WASHINGTON (Reuters) - U.S. authorities reported the first U.S. case of mad cow disease in six years on Tuesday and quickly assured consumers and global importers that meat from the California dairy cow did not enter the food chain.
John Clifford, the USDA's chief veterinary officer, said the case was "atypical" and that there was "no cause for alarm" from the animal. Cows can contract the disease spontaneously in rare cases and that it cannot be transmitted unless the brain or spinal tissue is consumed by humans or another animal, according to scientists.
Mad cow, or Bovine Spongiform Encephalopathy, is believed to cause the deadly brain disease variant Creutzfeldt-Jakob in humans who eat infected parts from animals with the disease. The first mad cow case in the United States was in late 2003 and caused the nation's beef exports to drop by nearly $3 billion the following year.
There is no evidence that humans can catch it from drinking the milk of an infected cow. However, fears of a potential backlash among consumers and big importers of U.S. beef caused Chicago live cattle futures to drop sharply.
The USDA has begun notifying authorities at the World Organization for Animal Health (OIE) as well as U.S. trading partners, but the finding should not affect the nation's beef exports, Clifford said. The USDA is still tracing the exact life of the infected animal.
The carcass of the cow, which the USDA said was infected by an "atypical" form of the disease, is under quarantine and would be destroyed. The cow, which was found at a rendering plant that processes diseased or sick animals into non-edible products for use in things like soap or glue, was not believed to have contracted the disease by eating contaminated feed, the USDA said.
"There is really no concern for alarm here with regards to this animal. Both human health and animal health are protected with regards to this issue," Clifford told reporters at a briefing at USDA headquarters.
Ahead of the announcement, rumors of the case pushed live cattle futures on the Chicago Mercantile Exchange down by as much as the 3-cent-per-lb daily limit. But prices pared some losses after the USDA said the beef had not entered the food chain.
Dennis Luckey, executive vice president of Baker Commodities Inc, a privately held Los Angeles-based processor of animal byproducts and used cooking oil, confirmed the carcass was handled by one of his company's facilities.
The carcass of the dairy cow was brought to the collection facility in Hanford, California, last Wednesday and a tissue sample was taken from its brain and sent to the University of California, Davis. The sample came back inconclusive and was then sent to USDA facility in Ames, Iowa, and returned on Tuesday as positive.
"The material is in quarantine now," Luckey said, adding that Baker Commodities is waiting on direction from USDA on how to dispose the carcass
The mad cow case comes just as the U.S. beef industry is trying to recover from fallout over a ground beef filler that critics called "pink slime". After a wave of unappetizing photos and reports blanketed the Internet, the nation's leading retailers pulled the product, leading one producer to idle several factories and another beef processor to file for bankruptcy.
"The impact should not affect exports. Now, I'm not saying it may or may not, but it should not," Clifford said of the mad cow case, noting that the United States has been recognized by authorities as having taken steps to control its risks for the disease.
Beef exports plunged nearly 75 percent in 2004 in the wake of the first U.S. incident in late-2003, with USDA reporting net cancellations of beef sales in five out of the first six weeks following the news. Overall beef exports were 321,967 metric tons (354,908 tons) in 2004, down from 1.27 million metric tons in the previous year.
Sales would not rebound to more than 1 million metric tons until 2010. The value of U.S. beef exports totaled $809 million in 2004, down from $3.86 billion in 2003, according to the U.S. Meat Export Federation.
Late on Tuesday, Mexico, a leading market for U.S. beef, said it had no plans to stop buying it.
Big players in the U.S. beef industry include Tyson Foods Inc and the U.S. operations of Brazil-based JBS. Tyson's shares closed up 1.5 percent at $17.93 on Tuesday, triple the gain of the wider stock market. JBS shares closed down 0.3 percent in Sao Paolo.
JBS USA said on Tuesday the company was confident U.S. beef exports, which surged to a record high last year - would not be affected by this latest case of mad cow disease.
Mad cow, a neurological disease caused by an abnormal form of a protein called a prion and can damage the central nervous system of cattle, was first diagnosed in the United Kingdom in 1986, according to the Office of the United States Trade Representative. Reported cases peaked in peaked at 37,316 in 1992, of which 99.9 percent of which were in the United Kingdome.
The first U.S. case was reported in an animal imported from Canada in 2003, while other cases were reported in 2005 and 2006, according to the agency.
Scientists said that as the dairy cow had not been eaten by other animals, there was no risk of the disease being spread.
"There's always been concern that there could potentially be a spontaneous form of mad cow disease that just arrives and doesn't get transmitted through feed," George Gray, director of George Washington University's Center for Risk Science and Public Health.
"It's not like classic mad cow disease that's transmitted by animals being exposed to the infectious parts of other animals."
Reporting by Roberta Rampton, Douglas Palmer and Timothy Gardner in Washington, K.T. Arasu, Julie Steenhuysen, Michael Hirtzer, Theopolis Waters, and Sam Nelson in Chicago. Writing by Matthew Robinson and Jonathan Leff.; Editing by Bob Burgdorfer