Most people infected by the Japanese encephalitis virus do not develop any symptoms. However, approximately one in 200 infections result in severe brain inflammation.
Japanese encephalitis (JE) is a brain infection that infects both humans and animals. The disease is caused by a Flavivirus (a genus of viruses in the family Flaviviridae) that affects the brain, causing inflammation that is potentially fatal. Epidemics of encephalitis were described in Japan from the 1870s onwards. The JE virus was first isolated in 1935, and has subsequently been found across most of Asia.