The Murray Valley Encephalitis virus - which causes inflammation of the brain - has led to hospitalisation of at least six Australians, Western Australia Today reported.
The virus causes fever, nausea and dizziness. In severe cases, victims can experience delirium or lapse into coma.
The two deaths have led the health department to issue a stern warning about the virus.
"It causes inflammation of the brain. People have suffered paralysis and brain damage of varying degrees. Every case is very significant, because about one-quarter of all cases die, and of those that survive they're left with severe nerve damage that can result in paralysis," a spokeswoman said.
There is yet no cure for the virus, nor a vaccine to prevent infection, she said.
In addition to the Murray Valley Encephalitis virus, mosquito-borne Kunjin, Ross River and Barmah Forest viruses are also causing infection in the country.
