| | CWD in Farmed Cervids
To date, three cases of Chronic Wasting Disease (CWD) in farmed cervids Alberta have been detected, all in 2002. In March 2002, the Canadian Food Inspection Agency (CFIA) confirmed CWD in a farmed elk from northern Alberta. The second case was confirmed by the CFIA in November 2002 in a 4-year old farmed white-tailed deer from a game farm north of Edmonton. A third case was found in another WTD from the same farm, as a result of testing during herd depoplutation. These were the first cases of CWD detected in farmed white-tailed deer in Canada. They were detected as a result of Alberta’s Mandatory CWD Surveillance Program, while Alberta’s first case, in an elk, was detected through the now defunct voluntary program. In all three cases the carcasses from depopulated herds were destroyed by incineration. Federal compensation was provided to livestock owners for any animals that were destroyed to control the disease. Alberta Agriculture and Rural Development (ARD) assisted the CFIA with the identification and depopulation of the trace out animals.
No new cases of CWD have been found in farmed cervids since then.
CWD in Wild Cervids
CWD has also been detected in wild cervids in Alberta. Wild elk and deer surveillance has been conducted in Alberta for nearly 10 years, with close to 31,000 cervids testing negative for the disease. In September 2005, Alberta's first case of CWD was confirmed by CFIA in a wild mule deer found 30 kilometres southeast of Oyen. To reduce the spread of the disease, Alberta Sustainable Resource Development staff, with the co-operation of landowners and residents, collected 133 wild deer in the same area in mid-September. Testing on these deer resulted in two more cases of the disease. In December 2005, Alberta recorded it first hunter-killed case of CWD in a wild mule deer located 15 kilometres from Empress, along the Alberta-Saskatchewan border.
As of December 2011, a total of 99 cases in wild vervids have been detected by the TSE laboratory in Edmonton.
CWD surveillance is focused on the Alberta/Saskatchewan border; however, hunter-killed deer (and elk) are accepted from anywhere in the province (as in previous years).
Please see Fish & Wildlife's website for further information and maps, as well as information for hunters.
Background Information on CWD
CWD is a progressive, fatal degenerative disease of the central nervous system affecting elk, mule deer and white-tailed deer. CWD belongs to a group of related diseases called Transmissible Spongiform Encephalopathies (TSE's), which includes diseases such as Scrapie in sheep and goats, Bovine Spongiform Encephalopathy (BSE) in cattle and Creutzfeldt-Jakob Disease (CJD) in humans. TSE's are thought to be caused by abnormal proteins, called prions. There is currently no scientific evidence to suggest that CWD is naturally transmissible to humans or livestock.
Elk and deer with CWD may not show any visible symptoms of the disease for several years. Eventually, as the disease progresses, animals may exhibit loss of condition, excessive salivation, trouble swallowing, difficulty in judging distance and drooping ears. These symptoms are not specific to CWD and can occur with other diseases as well. The only valid method to diagnose CWD is by examining the brain tissue after the animal has died. Specialized rapid testing (Bio-Rad) is conducted by ARD with confirmation by Immunohistochemistry (IHC) at CFIA's National Centre for Foreign Animal Disease (NCFAD) in Winnipeg.
CWD can pass from one animal to another and females can pass it to their offspring, but the exact mode of spread has not been identified. Experimental and circumstantial evidence suggests infected deer and elk probably transmit the disease through animal-to-animal contact or contamination of feed or water sources with saliva, urine and/or feces. Under certain circumstances, a heavily contaminated environment can be a source of infection.
The disease seems more likely to occur in areas where deer or elk are crowded or where they congregate at man-made feed and water stations. Artificial feeding of deer and elk may compound the problem.
Alberta had a moratorium on importing domestic elk and deer from 1988 to 2004. In September 2004, a Cervid Import Protocol was announced, allowing the importation of healthy elk and deer from North America into Alberta. A separate protocol with Saskatchewan only allows importation of healthy cervids for immediate slaughter at federally registered processing plants.
Since the fall of 1996, Alberta has conducted voluntary CWD surveillance on farmed and wild elk and deer in the province. On August 8, 2002, the Mandatory CWD Surveillance Program became effective in Alberta. This mandatory program was reviewed and updated during the Spring 2011 allowing more flexibility in sample collection by qualified third parties. Cervid owners are required to submit for CWD testing the heads from all farmed elk or deer over one year of age that die or are slaughtered. Product from slaughtered animals must be held at abattoirs pending CWD negative test results.
Monthly CWD test results are published on the Chief Provincial Veterinarian web page.
Click to read about the Alberta Mandatory Chronic Wasting Disease Surveillance Program.
For further information about CWD, please consult the following websites:
CFIA website, at:
http://www.inspection.gc.ca/english/anima/disemala/cwdmdc/cwdmdce.shtml
Alberta Agriculture and Rural Development website, at:
www.agriculture.alberta.ca
Alberta Sustainable Resources Development website, at:
http://www.srd.gov.ab.ca/
Unites States Department of Agriculture website, at:
http://www.aphis.usda.gov/animal_health/animal_diseases/cwd/ |
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