- Advisory number:
- Date issued:
- 25 Nov 2020
- Issued by:
- Dr Annaliese van Diemen, Deputy Chief Health Officer (Communicable Disease)
- Issued to:
- Health professionals and the Victorian community
- Residents and visitors to Victoria are being warned to protect themselves against mosquito-borne diseases such as Ross River virus and Barmah Forest virus.
- Ross River virus has been detected in mosquitoes in the Gippsland Lakes area around Ninety Mile Beach.
- These viruses can cause symptoms including joint pain and stiffness, headache, fever, rash and fatigue.
- The best protection from these diseases is to avoid mosquito bites - protective measures include regularly using mosquito repellent containing picaridin or DEET on all exposed skin, wearing long, loose fitting clothing when outside, and ensuring accommodation, including tents, are properly fitted with mosquito nettings or screens.
- Doctors should consider the possibility of mosquito-borne disease in patients presenting with a compatible illness, especially after travel to rural or regional Victoria.
- A blood test early in the illness can indicate potential acute infection and should be repeated two weeks later for confirmation.
- A range of information relating to protecting against mosquito bites is available on the campaign page on the Better Health Channel.
What is the issue?
Not all mosquitoes carry diseases – most are just a nuisance. However infected mosquitoes can carry a range of diseases including Ross River virus and Barmah Forest virus. These diseases can cause serious illness and occur regularly in regional Victoria.
Ross River virus has been detected in mosquitoes in the Gippsland Lakes area around Ninety Mile Beach.
Recent weather conditions are favourable to mosquito biting and breeding.
As COVID-19 restrictions ease, there are greater opportunities to travel around Victoria and enjoy increased outdoor activity. Taking measures to avoid mosquito bites is therefore a critical step to protect against diseases.
Who is at risk?
Anyone is potentially at risk of being bitten by mosquitoes and while most bites will only cause minor swelling and irritation, an infected mosquito can transmit potentially serious diseases.
All parts of Victoria where there are mosquitoes may carry a risk for Ross River virus infection, although the risk is greatest in rural and regional Victoria, including many coastal holiday areas. Infection appears to be rare in outer metropolitan areas.
Symptoms and transmission
Ross River virus and Barmah Forest virus disease are similar. Both can cause joint swelling and pain, fatigue and muscle aches which can persist for many months. A rash and fever may also develop. It takes three to nine days for symptoms of Ross River virus disease to occur after exposure, and occasionally up to 21 days. Barmah Forest virus disease symptoms occur between seven to ten days after a bite from an infected mosquito. While everyone recovers from the initial onset, symptoms may recur in some individuals for over a year or more.
Doctors should consider the possibility of mosquito-borne disease in patients presenting with a compatible illness, especially after travel to rural or regional Victoria. A blood test early in the illness can indicate potential acute infection and should be repeated two weeks later for confirmation.
Ross River virus and Barmah Forest virus disease must be notified by pathology services in writing within five days of diagnosis.
There are simple steps to protect against mosquito-borne diseases:
- Wear long, loose fitting clothes if mosquitoes are around.
- Use effective mosquito repellents containing picaridin or DEET on all exposed skin.
- Try to limit outdoor activity if lots of mosquitoes are about. The hours before and after sunrise and sunset is when most mosquitoes are more active, but some will also bite in the middle of the day.
- Use ‘knockdown’ sprays and plug-in vaporising devices indoors.
- Sleep under mosquito nets treated with insecticides if you don’t have flywire screens on windows on your home or are sleeping in an untreated tent.
- Sleep under a mosquito net if camping out in the open.
- Mosquito coils can be effective in small outdoor protected areas.
Treatment is symptomatic, with rest advisable in the acute stages of the disease. There is no vaccine currently available commercially to protect against Ross River Virus disease.
For more information please contact the Communicable Disease Prevention and Control section at the Department of Health and Human Services on 1300 651 160 (24 hours).
Reviewed 26 November 2020