CWD – FACTS from the Farm!
by R.A. Forrest, MSc|
WHAT IS CWD? Chronic Wasting Disease is a neurological disease specific to cervid species such as deer and elk. It is in the same family of disease as CJD in humans, scrapie in sheep and Bovine Spongiform Encephalopathy (BSE) or "mad cow" disease. All are Transmissible Spongiform Encephalopathies (TSE disease) meaning they can be passed to other animals and eventually results in sponge-like brain damage. The deer version is called CWD because it causes progressive eating dysfunctions resulting in gradual loss of weight and eventual death, usually by pneumonia.
HOW ARE THE SPONGY BRAINS FORMED? Since brain cells cannot regenerate efficiently, Spongiform texture is the result of individual brain cells being killed off, leaving open voids where the brain cells formerly resided. The individual cells are probably killed by the toxic presence of abnormal brain proteins known as "Prions" which are a diagnostic symptom of the TSE diseases. All tissue have prion protein, but only TSE victims develop excessive abnormal prion protein in their brains.
WHY IS THE PRION PROTEIN ABNORMAL? Virtually all, normal living protein material can be digested in proteinase enzymes. This is how the body cleanses itself of processed proteins for recycling or excretion. Abnormal prions apparently have a high manganese content, which seems to render proteinase digestion ineffective; hence abnormal prions cannot be dissolved via normal bodily functions resulting in toxic accumulations.
WHAT FORMS THE ABNORMAL "PRIONS"? Much controversy surrounds the cause of abnormal prion creation. While many suggest that the prions themselves are "self-replicating", this premise is in contravention with traditional biological principals whereby living cells needing RNA or DNA to identically replicate. Prions have no RNA or DNA. Alternate theories of toxic chemicals, heavy metals, nutritional deficiencies, bacteria, virus', viroids and virinos have been proposed, but NO theory has yet been proven as to the specific cause of abnormal prions.
HOW FAST DOES CWD KILL ITS VICTIMS? CWD is not very contagious unless animals are intensively exposed to the unknown pathogen. While evidence is not widely available, government research and publications indicate that the maximum natural incubation from exposure to death is 33 months +/- 2 months, or less than 3 years. Shorter durations have been documented and the earliest detectable disease has been in 4-month old artificially exposed fawn. Farmed cervid regulations require a 60-month safety factor, a margin not substantiated by collected data.
HOW IS CWD DETECTED? Clinical signs of CWD (a sickly, emaciated deer) are NOT diagnostic. Currently, TSE diseases are detected by observation of the brain vacuoles (void spaces) and by immunochemistry or ELISA tests upon brain or lymph nodes, whereby a chemical stain attaches to the abnormal prions allowing them to be detected by visual or optical methods. All tests are currently post-mortem, although several pre-mortem tests are being perfected. Only a few government-sponsored labs are allowed to do the testing.
ARE THE TESTS INFALLIBLE? NO! All test methods are somewhat subjective and are constantly subject to misinterpretation and interference. Bacteria have been known to confuse test results. False negatives are common during the early stage of disease and false positives are possible. Post-mortem sampling procedures and sample treatment after collection will potentially affect results. Human errors are always possible.
IS THERE A CWD CURE OR VACCINE? No! Since the actual cause of CWD is undetermined, there is as yet no cure or vaccine. While early stage infection might yet prove reversible, once clinical signs appear, the disease is terminal. Numerous private companies and government research efforts are being devoted to solving the CWD dilemma.
CAN CWD PERSIST IN THE ENVIRONMENT? Yes! Abundant evidence suggests that residual environmental contamination, probably via feces, urine, saliva or carcass debris, may play a more important role in disease transmission than direct animal-to-animal contact. Insects may be a factor as well.
IS THERE A RISK TO HUMANS? To date, NO EVIDENCE has been found of a human disease derived from eating or handling a CWD positive animal. However, some evidence does exist for BSE beef cows infecting an extremely minute fraction of human consumers with "new variant" CJD. All domestic cervids slaughtered for meat under government inspection must be tested negative for CWD. However, wild harvested animals are NOT required to be tested. As with any disease, precautions are advisable.
HOW DID TSE DISEASES ORIGINALLY START? Two TSE's, spontaneous human Creutzfeldt-Jakob disease (CJD) and sheep scrapie have been documented for many, many decades. But, most of the other TSE diseases found in mink, monkeys, cats, zoo animals, etc. have been created or manipulated by man's influence over animals.
