Health conditions

Japanese encephalitis

Japanese encephalitis (JE) is a rare but serious disease of the brain that is caused by the Japanese encephalitis virus (JEV). JEV is spread by infected mosquitos to humans and other animals, such as waterbirds, pigs and horses. Waterbirds and pigs are important in the JEV transmission cycle as they can pass the virus back to biting mosquitoes. JEV cannot be directly transmitted (by direct contact) from person to person, animal to person, or by eating meat from an infected animal.

At risk groups

JEV is typically found throughout Asia and the Pacific region, with historically a small number of notifications in far north Queensland, the Torres Strait and the Tiwi Islands in the Northern Territory.

Since February 2022, JE cases have been detected across several Australian states and territories. While there have been no human cases of JE reported in WA, there has been evidence of JEV in early 2023 in sentinel chickens in the Kimberley and Pilbara regions. JEV infection has also been found in feral pigs in the Kimberley.

JE is a vaccine-preventable disease. Persons eligible for vaccination are encouraged to get vaccinated against JE now. See Prevention section below for further details.

Signs and symptoms

Most people infected with JEV do not develop symptoms. However, in rare cases (less than 1% of infected people) encephalitis (swelling of the brain) may develop which can lead to death or long-term damage to the nervous system. Signs and symptoms of severe JE include headache, fever, convulsions, decreased consciousness (becoming drowsy or unresponsive), and disorders of the muscles, including paralysis.

Children under the age of 5 years and older people who are infected with JEV are at a higher risk of developing more severe illness, such as encephalitis. Infection during pregnancy can result in an increased risk of miscarriage and other complications.

The incubation period (i.e. the time from being bitten by an infected mosquito to developing symptoms to the disease) in humans is from 5 to 15 days.

If you are experiencing symptoms, especially if you have visited affected regions, please seek urgent medical assistance.

Diagnosis and treatment

JEV infection is usually diagnosed by testing blood or spinal fluid samples. Under the Public Health Regulations 2017 (WA) JE is an urgently notifiable infectious disease in Western Australia (WA).

There is no specific treatment for JE. Treatment usually involves management of symptoms.

Prevention

Taking steps to avoid mosquito bites is essential to protect yourself from JEV. Even if people are vaccinated, they should still use precautions to protect against mosquito bites, which will also protect them against other mosquito-borne diseases. No vaccine is 100% effective and the JE vaccine takes a few weeks to provide protection.

Ways to protect yourself from mosquito bites include:

  • apply and regularly reapply an effective insect repellent on exposed skin, ensuring you follow the instructions on the label
  • wear long, loose fitting clothing when outside
  • use insecticide sprays, vapour dispensing units (indoors) and mosquito coils (outdoors) to clear rooms and repel mosquitoes from an area
  • make sure accommodation, including tents, are properly fitted with mosquito nets or screens
  • cover all windows, doors, vents and other entrances with insect screens
  • remove any water-holding containers where mosquitoes may breed.

Effective mosquito repellents contain diethyltoluamide (DEET), picaridin, or oil of lemon eucalyptus (OLE).

Vaccination

Persons who wish to be vaccinated against JEV for travel purposes should visit their GP or travel medicine clinic for a private prescription.

The WA Department of Health is currently offering free JE vaccine to eligible persons in specific areas of the Kimberley and Pilbara. These areas are considered to be at highest risk of JEV transmission in WA, either because JEV has been detected nearby or because there are habitats nearby that could support JEV spread (wetlands, large numbers of waterbirds or feral pigs and JEV carrying mosquitoes).

Eligible persons currently include:

  • Kimberley residents who meet the following criteria:
    • All Aboriginal residents of the Kimberley
    • All non-Aboriginal residents of the Kimberley residing outside the suburbs of Broome, Cable Beach, Djugun, Minyirr and Bilingurr
    • All non-Aboriginal people experiencing homelessness residing in Broome
  • Pilbara residents who meet the following criteria:
    • Residents of postcode 6753 including Newman
    • Residents of postcode 6762 (Western Desert)
  • Persons living and/or working in an eligible suburb or postcode for at least a 30-day period who spend significant time outdoors (at least 4 hours per day), for unavoidable work, recreation, education or other essential activities. This excludes those working in the mining industry.
  • People who work directly with mosquitoes, and indirectly through sentinel animal surveillance systems in the Kimberley and Pilbara regions e.g. environmental health officers, entomologists, environmental consultants involved in mosquito management, rangers and park staff, and depot workers.
  • Diagnostic and research laboratory workers who are likely to handle live JEV.

There is limited supply of JE vaccines worldwide. Eligibility for vaccines will continue to be expanded in stages to those at highest risk of JEV infection as more vaccine becomes available.

Proof of eligibility

Types of vaccines

There are two vaccines available in Australia which are safe and effective for both adults and children.

  • Imojev® – a single dose, live attenuated virus vaccine
  • JEspect® (also known as Ixiaro) – a two dose, inactivated vaccine (given 28 days apart)

If you are pregnant or immunocompromised, please consult with your immunisation provider to ensure you receive the right vaccine.

