Health Advice

Japanese encephalitis

Japanese encephalitis is a rare but serious infection you can get from mosquito bites in some parts of the world. If you're travelling to an area where there's a risk of catching it, you can get a vaccine to help prevent it.

Check if you're at risk of Japanese encephalitis

Japanese encephalitis is not found in the UK. It's mostly found in rural areas of Asia, but it's rare for travellers to get it.

It's caused by a virus which is spread through mosquito bites.

Places where Japanese encephalitis is found include parts of:

  • India
  • China
  • Japan
  • South Korea
  • Indonesia
  • Southeast Asia (such as Thailand, Malaysia and Vietnam)

Check your travel risk

You can get health advice for a country you're travelling to on the TravelHealthPro website.

How to lower your risk of Japanese encephalitis

There are some things you can do to avoid mosquito bites when travelling to areas with a risk of Japanese encephalitis.

Do

  • use insect repellent on exposed skin, ideally containing at least 50% DEET

  • sleep under a mosquito net treated with insecticide

  • when possible, wear long-sleeved tops, trousers or long skirts, socks and shoes to protect your skin from mosquito bites

  • get advice from a travel vaccination clinic before you travel

Japanese encephalitis vaccine

A vaccine for Japanese encephalitis is recommended if you're travelling to a part of the world where the virus is found, especially if:

  • you're staying for more than a month
  • you're staying in a rural area
  • you're staying near or visiting rice fields, wetlands, or places where pigs are kept

You'll have to pay for the Japanese encephalitis vaccine. You can get it from travel health clinics and pharmacies with travel health services.

Symptoms of Japanese encephalitis

Most people who get Japanese encephalitis have no symptoms.

Some people get flu-like symptoms such as:

  • a headache
  • a high temperature
  • feeling or being sick
  • tummy pain

The symptoms usually go away on their own, but in some people the infection spreads to the brain and causes more serious symptoms such as:

  • a severe headache
  • feeling confused
  • not being able to feel or move parts of your body (paralysis)
  • seizures (fits)

Ask for an urgent GP appointment or get help from NHS 111 if:

You've recently travelled to an area where Japanese encephalitis is found and you have flu-like symptoms such as:

  • a headache
  • a high temperature
  • feeling or being sick
  • tummy pain

Tell anyone you speak to about your recent travel, and if you were bitten by a mosquito or might have been.

You can call 111 or get help from 111 online.

Call 999 if you or someone else has:

  • a severe headache and a stiff neck
  • sudden confusion (for example, not being sure of your name, age, or where you are)
  • sudden weakness or suddenly not being able to feel or move part of your body (paralysis)
  • a seizure (fit)
  • loss of consciousness
  • severe difficulty breathing

Important

Get medical advice quickly if you have Japanese encephalitis symptoms while you're travelling.

Treatment for Japanese encephalitis

You'll need to be treated in hospital if you're seriously unwell because Japanese encephalitis can be life-threatening.

Treatments for Japanese encephalitis include medicines to help relieve the symptoms, such as painkillers and steroids.

Japanese encephalitis can sometimes cause long-term complications such as paralysis, seizures, and loss of speech.