Joan Rothchild Hardin
How To Make Yourself Less Attractive to Mosquitoes
Are you one of those people who attract every mosquito in the neighborhood while others around you don’t get a single bite?
Mosquitoes have been around for about 170 million years – considerably longer than modern man. Archeological and fossil evidence says Homo Sapiens evolved around 276,000 years ago. So it seems modern humans have been dealing with mosquito bites from the very beginning.
A mosquito and a fly in this Baltic amber necklace are between 40 and 60 million years old.
There are about 2,500 to 3,000 different species of mosquitoes found around the world. (Mosquito Magnet, 2014) More than 175 species have been identified in the US alone. (Heubeck, 2005-2014) Makes you itch just to think about all those mosquitoes, doesn’t it?
The most common – and most dangerous – are the various species in the Culex, Anopheles, and Aedes genera. Culex pipiens, known as the northern house mosquito, is the principal carrier of West Nile virus. Anopheles carries the parasite that causes malaria. The parasite gets transmitted through the mosquitoes’ saliva when they bite us. Anopheles‘ bites are responsible for over one million deaths per year. Two species of Aedes are carriers of other dangerous diseases: Aedes albopictus, the Asian tiger mosquito, transmits dengue fever and eastern equine encephalitis while Aedes aegypti, the yellow fever mosquito, transmits dengue and yellow fever. (Mosquito World, undated) Mosquitoes cause more human suffering worldwide than any other organism – killing over one million people every year. They also transmit serious diseases and parasites to dogs and horses.
The National Center for Infectious Diseases (NCID), a division of the Centers for Disease Control and Prevention (CDC), publishes a list of some of the diseases transmitted by mosquitoes. (NCID, 2007) The American Mosquito Control Association (AMCA) also publishes information on mosquito-borne diseases affecting humans, horses and dogs. (AMCA, 2013) Below is a combination of both lists:
Rift Valley Fever
La Crosse encephalitis
St Louis encephalitis
Chikungunya – rarely fatal but causing excruciating joint pain that is debilitating and may persist for several weeks
Dog Heartworm (Dirofilaria immitis)
Eastern equine encephalitis – affects both horses and humans
Western equine encephalitis
Mosquitoes’ sensory organs seek sources of carbon dioxide and lactic acid – because these substances lead them to humans and other warm blooded animals. Chemical repellents like OFF! work because the DEET in them is highly effective at masking the smell of both carbon dioxide and lactic acid, not because mosquitoes don’t like the smell of the repellents themselves. (Reinagel, 2010) A common misconception is that mosquitoes are attracted to humans and some other warm blooded animals who have sweet or pleasant tasting blood. Mosquitoes aren’t particularly interested in our blood – although people who have Type O blood are known to get more bites than people with other blood types. What they ARE very attracted to is the scents emitted by various bacteria and other micro-organisms living on our skin. These can differ from person to person and on us at different times.
Mosquitoes can detect plumes of carbon dioxide in our exhaled breath at a distance of several hundred feet. At under 100 feet they smell the odors of the bacteria and micro-organisms living in our skin microbiota. (Mosquito World, undated)
It’s only the female mosquito that bites – and what she does isn’t actually a bite. She lands on your skin and uses heat sensors on her antennae and around her mouth to detect a capillary near the surface of the skin. When she finds one, she inserts her proboscis (a long, needle-like mouth part containing two tubes) into the vessel and draws some blood out through one tube. Through the proboscis’ second tube, she inserts a little of her saliva, which contains enzymes that keep the blood from coagulating so she can feed freely. These enzymes also act as a mild painkiller so we don’t notice that our skin has been punctured. The female mosquito needs a protein in human blood to make her eggs fertile. (Ferris, 2013)
Our body’s immune system recognizes these enzymes as foreign. Antibodies prompt our mast cells to release histamines, which arrive at the scene and start to do their work of healing the breach and neutralizing the foreign enzymes by binding to receptors, causing the blood vessels there to dilate. The increased blood flow attracts more white blood cells to help vanquish the invading antigens. The histamines cause the spot to swell and become itchy. (Mosquito World, undated)
Mast cells are a clever and important part of our immune systems and pretty interesting in their own right. To read more about how they work, see The Role of Mast Cells and My Own Struggle with Mast Cells Gone Wild. OUR SKIN MICROBIOME
High magnification reveals a host of bacteria underneath a human toenail. A new analysis has shown that the billions of bacteria that inhabit human skin are not only highly diverse but also change their composition over time.
