Carboxylic Acid in Skin Drives the Attraction of Mosquitos to Humans

Mosquito bites are an important vector in the transmission of infectious diseases around the world. While it has long been recognized that some people are more attractive to mosquitos than others, the mechanism is unclear.

De Obaldia et al. tested Aedes aegypti mosquito attraction to human odor and found that some people were exceptionally attractive to mosquitos while others were unattractive, a difference that remained stable over years. Gas chromatography and mass spectrometry analysis of human-worn nylon sleeves showed carboxylic acid (pentadecanoic, heptadecanoic, and nonadecanoic acid) levels to be elevated in subjects highly attractive to mosquitos, a finding confirmed in a larger cohort. This attraction could be weakened by the addition of odor from subjects who were exceptionally unattractive to mosquitos. When CRISPR-Cas9 was used to generate mosquitos that lack certain chemosensory co-receptors, attraction to human scent was severely impaired. However, the mosquitos’ ability to discriminate subjects of high versus low attractiveness was retained.