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9th March 2022

Should you be concerned about Japanese encephalitis virus?


The Japanese encephalitis virus (JEV) has been declared a disease of national significance with cases discovered in four states, including SA.

So, should you be concerned?

The mosquito-borne virus can potentially be deadly, however in majority of people the infection will be asymptomatic or present with mild symptoms.

University of Adelaide viral immunology expert Associate Professor Branka Grubor-Bauk, based at the Basil Hetzel Institute for Translational Health Research, says the virus is spread by mosquito bites.

“Mosquitoes acquire JEV mainly from water birds and pigs, and then transmit it to another animal or to humans. There is no human-to-human transmission,” she says.

“Major reservoirs of JEV are pigs and water birds. As such pig farmers and people working around piggeries are most at risk, but you can’t catch it from food (ie eating pork).

“The reason why JEV is currently spreading in Australia is because the east coast has had extremely wet weather this summer with heavy rain and floods. Migratory water birds are moving further south as there is a lot more water available. The virus is likely carried by infected waterbirds flying south and is moving between the birds and mosquitoes.

“To reduce your risk of exposure to JEV you should limit your exposure to mosquitoes, such as covering of bare skin, wearing protective loose clothing, using mosquito repellents and avoiding mosquito habitats such as pooled stagnant water, because standing water allows mosquitos to breed in large numbers.”

The Australian Government’s Department of Health says most people with Japanese encephalitis will be asymptomatic, however those with severe infection may experience:

  • sudden onset of fever
  • headache
  • vomiting.

If you believe you may be infected with the Japanese encephalitis virus, seek urgent medical assistance.

There is no treatment for Japanese encephalitis, but the Health Department advises that you can relieve the symptoms by:

  • getting plenty of rest
  • drinking plenty of fluids
  • taking paracetamol for pain or fever.