A six-year span without any bovine spongiform encephalopathy (BSE) cases in the U.S. is over as the prion disease has again been discovered in the nation’s cattle herd.
A dairy cow in a central California dairy has been diagnosed with atypical BSE — mad-cow disease — according to both state and federal officials. It is the fourth such infected animal discovered since 2003.
But “there is no public health threat due to the discovery of BSE in a dairy cow,” said Dr. Ron Chapman, director of the California Department of Public Health. “The food supply in California has not been affected by this discovery, and residents do not need to take any special precautions.”
Chapman said the detection “is evidence that the system of safeguards is working.” He said the cow in question was not destined to be slaughtered for food for human consumption and BSE is not transmitted in milk.
The BSE-infected cow is now nothing more than a carcass being held under the authority of Chapman’s office at one of central California’s four rendering facilities.
Ground zero for this mad cow was likely Hanford, CA, where it was sidelined for testing at a rendering plant transfer station that removes hides from carcasses. Hanford is located in California’s Central Valley, 30 miles south of Fresno.
Late Tuesday, the Huffington Post quoted a manager with Los Angeles-based Baker Commodities, which owns a rendering plant 50 miles from Hanford at Kerman, CA. Dennis Luckey told HP a tissue sample was randomly collected from the implicated cow on April 18 and originally sent to the University of California, Davis.
Test results at UC Davis were inconclusive, but the National Veterinary Services Laboratories at Ames, IA returned positive results for BSE on Tuesday.
The Veterinary Services Lab also said this BSE was atypical, the very rare form of the disease that researchers say is not generally associated with an animal consuming infected feed.
It is not yet known which dairy farm in the area sent the BSE-infected cow to the rendering station.
USDA disclosed the mad cow discovery Tuesday shortly after commodity markets closed, following some volatile beef trading. Although the activity might not have been connected to the BSE issue, the Wall Street Journal reported that rumors were rampant.
John Clifford, USDA’s chief veterinary officer, said in a news release that the animal carcass would now be destroyed at the facility where it is being held.
The USDA officials did not say it, but they also might have been lucky. The BSE-infected cow went to a rendering plant where USDA just happened to be taking tissue samples to test for mad cow on a regular basis.
The sample that returned the positive test result was one of 40,000 samples the department is taking on an annual basis.
However, the fact that a downer dairy cow went to a rendering plant, rather than a meat-slaughter plant, has everything to do with the 2009 regulation that outlawed turning non-ambulatory disabled animals into meat meant for human consumption.
Secretary of Agriculture Tom Vilsack imposed the current total ban on the slaughter of so-called “downer” cows, which can include those with BSE. About this mad cow discovery, Vilsack said: “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.”
The Center for Science in the Public Interest also issued a statement saying “there is no reason to believe the beef or milk supply is unsafe.”
“If the cow were exposed to the typical strain of BSE via animal feed — and the government says that’s not the case here — that would represent a significant failure,” it said. Had the BSE been feed-related, CSPI said the U.S. would have been hampered in its investigation by the lack of an effective animal ID system.
Was the implicated cow intended to be turned into pet food? According to the Food and Drug Administration: “Dogs, birds, reptiles and horses are not known to be susceptible to the infectious agent that causes BSE in cattle. However, cats are susceptible.”
The FDA says approximately 90 cats in the UK and several cats in other European countries were diagnosed with the feline version of BSE, or FSE, through commercial cat food or through meat scraps provided by butchers until implementation of BSE-related feed bans in those countries.
California joins Washington state, Texas and Alabama in experiencing the discovery of a mad cow within its borders. BSE is called mad-cow disease became it is a brain-wasting condition that can be transmitted to humans from eating beef that contains bits of the brain, spinal cord or digestive tract from infected cattle.
USDA does not expect the discovery of a fourth mad cow to change its BSE status under the World Animal Health system; Clifford said the U.S. will share its tests with laboratories in England and Canada.
Worldwide, there were 29 BSE cases in 2011, a 99 percent reduction since the peak of 37,311 cases in 1992. Clifford attributed the dramatic decline to feed bans as the primary control measure.
Eating BSE-contaminated meat can cause the human prion disease known as variant Creutzfeldt-Jakob disease. The deadly nerve disease is extremely rare and the few cases treated in the U.S. are believed to have originated in the United Kingdom and Saudi Arabia.
A mad cow outbreak in the UK that peaked in 1993 resulted in more than 150 human deaths and the need to destroy about 150,000 head of cattle.