Animal health officials announced the seventh case of mad cow disease in the United States in 20 years — an apparently spontaneous infection of a beef cow from a farm in southeastern Tennessee. The Agriculture Department said, “We do not expect any trade impacts” because the United States is rated internationally as a negligible risk for the disease, which is always fatal to cattle.
The cow was tested for bovine spongiform encephalopathy, the formal name for mad cow disease, after it arrived at a slaughter plant in South Carolina. “This animal never entered slaughter channels and at no time presented a risk to the food supply or to human health in the United States,” said the Animal and Plant Health Inspection Service. The USDA said the cow, which was approximately five years or older, had an atypical case of BSE.
“Atypical BSE refers to naturally and sporadically occurring forms, which are believed to occur in all cattle populations at a very low rate, and which have only been identified in older cattle when conducting intensive surveillance,” says the World Organization for Animal Health (OIE).
A preliminary investigation “has determined the cow originated in southeast Tennessee,” said the Tennessee state Agriculture Department. State veterinarian Samantha Beaty said her office would try to determine previous owners and locations where the infected cow lived so that siblings and offspring could be tested.
Incidents of classical BSE, caused by consumption of contaminated feed, have become rare with implementation of control measures. Classical BSE has been reported in 26 countries, mainly in Europe, Asia, the Middle East and North America.
Only the first of the seven U.S. mad-cow cases, in 2003, was classical BSE, said the USDA. The rest were atypical cases.
The OIE webpage on mad cow disease is available here.