An eight-year-old boy is critically ill in a Brisbane hospital with the Australian bat lyssavirus.

The boy was bitten or scratched by a bat two months ago in north Queensland, and became ill three weeks ago.

This morning Queensland Health's chief health officer, Jeannette Young, told a media conference the boy is critically ill but is in a stable condition.

Dr Young says the boy is in a coma with encephalitis type symptoms.

"This is an extraordinarily difficult and distressing time for the family and I really do ask that you take that into consideration," she said.

Dr Young says as a precaution, post-exposure drugs have been given to the family and those who have been in close contact with the boy.

Australian bat lyssavirus, which is closely related but not identical to the rabies virus, was first discovered in 1996.

It is only the third confirmed case of Australian bat Lyssavirus, with the previous two being fatal.

One was a woman who was bitten on the finger while trying to remove a flying fox from a child.

The other was an animal carer.

Queensland Health says the best protection is to avoid handling flying foxes, and if bitten, seek immediate medical attention.