Why do some people attract mosquito bites more than
others? Heidi Mitchell explains on Lunch Break.
It is peak mosquito season, and while some lucky outdoor
venturers seem unperturbed by the tiny insects, others appear to be relentlessly
assaulted. Scientists are trying to understand what makes certain humans more
attractive to the bugs. One expert, molecular vector biologist L.J. Zwiebel, a
professor of biological sciences at Vanderbilt University, weighs in.
Sweet Smell of Success
Mosquitoes find their mammalian prey through sensing the
heat and carbon dioxide mammals emit. Pregnant women and larger people are
sometimes the victim of multiple attacks, since they exert more energy than the
average person.
Mosquitoes are also guided by their sense of smell.
"Despite what my grandmother told me, I don't have sweet blood," says Dr.
Zwiebel, since mosquitoes cannot distinguish blood quality. "Mosquitoes are
attracted to our human odor, and that is largely a consequence of the bacteria
on our skin," says Dr. Zwiebel. The "flora and fauna on our skin" also smell
appetizing to mosquitoes, says Dr. Zweibel, and these can increase when we sweat
or spend a lot of time outdoors.
As far as Dr. Zwiebel knows, there is no scientific
basis to prove that having high cholesterol or diabetes, despite what some
websites claim, will keep bugs away. Nor will taking vitamin B supplements,
eating garlic or taking specific medications.
Skeeter Immunity
Reuters
A culex quinquefasciatus mosquito.
After 20 years in labs with the biting bugs, Dr. Zwiebel
says he can stick his arm into a container of mozzies and be bit hundreds of
times, yet "not have a hair out of place." Children, who have been bitten far
fewer times than adults, may have stronger reactions to bites, since their
immune systems haven't matured fully. But adults who are convinced they are
being victimized by the bloodsuckers usually are not. "There are some people who
have strong allergic responses to the bites which may make it seem like they're
being bit more often, but they're probably not," Dr. Zwiebel notes.
Fighting Back
For people covered in welts and itchy wounds, Dr.
Zwiebel says to stop scratching: When the mosquito bites, it leaves behind some
of its saliva, a substance that contains anticoagulants and a local anesthetic,
among other things. The body recognizes it as a foreign invader and sends
histamines in to counterattack. Scratching just spreads the saliva and
encourages the release of more antibodies, and more itching—a vicious cycle.
Those who swell up and itch a lot when bitten "should
speak with their doctor about taking an over-the-counter antihistamine daily as
a precaution," says Dr. Zwiebel. The bugs will still bite, but you may not
notice, since the drug prevents the allergic response that turns a painless bite
into an itchy nuisance.
Cleaner Is Meaner
Female mosquitoes are driven to bite you as they need a
blood meal to complete their reproductive cycle and produce fertile eggs, which
takes a huge boost of protein. To reduce the chances of being bitten, wash with
an antibacterial soap to reduce the volume of mosquito-attracting bacteria on
your skin.
Other ways to dodge bites: Avoid the outdoors at dawn
and dusk, when mosquitoes are most active. Set up an outdoor fan to shoo bugs
away. And wear long trousers and shirts if it's not too hot. Dr. Zwiebel also
suggests spraying your clothing with repellent that contains DEET, a chemical
that acts to confuse the mosquito's olfactory receptors. "It works, and until
something better comes along, it's the best thing available to prevent bites,"
he says.
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