Beef producers have experienced a significant rise in bovine ephemeral fever, commonly known as three day sickness, after receiving significant rain in February.
The arthropod-borne virus carried by mosquitoes and biting midges is more severe in heavier cattle, bulls pregnant and lactating cows, and some losses have been confirmed.
Some symptoms include a short fever, shivering, lameness and muscular stiffness.
St George livestock agent Andrew Wardle, GDL said three day sickness had been in that district for a good month.
"We have had reports from clients from Goondiwindi through to Cunnamulla who are holding back cattle and leaving them alone, as the symptoms only last a few days," Mr Wardle said.
"It is starting to ease now," he said
He said it was probably a bit more severe this year as it had been so dry for so long.
A spokesperson from the Longreach Veterinary Service, Longreach, confirmed outbreaks in the central west, in both the Longreach and Blackall districts.
"There have been significant cases reported in the Blackall district," they said.
Libby Harriman, Great Artesian Veterinary Service, Hughenden, said producers in the districts of Muttaburra, Hughenden, and as far as Richmond had been badly affected.
"It affects the heavier animals but they will respond to anti-inflammatory medication," she said.
"If you can treat livestock while they are lying down, then they need to be treated.
"The longer cattle are down the less chance they have to get up if untreated."
Mrs Harriman said any livestock walking around should recover if they have access to food and water.
She highly recommended producers vaccinating bulls against three day sickness as they could be left infertile after a bout of illness.
"The vaccination available should be administered over two shots, with a minimum two weeks apart," she recommended.