Vaccination against Japanese encephalitis is usually recommended if you're planning a long stay (usually at least a month) in a country where you could get the condition.
It's particularly important if:
You're visiting during the rainy season or there's a year-round risk because of a tropical climate
You're going to visit rural areas, such as rice fields or marshlands
You'll be taking part in any activities that may increase your risk of becoming infected, such as cycling or camping
Japanese encephalitis is found throughout Asia and beyond. The area it's found in stretches from the western Pacific islands in the east, across to the borders of Pakistan in the west.
It's found as far north as northeastern China and as far south as the islands of the Torres Strait and Cape York in northeastern Australia.
Despite its name, Japanese encephalitis is now relatively rare in Japan because of mass immunisation programmes.
Find out more about risk areas on the Travel Health Pro website
What is Japanese encephalitis & how do you catch it?
Spread through mosquito bites, Japanese encephalitis is a rare but serious viral brain infection. The virus starts with a mosquito biting an infected pig or bird, then going on to bite a human, transmitting the disease. The infection can’t be passed from person to person.
The virus is most common in South East Asia, the Pacific Islands & the Far East. The risk for most travellers is low, especially for short stay travellers. Those at higher risk are travellers to rural areas and those staying near to rice fields or pig farms for one month or longer.
Signs and symptoms
Japanese encephalitis doesn’t always present symptoms, but if they do occur they're usually mild and flu-like.
One in every 250 people develop more severe symptoms. This usually takes place five to 15 days after infection when it spreads to the brain. Severe Japanese encephalitis symptoms can include:
• High temperature (fever)
• Stiff neck
• ConfusionInability to speak
• Uncontrollable shaking of body parts
• Muscle weakness or paralysis
• Inability to speak
As these can be signs of many different diseases, you should seek immediate medical attention if you become unwell with flu-like symptoms and any of the symptoms listed whilst away or on your return.
The virus has no cure, however treatment can be given to aid the body as it fights off the infection. Symptoms usually require hospital treatments such as fluids, oxygen and medication.
The most effective way to prevent Japanese encephalitis is by means of vaccination.
It’s also important to protect against being bitten by mosquitos. To help prevent bites, you should:
• Use mosquito nets
• Wear long sleeves and trousers that are loose-fitting
• Spray rooms with insecticide
• Wear insect repellent
Vaccination against Japanese encephalitis usually consists of 2 injections, with the second dose given 28 days after the first or, when time is short, seven days after the first (an ‘accelerated’ schedule). The two doses should be completed at least seven days before your departure.
If you’re at higher risk of the disease, you should consider being vaccinated. It’s particularly important if:
• You’re travelling to a high-risk country during rainy season
• You’re visiting rural areas such as rice fields, marshlands or animal farms
• You’re likely to be doing activities that could increase your risk, such as cycling or camping