Barmah Forest virus infection

About Barmah Forest virus infection

Barmah Forest virus disease is caused by an alphavirus, which is spread by mosquitoes.

Barmah Forest virus disease occurs throughout most regions of Australia including regional Victoria, particularly around inland waterways and coastal regions. However, it's relatively rare in Victoria. There were less than 20 cases reported in Victoria each year between 2015 and 2023.

Epidemics occur from time to time and are related to environmental conditions that encourage mosquito breeding, such as heavy rainfall, floods, high tides and moderate temperatures.

Symptoms of Barmah Forest virus infection

Symptoms usually begin to appear between 7 to 10 (up to 21) days after becoming infected. However, many people infected with Barmah Forest virus will never develop any symptoms.

The symptoms of Barmah Forest virus disease are similar to Ross River virus disease, another mosquito-borne illness.

Symptoms and severity vary from person to person, but can include:

• fever
• chills
• headache
• tiredness or fatigue
• joint pain and swelling – may affect wrists, knees, ankles or small joints of the extremities, such as fingers or toes
• rash of variable appearance on the trunk and limbs
• muscle aches and pains
• swollen lymph nodes

Some people, particularly children, may show no symptoms.

Most people with Barmah Forest virus disease recover completely within 6 months. Current knowledge suggests that the body builds an immune response to the virus, which is likely to protect you against the disease for the rest of your life.

Some people may have symptoms that last longer than 6 months or recur, but these may be due to other causes. See your doctor to check your diagnosis if you are concerned about ongoing symptoms.

Transmission of Barmah Forest virus

People can be infected with Barmah Forest virus when they are bitten by a mosquito carrying the virus. It is suspected that mosquitoes pick up the virus from kangaroos, cattle and other animals that can act as a natural host for the virus.

Barmah Forest virus is not spread directly from one person to another.

Diagnosis of Barmah Forest virus infection

Blood tests can reveal if a person has been infected with Barmah Forest virus recently or in the past.

Prevention of Barmah Forest virus infection

There is no preventive vaccine available. Your only protection against Barmah Forest virus and the most effective way to prevent other mosquito-borne diseases is by avoiding mosquito bites and removing mosquito breeding sites around your home and property.

How to protect yourself from mosquitoes

Protect yourself and your family from exposure to mosquitoes and mosquito-borne diseases:

• Wear light-coloured, loose-fitting clothes and covered shoes outdoors.
• Use mosquito repellents containing Picaridin or DEET on all exposed skin.
• Limit outdoor activity if lots of mosquitoes are about.
• Use ‘knockdown’ fly sprays and plug-in repellent devices indoors.
• Cover all windows, doors, vents, and other entranced with insect screens.
• 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 or property by emptying pots and containers at least once a week.
• Visit our Protect yourself from mosquito-borne disease page for more information.

Treatment for Barmah Forest virus infection

There is no specific treatment available for Barmah Forest virus infection. Your doctor will be able to advise you on treating the symptoms.

Where to get help

• Your GP (doctor)
• Your local council
• Nurse-on-Call Tel. 1300 60 60 24 – for confidential health advice from a registered nurse, 24 hours a day, 7 days a week
• Department of Health, Communicable Disease Prevention and Control, Victorian Government. Tel. 1300 651 160