Japanese encephalitis

Japanese encephalitis is a virus that can cause inflammation of the brain. Most cases occur in Asia – it is not found in Africa or Central or South America. The infection is quite rare, but the serious form has a fatality rate of 30%. There is a major outbreak of Japanese encephalitis every 2-15 years.


Sudden fever, with vomiting and neck stiffness, sometimes leading to confusion, agitation and coma.

How do you catch Japanese encephalitis?

The disease is spread by infected mosquitoes, which bite between dusk and dawn. Japanese encephalitis mainly occurs in rural agricultural areas.

Incubation period

5 – 15 days


Diagnosis is confirmed by blood tests


Japanese encephalitis can be prevented by taking steps to avoid mosquito bites. A vaccine is available prior to travel following assessment by a travel nurse.


There is no cure for Japanese encephalitis. Supportive treatment aims to relieve symptoms and manage any complications.