers with vitamin B?</h2>
<p>Perhaps one of the most pervasive home remedies perceived to prevent mosquito bites is taking vitamin B. Anecdotal reports, and many personal testimonies, of the effectiveness of this approach abound, but there a few scientific investigations testing the claim. </p>
<p>Studies dating back to the 1940s <a href="http://science.sciencemag.org/content/100/2590/147.1">failed to provide proof</a> of protection from mosquito bites after taking vitamin B. More recently, <a href="https://www.ncbi.nlm.nih.gov/pubmed/16033124">a 2005 study</a> showed there was no evidence it influenced the attraction of mosquitoes to human skin-derived chemicals from volunteers taking vitamin B supplements. There is simply no evidence taking vitamin B will offer any significant protection from mosquito bites.</p>
<p>In reality, if there was even moderate scientific evidence that taking a vitamin supplement could prevent mosquito bites, our supermarket shelves would be full of “mosquito repellent pills”. It would be wonderful to be able to pop a pill a day to stop mosquito bites but we’re unlikely to have that luxury any time soon. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/chemical-or-natural-whats-the-best-way-to-repel-mozzies-36879">Chemical or natural: what's the best way to repel mozzies?</a>
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<p>In fact, products marketed as oral insect repellents are not recognised by <a href="https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=310.529">some government agencies</a> given the lack of any compelling evidence to support the claims.</p>
<p>Don’t use mosquito bite prevention as an excuse to boost your intake of vegemite either. It may be a <a href="http://www.huffingtonpost.com.au/2016/06/08/vegemite-what-it-is-ways-to-eat-it-and-why-its-so-good_a_21392025/">staple in most Australian households</a>, but it won’t make our summer backyard activities any less bite-prone, no matter how much vitamin B it contains (or how much you spread on your toast).</p>
<p>The reality is, if there was great science supporting any of these mosquito bite-blocking claims associated with food and drink, countless companies would be cashing in on selling “mosquito repellent vitamins” and I have little doubt topical insect repellents would disappear from our supermarket shelves. I don’t see that happening anytime soon.</p><img src="https://counter.theconversation.com/content/87178/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 insecticide manufacturers to provide testing of products and provide expert advice on, specifically, mosquito biology. Cameron has also received funding from local, state, federal and international agencies to undertake research into mosquito-borne disease surveillance and management strategies.</span></em></p>Bananas, garlic, vitamin B and beer. There is little scientific evidence backing claims that what we eat and drink changes how likely we are to be bitten by mosquitoes.Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/885482017-12-18T19:14:09Z2017-12-18T19:14:09ZAre mosquito coils good or bad for our health?<figure><img src="https://images.theconversation.com/files/197852/original/file-20171205-22977-u98sru.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some experts have likened burning a mosquito coil in a closed room to smoking 100 cigarettes. </span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/w/index.php?curid=41527545">By trini, CC BY 2.1 jp</a></span></figcaption></figure><p>The sight and smell of smouldering mosquito coils is a mainstay of summer. But is all that smoke really keeping away the swarms of mosquitoes, and is breathing in the smoke worse than mosquito bites for our health?</p>
<p>The burning of aromatic plant material to keep away swarms of mosquitoes is an integral part of many cultural traditions around the world. But it wasn’t until the early 1900s that the distinctively shaped mosquito coil was born, thanks to Japanese entrepreneurs Eiichiro and Yuki Ueyama and their <a href="https://www.japantimes.co.jp/news/2013/07/15/reference/mosquito-coils/">katori senk</a> (mosquito-killing incense).</p>
<p>While traditional coils and sticks were made from a pyrethrum paste, modern mosquito coils mostly contain either pyrethroid insecticides or plant-derived substances such as citronella. They’re cheap, portable and generally effective at reducing mosquito bites, but do they actually reduce the risks of mosquito-borne disease?</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/the-best-and-worst-ways-to-beat-mosquito-bites-70274">The best (and worst) ways to beat mosquito bites</a>
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</em>
</p>
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<h2>How do they work?</h2>
