Ross River virus (RRV) and Barmah Forest virus (BFV) are two of the most important mosquito-borne viruses
causing human disease in Western Australia. The diseases caused by infection with these viruses are known as
RRV disease and BFV disease. The two viruses have similar life cycles and cause similar symptoms in people.
In nature, RRV and BFV are passed back and forth between animals and mosquitoes. The only way humans can
catch the disease is through being bitten by a virus-carrying mosquito. RRV and BFV cannot be caught from
direct contact with another person or animal. The incubation period [the time between being bitten (infected)
and becoming sick] for both diseases varies from three days to three weeks, but is normally seven to fourteen
days. Fewer than one in three people will develop symptoms after being bitten by an infected mosquito. It
may be possible for humans to pass the virus back to mosquitoes that bite them but only during the incubation
RRV and BFV diseases are notifiable under the Health Act. This means a doctor who diagnoses either virus in a
patient is required to inform the Department of Health, so that more can be learnt about the distribution of
the viruses, and so that public health action can be taken if appropriate, such as measures to control
mosquitoes and the issuing of public warnings.
People suffering from RRV disease or BFV disease may develop a wide range of symptoms that are common to
both diseases. The symptoms vary from person to person but include painful and/or swollen joints, sore
muscles, aching tendons, skin rashes, fever, tiredness, headaches and swollen lymph nodes. Less common
symptoms include sore eyes, a sore throat, nausea, and tingling in the palms of the hands or soles of the feet.
The symptoms may be similar to some rheumatic diseases or other viral diseases, so they can only be reliably
diagnosed by a specific blood test ordered by a doctor.
Pain in the joints is much more common than swelling. The most commonly affected joints are the wrists,
knees, ankles, fingers, elbows shoulders and jaw. Pain usually develops rapidly and may be intense, and more
severe in different joints at different times. When they are severe or prolonged, the symptoms can cause
emotional distress or depression, and can affect family, social and work relationships. The symptoms in
children tend to be milder and the disease runs a shorter course. A rash tends to be more common to BFV
disease and swollen joints are not as common and may not last as long as with RRV disease.
Fever, nausea and skin rash usually disappear within the first two weeks of illness. Joint, muscle and tendon
pain may last much longer and can be distressing. Often people experience severe tiredness (lethargy) and
they may feel depressed.
Symptoms subside eventually and leave few or no after-effects. It is not possible to predict how long an
individual person will take to fully recover from either disease. Some adults recover within two to six weeks
after the onset of infection. However, many people will still be unwell at three months. Symptoms can persist
for up to a year or more in rare cases. People with persistent symptoms are generally not sick all the time.
After three months, many experience days when they are well and as time goes by these periods become more
frequent. However, symptoms may recur suddenly and without warning.
Make sure caravans, tents and swags are in good repair and are fitted with effective flyscreens. If sleeping
under the stars, use a mosquito bed net over your sleeping bag or swag. Even the best repellents only last up to
four hours, so they are not effective all night. When outside the tent, cover up and wear a repellent.
Mosquitoes can breed in a variety of domestic situations. They need only a week or so in a small amount of
standing water to breed. Examples include:
Roof gutters, pot plant drip trays, garden rubbish, animal drinking containers and bird baths. Drain
or empty these containers once a week.
Septic tanks and leach drains. These must be completely sealed to prevent mosquitoes laying eggs
and breeding in the tank. The vent pipe must be fitted with a mosquito-proof cowl or screen.
Rainwater tanks. These should be sealed and have insect proof mesh over the inlet, overflow and
For further information on mosquito control and RRV and BFV prevention please contact your local government
Environmental Health Officer
Environmental Health Directorate
Department of Health
PO Box 8172
PERTH BUSINESS CENTRE WA 6849
Telephone: (08) 9385 6001
Facsimile: (08) 9383 1819
For more information on RRV and BFV diagnoses, treatment, support groups and education programs, contact
the Arthritis Foundation on:
Telephone: (08) 9388 2199
Toll-free: 1800 011 041
Online: www.arthritiswa.org.au (External link)