State wraps up intensive testing of 41,000 wild whitetails in Wisconsin
Wrapping up the most extensive testing of deer in U.S. history, Wisconsin officials concluded Friday that chronic wasting disease does not appear to have spread beyond a region west of Madison.
Results from more than 41,000 white-tailed deer have turned up 207 animals that tested positive for the fatal deer disease.
Almost all of the infected deer – 201 – came from a 411-square-mileeradication zone of Dane, Iowa and Sauk counties where testing has shown the disease to be present in 1.64% of the cases. But officials believe the disease is far more widespread in some spots within the zone.
The state began intensive testing of deer about a year ago after chronic wasting disease was discovered on Feb. 28, 2002 – an effort the state Department of Natural Resources said has involved 1,200 people and thousands of hours, and cost millions of dollars.
As more positives became known, the DNR announced a week ago that it was doubling the size of the region where it plans to kill as many deer as possible in the hope of wiping out the disease. The process could take years, the DNR said.
With virtually all of the results in, DNR officials said they are confident that the disease does not appear to be in other parts of the state.
The massive deer testing program and the eradication policy are two key state strategies since the disease was discovered.
In most of the state, wildlife experts are 90% certain their strategy could detect the disease, even if only one deer in 100 were infected, said Julie Langenberg, a DNR veterinarian.
The exceptions, however, include the southeastern Wisconsin counties of Milwaukee, Waukesha, Racine, Kenosha and Sheboygan, where the DNR has a 70% to 80% confidence level. Other counties where the confidence level is below 90% because the DNR failed to test sufficient numbers of deer are: Grant, Eau Claire, Chippewa and Taylor counties.
Decisions on eating meat The final test results mean that people should be able to decide whether to eat deer shot during the 2002 season, the DNR said.
“People storing venison in the freezer awaiting CWD test results now know with a high level of confidence the chances that deer in the county where they hunt could have CWD or could have been in contact with a CWD-positive deer,” said Tom Hauge, the DNR’s director of wildlife management.
Test results show that Iowa County has the most positives with 107, followed by Dane County with 97 deer, Sauk County with two and Richland with one.
The DNR also concluded that there was no evidence of the disease in Marathon or Grant counties.
After the deer hunting season, a private Wauwatosa lab, Wisconsin Viral Research Group, said that three deer from the two counties were found to be positive. The lab had been hired by another company, Wildlife Support Services of Hayward, to perform tests that it had sold to sporting goods stores as an alternative to the DNR.
Both the DNR and Wisconsin Viral Research Group agree now that using one method of testing involving immunohistochemistry, the three deer tested at the private lab were not positive.
But Donald Carrigan, one of the lab owners, said another testing method that has since been patented showed positive results.
“We had a discussion about the relative merits of the two methods, and we agreed to disagree because there was no simple way to finally resolve this,” Carrigan said.
With testing completed, carcasses of deer that had been tested from the eradication zone and had been placed in cold storage also will get attention. Positives will be sorted out, and researchers will extract additional tissues. The positive deer will be incinerated. The other deer will be buried in a landfill.
Fears have subsided No link has been found between eating animals infected with chronic wasting disease and contracting brain disorders such as Creutzfeldt-Jakob, a fatal disease to humans. But lab studies have shown transmission is at least theoretically possible.
After the discovery in Wisconsin, many people appeared wary about whether to eat venison shot from last year’s hunt. But that concern appears to have ebbed.
“What we are hearing out in the field is that hunters are very comfortable with the end result of the testing,” said Peter J. Gerl, executive director of Whitetails Unlimited, a national organization based in Sturgeon Bay.
“We feel that it should take away some of the paranoia in the future.”
But Phil Muehrcke, a retired professor of geography at the University of Wisconsin-Madison, is less certain.
“My feeling is that this is great – that the state has not found it any more than it has,” said Muehrcke, who owns 400 acres in the zone and is a member of a group of landowners who are opposed to the state’s strategy of killing all of the deer in the zone.
But, he said, a 90% confidence rate means that “there is 1 chance in 10 that they have missed something. Would you take that risk? It is like playing Russian roulette with a gun that has a bullet in one of 10 cylinders.”
No extensive testing planned Muehrcke said he would like to see intensive testing again next year, but the DNR said it does not plan to duplicate 2002’s efforts.
Instead, the DNR plans to focus on areas such as southeastern Wisconsin, where test results lagged, and on areas such as Walworth County, where a deer that tested positive from a game farm escaped.
Another area of heightened surveillance will be the expanded 800-plus-square-mile eradication zone, but Langenberg said no decision has been made on whether to again test all of the deer killed there.
Wisconsin’s work involving more than 40,000 deer exceeds the testing efforts of other states. This fall, Colorado tested slightly more than 26,000 deer and elk, according to a spokesman for the Colorado Division of Wildlife. Another 11,500 deer and elk were tested between 1996 and 2001, according to the agency.
By comparison, Illinois tested about 4,000 deer, Indiana tested 3,477 and South Dakota tested 1,938, according to a Colorado survey.
“I believe firmly that surveillance was the most important thing we have done in our long-term management plan on CWD,” Langenberg said.
Samples and results are now going to researchers who will produce a treasure trove of new knowledge on the disease, she added.
For example, researchers will now examine age and sex characteristics, and if one sex appears to predominate, Langenberg said, Wisconsin could tweak its eradication strategy accordingly.
There also will be a closer look at areas where the disease is most virulent.