Researchers Find Out Why Certain People Attract Mosquitoes More Than Others Health

The female mosquito preys on any person, although some of us experience significantly more bites than others. Our skin might hold the key to understanding why. For this reason, Vosshall and Maria Elena De Obaldia, a former postdoc in their lab, decided to investigate the top theory to explain differences in mosquito attraction: personal odor variations linked to skin microbiota. A recent study showed that the strong odor produced by skin-exuding fatty acids may be what repels mosquitoes. Their results were published in Cell.

“There’s a very, very strong association between high levels of these fatty acids on the skin and being a mosquito magnet,” says Vosshall, Robin Chemers Neustein Professor at Rockefeller University and chief scientific officer of the Howard Hughes Medical Institute. Eight subjects were asked to wear nylon stockings over their forearms for six hours each day for the duration of the three-year trial. You’ve gone through this process multiple times. In the course of the following years, the nylons competed against each other in all conceivable pairings in a round-robin tournament.

De Obaldia created for them a two-choice olfactometer test consisting of a Plexiglas chamber divided into two tubes, each ending in a box with a stocking. In the main room they positioned Aedes Aegypti mosquitoes, which are the main vectors of Zika, Dengue, Yellow Fever and Chikungunya. They watched as the insects flew down the tubes, towards either one nylon or the other. Subject 33 was by far the most enticing target for Aedes aegypti, attracting the mosquitoes 100 times more than subject 19, who was the least attractive research participant, and four times more than the second most enticing subject.

The test samples were anonymized so the researchers could not know which person wore which nylon. However, in any study involving subject 33, they would find something was wrong because insects flocked to that sample. De Obaldia claims it would become clear shortly after the test started. As a scientist, that’s the kind of thing that really excites me. This is a real situation. This is not a case of nitpicking. It has a significant impact. Subjects were grouped into high and low attractors, and the researchers then asked what made each group unique. 50 molecular components higher in the sebum (a moisturizing barrier on the skin) of the very attractive individuals were found using chemical analysis techniques.

This led them to conclude that mosquito magnets generated significantly higher levels of carboxylic acids than the less attractive participants. Our distinctive human body odor is created by bacteria on our skin using ingredients from sebum. Vosshall’s team recruited an additional 56 participants for a validation study to validate their results. Subject 33 remained the most intriguing subject over time.

“Some subjects were in the study for several years, and we saw that if they were a mosquito magnet, they remained a mosquito magnet,” says De Obaldia. “A lot of things about the person or their behavior could have changed in that time, but that was a very stable trait of the person.” Mosquitoes have two distinct sets of olfactory receptors, known as Orco and IR receptors, which they use to detect two main groups of human odors.

The researchers developed mutants that lacked one or both receptors to see if they could give rise to mosquitoes that humans can’t recognize. While IR mutants lost their attraction to us to varying degrees but could still locate us, Orco mutants continued to be attracted to humans and could distinguish between mosquito magnets and low attractors. The scientists had not expected these findings. “The goal was to create a mosquito that would no longer be attracted to humans, or a mosquito with a weaker attraction to everyone and the inability to distinguish between subject 19 and subject 33. That would be fantastic, adds Vosshall, as it would encourage the creation of more potent insecticides.” “But we haven’t really seen that. It made me angry.”

These findings complement one of Vosshall’s recent studies, also published in Cell, which demonstrated the redundancy of Aedes aegypti’s extremely complex olfactory system. It is a failsafe that the female mosquito relies on to live and reproduce. You can’t do it without blood either. So “she has a backup plan, and a backup plan, and a backup plan, and is attuned to these differences in the skin chemistry of the people she’s tracking,” says Vosshall. It’s difficult to imagine a world where humans aren’t the main dish on the menu due to the mosquito scent tracker’s seeming unbreakability. However, changing the microbiomes on our skin is an option. It is likely that applying sebum and skin bacteria from the skin of a low attractive person like subject 19 to the skin of a high attractive person like subject 33 could have the effect of hiding mosquitoes.

“We didn’t do this experiment,” notes Vosshall. “It’s a tough experiment. But if that worked, imagine converting someone through a nutritional or microbiome intervention, where you bring bacteria to the skin that are capable of somehow altering how they interact with the sebum could be like Subject 33 in Subject 19. But that’s all very speculative.” It’s impossible to imagine a world where humans aren’t the most popular item on the menu given the seeming impenetrability of the mosquito odor tracker. However, altering our skin’s microbiota is an option. It is possible to obtain a mosquito masking effect by applying sebum and skin bacteria from the skin of a low irritant like Subject 19 to the skin of a high irritant like Subject 33. (ANI)

(This story has not been edited by Devdiscourse staff and is auto-generated from a syndicated feed.)