Insecticide resistance and population structure of the invasive malaria vector,Anopheles stephensi, from Fiq, Ethiopia

Abstract

AbstractAnopheles stephensiinvasion in Ethiopia poses a risk of increased malaria disease burden in the region. Thus, understanding the insecticide resistance profile and population structure of the recently detectedAn. stephensi population in Fiq, Ethiopia, is critical to inform vector control to stop the spread of this invasive malaria species in the country. Following entomological surveillance forAn. stephensiin Fiq, Somali region, Ethiopia, we confirmed the presence ofAn. stephensimorphologically and molecularly in Fiq. Characterization of larval habitats and insecticide susceptibility tests revealed that FiqAn. stephensiis most often found in artificial containers and is resistant to most adult insecticides tested (organophosphates, carbamates, pyrethroids) except for pirimiphos-methyl and PBO-pyrethroids. However, the immature larval stage was susceptible to temephos. Further comparative genomic analyses with previousAn. stephensi populations from Ethiopia using 1,704 biallelic SNPs revealed genetic relatedness between FiqAn. stephensiand east-central EthiopiaAn. stephensipopulations, particularly JigjigaAn. stephensi. Our findings of the insecticide resistance profile, coupled with the likely source population of FiqAn. stephensi, can inform vector control strategies against this malaria vector in Fiq and Jigjiga to limit further spread out of these two locations to other parts of the country and continent.