ROSCOE, Ill. -- State wildlife officials have confirmed the first known case in Illinois of chronic wasting disease in a deer.
The fatal brain condition was discovered in a sick deer shot Oct. 23 on private land just east of Roscoe near the Wisconsin border. The disease has infected deer and elk from Colorado to Wisconsin.
The Illinois Department of Natural Resources confirmed the diagnosis Friday.
Wisconsin plans to shoot as many as 25,000 deer to contain the spread of the disease. But Illinois officials said they must test more animals to see how widespread the problem is before they plan a response.
"We don't want to overblow this," said Carol Knowles, a department spokeswoman. "This might be the only case in Illinois."
But one expert on the condition said that's not likely.
"You're not going to see just one case of this," said Judd Aiken, of the University of Wisconsin School of Veterinary Medicine. "There will be more. I would bet on that."
Expanded testing for the condition coincides with the beginning of Illinois' deer shooting season, which begins Nov. 22. Officials say they expect to conduct tests in 36 counties, with an emphasis on the area near the Wisconsin border. They hope to collect about 3,500 deer samples from hunters around the state.
While scientists still know little about how animals spread chronic wasting disease, Aiken said it appears deer may spread it through saliva contact, especially when they gather to feed.
Chronic wasting disease is related to mad cow disease, though the strain is not known to spread through livestock. It is caused by an abnormally shaped protein that damages brain and nerve tissue.
There is no known way for deer to spread the disease to humans, but experts say hunters should take precautions when preparing deer for food, including cooking it thoroughly.