Japanese Encephalitis

The Japanese encephalitis virus is one of the most common travel related diseases with around 50,000 cases per year. It is spread by infected mosquitos found primarily in South East Asia and the Far East. There is a vaccine available to prevent this potentially fatal disease, so it is advised to see your travel doctor well before travel to high risk countries.


Japanese encephalitis is transmitted by the bite of an infected mosquito. The incubation period is generally between 6 and 16 days so it’s important to see a doctor as soon as possible after a suspected infection. Japanese encephalitis can not be transmitted from person to person.


Symptoms of Japanese encephalitis vary depending on the severity of the infection but may include:

  • lethargy
  • neck rigidity
  • high fever
  • headache
  • disorientation
  • tremors
  • gastrointestinal symptoms


There is no specific therapy to treat Japanese encephalitis. Patient care focuses on treating the symptoms displayed.


There are two methods of prevention of Japanese encephalitis:

  1. Vaccination
    Immunisation against Japanese encephalitis involves a course of vaccinations over a 30 day period. The vaccine is given on days 0, 7, and 28. A booster vaccine is required every 3 years.
  2. Mosquito Avoidance
    If you find yourself in a high risk area and you haven’t been vaccinated, then you can follow these tips for mosquito avoidance:
    • Use an insect repellent.
    • Stay indoors between dawn and dusk.
    • Cover up with light coloured, loose fitting clothing.
    • Avoid strong scented soaps and perfumes.
    • When sleeping, use a mosquito net impregnated with insecticide.

High Risk Destinations

Your travel doctor can give you specifics about prevention of this virus and whether vaccination is required or advised in your case, however, the broad regions where your are most likely to find the infected mosquitos are:

  • South East Asia
  • Far East

Specific high risk countries vary depending on recent outbreaks. These countries may include:

  • Bali
  • Bangladesh
  • Cambodia
  • China
  • India
  • Indonesia
  • Malaysia
  • Myanmar
  • Nepal
  • Pakistan
  • Papua New Guinea
  • Thailand
  • Timor
  • Torres Strait islands
  • Vietnam

Visit your doctor to determine the best method of prevention or treatment for you.