Most human infections cause no symptoms or mild ones such as headache or fever.
But a person with severe disease may present with inflammation of the brain, characterised by sudden onset of vomiting, high fever and chills, severe headache, sensitivity to light, neck stiffness and nausea or vomiting.
Children aged under 5 and older people are at a higher risk of developing more severe illness.
"We encourage Queenslanders to take necessary steps to prevent being bitten by mosquitoes, especially given the recent flooding event which may lead to an increase in mosquito numbers in coming weeks," Queensland Health said in a statement.
The human case follows a detection at a piggery in southern Queensland last week.
There have also been detections in NSW, Victoria and South Australia.
"There is no risk to humans from consuming pork or pig products. Pork products are safe to eat," Queensland Health said.
"The virus cannot be spread directly from person to person."
Queensland Health is working with the Department of Agriculture as well as state, territory and federal agencies to discuss a national response.
Support is also being provided to intensive livestock industry workers.
Further south, NSW officials are responding to an outbreak in animals of the mosquito-borne disease, which has never been seen in southern Australia before.
Officials realised last week Japanese Encephalitis was spreading in piggeries in the state's south after agriculture businesses noticed an increase in stillborn piglets.
The disease has been detected in six piggeries in NSW, one in Victoria and one in Queensland.
Four human cases have been detected in Victoria.
People have been warned to avoid being bit by mosquitoes and there are concerns the insects will spike in numbers due to the ongoing flooding crisis.
NSW health secretary Elizabeth Koff said officials were focused on preventing Japanese encephalitis from spreading to people.
Though most people who get infected experience no symptoms, children are vulnerable and on rare occasions get seriously ill.
Symptoms include fever, joint pain and rashes and in severe cases patients have suffered from neurological illness with headaches, convulsions and loss of consciousness.
"It's most concerning in the under-5 age group," Koff said.
She added NSW had secured "plentiful supplies" of vaccines that can protect against the disease.
In a warning issued last weekend, NSW chief health officer Kerry Chant said people should take care to protect themselves against mosquito bites.
"It is really important to protect yourself from mosquito bites as mosquitoes can spread viruses including Japanese encephalitis," she said.
The current Japanese encephalitis outbreak is the first time the virus has been detected in southern Australia, according to Australian chief veterinary officer Dr Mark Schipp.
"Biosecurity authorities are working with their human health departments to understand the implications and risks of human exposure," he said earlier in the week.
The wet summer has provided good breeding conditions for mosquitoes and stagnant pools of water left by the ongoing floods on the east coast could lead to an even bigger increase.
"Mosquitoes carry multiple and potentially dangerous illnesses, and people in rain-affected areas are particularly vulnerable right now given these conditions are ripe for mosquito activity," Queensland Health Minister Yvette D'Ath said.
"Some of the most common mosquito-borne illnesses are Ross River virus, Barmah Forest virus and malaria, though these are only some of what can be spread by a mosquito bite."
