Incidence of malaria among children living near dams in northern Ethiopia: community based incidence survey

Abstract Objective: To assess the impact of construction of microdams on the incidence of malaria in nearby communities in terms of possibly increasing peak incidence and prolonging transmission. Design: Four quarterly cycles of malaria incidence surveys, each taking 30 days, undertaken in eight at risk communities close to dams paired with eight control villages at similar altitudes but beyond flight range of mosquitoes. Setting: Tigray region in northern Ethiopia at altitudes of 1800 to 2225 m. Subjects: About 7000 children under 10 years living in villages within 3 km of microdams and in control villages 8-10 km distant. Main outcome measures: Incidence of malaria in both communities. Results: Overall incidence of malaria for the villages close to dams was 14.0 episodes/1000 child months at risk compared with 1.9 in the control villages—a sevenfold ratio. Incidence was significantly higher in both communities at altitudes below 1900 m. Conclusions: There is a need for attention to be given to health issues in the implementation of ecological and environmental development programmes, specifically for appropriate malaria control measures to counteract the increased risks near these dams. Key messages Environmental development may have important effects on the epidemiology of vector borne diseases such as malaria This may be particularly important where disease transmission is unstable—for example, in highland areas Children in villages near recently constructed microdams in northern Ethiopia had a significantly increased risk of malaria It seems that this irrigation development programme is leading to increased malaria transmission across a range of altitudes and seasons Intersectoral collaboration is necessary in development projects that may affect communities both positively and negatively