Carrying diseases such as malaria, West Nile virus and yellow fever, a few species of mosquitoes are responsible for more than one million deaths each year. Certain species of mosquitoes actually prefer feeding on humans, and even show preferences between people. A common wives’ tale suggests to kids that mosquitoes prefer sweeter blood (“eat more veggies!”). However, there is no scientific evidence supporting changing your diet (e.g. eating garlic, increasing vitamin B intake, avoiding bananas) as a method for avoiding mosquito bites. Instead, mosquitoes appear to be selectively targeting people based on their skin microbiota. Microbiota refer to the bacteria that naturally reside in or on the human body. Our skin alone is home to over 1000 different species of bacteria. After puberty, the composition of our individual microbiomes tend to stay constant, even with continuous exposure to new bacteria in the surrounding environment.
According to recent studies, our skin microbiota produce a combination of volatile compounds that determines a mosquito’s blood host preference. Researchers identified individual bacteria species on people’s skin using species-specific RNA sequences, like using fingerprints to identify individual humans. Once the bacteria in a person’s skin microbiome had been accounted for, researchers found that the presence and abundance of certain species of bacteria were correlated with a person’s attractiveness to mosquitoes. Interestingly, the combination of volatiles that are considered ‘attractive’ may differ based on the species of mosquito.
These findings are only correlational and there may be other factors that determine a person’s attractiveness to mosquitos. For example, genetics determining body odor likely play a role. The exact mechanisms that determine the composition of the skin microbiome and the volatile compounds produced are not yet known, but one could imagine targeting specific species of bacteria in the skin microbiota as a potential long-term mosquito repellent.
Managing Correspondent: Jeremy Gungabeesoon
News Article: Why Mosquitoes Bite Some People More Than Others. The Conversation
Original Article: Chemical signaling in mosquito–host interactions: the role of human skin microbiota. Current Opinion in Insect Science
Image Credit: Max Pixel