Japanese Encephalitis

Japanese Encephalitis | Health Guide & Blog | Travelpharm Online Pharmacy

Japanese Encephalitis


Japanese Encephalitis (JE) is a viral related mosquito-borne disease spread by the flaivirus. The culex mosquito bites the host and infects them with the virus. They are mainly found in rural areas where rice and pig farming is popular. This leads to a serious swelling of the brain, known as Encephalitis, eventually resulting to death.

Geographical and seasonal patterns affect the spread of disease annually. The number of infection cases increase mainly after the monsoon seasons, when mosquitoes are more active (especially in the South-East Asia region).

The disease is not passed on from person to person.

The cycle of incubation usually is around 5-15 days. Approximately 20-30% of infection cases will result in death and 30-50% of infection cases will end up having permanent neurological damage.

Classical symptoms include:

Most symptoms can vary from flu-like symptoms, a high fever, headache, convulsions, neck stiffness, nausea/ vomiting, muscle pain, meningitis and encephalitis.


To find out what vaccinations you will need for your travels, please visit our country guide and choose which countries you will be visiting.

The disease is more common in countries which belong to the Eastern and South-Eastern Asia. Mainly China alone contributes to 50% of incidents, and there is an estimated 70,000 new cases arise from this region every year.

We recommended travellers to consider the vaccine if they are staying for periods greater than one month or for shorter periods where visiting rural areas especially pig farms or rice plantations. Research laboratory workers and those who wish to reside abroad should consider the vaccination before travel as well.


The only licensed vaccine available in the UK for JE is IXIARO. It requires a primary injection followed by a booster injection in order to achieve long term immunisation.

It can be administrated from the age of 2 months and above and should be administrated 6-8 weeks prior to travel. The scheduled course of two injections is split over 28 days.

IXIARO - First dose of 0.25 ml on Day 0 and the second dose given on Day 28. Full immunity takes up to one week to develop after the second dose.

Currently, no clinical data stating booster injections are recommended for long term in adults or infants and children under 18 years. However, if planning for a lengthy stay abroad, then a booster injection may need to be considered after every 12-24 months.

**Not suitable for pregnant or breastfeeding mothers, neurological convulsions and people who have a hypersensitivity to the vaccination or have a fever.


The risk of acquiring JE is increased when you travel to a country that has a high risk factor and have not taken precautions to prevent being bitten by mosquitoes. To minimise this risk, we advise the following:

It is important to wear clothing that covers as much of the body as possible such as long sleeved clothing and long trousers.

If skin is exposed, the use of insect repellents should always be remembered. Mosquitoes may bite through thin clothing, so also spray an insecticide or repellent on them too. Spray especially in the evening, where the culex mosquitoes are more active.

Burning pyrethroid coils and heating insecticide impregnated tablets all help to control mosquitoes.

If sleeping in a room that has no screens, or out of doors, a mosquito net (which should be impregnated with insecticide) is a sensible precaution. Nets that have pyrethroid in the material or bound to the material have an expected life of 3-5 years and are superior to nets that require re-impregnation.

Portable, lightweight nets are available and it’s always a good idea to practice erecting nets before departure.

Regardless of what you read on the internet, there is no evidence that Garlic, Vitamin B and ultrasound devices prevent bites.