fb-pixel Skip to main content

Are you a mosquito magnet? It could be your smell

James Gathany/Associated Press

Some people are magnets for mosquitoes, emitting a tantalizing combination of chemicals that invite the pesky insects to dine on them.

Researchers at Rockefeller University in New York found people who have higher levels of certain acids on their skin are 100 times more attractive to the female Aedes aegypti, the type of mosquito responsible for spreading diseases such as dengue, chikungunya, yellow fever, and Zika.

The findings, published Tuesday in the journal Cell, could lead to new products that could mask or alter certain human odors, making it harder for mosquitoes to find human blood and potentially curbing the spread of disease.

Advertisement



Mosquito-borne diseases impact about 700 million people per year, and experts expect that number to increase as global temperatures rise, said Jeff Riffell, a professor at the University of Washington and a mosquito expert who wasn’t involved in the research. The A. aegypti mosquitoes are known to live in tropical or subtropical climates, but the insect now breeds year-round in the District of Columbia and parts of California.

Just by breathing, we’re broadcasting to mosquitoes that we’re there, said Leslie Vosshall, the chief scientific officer at the Howard Hughes Medical Institute and the lead researcher behind the new study. Female mosquitoes are built to bite for blood because without it they won’t have enough protein to reproduce.

“Think of it like a big protein shake,” Vosshall said. “It’s a way for them, over the course of one minute, to take in the equivalent of 150 pounds of food and then use that to produce eggs.”

Scientists already knew these mosquitoes have a preference for some humans over others but the reason isn’t fully understood.

Experts have found people seem to become more attractive to mosquitoes when they’re pregnant or after they’ve had a few beers, prompting further research into whether mosquitoes may be drawn to certain odors.

Advertisement



Vosshall, whose lab is at Rockefeller University, set out to find why some people seem to smell better to an A. aegypti mosquito than others.

Fortunately, nobody had to sit in a room full of mosquitoes to conduct this experiment. Instead, the researchers collected the natural scent from people’s skin by having them wear nylon stockings on their arms. They cut the stockings into two-inch pieces and placed two pieces of the fabric behind two separate trap doors in a clear plastic box where dozens of mosquitoes are flying around. The researchers would then open the traps and the insects would choose to either fly to the bait — the stockings — behind the first or the second door.

Vosshall said the researchers conducted a round-robin style tournament and counted each time an insect was drawn to a particular sample, much like points in a basketball game. One of the samples, described as being from “subject 33,” emerged as a favorite of the insects.

“Subject 33 won a hundred games,” Vosshall said. “They were totally undefeated. Nobody beat them.”

The study found that people like subject 33, who have higher levels of compounds called carboxylic acids on their skin, are more likely to be a “mosquito magnets,” Vosshall said.

All humans produce carboxylic acid through sebum, a waxy coating, on their skin. The sebum is then eaten by millions of beneficial microorganisms to produce more carboxylic acid. In copious amounts, the acid can produce an odor that smells like cheese or smelly feet, Vosshall said. That smell appears to attract the female mosquitoes on the hunt for human blood.

Advertisement



Notably, the nylon stockings used in the study didn’t actually smell like sweat, she said. The mosquitoes are incredibly sensitive to human odor; and perfume or cologne can’t cover it up. The experiment was conducted over the course of three years, and the same people continued to appeal to mosquitoes, regardless of what they ate that day or whether they changed their shampoo, Vosshall said

“If you’re a mosquito magnet today,” Vosshall said, “you will be a mosquito magnet three years from now.”