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Mad cow disease discovered in Central California dairy cow

POSTED April 24, 2012 4:03 p.m.

A dairy cow from Central California was confirmed as the nation’s fourth case of mad cow disease, the U.S. Department of Agriculture announced Tuesday.

The animal was never presented for slaughter for human consumption, said USDA Chief Veterinary Officer John Clifford, and at no time presented a risk to the food supply or human health.

“The detection of BSE (bovine spongiform encephalopathy or mad cow disease) shows that the surveillance program in place in California and around the country is working,” said California Agriculture Secretary Karen Ross. “Milk and beef remain safe to consume. The disease is not transmitted through milk. Because of the strength of the food protection system, the cow did not enter the food or feed supply. There are numerous safeguards in place to prevent BSE from entering the food chain.”

Dennis Luckey, executive vice president of Baker Commodities, told The Associated Press that the disease was discovered at its Hanford, Calif., transfer station when the company selected the cow for random sampling.

Luckey said the cow died at the dairy and was randomly tagged for the surveillance program.

Michael Marsh, chief executive of Western United Dairymen, told The Associated Press it was an adult cow over 30 months old, not a downed or sick animal, and it appeared normal when it was last observed. He said the cow was first tested on April 18.

The carcass of the animal is being held under state authority at a rendering facility in California and will be destroyed, according to the USDA.

"Samples from the animal in question were tested at USDA's National Veterinary Services Laboratories in Ames, Iowa. Confirmatory results using immunohistochemistry and western blot tests confirmed the animal was positive for atypical BSE, a very rare form of the disease not generally associated with an animal consuming infected feed,” said Clifford. "We are sharing our laboratory results with international animal health reference laboratories in Canada and England, which have official World Animal Health reference labs. These labs have extensive experience diagnosing atypical BSE and will review our confirmation of this form of the disease. In addition, we will be conducting a comprehensive epidemiological investigation in conjunction with California animal and public health officials and the FDA.”

Unlike typical BSE, which is believed to be transmitted through feed that is contaminated with mad cow diseased meat, atypical BSE is caused by a spontaneous protein infection in the brain.

Mad cow disease is a progressive neurological affliction among cattle that is always fatal. It belongs to a family of diseases known as transmissible spongiform encephalopathies. Affected animals may display nervousness or aggression, abnormal posture, difficulty in coordination and rising, decreased milk production, or loss of body weight despite continued appetite.

In 2011, there were 29 worldwide cases of mad cow disease, a 99 percent reduction since the peak in 1992 of 37,311 cases. This is directly attributable to the impact and effectiveness of feed bans as a primary control measure for the disease, said Clifford.

“The USDA has no reason to believe that any other U.S. animals are currently affected, but we will remain vigilant and committed to the safeguards in place,” said U.S. Ag Secretary Tom Vilsack in response to the finding of mad cow disease.

Human consumption of BSE infected meat has been linked to Variant Creutzfeldt-Jakob Disease. Variant Creutzfeldt-Jakob disease is a fatal human neurodegenerative condition. According to the World Health Organization, patients with vCJD usually experience psychiatric or sensory symptoms, which most commonly take the form of depression, apathy or anxiety, and occasionally unusual persistent and painful sensory symptoms. Neurological signs, including unsteadiness, difficulty walking and involuntary movements, develop as the illness progresses and, by the time of death, patients become completely immobile and mute.

Currently, the diagnosis of vCJD can only be confirmed following examination of the brain after death. There have been 175 cases of vCJD reported in the United Kingdom, and 49 cases in other countries from October 1996 to March 2011 — including three in the United States.

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