Rare mosquito-borne disease in Vic

A rare mosquito-borne disease has landed in Victoria for the first time, prompting urgent warnings to travellers.

A 45-year-old Melbourne man has been diagnosed with Japanese encephalitis after a recent trip to Bali.

The viral condition, which is spread by mosquitoes, is fatal in 20 to 30 per cent of cases.

It also causes long-term neurological problems in up to 50 per cent of people who contract it.

Chief health officer Rosemary Lester says the man's "highly unusual" diagnosis, the first in Victoria, shows the importance of seeking advice before overseas travel.

"Travellers should also take all measures to protect themselves, especially in areas where diseases are known to be carried by mosquitoes," she said in a statement on Tuesday.

Preventing mosquito bites with suitable repellent was the best way to avoid contracting Japanese encephalitis and similar diseases, she said.

There have been only nine cases of Japanese encephalitis notified in Australia.

The virus, which is the leading cause of viral encephalitis in Asia, cannot be spread from person to person.