NSW Residents Warned to Stay Vigilant This Mosquito Season
04 Dec 2025
Health alert as mosquito season begins in NSW
NSW residents are being urged to take extra care this summer following the unusually early detection of mosquito-borne viruses that can cause severe illness, including inflammation of the brain.
Surveillance has identified Japanese Encephalitis (JE) virus in mosquitoes earlier than expected for the 2025–26 season, with the first detection linked to mosquitoes collected from the Horsham region in Victoria. In addition, Kunjin virus has been found in western New South Wales, after routine monitoring detected the virus in a sentinel chicken near Cowra on 20 November 2025.
Health authorities say the early appearance of these viruses is worrying, as mosquito populations typically expand as temperatures rise.
According to NSW Health, mosquitoes can carry several serious infections, including Japanese Encephalitis, Murray Valley Encephalitis, Kunjin virus, Ross River virus and Barmah Forest virus. Preventing bites remains the most effective way to reduce the risk of illness.
Currently, 60 local government areas across NSW are classified as higher risk for Japanese Encephalitis, particularly regions west of the Great Dividing Range and in northern parts of the state. People living in, working in, or travelling to these areas are encouraged to be especially cautious.
A free and highly effective vaccine is available to protect against Japanese Encephalitis for eligible groups, including residents and workers in high-risk LGAs and people in certain occupations with increased exposure. The vaccine can be accessed through GPs, Aboriginal health services and participating pharmacists. Appointments are recommended in advance, as clinics may need time to obtain the vaccine and may charge a consultation fee.
For some individuals with ongoing exposure, a booster dose may be advised one to two years after the initial vaccination course.
There is no vaccine or targeted treatment available in Australia for Kunjin virus or most other mosquito-borne infections, making prevention critical. Mosquitoes are most active during the early morning and evening hours.
To lower the risk of mosquito bites, health officials recommend:
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Using insect repellents containing DEET, picaridin or oil of lemon eucalyptus, and reapplying as instructed
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Applying sunscreen first, then repellent, and reapplying after swimming
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Wearing long sleeves, long pants, socks and enclosed footwear, particularly at peak mosquito times
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Limiting outdoor exposure around dawn and dusk
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Using household mosquito control products such as sprays, vapour devices or outdoor coils
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Ensuring windows and doors are fitted with well-maintained insect screens
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Removing standing water around homes where mosquitoes can breed
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Choosing child-safe repellents and following age guidelines on product labels
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Protecting young infants with mosquito netting over prams or carriers
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Using screened tents or mosquito nets when camping
Mosquito-borne viruses cannot spread directly between people.
Further details about eligibility for the free JE vaccine and general mosquito-borne disease prevention advice are available through NSW Health resources.
https://www.health.nsw.gov.au/Infectious/jev/Pages/vaccination.aspx
https://www.health.nsw.gov.au/mosquitoes
News Source: NSW Health
