Plasmodium and Other Parasites in Pregnant Women and Children Around Margibi and Montserrado Counties, Liberia

Malaria caused by Plasmodium falciparum continues to be a global problem with devastating consequences, in particular for at-risk populations such as pregnant women and young infants. Pregnancy malaria is associated with low birth weight (LBW), maternal anemia, and gestational hypertension; both inflammation and the fetal response to infection may contribute to these poor outcomes. Placental malaria (PM) is caused by P. falciparum-infected erythrocytes that bind to the placental receptor chondroitin sulfate A (CSA) and sequester in the placenta, where they cause disease and may lead to death of the mother and her offspring. Women become resistant to PM as they acquire antibodies that target surface proteins of placental parasites. In areas of stable transmission, acute severe malaria syndromes are limited to children under 5 years of age. The pathogenesis of severe malaria remains poorly understood, although some evidence suggests that parasites causing severe malaria may express distinct antigens on the surface of infected erythrocytes. Thus, vaccines to prevent malarial disease may need to target distinct antigens in order to protect pregnant women or young children.

The primary hypothesis in this study is that the burden of P. falciparum infection around Margibi and Montserrado is sufficient to support future studies of malaria pathogenesis and immunity. In addition to assessing malaria burden this study will build up diagnostic laboratory capacity for malaria diagnostics. We plan to enroll 2920 pregnant women and 2920 children (6-12 months of age) into a cross sectional study that will be conducted in Margibi and Montserrado counties, Liberia. Women presenting for routine antenatal visits and presenting for well-baby clinic visits (e.g. vaccinations, vitamins) at C.H. Rennie Hospital in Margibi or Duport Road Health Center in Montserrado will be enrolled. Samples collected from the women and children will be examined for evidence of infection by Plasmodium and other parasitic diseases in order to assess prevalence in this key reservoir population. For our primary outcome, we will determine the prevalence of P. falciparum infection in these two key demographic groups, including their annual and seasonal variations, as these data will form the basis to design future natural history or interventional studies at these sites. For our secondary outcomes, we will determine the prevalence of other parasitic diseases, such as filaria, S. stercoralis, and schistosomes by serologic assays of blood samples.