Lots of different things attract mosquitoes to humans, but it's no myth that they find some people more enticing than others. In general, mosquitoes follow odors and the carbon dioxide that we exhale. A chemist with the USDA Agricultural Research Service, Ulrich R. Bernier, reported finding over 340 unique scents that human skin gives off, and scientists are trying to narrow down which are especially attractive to mosquitoes.
The knowledge is useful because the best scents can be used as bait to lure mosquitoes away from humans, and scientists can also try to figure out how to create mosquito repellent products that disguise or minimize them to create mosquito repellent.
But one of the more unusual attractants is your blood type. A few studies have shown that mosquitoes prefer people with type O blood.
As long ago as 1972, a study published in Nature magazine by Corinne Shear Wood and others showed that Anopheles gambiae mosquitoes preferred biting people with type O blood.
A more recent study, published in 2004, showed the same results using a different species of mosquito, Aedes albopictus.
It's easy to understand how mosquitoes might be attracted to different odors, but how can they tell what blood type a person is? The 2004 study also gave a clue to that.
Some people secrete sugars related to their blood type, and the study published in the July 2004 Journal of Medical Entomology divided the test subjects into groups according to whether they were secreters.
Those who were secreters in blood group O averaged 83.3% mosquito landing rates, while those who were secreters in blood group A averaged only 46.5% landing rates.
Mosquitoes may be able to sense the saccharides that people secrete from the skin, based on different blood types, and use that to select their preferred victims.
So if you're blood type O, are you doomed to be a mosquito magnet? Well, not really.
There are dozens of other things that attract mosquitoes also. Some you can't control, like exhaling carbon dioxide. Others you can, though. It's been shown that drinking just one beer will make you more attractive to mosquitoes, according to a 2002 study in the Journal of the American Mosquito Control Association and the results were confirmed in a 2010 study. Mosquitoes also like the odor of Limburger cheese, which turns out to be similar to the odor of smelly feet. If you sweat more, mosquitoes will come to that odor too.
So even if you're unlucky enough to have blood type O, you may still be less attractive to mosquitoes than others who lure them in different ways.
Photo credit: CDC