Impacts of pregnancy on malaria transmission: where maternity meets the mosquito
The World Health Organization (WHO) estimates that in 2015 alone, malaria caused 212 million clinical episodes and 429,000 deaths, mostly in children under the age of five years. The WHO recently recommended that mass drug administration (MDA) be used to accelerate Plasmodium falciparum elimination in areas approaching zero endemic transmission. The success of these campaigns, however, rely on achieving high population coverage (>80%) over sustained rounds of treatment to target groups that are more infectious to mosquitoes. Young children and pregnant women are often excluded from MDA programs due to safety concerns associated with the drugs being administered. While the non-inclusion of young children (< 6 mo. old) may have a negligible effect on transmission, the contribution of pregnant women to population level transmission has not been explored mechanistically. Because pregnant women in highbirth rate African countries can represent a substantial proportion of the population (up to 1.7%), and relative to non-pregnant hosts support higher parasitemia, are more attractive to biting mosquitoes, and are predicted to contribute more than expected to malaria infection in mosquito populations, this proposal investigates mechanistically if pregnant women could be an overlooked and important reservoir for malaria transmission at the population level. We will use a combination of experimental and mathematical approaches contextualized in the rodent malaria model (P. chabaudi AS system) to address these questions. Products from the proposed research will be the following: 1) a mechanistic assessment on the relative impact of pregnancy on overall malaria transmission, 2) provide data to inform the design of correlational field studies in the P. falciparum – human system investigating the relative role of pregnant hosts on population-level malaria transmission, as well as public health interventions, and 3) will provide basic insights into other systems (e.g. Zika) where vector-borne disease transmission could have important health implications for pregnant mothers and their offspring.