The animal has been euthanized and the carcass is being being held under state authority at a rendering facility in California and will be destroyed, officials said.
The carcass is at a Baker Commodities facility in Hanford, California, according to Dennis Lucky of the company.
See a video statement from USDA Chief Veterinary Officer Dr. John Clifford
Though eating contaminated meat or some other animal products from cattle with BSE is thought to be the cause of a fatal brain disease (variant Creutzfeldt-Jakob disease) in humans, the cow was never presented for slaughter. Milk does not transmit BSE.
BSE is usually transmitted between cows through the practice of recycling bovine carcasses for meat and bone meal protein, which is fed back to other cattle. In this case, the USDA reports that it was an atypical, rare form of BSE not likely carried by contaminated feed.
In humans, symptoms of vCJD involve psychiatric symptoms and behavioral changes, movement deficits, memory disturbances, and cognitive impairments.
The USDA says it remains confident in the health of the national herd and the safety of beef and dairy products and that as the investigation progresses, the group will continue to communicate findings with the public.
The Centers for Disease Control reports that the chance of contracting mad cow disease, even after consuming contaminated products, is less than one in 10 billion, if at all. California Department of Public Health Director and Public Health Officer Dr. Ron Chapman issued a statement today saying that residents do not need to take any specific precautions.
Unlike most other meat-borne illnesses such as E. coli bacteria, cooking does not kill mad cow disease. Consumers who do wish to exercise extra caution can follow the advice presented by the Web-based consumer advocacy group Consumeraffairs.com, which advises the avoidance of brains, neck bones and beef cheeks, bone marrow and cuts of beef that are sold on the bone. The group also says to choose boneless cuts of meat, and for ground beef, choose only meat that is ground on-site in the store. Pets such as cats and dogs are not at risk for the disease.