Two farms have been quarantined by the U.S. Department of Agriculture as the agency continues to investigate last month's discovery of mad cow disease at a California dairy farm.
Authorities also have launched an investigation at a calf ranch where the initial infected cow was raised 10 years ago, according to a statement released late Wednesday by the USDA.
Last week, the USDA documented the fourth confirmed U.S. case of Bovine Spongiform Encephalopathy (BSE) - a brain wasting disease affecting cattle - known commonly as mad cow disease, at a rendering facility in central California. USDA officials said the cow was never presented for human consumption and was not a threat.
The farm where the cow was initially discovered has been under quarantine since the discovery, agriculture officials said. Wednesday's announcement of a second quarantine involves a farm closely associated with the dairy where the sick cow was discovered last month, the USDA said. The agency is still trying to determine if any at-risk cattle are present at either of the two farms.
Read the full story: "USDA quarantines 2 farms in mad cow investigation"
The first U.S. case of mad cow disease in six years sparked fears of illness that prompted at least one major South Korean retailer to suspend the sale of American beef.
However, public health officials said the risk for disease for Americans is extremely low given that the affected dairy cow in central California was not part of the human food chain and was not exposed to bovine spongiform encephalopathy (BSE) through animal feed.
"It was never presented for slaughter for human consumption, so at no time presented a risk to the food supply or human health," said John Clifford, the Agriculture Department's chief veterinarian.
Read the full story: "S. Korea curbs U.S. beef sales after confirmation of mad cow disease"
After Tuesday's announcement confirming a case of bovine spongiform encephalopathy (BSE), sometimes referred to as "mad cow disease," in a dairy cow in California, you may want a refresher course in mad cow basics.
It's important to keep in mind that U.S. health officials said the public risk posed by BSE is extremely low, and that residents don't need to take any specific precautions.
Here are the facts:
The nation's fourth case of bovine spongiform encephalopathy (BSE), sometimes referred to as "mad cow disease," has been confirmed in a dairy cow in central California, the U.S. Department of Agriculture said Tuesday.
The carcass was at a Baker Commodities Inc. rendering facility in Hanford, California, according to Executive Vice President Dennis Luckey.
The company renders animal byproducts and had randomly selected the animal for testing last Wednesday, he said.
"We are in the business of removing dead animals from dairies in the Central Valley," he told CNN in a telephone interview. "As part of that program, we participate in the BSE surveillance program."
Public health officials said the risk to public was extremely low.
The sample was sent to UC Davis for initial testing, which came back inconclusive. It was then sent to the USDA's laboratory in Ames, Iowa, where it tested positive, the agency said.