A sensory appendage protein protects malaria vectors from pyrethroids

Pyrethroid-impregnated bednets have driven significant reductions in malaria morbidity and mortality in Africa since the beginning of the century (1). The intense selection pressure exerted by bednets has precipitated widespread and escalating pyrethroid resistance in African Anopheles populations, threatening to reverse gains made by malaria control (2). Here we show that a leg-enriched sensory appendage protein, SAP2, confers pyrethroid resistance in Anopheles gambiae. SAP2 expression is elevated in insecticide-resistant populations and is further induced upon mosquito contact with pyrethroids. SAP2 silencing fully restores mosquito mortality, whilst its overexpression results in increased resistance, likely due to the high-affinity SAP2 binding to pyrethroid insecticides. Mining of genome sequence data reveals a selective sweep near the SAP2 locus in three West African countries, with the observed increase in haplotype associated SNPs mirroring increasing resistance reported in Burkina Faso. Our study identifies a new insecticide resistance mechanism that is likely highly relevant to malaria control efforts.