Clinical characteristics of the West Nile fever outbreak, Israel, 2000

West Nile (WN) virus is endemic in Israel. The last reported outbreak had o ccurred in 1981. From August to October 2000, a large-scale epidemic of WN fever occurred in Israel; 417 cases were confirmed, with 326 hospitalizatio ns. The main clinical presentations were encephalitis (57.9%), febrile dise ase (24.4%), and meningitis (15.9%). Within the study group, 33 (14.1%) hos pitalized patients died. Mortality was higher among patients greater than o r equal to 70 years (29.3%). On multivariate regressional analysis, indepen dent predictors of death were age greater than or equal to 70 years (odds r atio [OR] 7.7), change in level of consciousness (OR 9.0), and anemia (OR 2 .7). In contrast to prior reports, WN fever appears to be a severe illness with high rate of central nervous system involvement and a particularly gri m outcome in the elderly.