Japanese Encephalitis

Japanese encephalitis is a viral disease found in East Asia. The infection is spread by the bite of an infected mosquito. This particular type of mosquito favours breeding sites in and around rice paddies and piggeries.

Most cases occur after the monsoon seasons in China, Myanmar, Thailand, Vietnam, Cambodia, Laos, Nepal, India, Philippines, Sri Lanka, Korea, Malaysia, Indonesia and Singapore


Japanese encephalitis causes headache, convulsions, swelling of the brain and meningitis and symptoms usually occur five to 15 days after being bitten by an infected mosquito. Initially a flu-like illness may occur, which may progress to brain swelling, resulting in symptoms such as high fever, confusion, convulsions, headache, neck stiffness and paralysis. Japanese encephalitis can result in death or permanent brain damage and disability. Severe disease can cause permanent neurological damage. About 30% of those with signs of infection will die from the disease.


There is no specific therapy available for the treatment of Japanese Encephalitis. Intensive care supportive therapy may be required.

Recommendations for Travellers

Prevention is focused on avoiding mosquito bites, especially during the hours between dusk and dawn which is when this mosquito is most active. Use of insect repellents, appropriate clothing and mosquito nets is recommended for those at risk.

Tips on how to avoid mosquito bites

  • To avoid bites wear clothing that covers as much of the body as possible such as long sleeved clothing and long trousers. 
  • Mosquitoes may bite through thin clothing, so spray an insecticide or repellent on them. Insect repellents should also be used on exposed skin.
  • Burning pyrethroid coils and heating insecticide impregnated tablets all help to control mosquitoes. 
  • If sleeping in an unscreened room, or out of doors, a mosquito net (which should be impregnated with insecticide) is a sensible precaution. Nets that have pyrethroid incorporated into the material or bound to the material with resin have an expected life of 3-5 years and are superior to nets that require re-impregnation.
  • Portable, lightweight nets are available and any outdoor shops now stock nets and it can be helpful to practice erecting nets before departure.  
  • Garlic, Vitamin B and ultrasound devices do not prevent bites

The Japanese encephalitis vaccination is a course of two vaccines over 28 days and may be recommended for travellers considering outdoor activities in high-risk areas, especially during the transmission season. Individuals should consider being vaccinated if they are travelling to a country where Japanese encephalitis is present and where their stay may be prolonged or they are at increased risk of exposure to the disease e.g. staying in or around rice growing areas.

For more information please visit fit for travel.

We provide vaccinations by appointment at our clinics in Farnborough in Hampshire and Woking in Surrey. If inconvenient, please contact us to take advantage of our Mobile Clinic service.

Two dose course

Price per dose: £95.00

To make an appointment please click here

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