Healthdirect Free Australian health advice you can count on.

Medical problem? Call 1800 022 222. If you need urgent medical help, call triple zero immediately

healthdirect Australia is a free service where you can talk to a nurse or doctor who can help you know what to do.

beginning of content

Japanese encephalitis

11-minute read

Key facts

  • Japanese encephalitis is a serious disease caused by the Japanese encephalitis virus (JEV).
  • Humans can catch JEV if they are bitten by infected mosquitoes.
  • Fewer than 4% of people who catch JEV will experience symptoms.
  • For people who have symptoms, Japanese encephalitis can cause death or nervous system complications.
  • You can reduce your risk of Japanese encephalitis by avoiding mosquito bites and getting vaccinated against JEV.

What is Japanese encephalitis?

Japanese encephalitis is an infection that can affect the central nervous system and cause serious complications and even death.

It is endemic (regularly found) in parts of Asia and the Torres Strait region of Australia.

Before 2021, only five cases of Japanese encephalitis had been seen in mainland Australia.

However, between January 2021 and February 2023, 45 people on mainland Australia were diagnosed with Japanese encephalitis. During this outbreak, 7 people died.

An emergency response to this outbreak involved:

  • vaccination of at-risk people
  • raising public awareness of Japanese encephalitis

As of June 2023, the emergence response to Japanese encephalitis was no longer needed at this time.

What are the symptoms of Japanese encephalitis?

Most people with Japanese encephalitis don’t experience any symptoms.

Less than 4 in 100 people with Japanese encephalitis will have any symptoms.

You may notice symptoms about 5 to 15 days after being bitten by a JEV-infected mosquito.

The Japanese encephalitis virus can cause encephalitis and meningitis.

These conditions are serious, and can cause symptoms such as:

JEV can also make you feel confused or agitated.

CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.

What causes Japanese encephalitis?

Japanese encephalitis is caused by the Japanese encephalitis virus (JEV).

JEV only spreads to humans via bites from infected mosquitoes.

Animals such as pigs, waterbirds and horses can also catch JEV. These animals can’t transfer the virus to humans. If you work closely with these animals — especially pigs — you’re at increased risk of being bitten by an infected mosquito.

You also cannot catch JEV:

  • through contact with infected people
  • by eating meat from an infected animal

When should I see my doctor?

If you have recently been in an area with reports of JEV, and you experience sudden symptoms, seek medical attention.

If you think you may have Japanese encephalitis, visit your nearest emergency department or call an ambulance on triple zero (000).

FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.

How is Japanese encephalitis diagnosed?

Your doctor can diagnose Japanese encephalitis by asking you about your symptoms. They may also ask if you have recently travelled to any areas where there are cases of JEV.

If your doctor thinks you have Japanese encephalitis, further tests can confirm your diagnosis. These may include a:

How is Japanese encephalitis treated?

There is no specific medicine or treatment for Japanese encephalitis.

If you have symptoms of Japanese encephalitis, you will likely need treatment in hospital to manage:

  • seizures
  • encephalitis
  • meningitis

Antibiotics will not help you recover because this illness is caused by a virus, not bacteria.

Can Japanese encephalitis be prevented?

The 2 best ways to prevent Japanese encephalitis are to:

  1. avoid being bitten by mosquitoes, especially in areas where JEV is common
  2. get vaccinated against JEV

What are the recommendations for the JEV vaccination?

Vaccination is a safe and effective way to reduce your chance of catching JEV.

Vaccination is recommended for people who:

  • spend a month or more in Asia or the Torres Strait region of Australia during the wet season
  • work in laboratories with JEV
  • work with mosquitoes
  • work with pigs

See the table below for details about the Japanese encephalitis vaccination.

How many types of vaccines are available?

2 types of vaccines against JEV are currently available in Australia.

When to get vaccinated?

All people over 2 months of age can get a JEV vaccine.

You should be vaccinated before you spend 1 month or more in Asia or the Torres Strait region of Australia in the wet season.

How many doses are required?

1 or 2 doses. The number of doses and time between doses will depend on:

  • the type of vaccine recommended for you
  • your age
  • your risk of getting JEV
How is it administered?


Is it free?

No — there is a cost.

Common side effects

The vaccine is very safe. Side effects are mild and temporary. They may include:

  • a sore arm
  • swelling where the needle went in
  • headache
  • fatigue

You can talk to your doctor about which vaccine is best for you or your child.

If you're not sure whether you should get vaccinated, you can ask your:

  • doctor
  • travel clinic

How can mosquito bites be avoided?

To protect yourself from mosquito bites, you can try these things:

  • Reduce skin exposure and avoid tight clothes. Instead, wear loose-fitting clothes such as long-sleeved shirts, long pants, long socks and enclosed footwear.
  • Avoid spending time outside at dawn or dusk, as this is when mosquitoes are most active.
  • Use insect repellent. Choose products that contain diethyltoluamide (DEET), picaridin or lemon eucalyptus oil — these are most effective against mosquitoes.
  • Stay in rooms that have flyscreens over the doors and windows.
  • Sleep in rooms that have mosquito nets.
  • Do not leave water containers open. Mosquitoes breed in stagnant water.