(Text Credit: resident-alien.blogspot.com) A 100 trillion or so micro-organisms live on and inside our bodies. One percent of these, about a trillion, live in and on our skin and determine our unique body odor. Without these bacteria, human sweat would be odorless. And these microbes, our skin’s microbiome, produce a variety of chemicals – some of which smell more attractive to mosquitoes and some of which don’t interest them at all. The composition of these trillion microbes varies greatly from person to person: We share 99.9% of our DNA with other humans but share only about 10% of our microbes. (Loria, 2014) Interesting tidbit: It’s not the smell of our blood but the unique odors given off by our skin microbiota that so-called blood hounds can pick up. We’re constantly shedding a cloud of minute skin flakes. Bloodhounds are particularly adept at following a trail of these flakes, sniffing their odors. (Black, 2012)
Dutch researchers demonstrated that it is certain types of micro-organisms living on our skin that attract mosquitoes. For the study, they asked 48 adult male volunteers to avoid consuming alcohol, garlic, onions, and spicy foods, and not to shower or wear scented cosmetics for two days prior to the sampling event. The men were also instructed not to use soap the last time they showered before the experiment. All 48 volunteers were free from chronic illnesses and not taking any medications on a regular basis. (Verhulst, 2011) (Loria, 2014) The men were given nylon socks to wear for 24 hours to build up a collection of their unique skin microbes. For the testing, researchers rubbed glass beads against the soles of the men’s feet to collect their scent as mosquito bait.
Our feet have approximately 250,000 sweat glands each and can excrete as much as a pint of moisture every day. The sweat from 9 of the 48 men in the sample proved to be especially attractive to mosquitoes. Mosquitoes largely ignored the odors of the sweat from 7 of the men. The ‘highly attractive’ group’s sweat contained a 2.62 times higher concentration of one common skin microbe (Staphylococcus spp.) and 3.11 times higher concentration of another common microbe (Pseudomonas spp.) compared to the 7 in the ‘poorly attractive’ group. There was no significant difference between the amounts of Brevibacterium spp. and Cornynebacterium spp. in the ‘highly attractive’ and ‘poorly attractive’ groups. The ‘poorly attractive’ group also had a significantly more diverse bacterial colony living on their skins. (Loria, 2014) (Verhulst, 2011) The microbial ecology of human skin is highly complex but science is still in the early stages of studying it. At this point, little is known about its species composition and only a small fraction of the micro-organisms living on – and in – us is culturable now – many species have not even been identified yet. The same is true for the microbes living in our gut microbiomes. Nonetheless, the findings from this study are leading to the development of new mosquito attractants and repellents. ANOTHER STUDY
Mosquitoes are attracted to beer drinkers – the reason why isn’t yet known Another study, this one conducted by the National Center for Biotechnology Information, found that mosquitoes and biting insects are also attracted to beer drinkers. Even one beer was found to increase the number of times subjects were bitten. The researchers hypothesized that the attraction was due to increases in the amount of ethanol in sweat or because alcohol raises body temperature, but neither was found to correlate with mosquito landings. This study also found that exercise, metabolism, clothing color, and pregnancy affected vulnerability to mosquitoes. (Salaky, 2013)
HOW TO AVOID BEING BITTEN BY MOSQUITOES (Reinagel, 2010), (Thompson, 2014), (Joseph, 2010), (Stromberg, 2013) and (Hadley, 2014) THESE ATTRACT MOSQUITOES:
Standing water can become a breeding ground for mosquitoes. Covering it with a screen is a deterrent.
Wearing solid, dark clothing and dark, flowery prints
Using beauty products and lotions such as hair spray, perfume, and suntan lotion
Having standing water around – such as in backyard pools and in undisturbed pails or buckets
Working up a sweat. When you exercise, you give off more lactic acid and more carbon dioxide.
