States in Australia where Japanese encephalitis has been identified and location of the Murray River where vaccination is recommended (see larger map)

What is Japanese Encephalitis?

Japanese Encephalitis is a virus that spreads to people through the bites of infected mosquitos.

Most people who are infected experience mild or no symptoms. In people who develop severe disease, early symptoms include fever, headache and vomiting. These symptoms may be followed by disorientation, coma, seizures, or death.

There are no medicines to treat or cure Japanese encephalitis.

Key points

• In 2021– early 2022, a Japanese encephalitis (JE) outbreak occurred in parts of Australia. The outbreak was focused in rural areas surrounding the Murray River, particularly near the border of Victoria and New South Wales. In November 2022, JE virus was detected in pigs in the Murray River region, confirming risk for JE in humans during the current Australian summer season.
• Most travelers to Australia are at very low risk for Japanese encephalitis.
• All travelers to Australia can protect themselves by preventing mosquito bites.
• JE vaccination is recommended for longer-term (e.g., one month or more) travel to the main risk areas in Australia (areas surrounding the Murray River and Outer Torres Strait Islands).
• Travelers to these areas should seek medical care immediately if they develop a fever, headache, vomiting, disorientation, coma, or seizures.

Traveler Information

• CDC Japanese Encephalitis Homepage
• Travelers’ Health Japanese Encephalitis Website
• Health Information for Travelers to Australia
• Prevent Mosquito Bites
• Japanese Encephalitis Vaccine Information Statement (VIS)

Clinician Information

• Japanese Encephalitis in the CDC Yellow Book (Health Information for International Travel)