Mosquito borne disease program Ross River and Barmah Forest virus The facts

In Australia, there are more Infection does not occur directly from General effects person to person. The picks than 70 different spread General effects of the virus vary greatly. up the virus from an infected animal and by insects. Only a few of these In more serious infections they can transmits it by feeding on another animal viruses are known to cause be severe, with fever, chills and high or human. illness in humans. Two arboviral temperature, severe headache and infections–– and The prevalence of the viruses varies irritation by strong light. Usually the according to the place and season. Barmah Forest virus––are important temperature is normal throughout, These viruses, particularly Ross River though there is still general discomfort because of their frequency and the virus, occur as a few sporadic cases or like that of the ’flu. Tiredness is disabling rheumatic symptoms they small outbreaks. At other times, when common and can persist or recur later in can cause. climatic conditions are conducive, large the illness. Ross River virus (RRV) is the most epidemics occur. Both viruses affect all Rheumatic symptoms common and widespread of the age groups and men and women are that infect humans equally susceptible. Rheumatic symptoms––such as pain, in Australia. tenderness, stiffness in and around the Symptoms joints and in the muscles, and difficulty Barmah Forest virus was discovered in Between 70–90 per cent of people moving––can appear suddenly. These 1974, more recently than Ross River virus infected with RRV have slight or no symptoms may be felt initially in only a (1963). It is also widespread in Australia symptoms. Between 10–30 per cent few joints and then develop gradually and causes a similar illness. However, of these develop an illness which may or explosively over the next two weeks. Barmah Forest virus disease has not include a rash, general effects and Any joint can be affected, including the yet been as intensively studied. The rheumatic symptoms. jaw, however symptoms tend to be more symptoms are similar to Ross River virus common and persist longer in the limbs. and anyone who thinks they may have Rash Individual joints can be quite swollen and symptoms of either disease should see A rash occurs in about half of all cases. ligaments near joints and tendons, such their doctor. This may be only a few spots on the as the Achilles tendon, can be painful. Both diseases can be confirmed by hands and feet or it may cover the whole blood tests. body. The rash consists of small red Recovery spots, often slightly raised. Sometimes The worst of the symptoms can last Infection it may look purplish or like bruises or up to eight weeks, however complete These viruses occur throughout Australia small blisters similar to chicken pox. The rest is generally required only for a and Ross River virus disease has been rash rarely itches, however, the skin may week or two. Some people need hardly found in eastern Indonesia, Papua New be sensitive to touch, especially on the any rest, especially if they respond to Guinea and the nearby Pacific Islands. hands or feet. treatment quickly. In the later stages of In Victoria, infection can be acquired The rash usually lasts around seven to the illness, stiffness can occur with rest in most parts of the State except the ten days and can occur up to two weeks or immobility, for example a long car trip, highest or driest. before or after other symptoms. It can be and it is relieved by movement. Most indistinguishable from the rash of rubella people do not need any treatment at and certain other infectious diseases. this stage. Continued overleaf

Department of Health The severity and extent of the symptoms Confirming the diagnosis In some areas, the breeding of gradually diminish. Some people will mosquitoes around the home or Anyone who develops symptoms of recover fully in three months and most workplace can be reduced by ensuring these viruses should see the doctor within one year. that water does not collect. On farms, so that the exact condition can be good irrigation practice can greatly diagnosed. This is important because the Long-term effects reduce the problem. features are very similar to rubella and Despite the severe effects that people the more serious condition, rheumatoid Personal measures include: sometimes suffer in the early stages arthritis, which need to be identified and • Wearing loose-fitting light-coloured of the illness, there is no permanent treated. Also, the prevalence of these clothing, especially in late afternoon damage, instability or weakness. diseases is useful for authorities that are and early evening. Strenuous exertion can briefly aggravate working to reduce the risk of infection • Having effective insect screening in the symptoms, however, in the later within the community. stages it is important to be mobile so that the home, including fireplaces in the secondary stiffness does not develop. Treatment warmer months. • Using a ‘knock-down’ insecticide (such Diagnosis In the acute stage of the illness and in later flare-ups of the rheumatic as pyrethrin) in the house before going A blood test will confirm that there has symptoms, anti-rheumatic treatments to bed. been recent Ross River virus or Barmah provide relief and allow people to resume • Using an insect repellent effective Forest virus infection, and it may need all or most of their essential activities. against mosquitoes on exposed areas to be repeated to be certain. The doctor With the range of treatments now of skin. See the brochure Protecting may also ask for other blood tests to available, there is a much better chance against Mosquito Bites and Disease. exclude other conditions. If there is fluid of finding an effective drug that does not in a joint, it can be removed through a produce troublesome side-effects. More information fine needle with local anaesthetic. This For more information, contact may allow an immediate diagnosis of Prevention your local council or the virus arthritis, though the exact kind will The species of mosquito that can Communicable Disease Prevention have to be shown by blood tests. The transmit the virus varies from place to and Control Unit of the Department fluid test can also help to exclude other place and with temperature and other of Health on 1300 651 160. kinds of arthritis. factors. Council Environmental Health http://www.health.vic.gov.au/ideas Officers can provide information about local environments.

Prepared by the Department of Health in conjunction with the Victorian Task Force. March 2010 PH575