Washington: The US authorities have detected a case of mad cow disease, the nation`s fourth, in a dairy cow in the state of California.
The carcass was shifted to a facility and will be destroyed, Xinhua quoted the US Agriculture Department as saying Tuesday.
The animal was not killed for human consumption, "so at no time presented a risk to the food supply or human health", the department said.
Bovine spongiform encephalopathy or mad cow is a fatal neurodegenerative disease in cattle that affects the brain and the spinal cord.
The disease could be transmitted to humans by eating food contaminated with the infected carcass. Milk does not transmit the disease.