This Web site contains the most recent West Nile virus data from the Centers for Disease Control. The main features include a 2003 Human Case Count and updated maps representing the spread of the virus. A downloadable document outlines the CDC's West Nile virus surveillance and control program, which involves weekly data collection for wild birds, sentinel chicken flocks, human cases, veterinary cases, and mosquito surveillance. The site also provides links to general information about the virus, from the ecology and virology of West Nile to epidemiological and laboratory issues.