Could your soap make you more attractive to mosquitoes?

A new study has found that the type of soap a person uses can increase their risk of mosquito bites.

mosquito bites can bring irritation and itching, as well as potential exposure to diseases carried by this insect with long proboscis. If you find that mosquitoes tend to be attracted to you, it might be time to dive into the root cause of the problem, starting with what you put on your body to attract or deter the insect.

Virginia Tech researchers examined whether certain soaps carried by a person attracted or repelled mosquitoes. They found that soaps interact in interesting ways with a person’s natural scent signature — think of it as your own unique scent profile — impacting the chemical compounds a mosquito reacts to in a human host.

Main author Clement Vinauger, PhDassistant professor of biochemistry at Virginia Tech, said Health that soaps tend to be scented with chemicals associated with the pleasant scents of flowers found in nature. He said mosquitoes also use “volatile substances emitted by plants” to find flowers and obtain sugars from their nectar. With all of this in mind, he and his team expected that the addition of these flower-scented chemicals to soaps used for human hygiene would have an impact on attracting mosquitoes to people.

“What was surprising about our results was the importance of the interaction between specific soap chemicals and each specific individual’s body odor in determining whether a person would become more or less attractive to mosquitoes after having applied soap to her skin,” Dr. Vinauger said. explain.

“In other words, we were surprised that some soaps, but not others, would increase the attractiveness of some people, but not others.”

The study was relatively small—Dr. Vinauger and his team had four participants wash with soap from four brands, Dial, Dove, Native and Simple Truth. These participants had both forearms rinsed for 30 seconds with deionized water and then dried with a paper towel.

A forearm would receive no further treatment, a nylon sleeve placed over it and wrapped in foil. Then they washed the other forearm with the different soaps for 10 seconds, then rinsed with deionized water for another 10 seconds, followed by the application of a nylon sleeve and aluminum foil . The sleeves were used to capture all the smell of the skin that a mosquito could register, including its natural scent which mixed with the soap.

Separately, the fragrances of the soaps were examined alone, with nylon sleeves washed with each soap and then rinsed. Similar to nylons applied to participants’ forearms, clean sleeves rinsed with water, but without soap, were used as controls.

After the scent collections, the sleeves were placed in small cups which were then placed in a cage, where the mosquitoes would finally be released to see which nylon attracted or repelled the insects.

The mosquito species used in the study was Egyptian Temples, the main species that spreads diseases like Zika, dengue and chikungunya.

All of the soaps contained limonene, which comes from citrus fruits and is known to repel mosquitoes. In the end, it doesn’t matter much. Three of the soap-washed sleeves attracted mosquitoes, with the exception of the Native brand soap which contained a coconut scent.

“Remarkably, the fragrances of all the soaps were mainly dominated by limonene, which is known for its repellent effect on mosquitoes. Despite this, three of the four soaps tested increased mosquito attraction,” Dr. Vinauger said, putting the results into context.

“Our results indicate that more than the absolute amount of a given chemical, what really matters for mosquitoes are the relative amounts of chemicals in the mixtures.”

Dr. Vinauger explained that about 20% of human hosts are responsible for about 80% of mosquito-borne disease transmissions. Given this reality, he stressed how crucial it is for us to understand what makes a mosquito bite one person rather than another.

“While other studies have determined which of the chemicals we produce as part of our body odor attract mosquitoes, the effect of the odors we regularly add to our smell remains to be determined,” he said. added.

Patrick “PJ” Liesch, MS, is the director of the UW-Madison Insect Diagnostics Laboratory and “the Wisconsin Bug Guy” who regularly lectures and appears in the media on all things insect. Liesch, who is not affiliated with this new study, said Health that mosquitoes can be attracted to people for a variety of reasons.

“Volatile chemicals associated with the skin may play an important role at closer distances and may help explain some of the notable differences in attractiveness from person to person,” he explained. “Each differs in their unique odor caused by volatile substances on the skin, and this can be influenced by factors such as genetics, age, gender, metabolism, diet, exercise, personal care and the microbiome of our skin.”

Regarding the new study, Liesch said that “the chemistry of soap is complex” – each type of soap can differ in its chemical composition and also in the changes it causes “in the volatile substances of the skin after use. “.

“Researchers in the recent paper found that very specific chemicals either increased or decreased the attractiveness of a mosquito species, although the exact reason is not fully understood in many cases,” he noted.

Liesch said “it’s too soon to tell” whether studies like this can tell someone how best to protect themselves from mosquito bites. He added that this research into soaps and their impact on attracting mosquitoes “is fascinating”, but there is still a long way to go before we can determine if we need to make any changes to our self-care routines.

“With around 3,600 known species of mosquitoes in the world, further testing would be needed,” Liesch explained. “Nevertheless, the study demonstrates that our personal care routines can influence the volatiles on our skin, which can impact our overall attractiveness to mosquitoes.”

He suggested some things people can do to avoid mosquitoes, besides buying different soaps. Above all, avoid places with high mosquito activity. You might want to switch up your outdoor activities and spend time on a screened-in porch, for example. You can also install fans if you are having a summer party outside in your garden to create air movement that could disperse insects.

“With their small body mass, mosquitoes may find it difficult to reach you if you are sitting near a fan. Additional options include wearing long-sleeved clothing to prevent mosquitoes from coming into contact with the skin and the use of EPA-registered repellents such as DEET, picaridin, IR3535, or lemon oil eucalyptus,” he said. Standing water in your garden can also be an important way to reduce local mosquito populations in your garden.

Liesch noted two takeouts. First, we don’t really understand all of the factors that come into play when it comes to mosquitoes’ attraction to humans. We don’t know if changing our self-care routine could change the way a mosquito reacts to us. Additionally, he said research like this could play an important role in the development of new and better mosquito repellents.

For Dr Vinauger, the new study offers “proof of concept that soaps interact with our body odor”. That being said, he and his team are looking for funds to add more volunteers and more types of soap to gain “a better understanding of the chemical processes involved.”

“The next big question for us is how long do these effects last? ” he said. “If I take my shower in the morning, does that still matter for the mosquitoes that I will encounter at the end of the evening?