Japanese encephalitis (JEV) has been found for the first time in feral pigs in far north Queensland.
The discovery of the mosquito-borne disease follows an outbreak across four states that is linked to the deaths of five people so far this year.
Biosecurity Queensland said a small number of feral pigs in the Skardon River area in western Cape York Peninsula had tested positive for the disease following routine testing.
The Indigenous community of Mapoon is the closest population base to Skardon River.
Health authorities said the risk of transmission to humans was very low.
Mosquito numbers low in area
The virus is transmitted to people and animals — primarily pigs, horses and migratory birds — through mosquito bites.
It cannot be transmitted directly from human to human nor from animal to human.
Tropical Public Health Unit director Richard Gair said JEV had not been detected in any people in the area.
"It is an isolated area and the mosquito numbers are very low," Dr Gair said.
"It is only quite rarely that humans will get the disease, and if they do get it, they aren't infectious.
"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 and vomiting."
Five people, including one in Queensland, are reported to have died of the disease this year with more than 40 human cases detected across the country.
Dr Gair said while there was a vaccine available for the disease, the best defence was to avoid being bitten by mosquitoes, through applying insect repellent and wearing loose clothing to cover up.
The disease is endemic in southern areas of Asia, as well as India and is detected seasonally in China.
Dr Gair said it could not be transmitted by eating pork or pig products.
In a statement, Biosecurity Queensland said landholders in the area had been contacted by the department about the positive samples detected in feral pigs.
