NSW Health has issued a warning about the rare but potentially fatal Murray Valley encephalitis virus which has been detected in a mosquito in the far west town of Menindee.
Murray Valley encephalitis (MVE) is spread to humans by infected mosquitoes.
In rare cases it can cause a severe brain infection which can lead to lifelong neurological complications or death.
A small proportion of infected people may experience symptoms such as fever, headache, nausea, vomiting, diarrhoea, muscle aches and loss of appetite.
NSW Health said the new detection was likely related to the recent flooding in Menindee, which has been facing inundation from the Darling River since late December.
The weather bureau has warned flood levels in Menindee could face record-breaking flood levels this week of 10.5 metres.
Executive director of Health Protection NSW Richard Broome said most people who were infected with the virus that caused MVE did not have any symptoms.
He said the only way to avoid the virus was to try to prevent mosquito bites.
"There is no vaccination or specific treatment for MVE, and the best way to avoid infection is to avoid being bitten by mosquitoes, which are most active between dusk and dawn," Dr Broome said.
"Avoiding mosquito bites will also protect against other mosquito-borne infections including Japanese encephalitis, Ross River fever and Barmah Forest virus."
The last time locally acquired cases of MVE were identified in NSW was in 2011.
Today the Victorian Department of Health also issued an alert about MVE after detections among mosquitoes in the north of the state.
This is the first detection in Victoria for more than 10 years but their last human case was reported in 1974.
South Australia has also warned residents there is a greater risk of MVE due to an explosion in mosquito populations at the moment.
SA Health has been notified of 38 cases of mosquito-borne diseases in South Australians this season, including one man who caught Japanese encephalitis virus (JEV).
MVE cannot be transmitted between humans and people cannot get the virus by touching an infected animal or eating animal products.
To help avoid the virus, NSW Health recommends:
- covering windows and doors with insect screens and checking there are no gaps in them
- removing items that might collect water (such as old tyres, empty pots) outside your house where mosquitoes can breed
- improving drainage on your property so water does not become stagnant
- wearing light, loose-fitting long-sleeved shirts, long pants and covered footwear and socks, especially around dusk and dawn
- applying repellent to all areas of exposed skin, using repellents that contain diethyltoluamide (DEET), picaridin, or oil of lemon eucalyptus
- re-applying repellent regularly, particularly after swimming, and being sure to always apply sunscreen first and then apply repellent
- using insecticide sprays, vapour-dispensing units and mosquito coils to repel mosquitoes
Three weeks ago the first Japanese encephalitis (JE) case of this mosquito season was detected in a resident of Lake Cargelligo in the Lachlan Shire.
NSW Health says supply of JE vaccine continues to be severely constrained in Australia but a vaccine clinic will soon be set up in Lake Cargelligo.
Pharmacist Mohammad Yousef has been vaccinating locals in Menindee and Wilcannia against JE.
"Mosquitoes here are very bad. A lot of people here are suggesting electric zappers," he told the ABC.
