Are you a mosquito magnet? Here’s why
Mosquitoes assault some people more relentlessly than others, with roughly one in 10 people being pursued more than others by female mosquitoes – males do not bite people. Sanchita Sharma writes.
Much like Pig-Pen, the grubby little boy who moves around with his own private dust-storm in Charles Shultz’s Peanuts, as a child I moved around with my own private swarm of mosquitoes.
As far back as I can remember, playing in the garden was done to the sound of chirping birds, chirruping crickets and a near-orchestral buzzing of mosquitoes, much like radio static. Like most other places in the tropics, I didn’t realise the blood-suckers were on stalker mode until I noticed they didn’t bother other people as much as me.
Wherever I went, I was accompanied by a dark, buzzing cloud over my head. One summer, I got curious enough to spend my whole vacation trying to outsmart mosquitoes. It soon became an experiment and I even kept a case-diary that doubled as a bloodied mosquito-swatter.
I looked for and found new mosquito-free places to hide. I dashed around a lot hoping to lose them. I asked my one and only blonde classmate over on several evenings in the hope that her fair skin and hair would make her easier to spot in the dark than me. I hung around with bigger kids who, I reasoned, had larger skin surface areas for mosquitoes to feast on. I found taller children (for mosquitoes who liked heights), and shorter ones (for mosquitoes with vertigo). I even found a kid who ate more sweets than I did after I hearing mosquitoes preferred “sweet blood”.
Nothing worked. My loyal swarm continued to buzz around my head and slyly snack on my arms and legs when I wasn’t looking.
Decades of research now proves that I wasn’t a paranoid adolescent. Mosquitoes assault some people more relentlessly than others, with roughly one in 10 people being pursued more than others by female mosquitoes -- males do not bite people.
Genetics account for almost 85% of your susceptibility to mosquito bites, but there are less known ways to evade the sting.
Movement and heat attract mosquitoes, say entomologists ( so now I know that sitting quietly would have helped me dodge the bite better than hectic, evasive action). Mosquitoes are attracted to carbon-dioxide and prefer active people who breathe faster and deeper from exertion. Activity and exercise produces more sweat and body heat, turning the person into a mosquito-magnet. Pregnant women, too, attract twice the amount of mosquitoes as they are about one degree warmer and exhale 21% more carbon dioxide.
Among the other compounds and odours – mosquitoes can smell from more than 50-metres away -- on the mosquito menu are Type-O blood and high concentrations of lactic acid from sweat glands, steroids, uric acid and cholesterol on the skin surface. It’s not that mosquitoes attack people with high blood cholesterol. Rather, they choose people more efficient at processing cholesterol, the byproducts of which remain on the skin's surface and lure mosquitoes.
The best way to stop the itch from bites and welts is to stop scratching: Mosquito bites leave behind some of its saliva, which contains anticoagulants and a local anaesthetic to numb your skin while it’s feasting. Scratching the skin’s surface spreads the saliva and makes the body to release more antibodies to fight it, triggering an allergic response that causes more itching.
With an exponential rise in mosquito-borne infections – South-east Asia alone (including Indian subcontinent) reported over 2.3 million cases in 2010, up from 1.2 million in 2008, shows the World Health Organisation data – destroying mosquito-breeding grounds and adopting some serious evasive action may soon be as necessary to stay healthy as eating. Each year, dengue causes 500,000 hospitalisations worldwide. About 2.5% of them die.
Among the safest mosquito-repellents are those containing DEET, a chemical that acts by muddling the mosquito's olfactory receptors. Repellents with 25% DEET (most formulas contain between 10% and 30%) protect users for up to five hours. In concentrations of 10% and less, DEET is safe for use on infants over 2 months old, says the American Academy of Pediatrics.
As always, grandma’s cautionary advice against all things living and dead is based on fact. Mosquitoes are the most active at dawn and dusk, so keeping doors and windows without screens shut during these hours to stop mosquitoes from swarming indoors is a start. When stepping out, wear loose clothes that cover your arms and legs. Keep in mind that if Lara Croft was a flesh and blood woman, she’d have died of malaria or dengue on her maiden adventure.