Where to get vaccinated

Clinic name and location Contact clinic to make a booking Eligibility for vaccination at this service
Balgo Health Centre
Balgo (Wirrimanu), WA 6770
Ph: (08) 9168 8953 Eligible persons
Beagle Bay Health Centre
Lot 53 Beagle Bay Road, Beagle Bay, WA 6725
Ph: (08) 9192 4914 Eligible persons
Bidyadanga Health Centre
Lot 86 Wangkaja Rd, Bidyadanga WA 6725
Ph: (08) 9192 4952 Eligible persons
Billiluna Health Centre
Billiluna (Mindibungu), WA 6770
Ph: (08) 9168 8144 Eligible persons
Broome Community Health
67 Dakas Street, Broome WA 6725
Ph: (08) 9194 2340 Eligible persons
Broome Regional Aboriginal Medical Service (BRAMS)
2 Dora St, Broome WA 6725

Ph: (08) 9194 4800
Aboriginal people and current clients/patients of BRAMS living in an eligible area
Derby Aboriginal Health Services (DAHS)
1 Stanley St, Derby WA 6728
Ph: (08) 9158 4200 Aboriginal people and current clients/patients of DAHS living in an eligible area
Derby Community Health
Ph: (08) 9193 3263 Eligible persons
Fitzroy Crossing Community health clinic
Ph: (08) 9166 1733 Eligible persons
Halls Creek Community Health Service
70 Roberta Avenue, Halls Creek, WA 6770
Ph: (08) 9168 9203 Eligible persons
Kalumburu Clinic
138 Kalumburu Boulevard, Kalumburu, WA, 6740
Ph: (08) 9161 4335 Eligible persons
Kununurra Community Health Service
96 Coolibah Drive, Kununurra, WA 6743
Ph: (08) 9166 4321 Walk in clinic Thursdays 8.30am-3.30pm Eligible persons
Kupungarri Clinic
Ph: (08) 9191 4747 Kupungarri residents
Looma clinic Ph: (08) 9192 9220  Eligible persons
Mulan clinic
Mulan, WA 6770
Ph: (08) 9168 8133 Eligible persons
Newman Community Health Centre, Newman Hospital  
Mindarra Drive, Newman WA 6753

Ph: (08) 9174 1660 Eligible persons
Noonkanbah (Yungnora) clinic
Ph: (08) 9191 4663 Eligible persons
Ord Valley Aboriginal Health Service (OVAHS)
1125 Ironwood Drive, Kununurra, WA 6743
Ph: (08) 9166 2200 Aboriginal people or existing clients of OVAHS living in an eligible area but within 150km of Kununurra
Puntukurnu Aboriginal Medical Service (PAMS)
65 Mindarra Drive, Newman WA 6753
Ph: (08) 9111 1777 Aboriginal people and current clients/patients of PAMS living in an eligible area
Ringers Soak clinic
Kundat Djaru Aboriginal Community, via Halls Creek WA 6770
Ph: (08) 9168 8418 Ringers Soak (Kundat Djaru) residents
Sonic Health Plus
54 Mindarra Drive, Newman WA 6753
Ph: (08) 9175 1231 Eligible persons
Wangkatjungka clinic Ph: (08) 9191 4755 Eligible persons
Warmun clinic
Ord Street, Warmun ,WA 6743
Ph: (08) 9166 3800 Eligible persons
Wunan Health and Wellbeing Centre
57 Bandicoot Drive, Kununurra, WA 6743
Ph: (08) 9168 1001 Limited vaccine supply. Please phone the service to discuss as it may require a few days’ notice to order vaccine. Current clients/patients of Wunan Health living in an eligible area.
Wyndham Community Health Service
Minderoo Street, Wyndham, WA 6740
Ph: (08) 9166 4321 Please phone to book an appointment. Eligible persons
Yura Yungi Aboriginal Medical Service Ph: (08) 9168 6266 Aboriginal people and current clients/patients of Yura Yungi Aboriginal Medical Service living in an eligible area

To report an adverse event following immunisation, contact the Western Australian Vaccine Safety Surveillance System (external site), email wavss@health.wa.gov.au or phone (08) 6456 0208.

For more information about the JE vaccines, please refer to the Japanese encephalitisvirus (JEV) vaccines | Australian Government Department of Health and Aged Care.

Further information

Where to get help

  • Find a GP/doctor
  • Consult with your GP, immunisation provider or HealthDirect on 1800 022 222 (available 24 hours)
  • For emergency or life-threatening conditions, visit your nearest emergency department or call 000 for an ambulance.

Last reviewed: 25-10-2023
Acknowledgements

Public Health


This publication is provided for education and information purposes only. It is not a substitute for professional medical care. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your healthcare professional. Readers should note that over time currency and completeness of the information may change. All users should seek advice from a qualified healthcare professional for a diagnosis and answers to their medical questions.