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What is Japanese encephalitis?

Page last updated 16 December 2021


Japanese encephalitis (or JE) is a rare but serious viral infection of the human brain caused by the bite of a particular type of infected mosquito. The disease is rarely found in mainland Australia, however, it is relatively common in many parts of Asia (e.g. Southeast Asia, India, China).

In the vast majority of cases (about 99%), people will experience very mild or no symptoms from an infection. In a small number of cases, infection may lead to swelling of the brain (encephalitis) and its associated symptoms, including headache, high fever, disorientation, coma, tremors and convulsions.  In people who do develop the disease, 10-30% will die and 50% will have a permanent disability.


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Sources & Citations

2. NSW Government Department of Health. Japanese encephalitis fact sheet. Available at: (accessed 16 November 2021).

3. Northern Territory Government. Japanese encephalitis. Available at: (accessed 16 November 2021).


MAT-AU-2102454  Date of preparation December 2021