Japanese Encephalitis

Japanese Encephalitis

Japanese encephalitis is a serious viral disease spread by mosquitoes, which can be found in popular travel destinations in most of Asia, especially in rural areas. the risk in big cities is extremely modest.


Where are you at risk of becoming infected?

The disease is transmitted via the Culex mosquito, which most frequently bites at night from sunset to sunrise.

There is a particular risk of infection in rural areas near wetlands such as rice fields or near pig farms and wading birds.

The disease does not spread directly from person to person, and is thus exclusively transmitted by mosquitoes.

Which areas?

The disease is found exclusively in Asia, especially Sri Lanka, India, Southeast Asia and China. 

In some countries, there is a high season for infection in certain months that follow the rainy season, while in other countries, such as Indonesia and the Philippines, there is a risk of infection all year round.

Outbreaks can occur all year round, and the risk of the disease in individual countries can therefore change.

Find your destination on Medical's Vaccine Recommendations for further information.

What symptoms can be seen in Japanese encephalitis

Most people develop no symptoms of the disease and recover completely on their own.

However, one in 100 infected people develop Japanese encephalitis symptoms, which can be life-threatening. It is impossible to predict who is at risk of being severely affected


  • severe headache

  • nausea and vomiting 

  • neck stiffness 

  • cramps 

  • unconsciousness

What treatment is available for Japanese encephalitis?

There is no treatment for Japanese encephalitis. The patient's symptoms are treated to avoid serious side effects, which can be especially neurological.

How is Japanese encephalitis prevented?

The most effective prevention is vaccination against the disease, which is recommended for people traveling to risk areas - usually for stays of more than 4 weeks.

In addition, effective prevention is:

  • to use impregnated mosquito nets

  • to wear loose clothing that covers the arms and legs

  • to use bug spray with up to 50% DEET

  • you should avoid camping near stagnant water, lakes, rice fields and farms with pig farms

How do you get vaccinated against Japanese encephalitis?

The vaccine is called Ixiaro, is inactivated and has a protection duration of 1 year after 2 doses and ten years after three doses. 

Vaccination can be given from ≥ 2 months of age.

2 doses must be given before departure with an interval of up to 7 days for adults, and the last dose should be given > 1 week before departure. Children should receive the 2 doses 28 days apart. "Off label" the interval can be shortened.