Travel Health Information Sheet
Updated August 2011
- What is Japanese encephalitis?
- What is my risk?
- Can it be treated?
- Is there a vaccine?
- How can I prevent it?
Japanese encephalitis (JE) is a virus disease spread by night biting mosquitoes. It can cause encephalitis, a serious inflammation of the brain, which can be fatal.
Where is it?
JE was first discovered in Japan; it is found in most countries in Asia and also in some remote parts of northeast Australia (see map below).
Map from: “Health Information for Overseas Travel 2010”
Countries like Cambodia, India and Thailand have specific JE seasons, usually around the time of their rainy season. In other counties, such as Indonesia, Malaysia and the Philippines, there is a risk of JE all year round.
You can check if you are visiting a risk area by looking at NaTHNaC’s country information pages.
What are the symptoms?
JE may just cause a mild, flu-like illness, but there is always a risk that brain inflammation (encephalitis) will develop.
Symptoms of encephalitis include:
- a high fever
- convulsions (fits)
- neck stiffness
There is no way to predict who will develop encephalitis and with this severe illness, permanent disability and even death can occur.
JE is spread by bites from mosquitoes that are active from dusk to dawn. These mosquitoes usually live in or near rice fields, swamps and marshes and get infected by feeding on pigs and wild birds carrying JE. You cannot catch JE directly from another person or from contact with pigs or birds.
Your risk depends on what you do and where you go. Most short trips are low risk, especially if you are just visiting cities. However, activities that increase your risk of mosquito bites can increase your chance of getting JE. Your risk is higher if you work or are staying in the countryside or live in infected countries for long periods of time.
JE is usually caught by local people, especially children, living in rural risk areas. To date, only two cases have been reported in United Kingdom (UK) travellers: one in 1982 and one in 1994.
There are no specific drugs or medicines to treat JE. Intensive hospital care may be needed, as the disease can be fatal or leave you with a permanent disability.
There are two different vaccines: a three dose course for children from the age of one year (which is unlicensed in the UK, but still acceptable to give) and a two dose, licensed vaccine for older adolescents and adults. Ideally, you should see your doctor, practice nurse or travel clinic at least a month before you travel, as you need a course of injections. However, even if your trip is at short notice, it is still important to get advice.
You should consider the vaccine if:
- You live, work or frequently visit risk countries.
- You spend a lot of time in rural areas, especially near rice fields, pig farms or marshes.
- You are camping, cycling or spending a lot of time outside in risk areas.
If you think you and your family are at risk, get advice from your GP or travel clinic about having the vaccine.
Remember - good insect bite avoidance is still important, even if you have been vaccinated.
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