Being outside early in the day or at twilight, when mosquitoes bite the most
Eating sweet, sugary foods
Eating salty foods or ones high in potassium: Salt and potassium increase the amount of lactic acid you off-gas. Unfortunately, fruits and vegetables are the foods richest in potassium. Cabbage, green peppers, cucumbers, blueberries, apples, and watermelon are relatively low in potassium. Potatoes, lima beans, acorn squash, spinach, prunes, raisins, bananas are high in potassium.
Eating limburger cheese: It’s made with the same bacteria that cause our feet to smell.
Drinking beer: Consuming even one bottle of beer makes you bait for mosquitoes. I’ve been unable to find what it is about beer that is so attractive to them but only learned that it’s not due to an increased amount of ethanol excreted in sweat or because alcohol increases body temperature. If you find out what the connection is between beer consumption and attraction to mosquitoes, please let me know.
Being pregnant: Pregnant women attract roughly twice as many mosquitoes as non-pregnant people. Pregnant women exhale about 21% more carbon dioxide and run about 1.26 degrees Fahrenheit warmer. Mosquitoes are attracted to both the carbon dioxide breathed out and the heat given off by warm blooded animals.
Using alpha hydroxy products on your skin: Many skin care lotions and creams contain lactic acid, which is highly attractive to mosquitoes.
THESE MAKE YOU LESS INTERESTING TO MOSQUITOES:
Wearing plain, light-colored clothing
Spraying your skin with a diluted mixture of essential oils that are known to repel mosquitoes – such as tea tree oil, geranium oil, oil of cedar, peppermint oil, lemon grass oil, and citronella
Dabbing small amounts of the above essential oils on your skin is also effective against mosquitoes. A good choice is TerraShield, made by doTerra – a blend of 15 essential oils, it repels mosquitoes and ticks for up to six hours. It has a pleasant citrus smell and can be dabbed directly on your skin.
Diffusing one of these essential oils or oil blends (such as TerraShield) into the air
Placing a few drops of these essential oils or oil blends on ribbons and strings and hanging them near air vents, windows or openings where bugs might come in
Applying crushed herbs directly on your skin. Crushed catnip, citronella, vanilla leaf, tea tree, lemon balm, clove, lavender, eucalyptus, sagebrush and pineapple weed are safe to use in this way.
Spraying your skin with an infusion of herbs and plants that mosquitoes don’t like – such as calendula, catnip, lavender, pennyroyal, rosemary, basil, lime basil, peppermint, horsemint, lemon balm, lemon thyme, lemon grass, chamomile and goldenseal
Planting fragrant herbs from the list above, plus aromatic plants – such as ageratum, citronella grass, citrosa, marigolds*, common lantana, fever tea, myrrh, stone root and pennyroyal – in your garden or in pots outside. They’re all natural mosquito repellents.
Using a garlic spray in your garden or a garlic-scented lotion on your skin
Eating garlic provides mild protection – both from the scent of your breath and the sulfurous compounds you’ll emit through your skin. Of course, eating garlic or smearing its scent on your skin will probably keep away more than mosquitoes!
Eating foods high in vitamin B – such as fish, brown rice, molasses, brewers yeast and wheat germ. Mosquitoes don’t like vitamin B.
TerraShield, made by doTerra is a blend of 15 essential oils that repels mosquitoes and ticks for up to 6 hours See here for a list of pest-repelling plants and here for another useful list with details on which plants to use and where to plant them, plus more on applying crushed herbs to your skin as a mosquito deterrent. Here’s a good article containing recipes for making your own natural mosquito repellent using essential oils. Non-chemical mosquito repellents contain a diluted mixture of essential oils that mosquitoes find distasteful or which confuse their ability to detect your own odors so they can’t find you and therefore won’t bite you.
* WARNING: Never keep marigolds in areas close to windows, patio tables and other outdoor areas where you spend time as the flowers’ bright colors often attract wasps. (wikiHow, undated) NOTE: I would have included Avon’s Skin So Soft in the list of mosquito repellents except that they contain some not so nice chemicals – including methylparaben and proplyparaben. Parabens are used as preservatives to increase shelf life in many cosmetic products (lotions, underarm deodorants and antiperspirants, hair care products, moisturizers, shaving products and make up), medicines and foods. Some of the major parabens we absorb or ingest in these products are benzylparaben, butylparaben, ethylparaben, isobutylparaben, methylparaben and propylparaben. The US Environmental Protection Agency (EPA) reports that parabens have hormone-disrupting qualities that mimick estrogen interfering with the body’s endocrine system. The EPA has linked methylparabens in particular to metabolic, developmental, hormonal and neurological disorders, as well as to various cancers. Companies like Burt’s Bees, Botanical Skin Works and Barefoot Botanicals do not use parabens in their products. For more information on products containing parabens visit www.thinkbeforeyoupink.org. For more information on the parabens-breast cancer link and some paraben-free alternatives, see here (Johnson, 2011) and here (Mercola, 2012).