<p>Mosquito coils contain a mix of substances. Along with the products that deter mosquito biting, there are also products that hold the coil together and enable it to smoulder slowly.</p>
<p>Mosquito coils work in one of two ways. Those that contain insecticides will kill (or at least “knock down”) mosquitoes, while those that contain aromatic substances (such as citronella) will repel mosquitoes or reduce the likelihood they’ll bite.</p>
<p>Mosquito coils and their role in killing or repelling mosquitoes has been well studied. Despite differences between the chemical constituents of products and the ways in which they are tested, they will generally <a href="https://parasitesandvectors.biomedcentral.com/articles/10.1186/1756-3305-5-287">reduce the ability of mosquitoes to bite people</a>.</p>
<p>The problem is, less nuisance-biting by mosquitoes is good but when there is a risk of disease, you need to stop all mosquito bites. Are mosquito coils doing enough?</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-do-wrist-bands-work-to-repel-mozzies-50186">Health Check: do wrist bands work to repel mozzies?</a>
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</em>
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<h2>Preventing bites and disease</h2>
<p>Mosquito-borne pathogens kill more than half a million people a year and make hundreds of thousands of people sick. Malaria is the worst of these, with recent reports from the <a href="http://www.who.int/malaria/publications/world-malaria-report-2017/en/">World Health Organisation</a> suggesting the steady improvements in the burden of disease are slowing, and the situation may even be getting worse. </p>
<p><a href="https://theconversation.com/explainer-what-is-dengue-fever-8571">Dengue</a> continues to have wide ranging impacts. Australia has also seen record-breaking epidemics of <a href="http://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1005070">Ross River virus disease</a> in recent years.</p>
<p>To prevent public health risk associated with mosquitoes, most people have to rely on “covering up” with long-sleeved shirts and long pants, sleeping under bed nets, <a href="http://www.phrp.com.au/issues/december-2016-volume-26-issue-5/a-review-of-recommendations-on-the-safe-and-effective-use-of-topical-mosquito-repellents/">applying topical insect repellents</a> or burning mosquito coils.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/197880/original/file-20171205-31128-1udv2f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/197880/original/file-20171205-31128-1udv2f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/197880/original/file-20171205-31128-1udv2f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/197880/original/file-20171205-31128-1udv2f7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/197880/original/file-20171205-31128-1udv2f7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/197880/original/file-20171205-31128-1udv2f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/197880/original/file-20171205-31128-1udv2f7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/197880/original/file-20171205-31128-1udv2f7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">No links have been found between mosquito coils and lung cancer.</span>
<span class="attribution"><span class="source">from www.shutterstock.com</span></span>
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<p>While there is <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1708-8305.2010.00402.x/full">general consensus</a> among experts that mosquito coils may be useful in preventing mosquito-borne disease, proving mosquito-borne disease prevention is missing. <a href="https://academic.oup.com/jtm/article/11/2/92/1803449">A review of 15 previously published studies</a> showed there’s no evidence burning insecticide-containing mosquito coils prevented malaria. <a href="http://www.ajtmh.org/content/journals/10.4269/ajtmh.2006.74.692#html_fulltext">Similar studies</a> indicated there was no strong evidence that routine burning of mosquito coils prevented dengue risk, either.</p>
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Read more:
<a href="https://theconversation.com/sniffing-out-new-repellents-why-mozzies-cant-stand-the-deet-33457">Sniffing out new repellents: why mozzies can't stand the DEET</a>
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<h2>Health concerns</h2>
<p>There’s growing concern about the adverse health impacts associated with the burning of mosquito coils and sticks indoors. The <a href="https://www.ncbi.nlm.nih.gov/pubmed/16180929/">insecticide products</a> used are generally considered safe, but it’s the particulate matter produced from a smouldering mosquito coil that poses the greatest risk. Is it correct to conclude “<a href="http://www.thehindu.com/sci-tech/health/mosquito-coils-incense-sticks-contain-carcinogens-says-expert/article6686633.ece">burning one mosquito coil in a closed room amounts to smoking roughly 100 cigarettes</a>” as some have claimed?</p>
