To the Editor: West Nile virus is endemic in Israel. The overwhelming majority of infections are mild and asymptomatic, but there have been periodic symptomatic outbreaks (1). In August 2000, an epidemic of West Nile virus broke out in Israel, with> 260 confirmed cases and 20 deaths by the end of September 2000. Hitherto, the only treatment for this condition has been supportive with no proven in vivo specific therapy, although ribavirin has shown promise in in vitro studies (2). We report an apparent dramatic response to intravenous immunoglobulin in an immunosuppressed patient and suggest that this was the result of specific antibodies in the Israeli immunoglobulin used.

A 70-year-old woman was admitted to the hospital because of fever and vomiting of 24 hours’ duration. She had a 12-year history of chronic lymphatic leukemia (Rai stage II) but was not on treatment. A routine outpatient assessment 1 week earlier had shown no unexpected findings.