Japanese encephalitis
![Disability-adjusted life year for Japanese encephalitis per 100,000 inhabitants in 2002
no data
less than 1
1-5
5-10
10-15
15-20
20-25
25-30
30-35
35-40
40-45
45-50
more than 50](/Images/godic/202501/21/Japanese_encephalitis_world_map_-_DALY_-_WHO2002.svg0553.png")
![The geographic distribution of Japanese encephalitis (in yellow)](/Images/godic/202501/21/Japanese_Encephalitis_Distribution0554.jpg")
Japanese encephalitis (JE), formerly known as Japanese B encephalitis to distinguish it from Economo's A encephalitis—is a disease caused by the mosquito-borne Japanese encephalitis virus (JEV).
The Japanese encephalitis virus (JEV) itself is a virus from the family Flaviviridae, part of the Japanese encephalitis serocomplex of 9 genetically and antigenically related viruses, some which are particularly severe in horses, and four known to infect humans including West Nile virus.