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

West Nile (WN) virus was first isolated and identifiedfrom the blood of a febrile woman in Uganda in 1937 (1); feverwas her only known symptom. In the early 1950s, severalreports from outbreaks in Israel were the first to detail theclinical characteristic of this illness; the clinical picture thatemerged was that of a benign febrile disease in young adults(2,3). In a later outbreak from Israel in 1957, a linkage betweenWN virus infection and severe central nervous system (CNS)disease was first noted, and a correlation between the age ofpatients and severity of disease was established (4).In the last decade, two outbreaks gained attention: thefirst from Romania in 1996, where a high percentage of CNSinvolvement was noted, and the second from New York in1999, in which several cases of flaccid paralysis weredescribed (5,6). The outbreak in New York was the first timeWN fever was reported in the Western Hemisphere (7).From August to October 2000, 417 laboratory-confirmedWN fever cases occurred in Israel; 326 were hospitalizedcases. We collected clinical data on 233 of the hospitalizedpopulation from 12 different hospitals throughout the country.We report the clinical characteristics of these patients.