Murray Valley encephalitis (MVE) has claimed a man's life in Western Australia's far northern Kimberley region. It is the first reported case of the virus this year.
Western Australia's Health Department has issued a warning to people in the Kimberley and the Pilbara to take extra precaution to avoid being bitten by mosquitoes around swamp and river systems.
According to the department's Acting Medical Entomologist Sue Harrington there are no specific cures for Murray Valley encephalitis.
"MVE virus is carried by mosquitoes and, although rare, infection can be fatal or cause severe illness, so it is important that people take precautions to avoid bites from mosquitoes that breed after heavy rains in March," Ms Harrington said.
"Initial symptoms of MVE include fever, drowsiness, headache, stiff neck, nausea and dizziness and people experiencing these symptoms should seek medical advice quickly," she added.
Health experts say that fever may be the only sign of the virus in young children.