WASHINGTON -- Investigators tentatively traced the first US cow with mad cow disease to Canada, which could help determine the scope of the outbreak and might even limit the economic damage to the American beef industry.
Dr. Ron DeHaven, the Agriculture Department's chief veterinarian, said yesterday that Canadian officials provided records indicating the sick Holstein was in a herd of 74 cattle shipped from Alberta, Canada, into this country in August 2001 at Eastport, Idaho.
"These animals were all dairy cattle and entered the US only about 2 or 2 1/2 years ago, so most of them are still likely alive," DeHaven said.
Canada immediately took issue with the US assertion that a cow with mad cow disease discovered in Washington state had probably come from Canada, saying such a conclusion was premature.
"As yet, there is no definitive evidence that confirms that the BSE-infected cow originated in Canada," the chief Canadian veterinarian, Dr Brian Evans, said at a news conference.
The sick cow's presence in that herd does not mean all 74 animals are infected, DeHaven said. Investigators will probably find where the other 73 animals are within a matter of days, he said. Finding them will help investigators determine if any other animals are sick and need to be tested.
In May, Canada found a lone cow with the disease in Alberta but has not been able to determine the source of infection.
If US and Canadian officials confirm that the sick cow in Washington state came from Canada, it might save the export market for the American beef industry because the United States could keep its disease-free status and continue trade.
Federal officials announced on Tuesday that tests indicated the cow, which ended up at a Washington farm in October 2001, had the brain-wasting illness. An international laboratory in England confirmed it Thursday.
Mad cow disease, known as bovine spongiform encephalopathy, is a concern because humans who eat brain or spinal matter from an infected cow can develop variant Creutzfeldt-Jakob disease. In Britain, 143 people died of it after an outbreak of mad cow in the 1980s.
Federal officials insist the nation's meat is safe because the brain, spinal cord, and lower intestine -- parts that carry infection -- were removed from the cow before its meat was processed for human consumption.
Despite those assurances, more than two dozen countries banned imports of US beef this week. The United States lost 90 percent of its beef export market, industry officials say, and producers stand to lose up to $6 billion a year in exports and falling domestic prices. Agriculture Department officials went yesterday to Japan, a top buyer that has banned American beef, to discuss maintaining trade.
Connecting the infected cow to Canada could deal another blow to the Canadian beef industry, which has struggled since it found its case of mad cow last May. It lost $1 million in trade per day as countries cut off beef imports.
Canada's Evans noted that details on the cow's records in the United States do not match the ones kept in Canada.
Canadian papers show the cow had two calves before it was shipped to the United States, which wasn't documented by US officials. Also, DeHaven said Canadian papers say the diseased cow was 6 1/2 years old -- older than US officials had thought. US records say the cow was 4 or 4 1/2 years old.
The age is significant because the animal may have been born before the United States and Canada in 1997 banned certain types of feed, considered the most likely source of infection. Cows get infected by eating feed that contains tissue from the spine or brain of an infected animal. Farmers used to feed their animals such meal to fatten them.
Although US officials have maintained the food supply is safe, the government recalled about 10,000 pounds of meat cut from the infected cow and 19 other cows slaughtered Dec. 9 at Vern's Moses Lake Meat Co., in Moses Lake, Wash.
Ken Peterson of the department's Food Safety and Inspection Service said: "It's too early to know how much of the product has been brought back, though we know that some of the product is beginning to be at least held at the retail facilities."
Officials say the slaughtered cow was deboned at Midway Meats in Centralia, Ore., and the meat was sent to two other plants in the region, identified as Willamette Valley Meat and Interstate Meat, both near Portland, Ore.
Meanwhile, the Food and Drug Administration is trying to find out if the cow ate contaminated feed -- a difficult task because the animal may have gotten the disease years before it appeared sick. The disease has an incubation period of four or five years.