There has only been one case of mad cow disease in The U.S., an infected dairy cow in Washington State in December 2003.
Since then, preliminary tests found the disease in three other cows, one of which turned up positive after extensive testing by the USDA earlier this week.
"Consumer confidence, I am very confident, will remain," Agriculture Secretary Mike Johanns said. "This is a situation where the firewalls worked. We do not have a human health risk. This animal did not enter the food chain. This animal never got near the food or feed chain."
A sample from the animal is being shipped to a laboratory in Weybridge, England; the same that provided confirmation of the Washington State mad cow case. The Agriculture Department will also administer additional tests.
Since the Washington State discovery, the U.S. government has tested over 375,000 cows, who must be killed in order to undergo mad cow testing.
Officials did not say whether the latest suspected cow was born in the States. The Washington State cow had been imported from Canada. The Agriculture Departmen was unable to track down all 80 cows that crossed over with the infected one.
Mad cow disease, or bovine spongiform encephalopathy (BSE), causes a variant of the brain-wasting ailment, Creutzfeldt-Jakob disease, in humans. It has killed over 150 people, most of them Britons, where an outbreak occured in the 1990's
"I don't anticipate problems with our trading partners," said Johanns. "They'll want to know what the issues are and what we have done. We want to assure them, and to assure the public, that what we are doing here is transparent."
After the Washington State scare, many foreign countries banned the import of U.S. beef into their markets.
