Toronto A cow in Alberta has been diagnosed with mad cow disease, Canadian officials announced Tuesday -- the first known case in North America in a decade.
U.S. health officials banned imports of cattle, beef, beef-based products and animal feed from Canada.
Canadian Agriculture Minister Lyle Vanclief told a news conference Tuesday at the Alberta provincial legislature in Edmonton that the 8-year-old cow from a farm in northern Alberta was slaughtered on Jan. 31 because of suspected pneumonia.
Routine testing failed to rule out bovine spongiform encephalopathy, or BSE, and further testing in England confirmed the finding on Tuesday, Vanclief said.
"The herd has been quarantined. A trace on the animal is being done," he said. "The animal did not go into the food chain."
No case of mad cow disease has ever been found in U.S. cattle, despite intensive testing for the disease. To help prevent its spread here, the U.S. government routinely bans the import of meat and livestock from countries where mad cow disease is found.
Mad cow disease, known scientifically as BSE, first erupted in Britain in 1986, and is thought to have spread through cow feed made with protein and bone meal from mammals.
Creutzfeldt-Jakob disease is the human form of mad cow disease and can cause paralysis and death. Humans develop new variant Creutzfeldt-Jakob disease when they eat meat from infected animals, scientists believe.
Both Canada and the United States outlawed the feeding of mammalian meat and bone meal to cattle, sheep and goats in 1997, a rule considered each nation's main defense against the disease. The incubation period for BSE can be eight years, so the new Canadian case could have been infected from feed predating the ban.
The only previous known case in Canada, in 1993, involved an animal born in Britain that was imported, Vanclief said. The herd was destroyed and there was no further spread of the disease, he said.
It was not immediately clear where the cow in the new case was born.
Authorities will trace the origin of the cow and how and where it was as part of an investigation into any possible spread of the disease, Vanclief said. They have also quarantined the farm and will "depopulate" the herd that the new case is from, along with any other herds that come into question.
Alberta is Canada's main cattle province, with almost 40 percent of the industry. Last year, Canada exported 1.7 million head of live cattle and 373,000 tons of beef product with a total value of $2.5 billion to the United States.
Canada has voluntarily halted issuing certificates for its cattle declaring it free of BSE, said officials who stressed it was an isolated case involving one cow of a disease that does not spread between live animals.
U.S. Agriculture Secretary Ann Veneman said in a statement that she spoke with Canadian officials and the situation "appears to be an isolated case."
"Information suggests that risk to human health and the possibility of transmission to animals in the United States is very low," Veneman said.
The FDA and U.S. Agriculture Department are working with Canadian officials to get more information about the sick cow, including records concerning its past ownership and what animal feed it was given.