June 30, 2005
The U.S. Agriculture Department says it has tracked the latest
confirmed case of "mad cow" disease to a 12-year-old animal born in Texas.
The agency said the cow was slaughtered last November for use in pet
food and did not enter the human food supply.
It is the second confirmed case of the devastating disease in the U.S., the first involving a domestically-bred cow. The first case, discovered in Washington state in December 2003, involved a cow imported from Canada.
"The source herd is now under a hold order as we identify animals of interest within that herd," said USDA chief veterinarian Dr. John Clifford.
"Animals of interest would include any animals that were born the same year as this animal, as well as any born the year before or the year after," he said.
In a statement on the USDA Website, Clifford said the safety of the human food supply was never in doubt. Given the age of the animal, Clifford said it is reasonable to believe it became infected before the 1997 ban against the use of cattle parts in animal feed.
The disease is not spread through contact. Only by consuming infected issue from other cattle do animals contract the disease. Clifford said the safety of Texas beef is not in question, but he said the agency could remain "vigilant."
USDA failed to diagnose the infection the first two times tissue from the infected animal was studied. It was only after the department's Inspector General intervened that the tissue was tested a third time and found positive for the disease.
Mad cow disease -- or bovine spongiform encephalopathy (BSE) -- is an invariably-fatal degenerative brain disease spread through infected meat. Cattle can be infected by eating protein supplements made with the ground-up remains of other animals, a practice now outlawed in most countries.
