Climate and satellite indicators to forecast Rift Valley fever epidemics in Kenya

All known Rift Valley fever virus outbreaks in East Africa from 1950 to May 1998, and probably earlier, followed periods of abnormally high rainfall. Analysis of this record and Pacific and Indian Ocean sea surface temperatur e anomalies, coupled with satellite normalized difference vegetation index data, shows that prediction of Rift Valley fever outbreaks may be made up t o 5 months in advance of outbreaks in East Africa. Concurrent near-real-tim e monitoring with satellite normalized difference vegetation data may ident ify actual affected areas.