Undernutrition enhances host attractiveness to mosquitoes and transmission of mosquito-borne diseases.

Undernutrition is prevalent in regions affected by mosquito-borne diseases. Understanding how insufficient nutrition affects the transmission of mosquito-borne pathogens is critical for combating these diseases. In this study, we found that undernourished mice were more attractive to multiple mosquito vectors. Mechanistically, undernutrition impaired the secretion of antimicrobial fatty acids from dermal sebaceous glands, thereby leading to the excessive proliferation of certain skin commensal bacteria, which produced volatile aldehydes that act as potent mosquito attractants. Furthermore, undernutrition rendered mice more susceptible to mosquito-borne pathogens, such as dengue virus (DENV), thus facilitating the transmission of DENV both to and from mosquitoes. Consistently, undernourished human subjects exhibited similar skin microbiota alterations and elevated aldehyde emissions and were more attractive to mosquitoes. Our study suggests that undernutrition may be a key driver of the transmission of mosquito-borne diseases in nature and highlights the necessity of addressing undernutrition in regions where such diseases are prevalent.