WASHINGTON -- The Agriculture Department says a new case of mad cow disease has surfaced in a dairy cow in California.
The case is the fourth in recent years. John Clifford, the department's chief veterinary officer, said the cow from central California did not enter the human food chain and that U.S. meat and dairy supplies are safe.
Clifford did not say when the disease was discovered or exactly where the cow was raised. He said the cow was at a rendering plant in Central California when the case was discovered through U.S.D.A. sample testing.
There have been only three known cases of mad cow disease in the U.S.
The Agriculture Department is sharing its lab results with international animal health officials in Canada and England, Clifford said.
Mad cow disease is a neurological disease formally known as bovine spongiform encephalopathy. It is always fatal in cattle.
Clifford sad the California cow is an atypical case in that it didn't get the disease from eating infected cattle feed.