ASIA Outbreak of West Nile Virus Infection

Abstract

From July 25 to October 1, 1999, 826 patients were admitted to Volgograd Region, Russia, hospitals with acute aseptic meningoencephalitis, meningitis, or fever consistent with arboviral infection. Of 84 cases of meningoencephalitis, 40 were fatal. Fourteen brain specimens were positive in reverse transcriptase-polymerase chain reaction assays, confirming the presence of West Nile/Kunjin virus. West Nile (WN) virus is a member of the Japanese encephalitis (JE) antigenic complex of the genus Flavivirus, family Flaviviridae. Mosquito-borne WN virus fever is endemic in Africa, the Middle East, and Southwest Asia. The antigenically and genetically related Kunjin virus is a WN virus counterpart in Australia and Southeast Asia and has recently been taxonomically classified as a subtype of WN virus. Until recently, WN virus infection in humans was considered a relatively mild, influenzalike disease with full recovery, although occasionally