<p>The link between smoking cigarettes and poor health outcomes is clear. What about mosquito coil smoke, especially if there’s almost daily exposure, as there is in some countries?</p>
<p>One study estimated the particulate matter produced from burning one mosquito coil was <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1241646/">equivalent to burning 75-137 cigarettes</a>. This amount of exposure <a href="http://journals.sagepub.com/doi/abs/10.1177/1420326X9400300510?journalCode=ibea">poses a health risk</a>, but there is a lack of clear evidence that the long-term exposure to mosquito coil smoke increases the risk of more serious health impacts such as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4771599/">lung cancer</a>. In the face of this uncertainty, the key message should be to avoid prolonged exposure, especially in enclosed spaces.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/chemical-or-natural-whats-the-best-way-to-repel-mozzies-36879">Chemical or natural: what's the best way to repel mozzies?</a>
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<h2>Balancing risks</h2>
<p>In Australia, all products that purport to kill or repel mosquitoes must be registered by the <a href="https://apvma.gov.au/">Australian Pesticides and Veterinary Medicines Authority</a>. Check the packaging for a registration number. There are dozens of variations on “mosquito coils”, including sticks, coils, candles and a variety of “smokeless”, plug-in devices. Fortunately, some of the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1241643/">more dangerous chemicals found in mosquito coils</a> are not used in products produced and sold locally in Australia.</p>
<p>There’s enough evidence to show that when used outdoors, burning a mosquito coil will assist in reducing mosquito bites, but should be used judiciously. Using them <a href="https://theconversation.com/the-best-and-worst-ways-to-beat-mosquito-bites-70274">in combination with topical insect repellents</a> probably provides the best protection. Their use in closed rooms is best avoided – “smokeless” devices are worth considering as an alternative.</p>
<p>Recently, consumer products have been made available in Australia that contain the insecticide <a href="https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-017-2219-0">Metofluthrin</a>, an insecticide shown to hold great potential for managing mosquito-borne disease. Products of this nature are better suited to indoor use than mosquito coils so may be important in controlling outbreaks of disease.</p>
<p>They also may help knock off that one stray mosquito in the bedroom whose annoying buzz is keeping you awake at night.</p><img src="https://counter.theconversation.com/content/88548/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p>Mosquito coils can help beat the bite of mosquitoes are most effective outdoors, and best avoided in closed, indoor settings.Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/501862015-11-16T02:45:47Z2015-11-16T02:45:47ZHealth Check: do wrist bands work to repel mozzies?<figure><img src="https://images.theconversation.com/files/100889/original/image-20151105-16249-98waog.jpg?ixlib=rb-1.1.0&rect=7%2C364%2C5176%2C3088&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The yellow fever mosquito Aedes aegypti isn't put off by this 'mosquito repellent' wrist band.</span> <span class="attribution"><span class="source">Cameorn Webb</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Mosquito repellent lotions, sprays and creams are a <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1708-8305.2010.00402.x/full">sure-fire</a> and <a href="http://www.ajtmh.org/content/59/2/323.short">safe</a> way to prevent mosquito bites – if you choose wisely and apply liberally. </p>
<p>Topical insect repellents that contain DEET or picaridin <a href="https://theconversation.com/aussies-vs-mozzies-a-users-guide-to-repellents-10964">provide the best protection</a>. Formulations that contain <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3059459/">plant-based ingredients</a> (such as tea tree oil) will provide some protection but you’ll generally need to <a href="https://theconversation.com/chemical-or-natural-whats-the-best-way-to-repel-mozzies-36879">apply these formulations</a> far more frequently. </p>
<p>Regardless of a repellent’s ingredients, putting a dab “here and there” is ineffective. You need full coverage. Any gaps will give the green light to blood-thirsty mozzies to attack. </p>
<p>Smearing sticky, smelly repellent is often the last thing you want to do on hot and humid evenings. So entrepreneurs have started manufacturing wrist bands, bracelets and patches that purport to repel mosquitoes without the mess. </p>
