Understanding Japanese Encephalitis: A Travel Health Advisory

What is Japanese Encephalitis?

Japanese Encephalitis (JE) is a serious viral infection transmitted by mosquitoes. The JE virus primarily affects the brain, leading to inflammation known as encephalitis. It is a member of the flavivirus family, which includes other mosquito-borne viruses such as dengue, yellow fever, and West Nile virus. JE is prevalent in rural and agricultural areas of Asia and the Western Pacific, posing a significant risk to travellers in these regions.

A Tragic Case Highlights the Risk

A tragic case of Japanese Encephalitis was reported in a 60-year-old Victorian man who merely visited Phuket, Thailand, on holiday and encountered the ‘wrong mosquito.’ While these mosquitoes predominantly inhabit rural areas, they are not confined to them. The JE virus circulates in pigs and wading birds, which makes eradication impossible. The infected mosquito typically feeds at dusk, injecting the virus into the bloodstream, where it attacks the brain, destroying brain cells and preventing their repair—a double whammy.

Geographical Distribution of JE

The disease is widespread across Asia. For a detailed view of affected areas, refer to the CDC map showing the prevalence of Japanese Encephalitis.

Disease Severity and Outcomes

Of those who fall ill from JE:

• About one-third die.
• One-third recover.
• One-third are left with permanent brain damage.

Prevention and Vaccination

Japanese Encephalitis is preventable through vaccination. In ‘at-risk’ areas, the vaccine is often administered to children. However, visitors typically do not have such protection. Despite its rarity, JE is a devastating disease. Since it is caused by a virus, treatment options are limited to supportive care, hoping the body and brain can recover on their own. Once symptomatic, the prognosis is often grim.

JE is not usually mentioned in glossy tour brochures. While it is considered a ‘rare’ disease, ‘rare’ does not mean ‘never.’

Several vaccines are available to protect against JE, with the most popular being a live vaccine. One dose administered to adults offers lifelong protection. This vaccine costs about $300, which is far cheaper than a day in the hospital or even a minor car repair. The vaccine has a low incidence of side effects.

Advice for Travellers

Every traveler to Asia should consider vaccination or at the very least, have a discussion about JE to determine the best plan for avoiding this dreadful disease. Consult with a travel health specialist to assess your risk and take appropriate preventive measures. Remember, while the disease is rare, the consequences of infection can be catastrophic.

Make an appointment at Dr Deb’s The Travel Doctor if you require a Japanese Encephalitis vaccine today. 

More resources on JE below:

• Australian man dies of JE after 10 days in Thailand
• Qld man in coma after Bali mosquito bite
• Medical Journal report Death from JE contracted in Bali 
• JE in Australian Backpacker
• JE after 2 week holiday Khao Lak Thailand
• JE case after 3 weeks in Thailand
• 11 year old girl dies in the USA from JE after 3 week visit to the Philippines
• How JE Affects The Brain
• Should travellers to Kokoda have JE Vaccine? 
• Overview of JE – CDC Yellow Book 
• Intercel And Previous JE Vaccine Trial 
• Chelsea’s story (video)
• Lots of information in MMWR from CDC in USA 
• JE cases found in Australia March 2022
•  Information about our JE vaccine research PIS