The specific combination of your soap scent and body odour can either attract or repel mosquitoes. — Soap Artisan
It's called break-bone fever by some – and for good reason.
Dengue fever, for sure, is not something you want to catch.
Perhaps worse again is yellow fever, which leaves an estimated 12% of sufferers with jaundice.
Small percentages of those infected by either can develop severe haemorrhagic infections that can prove fatal.
Both fevers are caused by viruses carried by the Aedes aegypti mosquito.
And while there is a yellow fever vaccine, which is required for entry into many African and Latin American countries, there is no widely used equivalent for dengue.
But what if a thorough scrub with a well-known soap brand could put the mosquitoes off their lunch for long enough to prevent transmission?
It could be possible, going by experiments by a team from Virginia Tech in the United States, who had their findings published in the journal iScience this month (May 2023).
Washing with some soaps attracts A. aegypti mosquitoes, it seems, while other soaps drive the bloodthirsty insects away.
But that is only half the story.
The effects of soap on the mosquitoes’ palates varied between different people and depended on “interactions between the soaps and each person’s unique odour profile”.
A person can “be extremely attractive to mosquitoes” while unwashed, then can be made even more attractive to mosquitoes with one type of soap, while repelling them with another brand, the team found.
The scientists first categorised the chemical odours emitted by four human volunteers, first when unwashed and then after washing with four brands of soap, i.e. Dial, Dove, Native and Simple Truth.
“What really matters to the mosquito is not the most abundant chemical, but rather the specific associations and combinations of chemicals, not only from the soap, but also from our personal body odours,” said senior author and neuroethologist Clément Vinauger.
“Everybody smells different, even after the application of soap; your physiological status, the way you live, what you eat, and the places you go all affect the way you smell,” added co-author and biologist Chloé Lahondère.
Vinauger suggested that coconut-scented soaps could perhaps be the best all-round bet to keep mosquitoes at bay. – dpa