AO+ REFRESHING COSMETIC MIST – TO REPLENISH THE MICROBIOME OF MICROSCOPIC ORGANISMS LIVING ON OUR SKIN
Artist Sonja Bäumel explores the skin microbiome in her Cartography of the Human Body project In doing the research for the post just before this one, Living Bacterial Skin Tonic – Instead of Soap?!, I came across this about a living bacteria skin tonic being developed by a Massachusetts start up called AOBiome – I’ve highlighted the last two sentences: The company’s scientists think that this product will be good for us because it could refill our bodies with microflora that do us good. In this way, it could actually be better for us than the antibacterial hygiene products that we are accustomed to using. Although these kill off bacteria, they can harm us due to the chemicals they contain (such as triclosan) which have been linked to various health problems. If you’re still not convinced that you would want bacteria on your skin, consider this: bacteria can assist in treating various skin conditions, such as eczema and acne. It helps to heal wounds that are resistant to antibiotics. It can also change body odour so that it keeps mosquitos at bay. This is especially good if one considers illnesses like malaria that can run rampant and affect many people. (Simolo, 2014) Our usual approach to the bacteria and other micro-organisms living on our skins – and everywhere else we can get to them – is to KILL THEM DEAD. We generally regard bacteria and their relatives as dangerous and just plain nasty. So this is an entirely new approach – a U turn in how to think about the bacteria living in and on our skin: This new spray contains billions of cultivated Nitrosomonas eutropha, an ammonia-oxidizing bacteria (AOB) It’s to be used in lieu of – or as an adjunct to – taking showers. Bathing with most soaps and shampoos KILLS ALL THE HEALTHY ELEMENTS OF OUR SKIN MICROBIOME. This new living bacterial skin tonic REPLENISHES the biome of microscopic organisms living on our skin. If you recall the Dutch experiment described above, in the OUR SKIN MICROBIOME section, one of the findings was that the group of men who were the least attractive to mosquitoes had a significantly more diverse bacterial colony living on their skins. So it makes sense to me that we would want to reverse our ill-considered search and destroy approach to bacteria and begin valuing and supporting our skin microbiomes, the trillion bacteria and other micro-organisms that dwell in and on our skin – for many reasons, not making ourselves so attractive to disease and parasite spreading mosquitoes being only one.
REFERENCES American Mosquito Control Association (AMCA). 2013. Mosquito-Borne Diseases. See: http://www.mosquito.org/mosquito-borne-diseases Black, J.G. (2012) Microbiology: Principles and Explorations, 8th edition. Wiley, p. 403. See: http://books.google.com/books? id=pnVMAgAAQBAJ&pg=PA403&lpg=PA403&dq=odors+skin+microorganisms+blood+hound&source=bl&ots=rjhDyvguWv&sig=qVThuBz4sVzeq-Mi4q2Rdr5ij9E&hl=en&sa=X&ei=BaaXU-7hNcvesASCl4CgBg&ved=0CDgQ6AEwBA#v=onepage&q=odors%20skin%20microorganisms%20blood%20hound&f=false Davis, L. (2014). Parabens Linked to Breast Cancer? Beauty News NYC – Skin Care. See: http://www.beautynewsnyc.com/skin-care/parabens-linked-to-breast-cancer/ Ferris, R. (2013). How to Deal With and Prevent Mosquito Bites. Business Insider – Science. See: http://www.businessinsider.com/a-few-tips-on-mosquito-bites-2013-7 Hadley, D. (2014). 