Ross River virus infection

What is Ross River virus infection?

Ross River virus infection (also known as Ross River fever and epidemic polyarthritis) is caused by an alphavirus. It is spread to humans by infected mosquitoes.

Other diseases caused by alphaviruses are:

• Barmah Forest virus
• chikungunya virus

Ross River virus infection is the most common mosquito-borne disease in Australia. It’s also found in:

• Papua New Guinea
• parts of Indonesia
• the western Pacific Islands

In Australia, it’s more common in the tropical areas of:

• Queensland
• the Northern Territory
• Western Australia

Ross River virus infection is more common:

• between February and May
• after heavy rainfall
• after high tides

What are the symptoms of Ross River virus infection?

Many people, particularly children, who are infected with Ross River virus never get symptoms.

About 3 in 10 people develop symptoms. These usually appear about 7 to 10 days after being bitten by an infected mosquito.

The illness usually begins with:

• painful, swollen joints (arthritis)
• muscle and tendon pain

The most commonly affected joints are the:

• fingers
• wrists
• ankles
• knees

Other symptoms include:

• fever
• headache
• muscle and joint pain, swelling and stiffness
• a raised red rash on your body, arms or legs
• fatigue (tiredness)
• swollen lymph nodes

Children tend to have milder symptoms and be sick for a shorter time than adults.

How long does it last?

It’s not possible to say how long Ross River virus infection will last for an individual.

Some adults recover from Ross River virus infection in 2 to 6 weeks.

Most people will get better over 3 to 6 months. At 6 months, about 1 in 20 people will still have joint pain and tiredness.

What causes Ross River virus infection?

You can catch Ross River virus infection if you are bitten by an infected mosquito. Mosquitoes live in still water, including puddles and buckets.

Outbreaks of Ross River virus infection can occur when and where mosquitoes breed. The highest risk is in warm, humid areas near water.

Ross River virus infection does not spread from person to person.

Climate change is likely to lead to more summertime wet weather events in south‐east Australia. This is likely to increase rates of Ross River virus infection.

When should I see my doctor?

See your doctor if you have symptoms of Ross River virus infection.

How is Ross River virus infection diagnosed?

Your doctor can diagnose Ross River virus infection by examining you. They may also ask you questions about where you live or have recently visited. This is to work out if you have a high risk of becoming infected.

Your doctor will organise a blood test to measure your antibody levels to the virus. You’ll need to have 2 blood tests taken. First when you’re sick, and another 2 weeks later. This allows your levels of antibodies to be compared.

Ross River virus infection is a notifiable disease. This means that if you have Ross River virus infection, the lab has to tell the local public health authority. They may ask to talk with you to try and find out where you caught Ross River virus infection.

Sometimes you may need other blood tests to rule out other types of arthritis.

How is Ross River virus infection treated?

There is currently no treatment for Ross River virus infection. There are also no antiviral drugs to treat viral arthritis.

Pain relief medicines such as paracetamol and anti-inflammatory medicines (such as ibuprofen) can help ease your symptoms.

It’s also important to rest, eat a healthy diet and get some exercise.

Can Ross River virus infection be prevented?

There is no vaccine for Ross River virus, so preventing mosquito bites is important. You can protect yourself by doing the following.

• Use an insect repellent containing diethyltoluamide (DEET), picaridin, or oil of lemon eucalyptus.
• Cover up when you’re outside, with loose light-coloured clothing and covered footwear.
• Stay indoors at dawn and dusk when mosquitos are most active.
• Cover windows, doors, vents and other entrances with screens.
• Remove any containers of water from around your home — to stop mosquitoes breeding.
• Use mosquito lanterns or coils to repel mosquitoes.
• Sleep under a mosquito net.

You should try to increase your mosquito bite avoidance measures after intense summertime rain. Research has shown that mosquito numbers increase about 2 weeks after a wet weather event.

Ross River virus infection complications

A small number of people — about 2 in 100 — will still have symptoms after a year.

If you still have symptoms after a year, it’s a good idea to visit your doctor. They may be able to provide some relief from symptoms and run more tests.