The cow confirmed Thursday as Canada’s 19th domestic case of BSE, and just its third case in the past five years, is still somewhat of a stranger to federal officials.
Representatives with the Canadian Food Inspection Agency (CFIA), on a conference call Friday, said they haven’t yet confirmed the cow’s age, its past travels or how or where it may have picked up risk materials that cause bovine spongiform encephaolpathy.
Paul Mayers, CFIA’s vice-president for policy and programs, told reporters Case 19 has been confirmed as having “classical” BSE — a form transmitted through infected feed sources — rather than “atypical” BSE, which occurs, typically in older cattle, with no clear cause.
If the Alberta cow is confirmed to be over 11 years old, it shouldn’t derail Canada’s efforts to restore the country’s status as “negligible risk” for the disease among beef-importing nations that follow standards set by the World Organization for Animal Health (OIE).
Countries deemed by the OIE to be a “controlled risk” for BSE are able to level up to “negligible risk” if the youngest of their domestic BSE cases was born over 11 years ago.
Canada’s Case 18, an Alberta dairy cow confirmed with the brain-wasting disease in February 2011, was born Aug. 23, 2004.
On Friday’s call, Mayers said the agency’s ongoing investigation will trace Case 19 back through its lifetime, focusing on its feed sources in its early life.
If age can’t be confirmed through paperwork, he said there are “slightly more gross” methods such as dentition — studying the animal’s teeth — to gauge age.
The agency said Thursday any “equivalent risk” animals discovered during the traceback/traceout will be destroyed and tested for BSE. Asked Friday about Case 19’s home herd, Mayers wouldn’t say what region of Alberta it’s in, but added it’s “not a large” herd.
Asked also how many farms Case 19 lived on or visited in its lifetime, he said it’s “certainly my hope that it’s not a huge number.”
Canada imposed a ban on ruminant-to-ruminant feeding in 1997, which removed all cattle parts, including specified risk materials (SRMs) such as nervous system tissues believed to harbour the BSE agent, from cattle feed.
Canada further tightened its feed rules in 2007, banning use of SRMs from rendered ruminants in any animal feeds, pet foods or fertilizers.
Asked Friday how Case 19 could have picked up infected SRMs, given the time since the feed bans were imposed, Mayers said it’s possible that before 2007, “certain tissues” with the potential to pose risk for BSE could have made their way into feed.
CFIA officials again emphasized on Friday’s call that no part of Case 19’s carcass got into Canada’s food or feed supply. The case was discovered as part of the Canada-Alberta BSE surveillance program.
Detecting a small number of BSE cases over time, even now, is “not unexpected” in the context of the 30,000-odd samples tested annually through federal/provincial BSE surveillance, Mayers said.
Case 19’s home farm has been quarantined to cut out the chance of any equivalent-risk animals being shipped off the property, he added.
A progressive, fatal disease of the nervous system in cattle, BSE is in the family of transmissible spongiform encephalopathies (TSEs) such as scrapie in sheep, chronic wasting disease in deer and elk, and Creutzfeldt-Jakob disease in people. No treatment or vaccine against BSE is yet available.
From a public health perspective, since the 1990s, about 180 cases of a variant form of Creutzfeldt-Jakob disease (vCJD) in people in Europe have been connected to consumption of contaminated beef from BSE-infected cattle.
Health Canada has said no cases of vCJD have ever been linked to eating Canadian beef and BSE in Canada poses an “extremely low” risk to human health. — AGCanada.com NetworkTagged BSE, CFIA, OIE