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Washington’s Chronic Wasting Disease Program – An Update
Kristin Mansfield DVM, Wildlife Veterinarian

NEW RULES BEING CONSIDERED To minimize the risk that CWD could be imported into Washington via infected carcasses, WDFW is considering implementing regulations that would restrict the importation of certain deer and elk parts from states and provinces where CWD is known to occur. These regulations may be put into effect as early as this fall. For areas where CWD is present, the following import regulations are being considered. Only the following are allowed into the state: Meat that is cut and wrapped either commercially or privately Meat that is boned out Hides (capes) with no heads attached Skull and antlers that have been cleaned of all meat and tissue Upper canine teeth known as buglers, whistlers or ivories that have been cleaned Finished taxidermy mounts In addition, if a hunter is informed that an animal he or she has harvested in another state tests positive for CWD, the hunter will be required to notify WDFW immediately. The public may comment on these proposed rules at the August 6 & 7 Fish and Wildlife Commission meeting. HUNTERS CAN HELP You can help by doing the following: Observe the guidelines if hunting in a state where CWD is known to occur Properly dispose of waste from deer and elk carcasses, regardless of where harvested (contact your local solid waste management department for details) Report any deer or elk exhibiting clinical signs of CWD to your nearest WDFW office Cooperate with WDFW employees or volunteers if asked for a sample from your deer or elk

Chronic wasting disease (CWD) of deer and elk continues to be an issue of great interest to hunters, wildlife managers, and the general public. It is a condition seen in mule deer, white-tailed deer, and elk that was first described in Colorado and Wyoming over 30 years ago. CWD is characterized by clinical signs such as weight loss, abnormal behavior including indifference to human activity, difficulty walking, tremors, hyper-excitability, excessive salivation, teeth grinding, difficulty chewing or swallowing, and excessive drinking and urination. It is always fatal in affected animals. There is no vaccine, treatment, or practical live animal test available for CWD.

The Washington Department of Fish and Wildlife (WDFW) began testing deer and elk for CWD in 1996. From 1996-2000, efforts were focused on testing animals that showed clinical signs consistent with CWD (“target animals”), such as emaciation and other characteristics as described above. Beginning in 2001, WDFW began a more intensive surveillance program for CWD, focusing on animals harvested during the fall hunting seasons. This approach relied on the efforts of over 100 WDFW employees and volunteers and the cooperation of hunters and meat processors. Volunteer groups such as Eyes in the Woods and the Inland Northwest Wildlife Council contributed greatly to these efforts. All of the 2,288 usable samples collected since 1996 have tested negative for CWD. However, more testing is required before we can conclude with a high degree of confidence that Washington is free of CWD.

As of June 2004, CWD has been diagnosed in wild deer and/or elk in the states of Wyoming, Colorado, Utah, New Mexico, Nebraska, South Dakota, Wisconsin, and Illinois and in the Canadian province of Saskatchewan. CWD has been diagnosed in captive deer and elk in the states of Montana, Wyoming, Colorado, South Dakota, Nebraska, Kansas, Oklahoma, Minnesota, Wisconsin, and the Canadian provinces of Alberta and Saskatchewan.

CWD is believed to be most commonly spread from animal to animal through direct contact; most likely via the saliva, urine, and feces of infected animals. CWD can also be transmitted by exposure to environments that have been contaminated by infected animals or their carcasses. The risk that carcass parts of infected animals could contaminate the environment has led some states and provinces to impose restrictions on the importation of certain hunter-killed deer and elk parts from outside areas. WDFW currently requests that hunters who harvest a deer or elk from an area where CWD is known to occur have their game processed in that area and only bring meat and carcass parts that have been thoroughly cleaned of all nervous and lymphatic tissue back to Washington. WDFW plans to make this recommendation into a regulation.

CWD belongs to a class of diseases known as transmissible spongiform encephalopathies (TSEs). This class of diseases also includes scrapie of sheep and goats, bovine spongiform encephalopathy (BSE, or “mad cow disease”) of cattle, and Creutzfeldt-Jakob Disease (CJD) of humans. CWD is only known to occur in mule deer, white-tailed deer, and elk. While BSE has been linked to the development of a particular form of CJD (termed variant Creutzfeldt-Jakob Disease, or vCJD) in humans, there have been no links between CWD and human disease. In this respect, CWD appears to be more similar to scrapie of sheep and goats, which has never been associated with human disease despite being present in sheep and goat populations for over two centuries.

In 2003, a cluster of human CJD cases was reported in the state of Washington in hunters who consumed venison. Subsequent investigation by the Washington Department of Health and the U.S. Centers for Disease Control revealed that all three had died of sporadic CJD (not vCJD), and that there was no evidence to conclude that the development of their disease was related to their consumption of venison. Several other alleged CJD clusters in humans who consumed venison have been investigated throughout the country by the U.S. Centers for Disease Control. In all cases, investigations revealed that the people had died of either a non-TSE neurological illness or of sporadic CJD and were not related to CWD.

WDFW plans to continue testing hunter-harvested animals for CWD, with the goal of collecting between 700-1000 samples per year. Beginning with the 2004 hunting season, more emphasis will be placed on collecting samples from areas of the state where relatively few samples have been collected to date. Hunters who regularly hunt in some of these areas may be contacted and asked to voluntarily assist WDFW with its sampling efforts by either bringing their deer or elk head in for sample collection, or collecting the necessary samples themselves and sending them to WDFW.