The National Centre for Foreign Animal Disease in Winnipeg has confirmed the fifth case of BSE in a Canadian dairy cow. Reportedly, the six year old cow from a farm in British Columbia was a downer animal and did not enter either the human food or animal feed chains.
The Canadian Food Inspection Agency (CFIA) has tracked the animal back to its birth farm and located its only offspring which is already dead. Since this animal was born after Canada imposed a regulatory feed ban eliminating the feeding of ruminant protein to other ruminants, the CFIA will be exploring routes by which the animal may have been exposed.
On a related topic, University of Wisconsin-Madison researchers have found that prions, the misshapen proteins thought to cause transmissible spongiform encephalopathies (TSE) such as BSE and Chronic Wasting Disease (CWD), can attach to soil minerals and remain infective. According to the researchers, many proteins bind to soil components but are usually altered and rendered inactive.
Sources:
Canada Food Inspection Agency
University of Wisconsin-Madison press release