Secrets of Why Mosquitoes Are Attracted to Some People More Than Others

SadaNews - Scientists are making some progress in decoding the complex chemical mixture that makes certain individuals more attractive to disease-causing mosquitoes.

Frédéric Simar, an expert in medical entomology at the "Research and Development Institute" in France, told Agence France-Presse: "It’s not a misconception... mosquitoes are indeed attracted to some people more than others... but we are not all attractive (to mosquitoes) all the time."

A range of sensory stimuli can lead mosquitoes to prefer one individual over another, particularly the scent and heat emitted by our bodies, along with the carbon dioxide we exhale.

Female mosquitoes, the only ones that bite, detect these signals through their highly sensitive receptors and choose their targets accordingly.

Swedish scientist Rickard Ineil told AFP, "We have known for over a hundred years that mosquitoes are attracted to carbon dioxide we exhale... this is the first signal that triggers their behavior."

Ineil, who recently published a study on this subject, explained that mosquitoes "begin detecting our scent" from as far as ten meters away and are attracted more by carbon dioxide.

As they approach, body heat and humidity make certain individuals more appealing to mosquitoes.

Blood Type Has No Relation

However, some common theories regarding this topic have not been proven correct. Simar stated that the idea that mosquitoes prefer certain blood types "has no scientific basis."

He added, "There have been some studies, but very few people participated in them," clarifying that mosquito bites are also unrelated to skin, eye, or hair color.

What About Scent?

Simar explained that "a combination of molecules produced by the microbiota on our bodies is usually more or less attractive to mosquitoes."

Research has shown that between 300 and 1000 different odor compounds are emitted by humans, but scientists are still in the early stages of understanding which of these attracts mosquitoes.

In Ineil's recent study, researchers released a type of mosquito known as "Aedes aegypti," known for transmitting yellow fever and dengue, on 42 women in a laboratory to determine which ones they preferred.

He stated, "We have shown that mosquitoes use a combination of scent-based compounds (we identified 27 out of 1000 that they will detect) to attract themselves to us."

The women whom the mosquitoes preferred to bite, including pregnant women in their second trimester, produced large amounts of a certain compound generated by skin oils.

Ineil confirmed that even a small increase in this compound called "1-octen-3-ol," or mushroom alcohol, was enough to make a difference, which was a surprise.

He added, "Mosquitoes are amazing creatures."

Beer Increases Attractiveness

Drinking beer may also be associated with attracting mosquitoes since it raises body temperature, increases the amount of carbon dioxide exhaled, and alters body odor, according to several studies.

In a study conducted in Burkina Faso, some volunteers consumed beer and then water after several days to determine which they preferred.

The malaria-carrying "Anopheles" mosquitoes were more attracted to the scent of people who drank beer.

In a study from 2023 in the Netherlands, 465 volunteers placed their arms inside cages filled with female Anopheles mosquitoes.

Volunteers who had consumed beer in the previous 24 hours were 1.35 times more attractive to the mosquitoes.

Understanding why mosquitoes prefer certain individuals is becoming increasingly important as climate change is expanding their range. For example, the tiger mosquito, which carries the chikungunya virus, is spreading to new areas.

Last year, chikungunya reached northeastern France in the Alsace region for the first time.

Simar stated, "This risk affects an increasing number of people."

So, what can be done to avoid mosquito bites?

Simar recommends wearing loose clothing that covers the skin, using mosquito nets, and applying repellent products.

He added, "Try to snack and reduce alcohol intake."