Rare form of BSE found in California dairy cow
By Jennifer Carrico and Doug Rich
The United States Department of Agriculture confirmed April 24 a positive case of bovine spongiform encephalopathy in a California dairy cow and reassured the public that the meat and milk supply is safe.
USDA Chief Veterinary Officer John Clifford said, "As part of our targeted surveillance system, the USDA's Animal and Plant Health Inspection Service has confirmed the nation's fourth case of BSE, in a dairy cow from central California. The carcass of the animal is being held under state authority at a rendering facility in California and will be destroyed. It was never presented for slaughter for human consumption, so at no time presented a risk to the food supply or human health. Additionally, milk does not transmit BSE."
National Cattlemen's Beef Association Cattle Health and Well-Being Committee Chairman Tom Talbot said in a statement, "USDA confirmed this afternoon a positive test result as part of its targeted surveillance program to test cattle for BSE. USDA has confirmed this dairy animal was discovered at a rendering facility and was never presented for human consumption and poses zero risk to human health. The bottom line remains the same--all U.S. beef is safe."
The U.S. has safeguards in place to protect human and animal health against BSE. These measures include a ban on specified risk materials from entering the food supply. The USDA also bans nonambulatory or "downer" cattle from entering the human food chain. On the animal health side, the Food and Drug Administration put a ban on ruminant material in cattle feed to prevent the spread of the disease in the cattle herd.
"Evidence shows that our systems and safeguards to prevent BSE are working, as are similar actions taken by countries around the world. In 2011, there were only 29 worldwide cases of BSE, a dramatic decline and 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.
There was a small but noticeable dip in livestock auction market prices after the announcement by Clifford, regarding detection of BSE in the U.S.
Nancy Robinson, vice president of Government and Industry Affairs at the Livestock Marketing Association said she expects this to be a short-term event.
"Our members go on with business and we hope that by doing that by tomorrow (April 25) it will have corrected itself," Robinson said. "Hopefully we won't see any dramatic effect in the marketplace."
The system worked as designed. The animal was detected and kept out of the food supply. Robinson said that once people realize that their meat is safe that we will not see big swings in the markets that we might have seen 10 years ago.
"We are confident that the food supply is safe and all of the mitigation steps are in place to keep specified material out of the food supply," Robinson said. "There was never any danger of meat from this animal getting into the food supply."
"There is so much confidence in the steps that have been taken that the effect on the markets will be small," Robinson said.
An 'atypical' case
Samples from this cow were tested at the USDA's National Veterinary Services Laboratories in Ames, Iowa, where it was determined that the animal was positive for atypical BSE--a very rare form of BSE not generally associated with infected feed.
"We are sharing our laboratory results with international animal health reference laboratories in Canada and England, which have official World Animal Health (OIE) 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," added Clifford.
Dr. Guy Longeragan, an epidemiologist and professor of food safety and public health at Texas Tech University, said the difference between a classical BSE case and an atypical BSE case is determined by what he called a protein fingerprint.
During a press conference by the NCBA on April 24, Longeragan said that worldwide there have been in excess of 180,000 classical cases of BSE but on a worldwide basis there have only been 60 atypical cases. Including the most recent case there have been only four confirmed BSE cases in the U.S. The last three cases have all been atypical.
"It is a very rare form of BSE," Longeragan said. "In terms of atypical BSE it is so rare our understanding of the transmission is more limited."
Longeragan said it is possible that atypical BSE is the result of a spontaneous event within the animal. He said that most of the atypical cases have been identified in much older animals. In the two previous U.S. cases the animals were quite old.
BSE is a progressive neurological disease among cattle and is always fatal. 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.
This was the fourth case of BSE in the U.S. The first case was confirmed on Dec. 23, 2003. That case was in an adult Holstein cow in Washington State. A June 24, 2005, case was confirmed on a Texas cow and a March 15, 2006, case was confirmed in a cow in Alabama.
"This detection in no way affects the United States' BSE status as determined by the OIE. The United States has in place all of the elements of a system that OIE has determined ensures that beef and beef products are safe for human consumption: a mammalian feed ban, removal of specified risk materials, and vigorous surveillance. Consequently, this detection should not affect U.S. trade," said Clifford.
"USDA remains confident in the health of the national herd and the safety of beef and dairy products. As the epidemiological investigation progresses, USDA will continue to communicate findings in a timely and transparent manner," he added.
Since April 2009, a Food and Drug Administration rule has been in place aimed to preventing BSE from reaching the food supply.
The rule requires beef and dairy producers to clearly mark animals that are 30 months of age or older. Rendering facilities are required to remove the brain and spinal cord of all cattle ages 30 months and older if they plan to use the dry material as a feed ingredient. This prevents any chances of that material getting into a food source.
In 1997, the U.S. and Canada banned the use of animal products in ruminant feed to prevent BSE transmission.
"The beef and dairy in the American food supply is safe and USDA remains confident in the health of U.S. cattle. The systems and safeguards in place to protect animal and human health worked as planned to identify this case quickly, and will ensure that it presents no risk to the food supply or to human health. 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. Secretary of Agriculture Tom Vilsack.