A severe infection of the brain and spinal cord caused by the bite of a Culex mosquito carrying the JE virus. The disease is most common in rural, agricultural areas of east and southeast Asia (e.g., Okinawa, Burma, Cambodia, Laos, Thailand) where mosquito larvae inhabit flooded rice fields and marshes. These mosquitoes feed outdoors from dusk until dawn. Transmission is highest in summer and fall.
Japanese encephalitis is not transmitted from person-to-person. It is the leading cause of viral encephalitis in Asia with 30,000 to 50,000 cases reported annually.