10 Ways to Guarantee You’ll Get Mosquito Bites. About.com – Insects. See: http://insects.about.com/od/flies/a/how-to-get-mosquito-bites.htm Hardin, J.R. (2014). Living Bacterial Skin Tonic – Instead of Soap?! AllergiesAndYourGut.com. See: http://allergiesandyourgut.com/2014/06/07/living-bacterial-skin-tonic-instead-bathing/ Hardin, J.R. (2014). My Own Struggle with Mast Cells Gone Wild. AllergiesAndYourGut.com. See: http://allergiesandyourgut.com/about-me/my-own-struggle-with-mast-cells-gone-wild/ Hardin, J.R. (2014). The Role of Mast Cells. AllergiesAndYourGut.com. See: http://allergiesandyourgut.com/symbiosis-versus-dysbiosis/the-role-of-mast-cells/ Helmenstine, A.M. (20). Natural Mosquito Repellent Recipe. About.com – Chemistry. See: http://chemistry.about.com/od/healthbeautyprojects/a/naturalmosquitorepellent.htm Heubeck, E. (2005-2014). Are You a Mosquito Magnet? WebMD – Allergies Health Center. See: http://www.webmd.com/allergies/features/are-you-mosquito-magnet Johnson, C. (2011). Are Parabens Really Harmful? Are There Alternatives? HappyMothering.com. See: http://www.happy-mothering.com/06/beauty/skincare-cosmetics/are-parabens-really-harmful-are-there-alternatives/ Joseph, S. (2010). Naturally Repel Mosquitoes and Ticks: doTerra Essential Oils. Dr. Mom Essentials. See: http://drmomessentials.com/naturally-repel-mosquitoes-and-ticks-doterra-essential-oils/ Loria, K. (2014). Some People Don’t Get Bitten By Mosquitoes — Why That’s True Will Surprise You. Business Insider- Science. See: http://www.businessinsider.com/skin-bacteria-attracts-mosquito-bites-2014-3 Mercola, R. (2012). 40 Women With Breast Cancer Had This “Cosmetic Ingredient” in Their Tissues. The Mercola Newsletter, Mercola.com. See: http://articles.mercola.com/sites/articles/archive/2012/04/02/toxic-parabens-on-breast-cancer-patients.aspx Mosquito Magnet. (2014). FAQs – Mosquitoes. See: http://www.mosquitomagnet.com/resources/faqs Mosquito World. (undated). Mosquito Bites. Mosquito World: Your guide to effective mosquito control. See: http://www.mosquitoworld.net/mosquitobites.php and http://www.mosquitoworld.net/mosquitospecies.php National Center for Infectious Diseases (NCID). 2007. Infectious Disease Information – Mosquito-Borne Diseases. Centers for Disease Control and Prevention (CDC). See: http://www.cdc.gov/ncidod/diseases/list_mosquitoborne.htm Reinagel, M. (2010). What to Eat to Avoid Mosquito Bites. QuickAndDirtyTips.com. See: http://www.quickanddirtytips.com/health-fitness/trends-fads/what-to-eat-to-avoid-mosquito-bites Salaky, K. (2013). Beer Drinkers Attract More Mosquitoes, Study Finds. The Daily Meal. See: http://www.thedailymeal.com/beer-drinkers-attract-more-mosquitos-study-finds Simolo, G. (2014). How a Company is Using Bacteria to Replace Soap. Wind.org. See: http://www.wind.org/view-post/How-A-Company-is-Using-Bacteria-to-Replace-Soap Stromberg, J. (2013). Why Do Mosquitoes Bite Some People More Than Others? Smithsonian.com. See: http://www.smithsonianmag.com/science-nature/why-do-mosquitoes-bite-some-people-more-than-others-10255934/?no-ist Thinkbeforeyoupink. Think Before You Pink – A Project of Breast Cancer Action. See: http://thinkbeforeyoupink.org/ Thompson, K. (2014). How to Control Mosquitoes. Pest Control – About.com. See: http://www.answers.com/guides/how-to-control-mosquitoes Verhulst, V. O. et al. (2011). Composition of Human Skin Microbiota Affects Attractiveness to Malaria Mosquitoes. PLoS One, 6:12. See: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0028991 wikiHow. (undated). How to Use Plants to Keep Mosquitoes Away. See: http://www.wikihow.com/Use-Plants-to-Keep-Mosquitoes-Away Wikipedia. (May 29 2014). List of Pest-repelling Plants. See: http://en.wikipedia.org/wiki/List_of_pest-repelling_plants
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