• The Washington Post


Mosquito season is in full swing. A lucky few people seem immune to the bites of the pesky insects. Others can’t seem to avoid them.

New research explains mosquitoes’ apparent selectivity. According to an article in Smithsonian magazine, an estimated 20 percent of people are “especially delicious” to mosquitoes.

Why? A number of factors are at play. Chief among them is blood type. “Not surprisingly — since, after all, mosquitoes bite us to harvest proteins from our blood — research shows that they find certain blood types more appetizing than others,” the article reports. Type O is at the top of the list. Additionally, about 85 percent of people secrete a chemical signal that indicates their blood type; these “secretors” are more prone to bites regardless of their blood type.

Another factor is the amount of carbon dioxide people emit when they breathe. Larger people exhale more of the gas, which may explain why adults tend to get bitten more often than children. This also means that obese people are more prone to getting bitten than average or underweight people, and tall people more prone than short. Sweat, high body temperatures and skin bacteria also play a role.

Pregnancy, which increases body temperature and carbon dioxide emission, may also increase the likelihood of bites.

And if you are enjoying a beer at a barbecue, you may have made yourself a mosquito target. No one has been able to pinpoint why drinking beer makes people more attractive to mosquitoes. Some have theorized that the elevation in body temperature and the amount of ethanol in sweat may play a role, but neither theory has panned out.

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