West Nile virus activity--United States, June 16-22, 2004.

As of June 22, 2004, seven states reported a total of 32 human cases of West Nile virus (WNV) illness to CDC through ArboNET. Twenty cases were reported from Arizona, six cases from California, two cases from Florida, and one case each from Nebraska, New Mexico, South Dakota, and Wyoming. Twenty-three (72%) of the cases occurred in males; the median age of patients was 52 years (range: 9-78 years), and dates of illness onset ranged from May 8 to June 7. Sixteen (50%) of the patients had neuroinvasive WNV illness, 14 (44%) had West Nile fever, and two (6%) had clinically unspecified illness.