top of page

Japanese Encephalitis

Japanese encephalitis is a type of viral brain infection that is spread through mosquito bites. It can cause swelling of the brain resulting in permanent brain damage or death. The World Health Organisation (WHO) estimates that there are around 68,000 cases of Japanese encephalitis worldwide each year. It’s very rare for travellers from outside risk areas to be affected by Japanese encephalitis. The people most at risk are those who live and work in rural areas where the condition is widespread.

Japanese traditional building on close left view with city in the background and peak of snowy topped mountain farther back


Symptoms usually develop between 5 to 15 days after being bitten. In most people the virus either causes no symptoms or flu like illness. Some people also develop more obvious and severe symptoms. These initially include symptoms include, a high temperature (fever) headache, feeling and being sick, diarrhoea and muscle pain.

Asset 2.png

High Temperature

Asset 4.png


Asset 6.png

Feeling Sick

Asset 34.png


Asset 5.png

Muscle Pain

The infection can then spread to the brain (encephalitis) causing more serious symptoms such as seizures, stiff neck, muscle weakness, changes in mental state and even slipping into a coma. Those that develop severe symptoms can be left with disability, permanent brain or death.  

Asset 33.png


Asset 24.png

Stiff Neck

Asset 5.png

Muscle Weakness

Asset 26.png

Mental Health Changes

Asset 30.png


Countries at risk

It's most common in rural areas throughout South East Asia, the Pacific islands and the Far East. Most cases occur in China, Myanmar (Burma), Thailand, Vietnam, Cambodia, Laos, Nepal, India, Philippines, Sri Lanka, Malaysia and Indonesia. Despite its name, Japanese encephalitis is now relatively rare in Japan, due to mass immunisation programmes.Risk is highest for travellers living or travelling in high risk areas for long periods, visiting rural areas, particularly during the rainy season or fieldwork, camping or cycling in rural areas. These activities means you are more likely to come in contact with infected mosquitoes.

Advice for travellers

The risk of becoming infected with Japanese encephalitis is highest during and after the rainy season, when numbers of mosquitoes increase suddenly. It may be useful to find out when the rainy season is when planning your trip, before booking your holiday. You also need to protect yourself from mosquito bites when travelling to high risk areas by:
• Sleeping in rooms with close-fitting gauze over the windows and doors
• If this is not possible or you are sleeping outside, use mosquito nets that have been impregnated with an insecticide, such as permethrin
• Spraying your room with insecticide in the early evening to kill any mosquitoes that have got in during the day
• Cover up with long-sleeved tops, trousers and socks – mosquitoes that carry the Japanese encephalitis virus are usually most active at dusk and enjoy warm, humid conditions
• Wearing loose-fitting clothes, as mosquitoes can bite through skin-tight clothing 
• Applying a good-quality insect repellent to any exposed areas of skin  Various types of repellents are available. Many contain DEET (diethyltoluamide), but some are available that contain dimethyl phthalate, or eucalyptus oil if you are allergic to DEET.


Vaccination is recommended to anyone travelling to high risk areas or involved in high risk activities. The vaccination protects 90% of people who are given it. Please contact the travel clinic six to eight weeks before travelling to check if you need vaccination. A course of two injections may be recommended for full protection, with the second dose being given 28 days after the first. If you continue to be high risk a booster can be given 12 to 24 months after the first course.  

Number of doses

From 2 months: Two doses

Second dose administered 28 days after first (or 7 days if insufficient time).



For over 18 years second booster recommended 12-24 months after finishing the course



Meningitis ACWY For Hajj/Umrah

Meningitis symptoms can develop quickly and they can be difficult to spot as they as similar to symptoms of flu. Infection with meningitis is an emergency and requires admission into a hospital where you will be given antibiotics. All pilgrims to Saudi Arabia for Hajj or Umrah are required to show proof of vaccination in the last three years against meningitis ACWY.


Vaccination is required at least 10 days before you are due to travel and you will also receive a certificate as part of your vaccination.

bottom of page