A dairy cow shipped for rendering from central California has been confirmed as the United States' fourth domestic case of BSE, at a time when the always-fatal bovine disease appears to be on the wane worldwide.
U.S. federal officials emphasized in their announcements Tuesday that the finding will not affect the country's "controlled risk" status for BSE (bovine spongiform encephalopathy) at the World Organization for Animal Health (OIE), nor is it expected to affect U.S. beef or dairy exports to any nations following OIE standards.
The animal's carcass is now held at a rendering facility in California and will be destroyed, said John Clifford, the U.S. Department of Agriculture's chief veterinary officer, in a release.
The carcass, he said, "was never presented for slaughter for human consumption, so at no time presented a risk to the food supply or human health." Furthermore, he said, "milk does not transmit BSE."
USDA's National Veterinary Services Laboratories in Ames, Iowa found the animal tested positive for "atypical" BSE, a form of the disease "not generally associated with an animal consuming infected feed," Clifford said.
Canadian and British OIE reference labs for BSE will now review USDA's findings, he said, noting both labs have "extensive experience" diagnosing the atypical form of the disease.
Also, he said, USDA will work with California state officials and the U.S. Food and Drug Administration (FDA) on a "comprehensive epidemiological investigation" of this particular case.
The Canadian Food Inspection Agency said Tuesday that USDA's finding "will not affect trade between the U.S. and Canada" as "both countries have implemented science-based measures to protect animal and human health."
"The systems and safeguards in place to protect animal and human health worked as planned to identify this case quickly, and will ensure that it presents no risk to the food supply or to human health," U.S. Agriculture Secretary Tom Vilsack said in a separate statement.
Clifford noted the substantial decline in the number of BSE cases reported each year worldwide, with only 29 seen in 2011 in the countries that test for the disease, down from the 1992 peak of 37,311.
"This is directly attributable to the impact and effectiveness of feed bans as a primary control measure for the disease," he said.
"USDA's ongoing BSE surveillance program tests approximately 40,000 high-risk cattle annually, bringing the total of tested animals to more than one million since the program began," Tom Talbot, chairman of the U.S. National Cattlemen's Beef Association cattle health and well-being committee, said in a separate statement. BSE, he said, is "fast approaching eradication worldwide."
By comparison, OIE guidelines currently require Canada to test about 30,000 samples per year. According to Canada's chief veterinary officer, Brian Evans, 7,718 surveillance samples from Canadian animals were tested between Jan. 1 and March 31 this year.
Canada has reported 18 cases of BSE in the domestic herd since the first was found in 2003. Canada's most recent case was in a six-year-old Alberta dairy cow, confirmed in February last year.
Globally, Evans said, the number of cases reported by countries that test for BSE has dropped by about 50 per cent every year over the past four or five years.
Domestically, he said, it will be a few more years before Canada can "fully demonstrate" the full effectiveness of the control measures in place to eradicate BSE from the Canadian cattle herd.
Canada, he said, is in the fifth year of its enhanced feed ban, and is "just at the mean average incubation period" for BSE.
"The real proof will come in the next two to three years, he said, and that's what the CFIA is focusing on," he said in a Canadian Cattlemen's Association newsletter.
"If we can sustain this effort through to 2015, we should be in a very good position at the international level to adjust our surveillance activities accordingly on the recognition that we've done our due diligence and that the measures we've demonstrated scientifically are effective measures," he said.
Then, he said, "we can then make further programming adjustments as part of the BSE roadmap forward."
Some producers, he said, might see the decline in cases as "a signal to finally put BSE behind them," but "continued vigilance at home is still required, given the fact that we have restored markets for beef products and live animals."
U.S. to adopt OIE beef import standards on BSE, March 12, 2012
BSE net catches Alberta dairy cow: CFIA, March 3, 2011