Ross River virus and Barmah Forest virus

Ross River virus and Barmah Forest virus are infections that are spread to humans through mosquito bites. They cause similar illnesses, including joint inflammation and pain. People of all ages are at risk of developing these infections. Ross River virus is the most common and widespread of mosquito borne diseases that infect humans in Australia. It is also known as epidemic polyarthritis.

What are the symptoms?

The majority of people infected with these viruses have slight or no symptoms. About three out of ten people will develop symptoms which usually appear within three to 21 days after infection and can include:

  • a rash on the trunk and limbs. The rash usually consists of small red spots and lasts around seven to ten days. It can occur up to two weeks before or after other symptoms. It may appear similar to rashes associated with other infectious diseases.
  • general illness with fever, chills, headaches and tiredness.
  • joint pain, stiffness and swelling. It commonly affects the fingers, wrists, ankles and knees, but any joint can be affected. Pain can also be felt in tissues surrounding joints, such as muscles, ligaments and tendons.

What causes it?

You can be infected if you are bitten by a mosquito carrying the virus. It is suspected that mosquitoes pick up the viruses from native animals, most likely kangaroos and wallabies. The viruses occur throughout most regions of Australia. Human infections tend to occur more often in regions with a warm, humid climate, that are close to bodies of water where mosquitoes breed. Outbreaks also occur when local conditions of rainfall, tides and temperature result in increased mosquito populations.

How is it diagnosed?

Anyone who develops symptoms of these viruses should see a doctor so that the exact condition can be diagnosed. Your doctor can diagnose Ross River virus or Barmah Forest virus infection from your symptoms and physical examination. A blood test can confirm that there has been recent infection by the virus, although it may need to be repeated to be certain. Your doctor may also order blood tests to help rule out other types of arthritis, as the symptoms may be similar.

What treatments are there?

Your doctor will tailor your treatment to your symptoms and how severe your condition is. There is no way of predicting exactly which treatment will work best for you. Your doctor may need to trial several different treatments before finding the one that is right for you.

Medicines used to treat Ross River virus and Barmah Forest virus include:

  • simple pain relief, using medicines such as paracetamol
  • non-steroidal anti-inflammatory drugs (NSAIDs).