You can find out more about insect bites here.

How is the spread of Japanese encephalitis prevented?

Japanese encephalitis is a nationally notifiable disease in Australia. This means, if you are diagnosed with Japanese encephalitis, your doctor will let your local public health authority know. They will check who you have been in contact with and take steps to control an outbreak.

Are there complications of Japanese encephalitis?

Japanese encephalitis can cause severe complications or death. Complications of Japanese encephalitis include permanent injury to your brain or nervous system.

About half of people who survive symptomatic Japanese encephalitis experience complications.

Resources and support

You can visit the Department of Health and Aged Care website for more information about Japanese encephalitis.

For information relevant to your state and territory click on the links below:

For more information on staying safe from JEV while travelling, you can:

If you need advice on JEV, call healthdirect on 1800 022 222 to speak with a registered nurse, 24 hours, 7 days a week (known as NURSE-ON-CALL in Victoria).

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: July 2023

Back To Top

Need more information?

These trusted information partners have more on this topic.

Top results

Japanese encephalitis | SA Health

Japanese encephalitis is a viral infection of the human brain caused by the Japanese encephalitis (JE) virus spread to humans by mosquito bites

Read more on SA Health website

Japanese encephalitis -

Japanese encephalitis - a vaccine-preventable viral illness that is spread by mosquitos - can cause inflammation of your brain (encephalitis).

Read more on myDr website

Japanese encephalitis fact sheet - Fact sheets

Japanese encephalitis fact sheet

Read more on NSW Health website

Japanese encephalitis | NCIRS

Japanese encephalitis NCIRS fact sheets, FAQs and other resources Australian Immunisation Handbook COVID-19 vaccines Immunisation coverage data and reports Education and training History of immunisation Immunisation schedules National and international resources NCIRS fact sheets, FAQs and other resources COVID-19 COVID-19 vaccination from community pharmacy Vaccination from community pharmacy Supporting conversations about vaccinations with Aboriginal and Torres Strait Islander people Haemophilus influenzae type b (Hib) Hepatitis B Human papillomavirus Influenza Japanese encephalitis Measles Meningococcal Mpox (formerly known as monkeypox) Mumps Pertussis Pneumococcal Poliomyelitis Rotavirus Rubella Varicella-zoster (chickenpox) Zoster Vaccines for Australian adults Vaccinations during pregnancy Homeopathy and vaccination MMR vaccine, inflammatory bowel disease and autism Thiomersal Vaccines, allergy and asthma Vaccine components Measles vaccination catch-up guide Injection site reactions Enhancing data quality of vaccination encounter records: tips and tricks Supporting and understanding delegations in HPOS to enable access to the Australian Immunisation Register NCIRS webinar series Patient communication resources Specialist immunisation services SKAI - supporting health professionals NCIRS newsletters Vaccine safety The Japanese encephalitis (JE) situation in Australia has been declared a Communicable Disease Incident of National Significance as of March 2022

Read more on National Centre for Immunisation Research and Surveillance (NCIRS) website

Japanese encephalitis | Safe Work Australia

This page provides persons conducting a business or undertaking with information on Japanese encephalitis and their duties under the model WHS laws.

Read more on Safe Work Australia website

Japanese encephalitis | Health and wellbeing | Queensland Government

Japanese encephalitis (JE) is a serious infection of the brain caused by a virus that can be spread by some (but not all) types of mosquitoes.

Read more on Queensland Health website

Japanese encephalitis | Australian Government Department of Health and Aged Care

Find out how we define and monitor cases of Japanese encephalitis, and where you can learn more about this disease.

Read more on Department of Health and Aged Care website

Japanese encephalitis virus (JEV) – Video – Mozzies aren’t just annoying | Australian Government Department of Health and Aged Care

JEV has been detected in Australia. Find out how you can protect yourself in this short video.

Read more on Department of Health and Aged Care website

Viral encephalitis - Better Health Channel

Viral encephalitis is inflammation of the brain caused by a virus and can cause permanent brain damage.

Read more on Better Health Channel website

Diseases | SafeWork NSW

Workers can be exposed to diseases while at work. Learn how to manage the risk of exposure to diseases in the workplace.

Read more on Safe Work Australia website

Healthdirect 24hr 7 days a week hotline

24 hour health advice you can count on

1800 022 222

Government Accredited with over 140 information partners

We are a government-funded service, providing quality, approved health information and advice

Australian Government, health department logo ACT Government logo New South Wales government, health department logo Northen Territory Government logo Queensland Government logo Government of South Australia, health department logo Tasmanian government logo Victorian government logo Government of Western Australia, health department logo

Healthdirect Australia acknowledges the Traditional Owners of Country throughout Australia and their continuing connection to land, sea and community. We pay our respects to the Traditional Owners and to Elders both past and present.