The QLD, NSW, Victoria, and South Australian state governments has issued out warnings about the increasing risk of the mosquito-borne viral disease Japanese encephalitis (JE) due to the La Nina weather pattern, informing people to stay alert and take the necessary precautions.

In Australia there has been one death and seven cases of acute encephalitis so far, as well as virus samples detected from commercial pig farms in southern and western NSW. Sonder has put together a helpful guide on this deadly disease so that you'll know what it is, how to detect it, and how to protect yourself from it.

What is Japanese encephalitis (JE)?

Japanese encephalitis is a serious infection of the brain caused by a virus that can be spread by some (but not all) types of mosquitoes, and affects a range of species including waterbirds, pigs, horses and donkeys, cattle, sheep, goats, water buffalo, chickens and others.

Where is it found?

JE is present in India, south-eastern parts of the Russia, many parts of Asia and Papua New Guinea. Australia is considered free of the disease; however, the far north of Australia's Cape York Peninsula is considered an area at risk and seasonal incursions of JE are occasionally detected in humans in the Torres Strait.

How do people get it?

JE is spread by the bite of an infected mosquito. Mosquitoes become infected with the virus after they bite one of the listed animals above, with pigs and waterbirds being most commonly affected animals in Australia.

What are the symptoms?

After a person is bitten by an infected mosquito, it usually takes five to 15 days for symptoms to appear. A vast majority of people (99%) affected with the JE virus generally show no symptoms. Those who do develop symptoms may experience a fever and headache.

Severe cases of the disease can result in symptoms that include high fever and chills, severe headache, photophobia, neck stiffness, nausea/vomiting, convulsions, and coma. Approximately one-third of severe cases die, and one-third are left with permanent disabilities.

Is there treatment?

There is no specific treatment for the JE virus aside from management of symptoms. The best way to avoid infection is to prevent yourself from being bitten by mosquitoes.

How do I protect myself?

Immunisation is important to protect yourself against the JE virus, and Australia has two JE vaccines available for use.

Prevention of mosquito bites is also important in protecting yourself from the virus. Some ways to avoid mosquito bites include:

  • Cover up as much as possible with light-coloured, loose-fitting clothing and covered footwear when outside, especially at dusk and the first few hours after sunset.

  • Use an effective insect repellent on exposed skin and reapply within a few hours. The best mosquito repellents contain Diethyl Toluamide (DEET), Picaridin, or oil of lemon eucalyptus.

  • Use insecticide sprays, vapour dispensing units (indoors) and mosquito coils (outdoors) to clear rooms or repel mosquitoes from an area.

  • Use mosquito-proof tents when camping.

  • Use mosquito nets when sleeping if there's no air-conditioning or mosquito screens on the doors and windows.

  • Cover all windows, doors, vents and other entrances with insect screens.

  • Remove any water-holding containers outside the house where mosquitoes could breed.


If you have any questions or need extra support, we're here to help you anytime, in any language. Simply start a chat with us via the home screen of the Sonder app.

Information sourced from Queensland Health and the NSW Government.

Image credit: Wolfgang Hasselmann on Unsplash

All content is created and published for informational purposes only. It is not intended to be a substitute for professional advice. Always seek the guidance of a qualified health professional.

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