The Tradeoff of Nutrition in Malaria Transmission

Nathan Garcia-Diaz, a student from Willamette University, worked in the lab of Dr. Ash Pathak.

Abstract The effects of nutrition on malaria transmission was studied by collecting the most influential components of Vectorial Capacity. Vectorial Capacity (C) measures the Anopheline mosquito’s efficacy at transmitting the Plasmodium berghei parasites, and the largest factors impacting C are Extrinsic Incubation Period (EIP) and Vectoral Survival Probability (VSP). In order to force the mosquito to decide where to allocate nutrients, four conditions were created by combining two different treatments: Low Nutrient Treatment (1% Dextrose) and High Nutrient Treatment (10% Dextrose); Gravid (No Oviposition Site) and Not Gravid (Oviposition Site). Data was collected for EIP by examining sporozoite prevalence, and VSP was measured by mosquito mortality at fixed intervals after the infectious blood meal. To gain a more comprehensive notion on mosquitoes’ infectiousness, sporozoite density was measured alongside the other variables. The results from VSP data indicate that mosquitoes were most likely to survive if given the high nutrient treatment, and less likely to survive if the mosquitoes had the not gravid status. Additionally, when comparing EIP data between Gravid and Not Gravid statuses in the low nutrient treatment, gravid mosquitoes were infected sooner and at a higher rate than the not gravid counterparts. This pattern was seen again in the parasite density, gravid mosquitoes being more infectious than not gravid mosquitoes. It can be concluded that when infected mosquitoes are in a nutrient deficient state, gravid mosquitoes prioritize caring for its progeny rather than assembling an immunological response.