TORONTO — Test results have cleared all other cattle in the original herd linked to North America's first mad cow case in a decade, Canadian officials said Sunday.
"The results from diagnostic testing on the first quarantined herd are negative," said Dr. Claude Lavigne of the Canadian Food Inspection Agency. "It means the incidence of BSE (bovine spongiform encephalopathy) in Canada presently remains in one cow."
Canada announced Tuesday that it had found one cow with the disease in a herd of 150 in Alberta province. Cattle feed from animal sources contaminated with BSE is considered the most likely cause of the infection case, officials said.
The human form of BSE is Creutzfeldt-Jakob disease, which causes paralysis and death. Scientists believe humans develop new variants of Creutzfeldt-Jakob when they eat meat from infected animals. More than 130 people have died of the disease, mostly in Britain.
Since the announcement of the BSE case in Canada, the United States, Japan, Australia, South Korea, Singapore, New Zealand, Indonesia and Barbados banned beef imports from Canada — despite reassurances from government and industry officials that the beef is safe.
Those bans brought immediate cuts in production and uncertainty to Canada's $22 billion beef industry.
"This news is very encouraging," Lavigne said of the test results. "The message to the world is a clear one — our systems are safe ... (and) there is nothing to indicate that the safety of Canadian beef has been compromised."
He said 17 farms were now under quarantine across Alberta, Saskatchewan and British Columbia while agriculture and veterinary investigators officials tried to determine which other herds may have had contact to the infected cow, or with poultry feed made from its rendered carcass.
Lavigne said calves sold out of the original herd before the infected case was discovered were now being removed from their current herds, slaughtered and tested, with results due later this week, officials said.
Early indications showed the infected cow might have been born on a Canadian farm, which would make it the first case of a North American-born animal contracting the illness known as mad cow disease which decimated the British beef industry in the 1990s.
Some U.S. legislators have criticized Canada's system for testing cattle products, noting the infected cow was slaughtered on Jan. 31 but confirmation of BSE came more than three months later. They want guarantees of improvement before reopening the U.S. market, which consumes more than 70 percent of Canada's beef product exports.
Dr. Brian Evans, chief veterinary officer for the Canadian Food Inspection Agency, Canada was examining its testing system.
"All of our policies will receive full scrutiny ... and any adjustments made if we feel it is demonstrable to improve public health," Evans said.
He added that it was possible more farms may be quarantined and cattle destroyed.
The previous case of BSE in North America was in 1993, involving a bull imported from Britain. The animal and its herd were slaughtered, but no trade bans resulted.
Mad cow disease first erupted in Britain in 1986 and is thought to have spread through cow feed made with protein and bone meal from mammals.
Canada and the United States outlawed the feeding of meat and bone meal to cattle, sheep and goats in 1997, a rule believed to be the main defense against the disease.
On the Net:
Canadian Food Inspection Agency: www.inspection.gc.ca/
Institute for Agriculture and Trade Policy: www.iatp.org/