Project Summary / Abstract – Burkina Faso ICEMR Project 2 Malaria control has been stagnating in Burkina Faso for years, including in vector control efforts. Insecticide resistance is widespread and modest, or inapparent malaria vector control has been achieve even from the deployment of next generation IRS and ITNs. To begin to reverse these trends, a reassessment of malaria vector bionomics and parasite transmission by mosquitoes in Burkina Faso is necessary, and the key goal of this Research Project 2 of the Burkina Faso ICEMR. Central to the issues is the diversity in ecozones within the country that vary in climate and vector diversity, from the northernmost Sahelian ecozone with a short but intense 2-3 month transmission season driven mostly by Anopheles coluzzii, to the southern Sudanian ecozone with a long rainy season lasting 5-6 months, extremely high human biting rates and sporozoite rates in vectors, persistent low levels of transmission during the dry season, and numerous vector species including An. gambiae s.s., An. coluzzi , An. funestus, An. nili, in rural regions and An. arabiensis in urban areas such as the city of Bobo-Dioulasso. This diverse set of highly competent and seasonally abundant vector species tend to occupy specific niches across ecological zones and vary in abundance across landscapes (rural village, towns and cities, migrant/artisanal gold mining camps) and seasons with different larval water sources. The variable spatiotemporal clustering of vectors, each vector species’ insecticide resistance status and their diverse and adaptable blood feeding habits and behaviors (e.g. endophily vs. exophily and endophagy vs. exophagy) have resulted in their resistance to indoor-applied vector control measures. New evidence from our RIMDAMAL II trial showing that An. gambiae s.l. preferentially transmits Plasmodium falciparum (Pf) sporozoites and An. funestus preferentially transmits P. ovale (Po) sporozoites likely increases the spatiotemporal heterogeneity and duration of human infections as does ours and others’ data showing antimalarials and sub-lethal insecticide exposure (including ivermectin) can influence sporogony outcomes. Our objectives in this project are to assess the natural vector bionomics and parasite transmission across spatio-temporal gradients in Burkina Faso in Aim 1, and to perform laboratory experiments of parasite transmission to validate our field findings in Aim 2, which will use natural parasite infections and mosquitoes with wild-type genetics, and also expose the infected mosquitoes to sub-lethal insecticide concentrations or drugs that the vectors are likely to encounter during the extrinsic incubation period in the field.