USDA Chief Veterinary Officer John Clifford today released the following statement on the detection of BSE in the United States:
"As part of our targeted surveillance system, the U.S. Department of Agriculture's (USDA) Animal and Plant Health Inspection Service (APHIS) has confirmed the nation's fourth case of bovine spongiform encephalopathy (BSE) in a dairy cow from central California. The carcass of the animal is being held under State authority at a rendering facility in California and will be destroyed. It was never presented for slaughter for human consumption, so at no time presented a risk to the food supply or human health. Additionally, milk does not transmit BSE.
"The United States has had longstanding interlocking safeguards to protect human and animal health against BSE. For public health, these measures include the USDA ban on specified risk materials, or SRMs, from the food supply. SRMs are parts of the animal that are most likely to contain the BSE agent if it is present in an animal. USDA also bans all nonambulatory (sometimes called "downer") cattle from entering the human food chain. For animal health, the Food and Drug Administration (FDA) ban on ruminant material in cattle feed prevents the spread of the disease in the cattle herd.
"Evidence shows that our systems and safeguards to prevent BSE are working, as are similar actions taken by countries around the world. In 2011, there were only 29 worldwide cases of BSE, a dramatic decline and 99% 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. 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 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.
"This detection in no way affects the United States' BSE status as determined by the OIE. 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: a mammalian feed ban, removal of specified risk materials, and vigorous surveillance. 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."
California Department of Food and Agriculture (CDFA) Secretary Karen Ross, in a statement, said the detection of BSE shows the surveillance program is working. "Milk and beef remain safe to consume. The disease is not transmitted through milk. Because of the strength of the food protection system, the cow did not enter the food or feed supply. There are numerous safeguards in place to prevent BSE from entering the food chain," she said.
"The atypical BSE designation is important because this is a very rare form of BSE not generally associated with an animal consuming infected feed. CDFA veterinarians are working with the USDA to investigate this case and to identify whether additional cows are at ris," adds Ross. "Feed restrictions in place in California and around the country for the last 15 years minimize that risk to the greatest degree possible. We will provide additional information about this case as it becomes available."
PF Perspective: USDA implemented enhanced surveillance of BSE following the first confirmed case in the U.S. About enhanced surveillance, USDA says, "The ongoing BSE surveillance program, which will sample approximately 40,000 animals each year, will continue to sample the cattle populations where the disease is most likely to be found. The statistically valid surveillance level of 40,000 is consistent with science-based internationally accepted standards. This level allows USDA to detect BSE at the very low level of less than 1 case per million adult cattle, assess any change in the BSE status of U.S. cattle, and identify any rise in BSE prevalence in this country."
"The targeted population for ongoing surveillance focuses on cattle exhibiting signs of central nervous disorders or any other signs that may be associated with BSE, including emaciation or injury, and dead cattle, as well as nonambulatory animals," states USDA, noting that samples are then set to the National Veterinary Services Laboratories in Ames, Iowa.
According to USDA, in January 2012, it performed 4,513 BSE tests; 5,313 in February; and 3,235 in March. It reports in 2011, it performed 40,482 tests; 44,301 in 2010; 44,217 in 2009; 43,145 in 2008; and 43,338 in 2007.
Background: On Dec. 23, 2003, USDA announced a presumptive positive case of BSE in a Holstein cow slaughtered in Washington. The infected cow entered the United States on September 4, 2001, as part of a shipment of 81 animals from the source herd in Canada. Then, in June 2005, an inconclusive BSE sample from Nov. 2004 (that had originally been classified as negative on the immunohistochemisty test) was confirmed positive. USDA identified the herd of origin for the index cow in Texas. On Feb. 27, 2006, an Alabama cattle producer contacted his herd vet and reported a "downer cow." On March 15, 2006, USDA confirmed the second native case of BSE in the United States.