Japanese Encephalitis

Japanese encephalitis is an infection of the brain caused by the Japanese encephalitis virus. Most infections cause little or no symptoms, but occasionally the brain becomes inflamed, bringing headache, vomiting, fever, confusion and seizures about 5 to 15 days after infection. The virus is generally spread by mosquitoes of the Culex type, with pigs and wild birds serving as a reservoir. The disease occurs mostly outside cities, primarily in East and Southeast Asia and the Western Pacific, and it was first described in Japan in 1871. A safe and effective vaccine prevents it; once infected there is no specific treatment and care is supportive, and permanent problems occur in up to half of the people who recover.