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Health alert – New Murray Valley encephalitis virus detections in northern Victoria (update)

Date issued: 25 January 2023 (update to alert issued 21 January 2023)

Issued by: Associate Professor Deborah Friedman, Deputy Chief Health Officer (Communicable Disease)

Issued to: Health professionals and the Victorian community


There have been more detections of Murray Valley encephalitis (MVE) virus in mosquitoes trapped at multiple locations across northern Victoria. These results mean that MVE virus is circulating widely in the mosquito population and indicate a significant risk to people in these areas, particularly Mildura and northern Victoria’s inland river regions. The risk area for MVE virus is similar to that for Japanese encephalitis virus (JEV) and the risk of human cases in the coming weeks is very high. This risk is expected to continue while mosquito numbers remain elevated.

Public health advice for Mildura and northern Victoria’s inland river regions

Residents and people visiting northern Victoria are strongly advised to take measures to reduce their risk of mosquito bites:

  • Residents, visitors and event patrons should wear an appropriate repellent at all times when outdoors.
  • Cover up – wear long, loose-fitting, light-coloured clothing.
  • Avoid time spent outdoors at dusk and dawn as much as possible.
  • Event organisers must consider their obligations to keep event patrons safe. This requires informing patrons of the risk of mosquito exposure and the necessary protective measures, including appropriate clothing and use of repellent. Organisers may wish to postpone outdoor events or relocate them indoors during this high- risk period, particularly for events scheduled around dawn and dusk.

Local councils are undertaking mosquito control activities in affected areas.

Key messages

  • Murray Valley encephalitis (MVE) virus has been detected in mosquitoes in northern Victoria this mosquito season.
  • MVE virus can cause a rare but potentially serious infection of the central nervous system and is spread to humans by infected mosquitoes.
  • Symptoms may include fever, headache, nausea, vomiting and muscle aches, although most infected people do not have symptoms. In serious cases, people can develop meningitis or encephalitis.
  • Anyone with symptoms should seek urgent medical care.
  • Clinicians should test for MVE virus and Japanese encephalitis virus in patients with a compatible illness.
  • Clinicians should notify the Department of Health immediately of suspected cases by calling 1300 651 160.
  • The risk of MVE virus infection and other mosquito-borne diseases is high this mosquito season. The best prevention is to protect against mosquito bites.
  • Read the full alert: New Murray Valley encephalitis virus detections in northern Victoria

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