Forecasting, warning, and detection of malaria epidemics: a case study.

Our aim was to assess whether a combination of seasonal climate forecasts, monitoring of meteorological conditions, and early detection of cases could have helped to prevent the 2002 malaria emergency in the highlands of western Kenya. Seasonal climate forecasts did not anticipate the heavy rainfall. Rainfall data gave timely and reliable early warnings; but monthly surveillance of malaria out-patients gave no effective alarm, though it did help to confirm that normal rainfall conditions in Kisii Central and Gucha led to typical resurgent outbreaks whereas exceptional rainfall in Nandi and Kericho led to true malaria epidemics. Management of malaria in the highlands, including improved planning for the annual resurgent outbreak, augmented by simple central nationwide early warning, represents a feasible strategy for increasing epidemic preparedness in Kenya.