Deer – Why No Live Testing for CWD?

By E.M Fay

Photo by  Dr. Elizabeth Williams, University of Wyoming

Chronic Wasting Disease is a very real problem in North America, both in Canada and the United States. A transmissible spongiform encephalopathy (TSE), it is a progressive, fatal, degenerative disease affecting elk, white-tailed deer, mule deer, and moose. CWD is manifested as brain damage, loss of body condition, behavioral changes, excessive salivation, and death.

Caused by abnormal proteins, called prions, which accumulate in the brain, the disease spreads from one animal to another and females can pass it to their young.  A probable route is through contaminated water and food via animal saliva and feces. Contagion is more likely when the animals are in crowded situations and when they congregate at man-made feed and water stations.

Although CWD has been found in both wild and captive cervids, there has been no evidence of possible transmission to domestic animals or livestock.  There is also none showing CWD affecting humans, but the World Health Organization advises against eating meat from affected animals:
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex3594

As CWD has been documented in at least 19 states, Departments of Natural Resources have been testing many animals for the disease.  It is illegal to import deer from one state to another, but of course deer do not know about crossing state boundaries; and also, some humans who keep captive deer or elk for personal or commercial purposes, such as “canned” hunts or for slaughter, do not follow the rules.  The fear of CWD spreading to new states has led to some private properties being invaded by DNR personnel to carry out testing on captive animals.  Unfortunately, this testing is done only after killing them.

In one example, in September, armed wildlife agents from the North Carolina Wildlife Commission brought a warrant to a farm in Asheboro, Randolph County.  They killed nine deer there, seven of which were exotic fallow deer; the other two were white-tailed deer who were being rehabilitated either from injury or being orphaned.

The farm owner, Mr. Wayne Kinley, had not been notified ahead of time, and there was no appeal process available to him. The deer had been living peacefully in a two-acre enclosure on the farm.

In August, wildlife agents similarly invaded another North Carolina property and shot and killed 2 orphaned fawns. The property owner, Freddy Snow of Dobson, was not even at home when they were killed.  Officials said that neither Kinley nor Dobson had a license to keep captive deer.

Although the agents stated that these deer were killed to test for Chronic Wasting Disease, CWD has not yet been found to be present in North Carolina.

Kinley stated that the killing was done with 12-gauge shotguns, which is considered by some to be a less “humane” method than shooting with a rifle. And wildlife officials admitted afterwards that none of the deer tested positive for the disease.

Change.org circulated an online petition, asking citizens to demand that the governor of NC provide protection for tame or rehabilitated deer.  (The petition was created by Millie Bowling of Liberty, NC.)

I spoke with Gordon Myers, Executive Director of the North Carolina Wildlife Resources Commission. He justified the kills for these reasons: You can’t tell if a deer has been imported from another state; if it has been, then there is a chance of CWD. The fallow deer were illegally imported, he said.  He believed that the owner was using them to make chandeliers from their antlers.  (We tried to ask the owner to confirm or deny this allegation, but could not reach him.)

Myers also noted that there has been a big increase in cases of CWD since 2002, and they test for safety’s sake, so out-of-state deer do not communicate it to the local deer population.

When I asked what about the orphaned fawns, who were local, according to the rehabber, Myers said they cannot be sure of that.

Why kill the deer first, instead of testing for CWD on live deer?  Myers replied that the only practical method is testing brain tissue or lymph nodes, which has to be done after death.  We checked this statement with two other sources: a Wildlife Technician in Wisconsin, a state that has seen many cases of CWD in recent years; and a Senior Staff Veterinarian and CWD Program Manager for APHIS (Animal and Plant Health Inspection Service).

The Wisconsin Wildlife Technician told us that there is a live tonsil biopsy test but it is not approved for use by the DNR in Wisconsin.  He said it is used mainly for research purposes.
The CWD Program Manager told us that while tonsils may be collected from live animals, the sampling data collected by the national reference testing laboratory over approximately 10 years has shown that collection of tonsil samples is not very reliable.  “Most often the proper sample (the tonsil) is not correctly collected because it is difficult to reach and visualize the tonsillar tissue located far back in the animal’s throat while the animal has been anesthetized for this procedure,” she said. “Therefore, many times the sample submitted as ‘tonsil’ is found in the laboratory testing process to be an adjacent section of soft tissue oral mucosa – and not suitable for CWD testing.”

According to the Chronic Wasting Disease Alliance, however, researchers from the USDA and Colorado State University have evaluated and validated another live testing method using rectal-tissue biopsies in captive and wild elk in Colorado.  It appears to be nearly as accurate as post-mortem testing.

“The key advantage to the rectal biopsy test is that it can be performed on live animals. Until now, there was no practical live test for CWD in elk,” said Research Wildlife Biologist Dr. Kurt Ver Cauteren with APHIS’ Wildlife Services.

“The use of this new live test in the initial screening, surveillance and monitoring of CWD will greatly aid in the management and control of the disease in the wild, as well as in captive settings,” said Ver Cauteren.

Chronic Wasting Disease Alliance reports that many thousands of captive elk have been killed in the western United States and Canada in order to control CWD, as well as thousands of free-ranging mule deer, white-tailed deer, and elk.

(Learn more about CWDA’s work at: www.cwd-info.org )

As congested areas with man-made feed and water stations – e.g., on “deer farms” with animals kept prisoners in a limited space – are more likely to encourage the spread of CWD than when deer and elk live in wide-open, natural habitats, it is not unreasonable to posit the theory that humans have facilitated the spread of CWD by keeping these wild animals in unnatural circumstances.  This would be not unlike the phenomenon of BSE, or “mad cow disease,” which even the CDC acknowledged could have been caused by farmers feeding unnatural foods such as meat and bone meal to herbivorous cattle.

While we at C.A.S.H. are in favor of the development of a live testing method, we could wish that the motives behind such studies were concern for the health and welfare of the animals themselves.  However, motivation seems to be at least partly on behalf of the captive deer and elk “industry.”

The promising progress shown in finding a new live testing method should be encouraged, with government funds channeled in that direction, rather than spent on continuing the inhumane post-mortem test that leads to “shoot first, ask questions later,” as is currently being practiced.

CWD information at: http://www.aphis.usda.gov/animal_health/animal_diseases/cwd/
http://www.health.ny.gov/diseases/communicable/zoonoses/cwd.htm
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E.M. FAY is the Associate Editor of the C.A.S.H. Courier