Identifying malaria elimination strategies in the presence of human movement in Bangladesh

Abstract

Background: Malaria transmission in the Chittagong Hill Tracts (CHT) districts in Bangladesh is characterized by considerable heterogeneity in incidence and the frequent mixing and importation of parasites across districts. Thus, elimination efforts must account for human mobility between endemic and non-endemic locations, and the relative importance of local transmission and parasite importation domestically. Methods: We construct a metapopulation malaria model, parameterized by human mobility data and fit to epidemiological data, to guide elimination efforts in the region. Results: We find substantial heterogeneity in the transmission intensity across the CHT, with the estimated basic reproduction number varying greatly across places with similar levels of observed incidence. When vector control interventions are applied locally, the greatest impact in reducing overall incidence are in places with both high transmission intensity and high connectivity with more populated districts in the western part of the CHT. Conclusions: Local elimination in several areas with low or intermediate incidence has a moderate impact in reducing overall incidence, indicating that only focusing on high incidence areas is not sufficient for malaria elimination. More generally, our modeling framework can be used to prioritize resource allocation and identify the conditions necessary for malaria elimination in the region.