Department of Health

Japanese encephalitis virus detected in Horsham area

01/12/25

The Department of Health has confirmed the first detection of Japanese encephalitis virus (JEV) in mosquitoes for the 2025–26 season and is reminding Victorians to understand the risks of mosquito-borne diseases when spending time outside over the warmer summer months.

The virus was found in a mosquito trap in the Horsham Rural City Council area as part of Victoria's Arbovirus Disease Control Program and marks the first time JEV has been detected in Australia this season.

The Department is working closely with Horsham Rural City Council to treat mosquito breeding sites and reduce the risk to the community.

Japanese encephalitis is a rare but potentially serious disease caused by a virus transmitted through mosquito bites. Most people infected have no symptoms or only mild illness, but in rare cases (around 1 in 250) it can cause severe brain infection (encephalitis), which can be fatal.

Victoria's Chief Health Officer, Dr Caroline McElnay, said that detecting Japanese encephalitis virus in mosquitoes plays a vital role in informing the community of current health risks.

"Mosquito-borne diseases like Japanese encephalitis can have serious health impacts, but they are preventable," Dr McElnay said.

"A free Japanese encephalitis vaccine is available for eligible people due to their increased risk of exposure."

"Simple actions like wearing repellent, covering up, and limiting outdoor activities at dawn and dusk can help reduce your risk."

"Anyone can be bitten by mosquitoes, but people living, working or spending time outdoors in northern Victoria – especially near rivers – may be at higher risk."

The best protection is to avoid mosquito bites. Simple steps include:

  • Wearing long, loose-fitting, light-coloured clothing outdoors
  • Using mosquito repellents containing picaridin or DEET
  • Limiting time outside when mosquitoes are most active (dawn and dusk)
  • Removing stagnant water around your home where mosquitoes breed

A free Japanese encephalitis vaccine is available in 24 local government areas across Victoria, including Horsham Rural City Council, for eligible people at increased risk, including those not eligible for Medicare.

A booster dose may be recommended for some people with ongoing risk of exposure, one to two years after completing their primary course.

Victorians are encouraged to speak with their GP, local council, Aboriginal health service, or community pharmacy for more information about JE vaccination.

For details on vaccine eligibility and how to protect yourself from mosquito-borne disease, see Japanese encephalitis on the Department of Health's website or visit the Better Health ChannelExternal Link .

Reviewed 01 December 2025

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