Heterogeneous exposure and hotspots for malaria vectors at three study sites in Uganda

Heterogeneity in malaria transmission has household, temporal, and spatial components. These factors are relevant for improving the efficiency of malaria control by targeting heterogeneity. To quantify variation, we analyzed mosquito counts from entomological surveillance conducted at three study sites in Uganda that varied in malaria transmission intensity. Using a Bayesian zero-inflated negative binomial model, validated via a comprehensive simulation study, we quantified household differences in malaria exposure and examined its spatial distribution. We found that housing quality explained large variation among households in mosquito counts. In each site, there was evidence for hot and cold spots, spatial patterns associated with urbanicity, elevation, or other environmental covariates. We also found some differences in the hotspots in rainy vs. dry seasons or before vs. after control. This work identified methods for quantifying heterogeneity in malaria exposure and offered a critical evaluation of spatially targeting interventions at malaria hotspots.