- Advisory number:
- Date issued:
- 03 Nov 2022
- Issued by:
- Associate Professor Deborah Friedman, Deputy Chief Health Officer (Communicable Disease)
- Issued to:
- Health professionals, residents and visitors in north and north western Victoria
- Flooding and heavy rainfall have increased the risk of viruses transmitted by mosquitoes in Victoria this season.
- Japanese encephalitis (JE) virus can cause a rare but potentially serious infection of the brain.
- JE virus is transmitted to humans by infected mosquitoes.
- There have been no confirmed cases of JE and no detections of JE virus in mosquitoes this season.
- In Victoria, a JE vaccine is available free-of-charge for specific groups most at risk of exposure to JEV.
- Eligibility criteria for JE vaccine have now been expanded to include more Victorians in northern Victoria where mosquitoes are prevalent.
- The simplest and best way to prevent JE virus infection and other mosquito-borne diseases .
What is the issue?
Flooding, pooling of stagnant water and increased mosquito breeding have increased the risk of mosquito-borne diseases this season.
Japanese encephalitis (JE) is a rare but potentially serious infection of the brain caused by the JE virus that can be spread to humans through bites from infected mosquitoes. Most JE virus infections cause no symptoms, however less than one per cent of people with infection may develop encephalitis which may lead to death or permanent disability. Symptoms include fever, vomiting, headache, neck or back stiffness, sensitivity to light, confusion, seizures, and sometimes coma.
A mosquito surveillance program is in place in Victoria. To date this season, JE virus has not been detected in mosquitoes or other animals and no human cases of JE have been notified to the Department of Health.
Other mosquito-borne diseases in Victoria include Ross River virus, Barmah Forest virus, and Murray Valley encephalitis (MVE) virus.
Who is at risk?
People most at risk of JE virus include people in northern Victoria, and along the Murray River who spend significant time outdoors and are exposed to mosquitoes. People who live near or work with pigs in these areas are also considered at higher risk. The overall risk of infection and developing serious illness is low.
For the public
Prevent mosquito bites
In Victoria, there are several mosquito-borne diseases that can occur. The most effective way to reduce your risk of JE virus or other infections transmitted by mosquitoes is by avoiding mosquito bites and removing mosquito breeding sites around your home and property.
Protect yourself and your family from mosquito-borne diseases:
- Limit outdoor activity if lots of mosquitoes are about, especially at dusk and in the evening.
- Cover up as much as possible with long, loose-fitting clothing when outdoors. Mosquitoes can bite through tight clothing.
- Use mosquito repellent that contains picaridin or DEET on all exposed skin. Don’t forget your ankles, feet and scalp (or wear a hat).
- Make sure your accommodation is mosquito-proof. Avoid leaving doors and windows open between peak mosquito biting times (about 7pm – 7am) unless they are fitted with insect screens.
- Use ‘knockdown’ fly sprays and plug-in repellent devices indoors.
- Sleep under mosquito nets treated with insecticides if you don’t have flywire screens on windows on your home or are sleeping in an untreated tent or out in the open.
- Mosquito coils can be effective in small outdoor areas where you gather to sit or eat.
- Make sure there is no stagnant water around your home. Empty pots and containers regularly.
- Visit for more information on how to protect yourself from mosquito bites.
While there is a limited supply of JE vaccine globally, it is available for Victorians who are most at risk of contracting the virus.
JE vaccine eligibility
JE vaccine is now available for anyone aged two months or older who lives or works in any of the high-risk local government areas (listed below) AND:
- Spend significant time outdoors (four or more hours per day), for unavoidable work, recreation, education or other essential activities, OR
- Are living in temporary or flood damaged accommodation (e.g. camps, tents, dwellings exposed to the external environment) that place them at increased risk of mosquito bites, OR
- Are engaged in the prolonged outdoor recovery efforts (clean up) of stagnant waters following floods*
*Vaccination can be administered after arrival in flood affected areas to those from other regions deployed for prolonged recovery efforts
Priority local government areas include, Campaspe, Gannawarra, Greater Shepparton, Indigo, Loddon, Mildura, Moira, Swan Hill, Wodonga, Towong and now Benalla, Wangaratta, and Strathbogie.
The risk of exposure to mosquitoes is low at an elevation over 500 metres. Therefore, JE vaccination is only recommended for individuals who spend significant time outdoors below this elevation in these LGAs.
Contact your GP to discuss if the JE vaccine is appropriate for you.
Reviewed 04 November 2022