<p>But don’t ditch the repellents just yet. While slipping on a wrist band or sticking on a patch may be an attractive alternative, when <a href="http://www.sciencedirect.com/science/article/pii/S0001706X12003452">tested</a>, they’re typically shown to be the least <a href="http://www.nejm.org/doi/full/10.1056/NEJMoa011699">effective</a> of the commercially available repellents. </p>
<h2>What repels mozzies?</h2>
<p>When mosquitoes are searching for a blood meal, they’ll home in on the carbon dioxide we exhale and then respond to the smelly cocktail of chemicals and microbes on our skin. That’s why <a href="https://theconversation.com/health-check-why-mosquitoes-seem-to-bite-some-people-more-36425">some people are bitten</a> by mosquitoes more than others. </p>
<p>When there’s insect repellent on your skin, the mosquitoes are either <a href="https://theconversation.com/sniffing-out-new-repellents-why-mozzies-cant-stand-the-deet-33457">repelled by the unpleasantness of the odours</a> or they’re confused and lose their appetite for blood. </p>
<p>A small number of wrist bands, bracelets and patches are <a href="http://apvma.gov.au/">registered in Australia</a> as mosquito repellents. These are infused with botanical products such as citronella or peppermint oil. The vapour released purportedly keeps mosquitoes away. </p>
<p>Wrist bands containing botanical products provide very little protection. While topical formulations containing plant extracts <a href="http://www.bioone.org/doi/abs/10.2987/09-0016.1">may repel some mosquitoes</a>, the vapours released from these wrist bands just aren’t strong enough to block mosquito bites.</p>
<p>One <a href="http://www.entsocnsw.org.au/images/stories/media/40%20webb%20and%20russell%20wrist%20bands.pdf">detailed study</a> using wrist bands infused with botanical extracts found there was a reduction in biting mosquitoes, but only for a few centimetres either side of the band. Wearing a wrist band won’t provide “whole body” protection.</p>
<p>Laboratory studies have shown that wrist bands <a href="http://europepmc.org/abstract/med/10901639">impregnated with DEET</a> provide some protection against mosquitoes. But a key selling point of wrist bands and patches containing botanical extracts is that they’re an alternative to DEET. They’re primarily marketed to those looking for a “natural” alternative.</p>
<p><a href="http://jinsectscience.oxfordjournals.org/content/15/1/140">Patches containing vitamin B1</a> offer no protection.</p>
<h2>What about mosquito repellent clothing?</h2>
<p>An ever-increasing range of “mosquito repellent” clothing is available in camping, adventure and fishing stores. These items are typically made from material pre-treated with insecticides such as <a href="http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0004109">permethrin</a>. </p>
<p>Insecticides are commonly applied to bed nets and they’ve proven effective in <a href="http://www.cdc.gov/malaria/malaria_worldwide/reduction/itn.html">reducing malaria prevalence</a> in some regions.</p>
<p>There is <a href="http://onlinelibrary.wiley.com/doi/10.1111/mve.12068/full">growing evidence</a> that these products can provide some protection from biting insects. </p>
<p>The problem is, they may stop a mosquito biting through your shirt but they’re unlikely to stop mosquitoes biting exposed areas of skin. </p>
<p>After washing, any protection offered by these clothes is likely to fade.</p>
<h2>The dream of ditching topical repellents hasn’t arrived</h2>
<p>It’s a hassle applying topical repellents, especially to children. There is also often a <a href="http://www.cmaj.ca/content/169/3/209.short">misplaced perception</a> that “chemical repellents” are a health risk. </p>
<p>Despite the evidence that wrist bands and patches provide little, if any, protection from biting mosquitoes, there is clearly demand from the public for alternatives to topical repellents.</p>
<p>A recent crowd-funding venture for <a href="http://www.wired.com/2013/08/this-little-sticker-works-like-an-anti-mosquito-forcefield/">a mosquito repellent patch</a> raised more than US$500,000 without any scientific studies published to back up their claims. </p>
<p>Many are in love with the dream and health authorities need to <a href="https://www.mja.com.au/journal/2015/202/3/are-we-doing-enough-promote-effective-use-mosquito-repellents">address this</a> in their health messages. But, for now at least, nothing works as well as topical repellents, especially those containing either DEET or picaridin, in beating the bite of mosquitoes.</p><img src="https://counter.theconversation.com/content/50186/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 mosquito biology.</span></em></p>While slipping on a wrist band or sticking on a patch may be an attractive alternative, they’re unlikely to provide any substantial protection from biting mosquitoes.Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.