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.
PIP: This paper assesses the impact of microdam construction on the incidence of malaria in nearby communities in Tigray, Ethiopia, in terms of possibly increasing peak incidence and prolonging transmission. Four quarterly cycles of malaria incidence surveys, each taking 30 days, were undertaken in eight at-risk communities close to dams paired with eight control villages at similar altitudes but beyond the flight range of mosquitoes. Samples included about 700 children under 10 years of age living in villages within 3 km of microdams and in control villages 8-10 km distant. Results showed that the overall incidence of malaria for the villages close to the dams was 14.0 episodes/1000 child-months at risk compared with 1.9 in the control villages. Incidence was significantly higher in both communities at altitudes below 1900 m. This paper suggests the need to address health issues in the implementation of ecological and environmental development programs, specifically regarding appropriate malaria control measures to counteract the increased risks near these dams.