Japanese Encephalitis: What Travellers Need to Know

Expert Guidance from the International Travel Vaccination Centre, Sydney

What is Japanese Encephalitis?

Japanese Encephalitis (JE) is a serious viral infection transmitted by Culex mosquitoes, which are common in rural and agricultural regions of Asia, the Western Pacific, and certain parts of Australia. The disease affects humans, pigs, and birds, and can be life-threatening for a small percentage of people who contract it. Most individuals infected with the Japanese encephalitis virus (JEV) experience no symptoms. However, those who develop symptoms can suffer from severe and potentially fatal neurological complications, making prevention crucial for travellers.

  

Top Countries and Regions at Risk for Japanese Encephalitis

Japanese encephalitis is prevalent in many regions across Asia and the Western Pacific, with the highest risk areas including rural and agricultural regions where mosquito populations thrive. The JE virus is endemic in countries such as India, China, Thailand, Vietnam, Indonesia, the Philippines, Malaysia, Nepal, Cambodia, Laos, and Myanmar. Additionally, parts of Bangladesh, Papua New Guinea, Japan, and South Korea also experience cases. 

High-risk areas often include rural towns, farming communities, and areas with rice paddies or pig farms due to ideal mosquito breeding conditions. Travellers visiting or staying in these regions, especially in cities or towns near agricultural zones, should be aware of their risk and consider vaccination for adequate protection.

 

Symptoms of Japanese Encephalitis in Humans

Japanese encephalitis often presents a complex range of symptoms, and while most people infected with the virus do not experience any noticeable signs, those who do can face a sudden onset of severe and potentially life-threatening health issues. Symptoms can manifest within 5 to 15 days following exposure to an infected mosquito.

• High fever: A rapid and intense fever is often one of the first signs, frequently exceeding 38°C (100.4°F). The sudden spike in temperature can lead to extreme fatigue and weakness.
• Severe headache: Persistent headaches are common and often described as intense and throbbing, making daily activities nearly impossible for those affected.
• Vomiting and nausea: The infection may cause frequent nausea and vomiting, contributing to dehydration and worsening overall discomfort.
• Neck stiffness: Stiffness in the neck can be a sign of brain or spinal cord inflammation, indicating the virus’s effect on the central nervous system. This symptom is particularly concerning as it suggests the infection is more severe.
• Confusion and disorientation: As the virus affects the brain, patients may experience mental status changes, including confusion, difficulty concentrating, and disorientation. This can be frightening for both the individual and their loved ones.
• Seizures and tremors: Seizures, involuntary muscle movements, and tremors are more likely in children but can occur in adults as well. These symptoms are clear indicators of significant neurological involvement.
• Neurological symptoms and coma: In its most severe form, Japanese encephalitis can lead to inflammation of the brain (encephalitis), causing seizures, paralysis, loss of consciousness, or even coma. Long-term complications, such as memory loss, speech impairments, and motor deficits, may persist in those who survive severe infections.

 

Given the serious nature of these symptoms, prompt medical attention is crucial, particularly for those who have recently travelled to or lived in high-risk areas. Early detection and supportive care can make a substantial difference in managing the disease and reducing its impact. If any of these symptoms arise, seeking emergency care is highly recommended, as it may be life-saving.

Is There Japanese Encephalitis in Australia?

Yes, Japanese encephalitis has been identified in certain regions of Australia. Cases have been recorded in northern areas as well as parts of southern Queensland, New South Wales, and Victoria. The virus is spread by mosquitoes, primarily in rural and farming areas where environmental conditions support mosquito breeding. Public health officials recommend vaccination for individuals living in or travelling to these regions, especially those engaged in outdoor activities or working in areas with high mosquito populations. 

The JE Vaccine: Protection for Travellers in High-Risk Areas

The Japanese Encephalitis (JE) vaccine provides effective protection against the potentially life-threatening Japanese encephalitis virus. It is highly recommended for individuals travelling to or living in areas where the virus is prevalent.

There are two types of JE vaccines available:

• IMOJEV: A live vaccine suitable for adults, providing long-term immunity of five years or more with a single dose. For children above 9 months, two doses are required.
• Jespect: An inactivated (non-live) vaccine recommended for immunocompromised individuals and pregnant women. This vaccine is administered as a two-dose series, with the second dose given 28 days after the first.

The JE vaccine plays a critical role in reducing the risk of severe illness, including brain inflammation and long-term neurological damage, making it an essential preventative measure for travellers and residents in high-risk regions. While generally well-tolerated, mild side effects such as redness at the injection site, mild fever, or headache may occur.

 

How Many Doses of the Japanese Encephalitis Vaccine Do You Need?

The number of doses required depends on the vaccine type and individual circumstances:

• IMOJEV: A single dose for adults, or two doses for children over 9 months.
• Jespect: Two doses are required for all individuals, with the second dose administered 28 days after the first.

This vaccination schedule provides robust and long-lasting protection against JE disease. A booster dose may be required after several years for those with ongoing exposure risk.

Our team at the International Travel Vaccination Centre will assess your travel history, health conditions, and ongoing risk to tailor a vaccination plan that ensures you are fully protected.

How Long Does the Japanese Encephalitis Vaccination Last?

After completing the initial two-dose JE vaccine series, immunity typically lasts for several years. Depending on your travel plans and potential continued exposure, a booster dose may be recommended to ensure ongoing protection. Our experienced travel doctors can assess your risk and advise on the optimal schedule for JE vaccination.

Do I Really Need the Japanese Encephalitis Vaccine?

If you are planning to travel to regions where Japanese encephalitis is prevalent, vaccination is highly recommended. High-risk activities include working outdoors, visiting rural or farming areas, or staying in places with large mosquito populations. The JE vaccine significantly reduces the risk of contracting this potentially life-threatening disease. Book an appointment with our expert travel doctors at the International Travel Vaccination Centre for personalised advice and peace of mind during your travels.

Can You Fully Recover from Japanese Encephalitis?

Recovery from Japanese encephalitis depends on the severity of the disease. While many individuals with mild cases make a full recovery, severe cases can lead to long-term complications, such as cognitive impairments, motor skill deficits, or even death. Intensive medical care, rehabilitation, and ongoing support may be necessary for those with severe infections. The best way to minimise risk and ensure safety is through vaccination and preventive measures.

What Are the Side Effects of the Japanese Encephalitis Vaccine?

The JE vaccine is considered safe and effective, with most side effects being mild and temporary. Common reactions include:

• Pain, redness, or swelling at the injection site
• Mild fever
• Headache or muscle pain

Serious side effects are extremely rare but may include severe allergic reactions. If you have any concerns, our travel doctors at the International Travel Vaccination Centre will provide detailed guidance on what to expect and ensure your vaccination experience is as comfortable as possible.

Protect Against the JE Virus at the International Travel Vaccination Centre

At the International Travel Vaccination Centre, we are dedicated to safeguarding your health while travelling. Our experienced team offers comprehensive travel health advice, tailored vaccination plans, and up-to-date information to protect you from Japanese encephalitis and other travel-related diseases.  

Book Your Consultation at ITVC Today

Ensure a safe and healthy trip. Contact the International Travel Vaccination Centre today on 1300 557 070 or book an appointment online for expert advice and the highest standard of care in travel medicine.