November 3, 2002 Chicago Tribune by Jeremy Manier and Lew Freedman
With the start of deer hunting season in Illinois on Nov. 22, hunters
will assume the urgent role of research assistants for wildlife
officials trying to gauge the deadly spread of chronic wasting
disease among the state's deer population.
The first Illinois deer infected with the ailment was found Friday, and experts fear that more cases inevitably will appear once the state begins its greatly expanded testing effort. Officials will collect about 3,500 deer samples from hunters around the state, focusing on the region near the Wisconsin border where the first case appeared. "You're not going to see just one case of this," said Judd Aiken, an expert on chronic wasting disease at the University of Wisconsin School of Veterinary Medicine. "There will be more. I would bet on that."
A major reason for such pessimism is the long incubation period of chronic wasting disease, a fatal brain condition that is lethal in animals but has not been shown to affect humans. Infected deer and elk can live for years before becoming emaciated or show other signs of the ailment, by which time they may have spread the disease to many other animals.
"We can hope that [the first Illinois case] is isolated, but from what we know it probably is not," said Brent Manning, director of the Illinois Department of Natural Resources.
If an outbreak in Illinois is extensive enough, state officials will have to decide whether to follow the lead of Wisconsin, which plans to destroy up to 25,000 deer in an effort to eradicate the disease from the state.
Chronic wasting disease, related to the condition known as mad cow disease, has spread from Colorado during the last few decades. The discovery of the disease in Wisconsin deer earlier this year marked its first appearance east of the Mississippi River.
Illinois hunters should provide the best indication of how serious the problem has become, Manning said. "We need their eyes, their ears and their understanding," he said.
The first case in Illinois was a young female deer shot Oct. 23 by a landowner east of Roscoe, a town near Rockford. State officials said the man, whom they did not identify, saw that the doe was sick and feared it would infect his sheep.
Subsequent tests confirmed that the doe had chronic wasting disease, and Illinois officials announced the results Friday.
Wisconsin officials faced a similar predicament in February when tests revealed the state's first three infected deer. Officials then sampled 500 deer from the surrounding area and found 18 more cases, leading to estimates that 2 percent of deer in the state were affected.
Officials determined that killing all deer within the most affected areas would be the only way to effectively stamp out the disease. The state's plan for aggressively hunting deer in zones around the site of the main outbreak drew heated opposition from some landowners who did not want sharpshooters on their property and others who objected to the wholesale killings.
Right now, it's impossible to know whether Illinois will need such drastic measures to protect its 750,000 deer, said BobManwell, a spokesman with the Wisconsin Department of Natural Resources who has helped coordinate the state's response to the disease.
"It depends on what they find and where," he said. But, he added, "If you're going to try to get rid of [the disease], there's only one way."
Even before the first confirmed case in Illinois, state biologists had visited Wisconsin to consult with that state's experts, said Manning, the head of the Illinois DNR.
Experts do not know how the infected deer got to Illinois. If it was a recent escapee from a farm, it could mean fewer wild animals were affected.
But if the deer traveled from Wisconsin, that would indicate the outbreak has spread farther than officials knew. Wisconsin's main deer eradication zone is about 70 miles north of Roscoe, but deer could have spread the disease between the two areas.
Scientists still know little about how animals spread chronic wasting disease. Aiken, of the University of Wisconsin, said it appears that deer may spread the disease through saliva contact, especially when they gather for feeding.
The discovery of Illinois' first case of chronic wasting disease at the onset of hunting season may be a blessing in disguise because so many hunters will be in the woods and on the lookout for suspicious deer, said Manning.
Although chronic wasting disease has not affected humans, experts say hunters should take precautions, such as wearing gloves when handling game and not eating the brain or other part of a deer's central nervous system. But state officials say venison should be safe to eat if it's thoroughly cooked.
Manning, an active hunter himself, said he is planning to participate in the shotgun deer season. "I will still be hunting," he said--and, "I still will be eating venison."
CORRECTION: Additional material published Nov. 8, 2002.
CORRECTIONS AND CLARIFICATIONS.
An article Sunday, Nov. 3, on chronic wasting disease in deer quoted Illinois officials as saying that hunters should take precautions such as cooking venison thoroughly. While there is no scientific evidence that CWD in deer can be transmitted to humans, experts believe that normal cooking temperatures do not destroy the infectious agent.