Publications

Despite the use of accepted interventions to combat malaria, such as insecticide-treated bed nets and artemisinin-based combination therapy, malaria remains a leading cause of morbidity and mortality in Uganda. We investigated associations between household factors and malaria incidence in a cohort of children living in a highly endemic region of Uganda. Living in a modern house, defined as the use of non-earth floors, non-thatched roofs, and non-mud walls, was associated with approximately half malaria incidence compared with living in a traditional home (incidence rate ratio [IRR] = 0.54, P = 0.001). Other factors found to be associated with a lower incidence of malaria included living in town versus rural setting; sleeping in a room with openings to the outside (windows, eaves, and airbricks); and having an older and more educated primary caregiver. This study adds to the growing body of evidence that improved house construction may be associated with a lower risk of malaria.

The intensification of control interventions has led to marked reductions in malaria burden in some settings, but not others. To provide a comprehensive description of malaria epidemiology in Uganda, we conducted surveillance studies over 24 months in 100 houses randomly selected from each of three subcounties: Walukuba (peri-urban), Kihihi (rural), and Nagongera (rural). Annual entomological inoculation rate (aEIR) was estimated from monthly Centers for Disease Control and Prevention (CDC) light trap mosquito collections. Children aged 0.5-10 years were provided long-lasting insecticidal nets (LLINs) and followed for measures of parasite prevalence, anemia and malaria incidence. Estimates of aEIR were 2.8, 32.0, and 310 infectious bites per year, and estimates of parasite prevalence 7.4%, 9.3%, and 28.7% for Walukuba, Kihihi, and Nagongera, respectively. Over the 2-year study, malaria incidence per person-years decreased in Walukuba (0.51 versus 0.31, P = 0.001) and increased in Kihihi (0.97 versus 1.93, P < 0.001) and Nagongera (2.33 versus 3.30, P < 0.001). Of 2,582 episodes of malaria, only 8 (0.3%) met criteria for severe disease. The prevalence of anemia was low and not associated with transmission intensity. In our cohorts, where LLINs and prompt effective treatment were provided, the risk of complicated malaria and anemia was extremely low. However, malaria incidence was high and increased over time at the two rural sites, suggesting improved community-wide coverage of LLIN and additional malaria control interventions are needed in Uganda.