What is the potential impact of insecticide treated nets in a semi-arid region of northern Kenya? An investigation of vector populations prior to ITN roll-out in Turkana, Kenya

Abstract The malaria ecology of northern Kenya differs from the rest of the country. Transmission is highly seasonal and intense, despite the arid environment and low population density. The region faces several threats to malaria control including identification of significant P. vivax infection and an emerging invasive species, An. stephensi. Turkana County implemented its first mass bednet distribution in late 2024. Prior to this, we established a surveillance program to understand mosquito density, vector diversity, host preference and contribution to malaria transmission. We captured mosquitoes in rural and peri-urban areas, indoors and outdoots, over one year. Twenty-percent of female anophelines were captured outdoors but P. falciparum infection was higher in outdoor collections. An. coluzzi, a vector commonly found in West Africa, was the second most abundant species and had the highest P. falciparum infection rates. These data will be useful in predicting the impact of ITN distribution in this unique context.