ST. LOUIS — If you always seem to be the one covered in itchy red mosquito bites while your friends remain untouched, you’re not imagining it. Research shows that about 20% of people consistently attract more mosquito attention than others, and scientists are still working to figure out why this is.
Beyond being a nuisance, mosquito bites can spread deadly diseases including malaria, dengue fever, yellow fever, Zika and West Nile virus. Malaria alone accounted for an estimated 250 million cases worldwide in 2022, leading to more than 600,000 deaths, according to the World Health Organization.
Various studies show that a range of biological and environmental factors seem to make certain people more appealing to mosquitoes:
Blood type
A 2004 study from the Institute of Pest Control Technology found that mosquitoes landed on people with Type O blood nearly twice as often as those with Type A. People with Type B fell in the middle. Researchers also noted that about 85% of people secrete a chemical signal indicating their blood type, and mosquitoes were more drawn to these “secretors” regardless of type. Another study from the American Journal of Entomology in 2019 confirmed that mosquitoes preferred Type O blood when given multiple feeders to choose from.
Exercise and warmth
Intense physical activity increases lactic acid (a syrupy organic acid produced in the muscle tissues). Ammonia and heat are also produced during exercise and mosquitoes are capable of detecting all of these things at close range. In 2020, the Science journal published a study finding that disabling a heat-sensing mechanism in mosquito antennae made it harder for them to locate humans, and even though they had other ways to do so, it suggests that heat could certainly be a factor.
Carbon dioxide
Mosquitoes can sense carbon dioxide in human breath from as far as 100 feet away, using a sensory organ called the maxillary palp. People who exhale more CO2 over time might be more likely to attract them.
Skin bacteria
Other research suggests that people with high amounts of certain bacteria on their skin were more likely to be bitten, while those with a more diverse bacterial community were less so. This could explain why ankles and feet are more attractive to them too, as they are home to more odor than other-producing bacteria than other parts of the body.
Taste
Last year, Yale University researchers found that compounds in human sweat influenced mosquito bites. Some amino acids and salts triggered more bites, while bitter compounds made them less likely. The study suggested some people may simply “taste better” to mosquitoes too.
A different kind of buzz
A recent study out of Amsterdam found that drinking beer has the potential to draw more mosquitos too., finding that they were 1.35 times more likely to bite beer drinkers than those who remain sober. A 2010 study also had some findings linking beer to mosquitoes, though researchers could not link the effect to higher carbon dioxide output or body temperature.
Pregnancy
Pregnant women exhale more carbon dioxide than the average person, and are warmer around the abdomen, and given what we know about the mosquito studies for heat and carbon dioxide, this could suggest that they too become greater targets. A science direct study has them being twice as likely to be bitten.
Clothing color
A 2022 University of Washington study found that mosquitoes use vision along with scent to locate humans, showing a preference for darker or longer-wavelength colors such as black, red, orange and cyan. Green, purple, blue and white were largely ignored. So if you’re an individual who gets bit a lot, maybe try a wardrobe switch if you’re going on a hike.
Genetics
Researchers believe genetics play a significant role, influencing traits such as body odor, metabolism and blood chemistry. A study found that some body odors mosquitoes rely on may be genetically driven.
Scientists hope these insights could lead to new repellents, and they’re even trying to develop drugs that stimulate natural mosquito-deterring chemicals in the skin that would be able to keep them away for weeks.
For now though, bug spray, protective clothing and clearing standing water remain the most effective defenses, especially for those people out there who mosquitoes can’t seem to resist.
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