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Why do mosquitoes bite some people more than others? How do you smell?

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Some people are like magnets for mosquitoes and emit a tempting chemical compound that invites pesky insects to eat on them.

Researchers at Rockefeller University in New York found that people with higher levels of certain acids in their skin are 100 times more attractive to women. aedes aegyptiThe mosquito species responsible for the spread of 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, make it harder for mosquitoes to find human blood, and potentially curb the spread of disease.

Mosquito-borne diseases affect about 700 million people a 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 was not involved in the study. A. aegypti mosquitoes are known to live in tropical or subtropical climates, but the insect now breeds year-round in the Territory of California and parts of California.

Just by breathing we publish to mosquitoes that we’re there, said Leslie Vosshall, chief scientist at the Howard Hughes Medical Institute and principal investigator behind the new study. Female mosquitoes were created to bite for blood because without blood they wouldn’t have enough protein to reproduce.

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

How to get rid of mosquitoes and other tips for dealing with these annoying insects

Scientists already knew that these mosquitoes prefer some people over others, but this is because not fully understood.

Experts have discovered that people seem more attracted to mosquitoes when they are pregnant or after drinking a few beers, leading to more research into whether mosquitoes can be attracted to certain scents.

Vosshall, whose laboratory is located at Rockefeller University, We set out to find out why some people smell better to A. aegypti mosquitoes. than others.

Fortunately, no one 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 wearing nylon stockings on their sleeves. They cut the socks into two-inch pieces and placed the two pieces of fabric behind two separate trap doors in a clear plastic box where dozens of mosquitoes were flying. The researchers would then open the traps and the insects would choose to fly into the bait – the stockings – either behind the first or second door.

Vosshall said the researchers ran a loop-style tournament and counted each time an insect was drawn to a particular sample, such as scores in a basketball game. One of the specimens described to be from Subject 33 turned out to be a favorite of insects.

“The issue won 33 hundred games,” Vosshall said. “They were completely undefeated. No one beat them.”

The research found that people who liked subjects 33 who had higher levels of compounds called carboxylic acids in their skin were more likely to become “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 acids. Too much acid can produce an odor that smells like cheese or foot odor, Vosshall said. This scent seems to attract female mosquitoes looking for human blood.

Specifically, he said, the nylon stockings used in the study didn’t actually smell like sweat. Mosquitoes are incredibly sensitive to human odor; and perfume or cologne cannot cover it. The experiment was conducted over 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,” said Vosshall, “three years from now you’ll be a mosquito magnet.”

The study did not answer why some people have more carboxylic acids in their skin than others. But Vosshall said the composition of the skin microbiome is unique in each individual.

“Everyone has a completely unique village of bacteria living on their skin,” Vosshall said. Said. “Some of the mosquito magnetism differences we see here may simply be differences in bacterial species.”

LJ Zwiebel, a professor at Vanderbilt University who was not involved in the research, said that although carboxylic acids were clearly involved in the study, there was no “single compound” that attracts mosquitoes. He said it’s probably a “cocktail” of different ingredients that mosquitoes have come into and bite at.

“The mosquito is a multimode magnet that uses many different signals,” Zwiebel said. Said. Carboxylic acids are “an important component, but not the only component.”

Zwiebel said her advice for someone who doesn’t want to be bitten by mosquitoes is to take a shower to reduce “all those watery compounds” that have “unique odors” in your skin, especially around your feet.

Vosshall said: The future lies in figuring out how to “manipulate” odors from the skin and potentially from the bacteria that live there. For example, scientists could develop a probiotic skin cream that blocks or reduces the levels of certain byproducts that can make a person less attractive to mosquitoes.

“Only once you understand what makes people mosquito magnets can you start brainstorming ways to stop it,” Vosshall said.

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