Mosquitoes are attracted to the smell of bacteria on human feet.

The attraction between mosquitoes and human feet is primarily driven by Brevibacterium linens, a bacterium that thrives in moist, warm environments. This specific microbe is responsible for the pungent odor of human feet and is also used in the industrial fermentation of Limburger cheese. Research conducted by Dutch scientist Bart Knols in the 1990s first highlighted this connection, earning him an Ig Nobel Prize in 1996 for his study on the preference of the Anopheles gambiae mosquito.The Anopheles gambiae mosquito is a major carrier of malaria and has evolved to seek out human hosts by detecting carbon dioxide and specific skin volatiles. In controlled laboratory experiments, Knols demonstrated that these mosquitoes were significantly more attracted to the smell of Limburger cheese and sweaty feet than to other parts of the body. The bacteria consume dead skin cells and sweat, releasing methanethiol and other sulfur-containing compounds that act as chemical beacons for the insects.While carbon dioxide helps mosquitoes find a host from a distance, skin odors like those from foot bacteria help them decide exactly where to land and bite. Studies published in journals like 'The Lancet' have confirmed that individuals with a higher diversity of skin microbes are often less attractive to mosquitoes, whereas those with high concentrations of specific bacteria like Brevibacterium are bitten more frequently. Understanding these chemical interactions helps researchers develop more effective traps and repellents to combat mosquito-borne diseases.