The body wash you use in the shower can react with your natural odor and make it more attractive to mosquitoes.
Mosquitoes use various methods to find a target for their next blood meal, such as detecting an animal’s body heat, scent, and the carbon dioxide they emit.
To find out if the bath gel we use can have any effect, Clement Vinauger at Virginia Polytechnic Institute and State University and his colleagues selected varieties from the Dial, Dove, Native and Simple Truth brands.
First, they placed two nylon strips on one of the forearms of four volunteers and wrapped that area with aluminum foil to collect the natural odor of the participants.
Next, the researchers washed part of each participant’s other forearm with about 1 gram of one of the body washes for 10 seconds, before rinsing it with water for another 10 seconds. They then similarly applied two strips of nylon and aluminum foil to these forearms, to pick up the scent of washing. The researchers repeated this with the other three body washes.
One hour after each sample was taken, they took two strips, one from each of the body wash-exposed areas and one from the body wash-free areas, for chemical analysis, while the other exposed and body wash-free strips body wash were analyzed. put in separate cups.
The researchers placed these inside cages with 16 to 25 females. Aedes aegypti mosquitoes, which can transmit yellow fever, which were free to visit any of the canopies.
Simple Truth body wash appeared to increase the attractiveness of all participants, as measured by the number of times mosquitoes landed on strips exposed to body wash compared to strips without body wash. The Dove wash had a similar effect, but the increase in attractiveness was only pronounced for three of the participants.
Dial’s body wash made participants more attractive to mosquitoes, but less so than Simple Truth or Dove.
In contrast, mosquitoes tended to avoid strips washed with Native body wash, but displayed a particularly strong aversion to one participant’s Native washed strip.
This suggests that the fragrances of the body washes and the individual odors of the participants combined to create an odor that the mosquitoes detected.
“Our study highlights the importance of the interaction between the specific chemicals in soap and each person’s body odor in determining whether a person becomes more or less attractive to mosquitoes after soap is applied to the skin,” Vinauger says.
Chemical analysis of the experiment suggests that the compounds benzaldehyde, benzyl benzoate, and γ-nonalactone can repel mosquitoes.
The researchers plan to repeat their study with a larger group of participants and more body washes, and will investigate how long any potential mosquito-attracting or repelling effects of a wash last after it is removed from the skin.
“The discovery that personal care products can cause mosquitoes to be attracted to or repelled by the user opens the door for developing easy-to-use mosquito repellents,” he says. walter loyal from the University of California, Davis.
“The chemicals in such products may not directly affect mosquito behavior, but they may alter the specific proportion of human emissions that attract mosquitoes,” he says. “Regardless of the mechanism, reducing human-mosquito interactions mitigates the transmission of vector-borne diseases.”
new scientist reached out to the makers of the four body washes for comment, but did not hear back before publication.