Japanese Encephalitis
Japanese encephalitis virus (JEV) has recently been detected in piggeries in New South Wales, Queensland and Victoria and human cases have been reported.
Currently, mosquito numbers are high along many parts of the Murray River and its surrounds, from Mildura to Wodonga. People with increased exposure to mosquitoes may be at a higher risk of infection, particularly people working or living on pig farms, camping, or working or spending time outdoors in these regions since 1 December, 2021.
JEV is spread to humans via mosquito bites. It can cause a rare and potentially life-threatening infection of the brain (encephalitis).
Most JEV infections are asymptomatic, however approximately one percent of those infected can develop encephalitis which may lead to death or permanent disability (prolonged neurological complications). Usually symptoms develop 6-16 days after being bitten by an infected mosquito.
Symptoms
Symptoms include:
- fever
- headache
- convulsions
- neck or back stiffness
- sensitivity to light
- vomiting or confusion
- coma (rarely)
Anyone experiencing these symptoms, particularly if they’ve visited northern and north-west Victoria, the Murray River and its surrounds or been in contact with pigs, should seek urgent medical attention.
Japanese encephalitis is confirmed through a combination of laboratory testing and clinical assessment.
There are no treatments for Japanese encephalitis. Treatment consists of relieving the symptoms and in more severe cases, hospitalisation for supportive care.
Prevention
People with increased exposure to mosquitoes may be at a higher risk of infection, particularly when camping, or working or spending time outdoors in northern and north-western Victoria and the Murray River regions.
People who work with or are in contact with pigs may also be at increased risk of infection.
Children aged <5 years old and older people are at a higher risk of developing more severe illness, such as encephalitis.
Individuals travelling to regions associated with JEV cases for holiday purposes are recommended to take additional precautions to avoid mosquito contact.
There are two ways to protect yourself:
- Avoiding mosquito bites (physical barriers).
- Vaccination.
Steps to protect yourself against mosquito-borne diseases include:
- Wearing long, loose-fitting clothes while outdoors.
- Using mosquito repellents containing picaridin or DEET on all exposed skin.
- Prompt washing and covering of cuts and scratches caused with outdoor activities.
- Limiting outdoor activity if lots of mosquitoes are about.
- Using ‘knockdown’ fly sprays and plug-in repellent devices indoors.
- Using mosquito coils in small outdoor areas where you gather to sit or eat.
- Making sure your accommodation is mosquito-proof.
- Sleeping under mosquito nets treated with insecticides if you don’t have fly wire screens on windows on your home or are sleeping in an untreated tent or out in the open.
- Prevent mosquitos breeding around your home by removing sources of stagnant water.
Visit Beat the Bite! on Better Health Channel for more information.
Vaccination
The South Eastern Public Health Unit (SEPHU) currently advises that there is no need for vaccination for our staff and students travelling to and visiting the affected areas. The current supply of JEV vaccine is being prioritised in Australia for high-risk groups, including:
- those who work or live at piggeries;
- those who work with mosquitoes, including field and lab-based workers:
- environmental health officers and workers (urban and remote) and entomologists who work:
- directly with mosquitoes through their surveillance, control or management; and
- indirectly through management of vertebrate mosquito-borne disease surveillance systems (e.g. sentinel animals); and
- laboratory staff working with JEV
- environmental health officers and workers (urban and remote) and entomologists who work:
More information is available at the Japanese encephalitis virus (JEV) vaccines page.
Background information
JEV is a leading cause of vaccine-preventable encephalitis (brain infection) in Asia and the Western Pacific. The virus is associated with pigs and water birds.
It has recently been detected in piggeries in New South Wales, Queensland and Victoria and human cases have been reported.
Japanese encephalitis cannot be spread directly from person to person. It cannot be caught through eating pork or pig products.
Currently, mosquito numbers are high along many parts of the Murray River and its surrounds, from Mildura to Wodonga. People with increased exposure to mosquitoes may be at a higher risk of infection, particularly people working or living on pig farms, camping, or working or spending time outdoors in these regions since 1 December, 2021.
Current status
JEV has been declared a Communicable Disease Incident of National Significance. Currently, Victoria has a number of confirmed human cases of JEV.
Locally-acquired JEV infection has not occurred previously in Victoria. These detections in Victoria, NSW, SA and QLD are the first known local detections of the virus in these parts of Australia.
The extent of the spread of JE virus in Victoria is under investigation and it is not yet clear whether these infected mosquitoes are circulating elsewhere in Victoria. Refer to the Agriculture Victoria website for a map of Local Government Areas with infected premises and other information.
Further information can be found at the following websites:
https://www.betterhealth.vic.gov.au/campaigns/beat-bite
https://www.health.vic.gov.au/health-advisories/japanese-encephalitis-virus-detected-in-victoria