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Fins, Feathers and Fur
By Dave Thompson
Wednesday July 21, 2010 Back in January, I discussed a parasite-borne disease, affecting primarily moose, known by its common name of “Moose Measles”. This month I’d like to discuss another, more widespread disease, especially prevalent in certain states in the USA. Its common term is “Chronic Wasting Disease” (CWD) and has now been identified in at least two Canadian provinces, Saskatchewan and Alberta. It belongs to a family of diseases known as Transmissible Spongiform Encephalopathies, or, TSE. Also included in this family is Bovine Spongiform Encephalopathies, or, BSE, known commonly as “Mad Cow Disease”. It is also similar to “Scrapie” in sheep. However, researchers believe that a ‘species barrier’ exists that prevents TSE from developing in humans. No human case of “Chronic Wasting Disease” has ever been proven, although this cannot be said for BSE. It is little understood but is the subject of much research, testing and eradication efforts to limit its spread. It was first diagnosed in Colorado & Wyoming white-tailed deer in the 1970’s, then in Colorado elk in 1981. In 2001, it was found in Saskatchewan, then, in 2005, in Alberta along the Saskatchewan border.
This disease manifests itself by attacking the central nervous system of white-tailed deer, mule deer, moose and Rocky Mountain elk, both captive and free-ranging. Symptoms include extreme weight loss, listlessness, lowered head, unawareness, wide unsteady stance, excess salivation and in some cases, hyperactivity and nervousness and is always fatal. It is not known how it is spread between hosts but is thought to have a very long incubation period.
Most infected USA states have enacted laws preventing potentially infected (untested) animals from being transported across state lines. Except for Wisconsin, it’s been proven that all other states and provinces contracted the disease due to interstate transportation of infected deer and elk. However, many animal experts believe that the gradual increase in environmental temperatures is slowly pushing some species, especially white-tailed deer, further north in search of cooler climes. Animal high-density population areas and other areas have been subject to culling practices by killing, even in areas with no evidence of CWD. This is an especially unpopular method of control and subject to much controversy and opposition. However, lack of specific knowledge on how to control the disease has led to these stringent restrictions and methods. Alberta currently allows importation of deer and elk from other provinces and the USA under strict criteria. They also conduct a testing surveillance program, concentrating on areas along the above-mentioned border. Additionally, they have an animal culling program but are considering decreasing the kill rate of suspected animals. This has caused some uproar among proponents of strict control measures, as it is the only proven method of reducing the spread of the disease to the west. Also, the Canadian Food Inspection Agency (CFIA) is discussing down-listing it from its current Reportable Disease status.
As for British Columbia, the only control now in place is the banning of the importation of intact animal carcasses from now on.
As stated, even though no human case of CWD has ever been proven, simple precautions are advised for those who come in contact with wild meat, either through consumption or handling. Do not shoot, handle or consume any animal that appears sick or acting abnormally. Report any such sighting to your local Conservation Officer. Wear latex gloves when field dressing your animal. Bone out the meat rather than saw through bone and avoid cutting through or handling the brain or spinal tissue. Avoid consuming brain, spinal cord, spleen, eyes and lymph nodes. Careful field dressing, with the removal of fatty tissue, membranes and cords will eliminate most risks. Wash thoroughly when finished with soap and bleach water.
For extensive, detailed information on CWD, check out “Chronic Wasting Disease Alliance” on the web. They provide links to many excellent papers on the subject.
Until next time, stay safe and enjoy the great outdoors.
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