A disease carried by mosquitoes which killed nine people in south-eastern Australia in 1974 has been found in Victoria.
The Murray Valley encephalitis (MVE) virus can cause swelling in the brain and eventually death in a small percentage of humans who contract the disease.
The state government said the virus has been found in two chickens around Kerang, 280km north-east of Melbourne.
Victoria's chief health officer John Carnie warned people near Kerang to avoid mosquito bites, but said the risks to humans was low.
Dr Carnie said even those who do show symptoms usually only get a headache, fever or neck stiffness.
He said dry, colder weather around the Murray River made for poor breeding conditions for mosquitoes and meant the risks of getting the MVE virus would decrease.
"If it progresses to inflammation of the brain (encephalitis) the symptoms are confusion, drowsiness, convulsions and then coma but the risks are extremely low," Dr Carnie said.
"People experiencing such symptoms should seek urgent medical attention from their GP or their local hospital.
"If you must engage in outdoor activity, wear long sleeved shirts, long pants, use mosquito repellent on exposed skin and get rid of areas harbouring mosquito larvae such as stagnant water.
"If you are out at dusk or dawn, when they are most active, you should prevent mosquito bites.
"We will be writing to doctors in Victoria to be on the lookout for any cases in the unlikely event we get a human case."
The disease is usually found in northern Australia but occasionally turns up in further south, possibly through migratory birds.
Dr Carnie assured Victorians the chances of humans experiencing any symptoms of the disease were low - about one in 1,000 if you are infected.
There were over 20 human cases in Victoria and 58 around the country during the 1974 outbreak.
While harmless to chickens, in humans the virus can travel to the brain and, in rare cases, can result in brain damage and death.
