Alberta’s most recent case of BSE is disappointing but it shows surveillance programs are working, says Gerald Ollis, the province’s head veterinarian.
More than 200 private veterinarians in Alberta have been trained to collect potential BSE samples on the farm in addition to the cattle checked by the Canadian Food Inspection Agency.
“If you are only doing your testing in an abattoir or at a rendering station, you are not going to get them all because many people would just bury them on the farm,” Ollis said Jan. 23.
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So far for 2006, Alberta had tested more than 1,200 samples. In 2005, there were 30,500 tested. The last confirmed case was in January 2005 on an Innisfail, Alta., ranch.
Private vets called to a farm can more fully assess cattle to ensure potential cases fit one of the four categories of dead, diseased, downer or distressed animals.
“Not all 4-Ds can qualify. There is a misconception out there. A lot of producers are misunderstanding what we are looking for,” Ollis said.
If an animal older than 30 months of age has died for no apparent reason, it may be tested for BSE. Accidental deaths like drowning or lightning strikes are not candidates.
Downers are included because BSE-infected animals have poor motor skills.
The diseased criteria means the animal should have a body condition score of two or less. This means it has lost weight and is growing thin. Animals with lumpjaw are not included, although those with cancer eye may be tested.
Those with a body condition score of one and that appear emaciated may be tested. However, some of these cases turned out to be Johnes’ disease, another cause of drastic weight loss.
If a normally quiet animal shows a temperament change and appears mean or wild, it could be tested.
The distressed category test includes an animal that has to be slaughtered for humane reasons such as serious pneumonia or a broken leg.
While all four cases came from the northern half of the province, that region has not been targeted for increased testing.
So far all the cases were born between 1996 and 2000 and exposed to contaminated feed over a limited time. This is referred to as a BSE temporal cluster.
The CFIA believes Canada’s cases may have resulted from an initial BSE infection that entered North America through cattle imported from the United Kingdom from 1982-89.
One or more of these imported animals, without necessarily demonstrating signs of disease may have been used in the North American feed system between 1991-92 and caused the first generation of BSE in Canadian cattle.
The low level of infection could have circulated undetected and recontaminated the feed system between 1996 and August 1997, potentially lingering in the system until 1998. This could have then caused the second generation of BSE in Canada, which became evident in May 2003 when the first animal from this era was diagnosed with the disease.
