USDA announced on April 24 it had confirmed that a dairy cow from central California was infected with bovine spongiform encephalopathy (BSE), the first case of what often is called mad cow disease in the U.S. since 2006.
The animal was found at a rendering plant that processes diseased or sick animals into non-edible products for use in things like soap or glue. It was never presented for slaughter for human consumption, so at no time presented a risk to the food supply or human health, USDA officials said. They added that milk does not transmit BSE.
“The carcass of the animal is being held under state authority at a rendering facility in California and will be destroyed,” officials said. It is the fourth confirmed case of BSE in U.S. history.
"Evidence shows that our systems and safeguards to prevent BSE are working, as are similar actions taken by countries around the world,” said USDA Chief Veterinary Officer John Clifford. “In 2011, there were only 29 worldwide cases of BSE, a dramatic decline and 99 percent reduction since the peak in 1992 of 37,311 cases. This is directly attributable to the impact and effectiveness of feed bans as a primary control measure for the disease.
"Samples from the animal in question were tested at USDA's National Veterinary Services Laboratories in Ames, Iowa. Confirmatory results using immunohistochemistry and western blot tests confirmed the animal was positive for atypical BSE, a very rare form of the disease not generally associated with an animal consuming infected feed.
"We are sharing our laboratory results with international animal health reference laboratories in Canada and England, which have official World Animal Health (OIE) reference labs,” Clifford continued. “These labs have extensive experience diagnosing atypical BSE and will review our confirmation of this form of the disease. In addition, we will be conducting a comprehensive epidemiological investigation in conjunction with California animal and public health officials and the FDA.”
BSE is a progressive neurological disease among cattle that is always fatal. It’s believed transmissible to humans who eat infected parts from animals, resulting in the deadly brain disease Creutzfeldt-Jakob. BSE belongs to a family of diseases known as transmissible spongiform encephalopathies. Affected animals may display nervousness or aggression, abnormal posture, difficulty in coordination and rising, decreased milk production, or loss of body weight despite continued appetite.
The first U.S. case of BSE was discovered in December 2003. It set off shock waves of fear about the U.S. food supply and foreign bans on beef imported from the U.S. But it also resulted in a ban on ruminant material in cattle feed, removal of specified risk materials and a vigorous surveillance program that identifies and removes questionable animals.
Subsequent cases were discovered in June 2005 and March 2006.
"This detection in no way affects the United States' BSE status as determined by the OIE,” said Clifford. “The United States has in place all of the elements of a system that OIE has determined ensures that beef and beef products are safe for human consumption. Consequently, this detection should not affect U.S. trade.
"USDA remains confident in the health of the national herd and the safety of beef and dairy products. As the epidemiological investigation progresses, USDA will continue to communicate findings in a timely and transparent manner."