Japanese encephalitis

Definition

A mosquito-borne viral disease of the central nervous system caused by Japanese encephalitis virus (JEV, family Flaviviridae), maintained in enzootic cycles between ardeid birds and Culex mosquitoes, with humans and domestic animals as dead-end hosts. In endemic regions of Asia and the western Pacific, clinical cases present with acute encephalitis, seizures, and high mortality or neurological sequelae; most infections are asymptomatic.

Etymology

From Japanese (first described in Japan, 1871) + encephalitis (Greek enkephalos 'brain' + -itis 'inflammation')

Example

In rice-growing regions of Southeast Asia, Culex tritaeniorhynchus and Cx. gelidus transmit JEV to amplifying hosts among wading birds; vaccination of pigs—the principal vertebrate amplifier near human settlements—reduces spillover risk to humans.

Synonyms

• JE

Related Terms

• Arbovirus
• vector competence
• Culex
• enzootic cycle
• flavivirus
• West Nile virus
• St. Louis encephalitis
• vaccine vector control

Usage Notes

Distinguished from other flavivirus encephalitides (West Nile, St. Louis encephalitis) by geographic range and primary mosquito vectors; 'Japanese' refers to historical origin, not current distribution, which extends across South and Southeast Asia to northern Australia. The term denotes the disease, not the virus (JEV).