Barmah Forest Virus

Barmah Forest is a viral disease, transmitted to humans by the bite of a mosquito.

It is a vector-borne disease. The virus is endemic to Australia and Papua New Guinea.

The reservoir for the disease hasn't been fully established but it is likely mosquitoes pick up the virus from infected marsupials (possums, kangaroos and wallabies).

Barmah Forest is the second most common arboviral disease (diseases transmitted by insects) in Australia. Major outbreaks have occurred in the past.

The disease is notifiable in Australia. Fewer cases are being reported in the last few years than 10 years ago.

Most cases occur in Queensland followed by NSW. It does occur in the southern states, but the numbers vary with climatic conditions. Outbreaks of the disease often occur after heavy rains.

There have been more than 120 notifications across Australia in 2026. Over 70 cases have been notified in QLD.

Barmah Forest virus disease is like Ross River Fever but causes less morbidity. Treatment can only be directed towards the relief of symptoms.

There is no vaccine.

The disease was first isolated in 1974 and named after the Barmah Forest region in northern Victoria.

Determinants of risk are very similar to RRVD.

• Local mosquitoes known to carry the virus (Aedes camptorhynchus, Aedes vigilax, and Culex annulorostris,)
• Presence of likely vertebrate reservoirs for the disease (kangaroos and wallabies in rural areas and possums in urban areas)

It is more common in summer and autumn (spring in WA).

Fact sheets are available from most State health departments. See NSW, VIC, WA, QLD.

Individuals at most risk are those intending to do outdoor activities such as camping, fishing and hiking. The mosquitoes are most active early morning and at dusk.

Barmah Forest virus disease should always be suspected along RRVD (Ross River virus disease) in a traveller with a history of inflamed joints, muscle pains and fever who has visited an area or risk either in Australia or PNG.

Preventing Barmah Forest virus relies on effective mosquito avoidance. For detailed guidance, see Mosquito Avoidance Measures.

• Reduce exposure time by modifying activities
• Wear light-coloured clothing, and cover arms and legs as much as possible.
• Permethrin impregnation of clothing and bedding may be useful if there are a high prevalence of mosquitoes in your accommodation.
• Avoid highly scented perfumes, deodorants or toiletries.
• If possible, sleep under mosquito nets (preferably impregnated with permethrin) and if available, take advantage of ceiling fans and air-conditioning.
• Use mosquito repellents on exposed skin (see below).
• Use insecticide aerosols, mosquito coils or other agents in the immediate environment.

Repellents

The repellent of choice should contain DEET (N, N-diethyl-meta-toluamide). The higher the concentration of DEET, the longer the duration of protection. However, it should be noted that the general consensus is that there is no added benefit beyond 50% DEET concentration. DEET is toxic when ingested and may cause skin irritation in some people. If you have not used a DEET product before, or you have sensitive skin, it is advisable to test on a small area of skin before applying to larger areas of the body. DEET has been used over a long period of time, and by many millions of people with few reported serious side effects. Despite this, a few precautions should be undertaken:

• Apply DEET lightly to exposed areas only
• Where possible, wash off on returning indoors
• Do not apply to open cuts or sores
• Do not use aerosol applications to the face directly. Apply to the hands and then rub on the face avoiding the eyes and mouth
• Do not allow children <10 years to apply themselves. Weaker DEET formulations are available for children (10% DEET concentration)
• If sunscreens are to be used with repellents, then the sunscreen should be applied first. Wait 20 minutes before applying repellent

Picaridin, also known as Icaridin (1-piperidinecarboxylic acid 2-(2-hydroxyethyl)-1-methylpropylester), is a new alternative to DEET, and is a non-toxic, non-penetrative solution that is considered to be environmentally friendly and suitable for anyone 2 years and above. The recommended level of Picaridin is 20-25% and lasts for around 4-6 hours before the need to reapply. A 20% concentration of Picaridin is thought to be as effective as 20-30% of DEET.