SO WHERE DID CWD COME FROM? Observational evidence and most theories suggest that CWD, like BSE, originated from the sheep TSE disease, scrapie, which has been documented for over 400 years in Europe and about 60 years in North America. In the 1950's and 1960's, northeastern Colorado, specifically Larimer County, Colorado had a high infection rate for sheep scrapie. Close proximity of wild deer to sheep may have randomly passed the disease, or more logically the human-induced close confinement of deer and sheep undergoing artificial stress events, may have mutated and passed the disease to deer.
WHEN DID CWD FIRST APPEAR? The first cases of classic "chronic wasting" appeared in the late 1960's in captive wild deer held in interchangeable deer research facilities operated by Colorado State University (CSU) and the Colorado Division of Wildlife (CDOW) at Ft Collins, Larimer County, Colorado. Wild deer cases were not observed until the late 1970's and then only with in a 50-kilometers (usually within a 5-km radius) of the research facilities even though sampling occurred outside that radius.
WHAT KIND OF EXPERIMENTS WERE DONE ON DEER IN THE 1960's? Many unusual and controversial studies were performed. Fully documented research studies placed starved deer and sheep into common pens to determine stress-induced activity, time to death, or preferred food under stressed conditions. Nuclear radiation studies had deer and sheep injected with, fed or exposed to contaminated radioactive materials to determine death dosages and behavioral aberrations. Eventually cross-species (non TSE) disease transmission studies were also attempted. The US Fish and Wildlife Service conducted lethal dosage pesticide studies at it's tiny confined Denver Federal Center deer pens located in nearby Lakewood, Colorado.
CHRONOLOGICALLY, WHERE in the world HAS CWD BEEN FOUND?
1970's: The Wyoming Sybille Wildlife Research facility, a private zoo and the Toronto, Canada Zoo all of which had received animals from the Colorado research facilities. Exposed animals were sent to at least four other Colorado deer research pens at Meeker, Kremmling, USFS Fraser and the USFW Federal Center pens. Additionally, animals were shipped to facilities and zoos around the continent. Numerous positive wild animals were found in and around the Ft Collins area.
1980's to mid 1990's: CWD was found in Rocky Mountain National Park, and in wild animals of SE Wyoming. The "endemic area" was spreading predominately north and east. Until 1991, deliberate and knowingly, the CDOW moved exposed research animals to numerous locales around Colorado including fawning pens at Pawnee Grasslands and to nutrition research pens in far NW Colorado near the Utah border. CWD research tissue samples sent all over the country, including the University of Wisconsin at Madison. SEE inset MAP below.
1996-98: CWD was found on a Saskatchewan, Canada game farm, which had in turn, infected several dozen other SK farms over several years. The SK source farm was found to have had elk from a South Dakota farm, which had received deer from the Denver Zoo, which in turn, had gotten deer from the CDOW. Domestic cases were found on a farm in Montana and one in Oklahoma, which traced a history of animals from the South Dakota source farm.
1999-2000: Domestic cases were found in NE Colorado, in the wild and in domestic elk of Nebraska and in South Dakota. The endemic area was expanding. A few wild CWD cases in SK, Canada. A single case was found in South Korea from animals imported from SK, Canada.
2001: A large outbreak emanating from a NE Colorado elk farm but was caught by a state-mandated domestic cervid CWD surveillance program with several Colorado farm animals and one Kansas animal positive. The NE Colorado source herd was in the endemic area near the CDOW's Pawnee Grassland fawning pens and had animals from two elk farms near Ft. Collins.
2002: Implementation of the USDA CWD program. Rapid depopulation completed upon the exposed domestic cervid herds. Much increased wild surveillance. Numerous positive Wisconsin wild animals found west of Madison WI. and south into Northern Illinois. CWD found widely dispersed in Western Colorado wild animals, but clustered near the above-mentioned CDOW research facilities. Alberta had one CWD elk on a farm, which had years ago received animals from the South Dakota source farm. Positive animals found in Utah near the border with Colorado. Several CWD animals found in Southern New Mexico. Two infected deer farms in Southern Wisconsin, but were not the source of wild CWD.
2003: More wild positives in WI, UT, NM, SD WY and CO. More domestic positives found in WI and MN. Greatly increased lab testing abilities and surveillance programs were instigated all around the continent. Two more CWD cases in Alberta domestic whitetail deer and then UNRELATED BSE in a beef cow closed the Canada ruminant trade.
