What is Japanese Encephalitis?
Learn about this serious disease and how to protect yourself from it.
Sonder Health avatar
Written by Sonder Health
Updated over a week ago

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 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 the most commonly affected animals in Australia.

Although animals can be infected with JE, they cannot transmit the virus to humans. It also cannot be transmitted from human to human, or by eating meat from an infected animal.

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. Some ways you can manage symptoms include:

  • Ensuring you get plenty of rest

  • Drink plenty of fluids

  • For pain or fever, take paracetamol or OTC pain medicine.

Always seek advice from medical professionals, for extreme discomfort or severe symptoms. If you need some support or some assistance on what to do, our Sonder support team is available 24/7 to help you out.

How do I protect myself?

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

Due to a number of weather events across Australia, a number of states are offering free JE vaccines for specific priority groups.,


The NSW state government has made the JE vaccine available free-of-charge for specific priority groups:

  • Live or work in any of the following Local Government Areas (LGAs): Albury, Balranald, Berrigan, Carrathool, Dubbo Regional, Edward River, Federation, Goulburn Mulwaree, Greater Hume, Griffith, Lockhart, Murray River, Temora, or Wentworth and

  • are aged 50 years or older and

  • spend significant time outdoors (four hours per day).

South Australia

The SA state government will make the JE vaccine available free-of-charge for specific priority groups as outlined on the official SA Health website here.


The Victorian state government has made the JE vaccine available free-of-charge for specific priority groups:

  • If you are aged 50 years and over, spend a significant amount of time outdoors (more than four hour a day) and you live or work in one of the local government areas of Campaspe, Gannawarra, Greater Shepparton, Indigo, Loddon, Mildura, Moira, Swan Hill, Wodonga and Towong.

  • It is also recommended for people who work at or live on a piggery; people who work directly with pigs (i.e. pig transport, veterinarians and others involved in the care of pigs); people who work in pork abattoirs or rendering plants; and people who work directly in mosquito surveillance (field or laboratory) or work in mosquito control.

JE vaccines are available from selected GPs, Local Public Health Units (LPHUs), community pharmacies and some local councils across Victoria. If you are not eligible for the government-funded JE vaccine, you can purchase the vaccine by private prescription. Contact your local GP to discuss if the JE vaccine is appropriate for you.

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.

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.

Did this answer your question?