Spatio-temporal Patterns of Drug Resistant Malaria in Democratic Republic of Congo
There are important gaps in the knowledge about how malaria spreads that pose obstacles to successful and sustained control and elimination. This study is an extension of previous work in which investigators used 8,838 dried blood spots from the 2007 Demographic Health Survey (DHS) in the Democratic Republic of the Congo (DRC) to map Plasmodium falciparum malaria prevalence. The goal is to measure the movement of genetic markers (gene flow) to understand the factors that prevent transmission (barriers) or promote it (corridors). Barriers can be caused by humans, such as malaria control programs, or they can be natural, such as mountains that restrict mosquito vector habitat because of cool temperatures. Corridors can also be created by humans, such as roads, or they can be natural, such as rivers used for transportation. To achieve the goals of this study, researchers use existing data and specimens from the DRC, a country with high but spatially variable malaria endemicity. The project takes advantage of existing DNA samples from the large population-based 2007 and 2013 DHS data, each involving >10,000 people in geocoded survey clusters. Researchers measure relationships between genetic and geographic distance of Plasmodium falciparum malaria parasites in different areas of the DRC. They hypothesize isolation by distance; i.e., genetic relatedness decreases with geographic distance, which they measure as Euclidean and river/road network distances. They will also determine whether the genetic distances are different for drug-sensitive compared to drug-resistant strains. They hypothesize little or no genetic distances between clusters for resistant strains, which have emerged only recently. Lastly, they will identify factors that prevent or promote diffusion of drug-sensitive and drug-resistant malaria parasites. They hypothesize that malaria control programs, transportation routes, human migration patterns, and other population-environment characteristics will affect diffusion of drug-resistant malaria. The results of this study can have a significant impact in the DRC and in other malaria-endemic countries. In the DRC, results will help target and evaluate interventions. The study also serves as a prototype for other malaria-endemic countries that could use their DHS dried blood spots similarly. This project combines spatial theory and methods, landscape genetics, and high-throughput molecular tools to provide information about how drug resistance diffuses over space and time.
Principal Investigator: Michael E. Emch
Funding Source: National Science Foundation
Grant Number: BCS-1339949
Funding Period: 9/1/2013 - 2/28/2017
Primary Research Area: Population Health