This site is intended for healthcare professionals

Sign in
Go to /sign-in page

You can view 5 more pages without signing in

Japanese B encephalitis

Authoring team

Japanese encephalitis (JE) is a mosquito-borne (Culex tritaeniorhynchus) infection caused by a single-serotype RNA flavivirus (1).

  • tend to occur in wet areas (rice paddies and other open water sources) where Culex tritaeniorhynchus (and similar species) lay eggs
  • pigs and aquatic birds are important as principal vertebrate amplifying hosts
  • is not transmitted from person to person (2)
  • humans rarely develops enough viremia to infect feeding mosquitoes (dead-end JE virus hosts)
  • <1% of human JEV infections result in JE (1)

The infection risk to travellers is 1:5000/month if living more than a month in rural areas during the season

It rarely (1 in 300 cases) proceeds to encephalitis but tends to be more serious in non-immune older patients. It is a greatly-feared disease, fatal in 25% of cases and causing parkinsonism, paralysis and retardation in 30-70% of survivors. It also causes abortion and foetal death.

Japanese and other children are routinely immunised.

Reference:

  1. Campbell GL et al. Estimated global incidence of Japanese encephalitis: a systematic review. Bull World Health Organ. 2011;89(10):766-74
  2. Immunisation Against Infectious Disease - "The Green Book". Chapter 20 Japanese encephalitis (January 2013, updated February 2024)

Related pages

Create an account to add page annotations

Create a free account

Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.