Locally acquired West Nile encephalitis.

BACKGROUND: West Nile virus (WNV) has spread rapidly across the United States since 1999, causing epidemics of neurologic illnesses including meningitis, encephalitis, and acute flaccid paralysis. West Nile encephalitis can be fatal; recovery can be incomplete; and constitutional and neurological symptoms can persist for months to years. OBJECTIVES: To raise awareness of an important epidemiologic cause of febrile illness with neurologic involvement in the United States. CASE REPORT: We report the case of a 46-year-old woman who presented with fever, altered mental status, and maculopapular rash, who was diagnosed with locally acquired WNV encephalitis. CONCLUSION: Infection with WNV should be considered in patients presenting to emergency departments with fever and neurologic symptoms. Recommended evaluation includes serologic testing of cerebrospinal fluid and serum.