Mosquito-borne diseases

Not all mosquitoes carry diseases – most are just a nuisance. However infected mosquitoes can carry a range of diseases including Ross River virus and Barmah Forest virus. While endemic across the state, these diseases occur more frequently in regional and coastal areas.

Mosquito numbers are high along many parts of the Murray River and its surrounds, from Mildura to Wodonga.

Recent mosquito breeding is forecast to further increase mosquito biting in the upcoming weeks.

As COVID-19 restrictions ease, there are greater opportunities to travel around Victoria and enjoy increased outdoor activity. Taking measures to avoid mosquito bites is therefore a critical step to protect against diseases.

  • Mosquito-borne diseases can cause life-threatening illness.
  • There are many simple things you can do to avoid getting bitten by mosquitoes.
  • Use an effective mosquito repellent, containing either picaridin or DEET, on all exposed skin.
  • Wear loose fitting clothes that cover your skin.
  • Try to limit outdoor activity if lots of mosquitoes are about (usually dusk and dawn).
  • Take action to prevent mosquito breeding around your home.

For more information, go to the Better Health Victoria's website by clicking here

For resources, click below:

Japanese encephalitis virus (JE virus)

Japanese encephalitis virus (JE virus) has been detected in Victoria for the first time. JE virus is a rare but potentially serious infection of the brain caused by a virus spread to humans through mosquito bites.

The virus is mostly spread to humans from pigs via mosquito bites and cannot be spread from human to human. It also cannot be spread by eating pork. 

A comprehensive response across human and animal health sectors is underway in Victoria and to implement control measures. Examples of this response include; vaccinating those at risk, surveillance of animals for JE virus, public health information, and mosquito testing and control activities.

The Beat the Bite website on the Better Health Channel provides information about mosquito borne diseases and mosquito bite prevention for the general public. Find out more by clicking here.

For more information, including the Victorian Department of Health's latest response to the virus, click here

JEV Forum

In partnership with the Department of Health and Agriculture Victoria and Albury Wodonga, Loddon Mallee and Goulburn Valley public health units a JEV Forum was held in April 2022. Speakers included Professor Deborah Friedman, Deputy Chief Health Officer – Communicable Diseases, Victorian Department of Health and Dr Graeme Cooke, Chief Veterinary Officer, Agriculture Victoria.

To listen to the recording of the event, go to

Ross River virus

Recent rainfall has been favourable to mosquito breeding in coastal areas and around the Murray River and its major river systems. Ross River virus has been repeatedly detected in mosquitoes in these inland areas. There is increased risk that people living in or travelling to these areas may be infected by mosquitoes carrying Ross River virus.

Ross River virus is endemic throughout Victoria. All mosquitoes may carry a risk for Ross River virus infection, although the risk is greatest in rural and regional Victoria, including many coastal and riverine holiday areas. Infections occasionally also occur in outer metropolitan areas. Ross River virus can cause joint swelling and pain, fatigue and muscle aches which can persist for many months. A rash and fever may also develop. It takes three to nine days for symptoms of Ross River virus disease to occur after exposure, and occasionally up to 21 days.

For more information, click here

Murray Valley encephalitis

MVE virus was first isolated from patients who died from encephalitis in the Murray Valley in Victoria and South Australia in 1951. It was previously included as one of the causative agents in the disease called ‘Australian encephalitis’, which also included disease caused by Kunjin virus, another flavivirus. These viruses are now accepted as causing two separate diseases: MVE and West Nile/Kunjin. Since 2010, Kunjin has been known as West Nile/Kunjin virus.

MVE virus commonly infects humans without producing apparent disease (subclinical infection). Only one person in about 800 of those infected with MVE virus develops clinical disease. It may also cause a comparatively mild disease with features such as fever, headache, nausea and vomiting. In a small percentage of all people infected, mild disease may be a prodrome to disease progression and the involvement of the central nervous system. This can result in meningitis or encephalitis of variable severity. Signs of brain dysfunction, such as drowsiness, confusion, fitting, weakness or ataxia, indicate the onset of encephalitis.

For more information, click here