Japanese Encephalitis (JE) Virus: Structure, life cycle, pathogenesis and diagnosis

Japanese Encephalitis (JE) virus was initially isolated in Japan in 1935. It is a leading cause of vaccine-preventable encephalitis (inflammation of the brain) in Asia and the western Pacific.

The virus is maintained in an enzootic cycle between mosquitoes and amplifying vertebrate hosts (mainly pigs). The highest risk months for JE transmission are August, September and early October.

Properties of JE Virus:

Structure of Japanese Encephalitis virus

Transmission Cycle of Japanese Encephalitis Virus 

Fig: Japanese Encephalitis Virus Life Cycle

Population at risk

In endemic countries: 

Clinical Feature (Sign/symptoms)

Diagnosis of Japanese Encephalitis

Diagnosis of Japanese encephalitis is based on a combination of clinical signs and symptoms and specialized laboratory tests of blood or CSF.


JE Vaccine