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Chronic Wasting Disease FAQ


Q. What is Chronic Wasting Disease?
A. Chronic Wasting Disease is a fatal disease of the central nervous system of captive and free-ranging mule deer, white-tailed deer, moose, and Rocky Mountain elk. The disease belongs to a group of diseases called transmissible spongiform encephalapathies (TSEs) that are not fully understood.
Q. What causes these diseases?
A. CWD and other TSE's are caused by similar but little understood agents that produce tiny sponge-like holes in brain and upper spinal cord nerve tissue. Stanley Prusiner, a neurologist at the University of California's School of Medicine won the Nobel Prize for Medicine in 1997 for his more than twenty years of work investigating the pathogens responsible for TSEs. He deduced that abnormally shaped proteins that lack DNA called "protease resistant prions" transform other normal prions into their own image. The body is unable to break down and remove these prions so they accumulate in various tissue including the brain thus causing the disease. Scientists aren't sure how protease resistant prions are naturally transmitted in a particular species.
Q. How long has Chronic Wasting Disease been known in free ranging herds?
A. The first case of Chronic Wasting disease in wild elk or deer populations was detected in Colorado in 1981, though it is unlikely this was the first actual case. Since that time the number of cases and locations where the disease has been found has increased. The reason for this increase in unclear but likely is the result of increased surveillance as well as increased distribution of the disease. CWD has been found in the wild in areas of 11 states and two Canadian province including Colorado, Wyoming, Nebraska, South Dakota, Wisconsin, New Mexico, Utah, Illinois, New York, West Virginia, Kansas and the provinces of Saskatchewan and Alberta. Federal and state agencies are working to control any spread of CWD in these areas.
Q. Where has CWD been found in Montana?
A. CWD has not been found in Montana's wild deer and elk populations. However, in June 1998 and again in June 1999, elk shipped to Oklahoma from an alternative livestock facility near Philipsburg were confirmed to have CWD. In November and December 1999, all 83 elk at the Philipsburg facility were destroyed. Nine of the elk later tested positive for CWD.
Q. What kind of testing and surveillance is in place in Montana on native deer and elk, and on alternative livestock farms and what are the results?
A. FWP has conducted statewide sampling of wild deer and elk for CWD since 1998, with approximately 9,300 animals taken by hunters showing no CWD infections. Since 2002, FWP has concentrated sampling efforts in northeastern and southeastern Montana along borders with states and provinces where CWD is known to occur. FWP also tests elk and deer that display clinical symptoms that suggest CWD and none of these animals have tested positive. Old age, other diseases and chronic malnutrition can result in symptoms similar to CWD.

Any elk or deer that dies on a licensed alternative livestock facility in Montana must be tested for CWD by law. Nearly 3,800 animals to date have tested negative for CWD. The only positive animals found were the nine that tested positive at the Philipsburg alternative livestock facility in 1999.
Q. What do deer and elk with CWD look like?
A. Symptoms suggestive of CWD are: emaciation, listlessness, blank facial expressions, excessive salivation, lowered heads and, in some cases, hyper-excitability and nervousness. FWP encourages hunters and others who see animals with any of these symptoms to contact the nearest FWP office.
Q. Should hunters be concerned, and if so what should they do?
A. CWD is not known to be transmissible to humans or to cause disease in humans. However, hunters should take common sense precautions: avoid shooting animals that look sick (report those animals to the nearest FWP office); wear rubber gloves when field dressing game; minimize contact with brain and spinal cord tissue; avoid eating brains, lymph nodes, or spinal cord tissues.

Hunters harvesting elk, deer or moose in states known to have CWD should be aware that only quarters, boned out meat, processed meat, cleaned skull plates, antlers or taxidermy mounts can be brought into Montana. The remaining carcass must be left or disposed of in the state where it was harvested. Hunters within Montana are encouraged to dispose of carcasses from processed animals in local land fills rather than discard them in the woods.
Q. Is CWD transmissible to domestic livestock?
A. CWD is not known to be a disease that can be naturally transmitted to domestic livestock. Studies are underway now to understand more about the disease.
Q. What should I do if I see a deer or elk that looks like it may have CWD?
A. Hunters or others who notice animals that seem to display symptoms of CWD should immediately contact the nearest FWP office and report the animal and location it was last seen.
Q. What animal-related TSE's have been found in the United States?
A. TSE's that have been found in the U.S. are: scrapie in sheep and goats, transmissible mink encephalopathy, and chronic wasting disease of deer and elk. A small number of cases of bovine spongiform encephalapathy, or BSE, have been confirmed in the US.
Q. What is the history of this relatively rare family of diseases?
A. Little is known about these Transmissible Spongiform Encephalopathies. The following is a brief chronology:
  • Scrapie has been diagnosed in domestic sheep and goats since the mid-1700's, but the industry has been unsuccessful in eliminating the disease.
  • In the 1970's, CWD was diagnosed in captive deer in wildlife research facilities in Colorado and Wyoming.
  • In 1981 the first case of CWD in Colorado free-ranging wild elk was diagnosed and in 1986 the first case of CWD in free-ranging big game in Wyoming was diagnosed in an elk.
  • CWD has now been reported in free ranging deer and elk in 11 states and 2 Canadian province while it has been reported in captive deer and elk ("game farms") in 9 states and 2 Canadian provinces.
  • The first case of Bovine Spongiform Encephalopathy in cows was identified in 1985-86 in Great Britain. A number of countries in Europe have now identified BSE in cows.
  • In May of 2003, Canada reported their first case of BSE in cattle. Since then, five additional cases have been reported. In December of 2003, a case of BSE was reported in a cow in Washington state. That cow was later found to have been imported from Canada. Since that time, two additional cases of BSE have been detected in the U.S.
Q. What are the differences between BSE (bovine spongiform encephalapathy) in cows and CWD in deer and elk?
A. It is believed the outbreak of BSE in Europe resulted from the practice of using meat and bone meal from animals, including sheep byproducts that could have been contaminated with scrapie, in feed for cows. There is some evidence that Bovine Spongiform Encephalopathy in cows in Europe can be passed to humans who eat beef products contaminated with the abnormal prions that cause the BSE, resulting in a fatal brain disease called "new variant" Creutzfeldt-Jacob disease. There have been approximately 195 cases of "new variant" Creutzfeldt-Jacob disease identified in Europe, with the majority of those diagnosed in the UK.

Deer and elk in the wild browse on naturally occurring plants in their habitat. The use of recycled protein in the preparation of food products for ruminants is not allowed in the US. There has been one cases of "new variant" Creutzfeldt-Jacob disease diagnosed in the US, however that case was diagnosed in an individual that was born and raised in the U.K. and had recently moved to the U.S. There currently is no evidence that CWD can be transmitted to humans.