WHAT IS THE STATUS OF THE COLORADO FARM CWD CASES? In 1997 Colorado elk farmers voluntarily began disease testing for CWD. A mandatory program was installed and discovered the first domestic CWD case in 1999, with many more in late 2001. By early 2002, ALL Colorado domestic cases and their herd mates, as well as most farms in the endemic wild CWD area, (total ~4,500 head) were depopulated with 56 positive cases, 48 from the NE Colorado original source ranch and six separate cases within the NE Colorado endemic area presumed to have been transmitted from the wild. NO additional cases since early 2002.
WHAT CONTROLS HAVE BEEN PLACED ON COLORADO ELK FARMS? Despite a mandatory and SUCESSFULL CWD surveillance program on all farm cervid deaths, in 2002 the Colorado Dept of Agriculture (CDOA) and the CDOW, subjected to undue pressure from Governor Owens and the press, executed a Memorandum of Agreement (MOA). The MOA unilaterally gave away the exclusive and proper legislative authority of the CDOA to regulate farmed cervids as Alternative Livestock. Onerous new rules dictated by the CDOW restricted farm cervid import, export, fencing, testing, wild animal contact, intra-state movement, etc. with review and veto authority from the CDOW. These rules were imposed upon elk farms, which were in the midst of already successfully eradicating CWD from their herds with the help of the CDOA by mid-2002. NO controls were demanded or imposed upon wild animal movements, disease sources, or government sponsored and/or operated research activities.
HOW DID CWD SPREAD AROUND COLORADO? While many insinuate that game farms have spread CWD, NO case of wild CWD has been tracked back to a domestic elk farm and ALL exposed farms have been depopulated. To the contrary, at least six domestic cases, as well as, the initial NE Colorado source farm must have obtained the disease from the wild. Wild animal migrations have moved the disease in all directions from Larimer County and government research animal movements have jumped CWD all across Western Colorado.
SO WHO IS REALLY RESPONSIBLE FOR CWD? While the evidence of the origin of CWD back in the 1960's is somewhat cloudy, the movement of the disease since then is not at all ambiguous. While CSU has not made any specific animal information available, Colorado Open Records requests and the CDOW have published a portion of their research activities, which acknowledged exposed research animals co-mingled with wild study subjects. Captive wild deer held in contaminated pens escaped, were returned to the wild, or when dead, were disposed of in an unknown fashion. Further, exposed animals were given or sold to zoos, universities and private individuals. Diseased tissue samples were sent around the continent. In 1996, CDOW internal documents (See inset memo above) admitted the potential liability of the CDOW for the eventual and possible introduction of CWD into domestic elk herds. While some mitigation steps were then taken in 1997, such as providing double fence materials, by 1999 the disease had entered the Colorado domestic farms, but was fortunately caught by mandatory industry surveillance and was eliminated by 2002.
CAN CWD BE CONTROLLED? Predominately, CWD HAS BEEN controlled in domestic cervids that are not exposed to infected wild animals. Recent discussions at the United States Animal Health Association Annual Meetings in October included the following key points:
Comments attributed to Dr. Mike Miller of the CDOW suggested that 'There is no apparent and practical means of eliminating the disease from the wildlife in Colorado.' Here in Colorado wild CWD movement remains unabated to date.
SO IF CWD IS PREDOMINATELY AN UNCONTROLLED WILD CERVID DISEASE, WHY ARE CERVIDS FARMERS SUBJECTED TO CONTINUING ONEROUS REGULATIONS? Quite simply, an agenda to defer attention and responsibility away from the ongoing wild problem. The Zero CWD risk currently demanded of farmers via excessive regulations, regulations not based upon scientific fact, will NOT have a significant impact upon the steady progress of the wild disease. Onerous rules serve only to eliminate farmers from a private business that "competes" with government agencies; agencies which desire to control cervid species, exclusively. To date, scores of farmers have been put out of business with virtually NO impact on the rampant progression of wild disease. "FACTS from the Farm" suggests that corrective, scientifically justified regulations and procedures are now necessary.
About the Author: Mr. Forrest, a graduate of the Montana School of Mines, has over 30 years of investigative earth science background, directs and compiles CWD research for the Foundation and was formerly a full time elk farmer depopulated by CWD concerns. His detailed, factual research and writings on CWD may be viewed at www.stopcwd.org. The information presented above is excerpted from extensive published and unpublished literature, all of which are available for review. Inquires welcome (719-657-0942), firstname.lastname@example.org.
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