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What are the symptoms of Japanese encephalitis?

Page last updated 03 April 2020

For most people (around 99%), there will be no symptoms of infection. However, in a small number of cases, symptoms of Japanese encephalitis may begin 5-15 days after infection from a mosquito bite.  


The initial symptoms may be severe shivering and chills, fever, headache, nausea and a stiff neck. Neurological (nervous system) symptoms may include disorientation, unconsciousness, tremors, seizures, convulsions, paralysis, coma, and death. Recovery can take a long period of time, and carries a high likelihood of on-going neurological symptoms, including deafness and partial paralysis.




Less than 1% of people infected with the Japanese encephalitis virus develop clinical illness.


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Sources & Citations

1. Australian Government, Department of Health. The Australian Immunisation Handbook. Japanese encephalitis. Available at: (accessed 10 March 2020).

2. NSW Government, Department of Health. Japanese encephalitis fact sheet. Available at; (accessed 10 March 2020).

7. Centers for Disease Control and Prevention. Japanese encephalitis – symptoms & treatment. Available at: (accessed 10 March 2020).

SPANZ.IMOJ.18.04.0141(1)a - Date of preparation March 2020