Mad Cow Suspect Found in the United States

WASHINGTON, DC, June 13, 2005 (ENS) - A U.S. beef cow has tested positive for mad cow disease, and a sample of the animal's brain has been sent to an independent laboratory in the United Kingdom for confirmatory testing, Agriculture Secretary Mike Johanns said late Friday night. The suspect animal was a downer cow, one unable to walk, so it never entered the food chain, Johanns said.

Only one case of mad cow disease has been confirmed in the United States, in a dairy cow in Washington State in December 2003. Since then, preliminary tests indicated the possibility of the disease in three cows, but further testing had ruled out any infection.

USDA officials decided last week to perform additional tests, and test results on one of those three cows turned up positive.


Agriculture Secretary Mike Johanns was governor of the farming state of Nebraska before he took over the USDA on January 21. (Photo courtesy USDA)
Johanns said the Agriculture Department Office of Inspector General had recommended the additional testing, but the secretary did not say why. The Inspector General's Office is an independent arm of the department that performs audits and investigations.

Formally called bovine spongiform encephalopathy, or BSE, mad cow disease happens when proteins in the body bend into misfolded shapes called prions. Prions deposit plaque that kills brain cells, leaving spongy holes in the brain. The disease is always fatal.

People can get a form of the disease, called variant Creutzfeldt-Jakob disease, by eating contaminated meat. The disease has killed about 150 people worldwide, mostly in the United Kingdom, where there was an outbreak in the 1980s and '90s.

Since the first case of mad cow disease was found in December 2003 in Washington state, about 375,000 U.S. animals have been tested for the disease, usually those that appear sick.

Tissue from the three suspect animals has been tested three times, using three different procedures.

Results were positive for one cow on one of the three tests. The other tests were either inconclusive or negative for all three cows.

Initial screening called rapid tests indicated the potential for mad cow disease in the three cows.

These three animals tested inconclusive in initial screening, called rapid tests. Rapid tests check for mad cow disease by removing normal proteins, then adding chemicals that bind to the abnormal BSE prions so that researchers can see them.


USDA biologist Larry Stanker (standing) and chemist David Brandon review results of a rapid immunoassay. They are developing new technology for sensitive detection of BSE, mad cow disease. (Photo by Pegg Greb courtesy USDA)
Tissue from the three cows was was later subjected to immunohistochemistry, or IHC, testing. The IHC is an internationally recognized confirmatory test for BSE that stains brain tissue samples to highlight the misfolded prions.

All three inconclusive samples tested negative using the IHC test, said Dr. John Clifford, chief veterinary officer with the USDA's Animal and Plant Health Inspection Service (APHIS).

Last week, the USDA Inspector General's Office recommended that the three tissue samples be subjected to a second internationally recognized confirmatory test, the Western Blot, or immunoblot. This test destroys normal protein to leave only the abnormal prions.

Both tests both tests are accepted by the OIE, the World Animal Health Organization.

Clifford said USDA officials received the results of the Western Blot test last Friday night, and, "of the three samples two were negative, but the third came back reactive on that test."

"Because of the conflicting results on the IHC and Western Blot test," said Clifford, "a sample from this animal will be sent to the OIE recognized reference laboratory for BSE in Weybridge, England. USDA will also be conducting further testing which will take several days to complete."

Clifford hastened to reassure the public that no meat from the suspect animal entered the food supply. "It was a nonambulatory downer animal and as such was banned from the food supply," he said. "It was taken to a facility that handles only animals unsuitable for human consumption, and the carcass was incinerated."

Both Johanns and Clifford said the U.S. meat supply is safe because no "specified risk materials" are allowed into the human food supply. These are nervous system tissues such as brain and spinal cord tissues, the eyes, and the small intestine. These parts are considered risky because in animals with BSE disease, the brain and spinal cord contain the greatest concentration of the BSE agent.


Veterinarian John Clifford is deputy administrator for APHIS' Veterinary Services' program. (Photo courtesy USDA)
The agriculture officials did not release the location where the suspect animal was raised. They would only say that there was no information that it was an imported animal. Clifford said the animal was an aged animal. "It was getting up in age and was a beef breed."

The age of BSE suspect animals is important because it takes at least 20 months for the disease to develop.

Secretary Johanns emphasized that he did not want this discovery of a suspect animal to derail beef trade talks now underway with other countries.

"I feel very strongly that this information should not impact our discussions with Japan, Korea or Canada," he said.

"As the doctor pointed out, this is an aged animal," said Johanns. "Our discussions with Japan have related to 20 month animals as you know. Our discussions with Korea have related to 30 month animals, and the rule relative to Canada, or the Minimal Risk Rule in general, I should say relates to animals under 30 months and meat product under 30 months."

The United States closed its border to Canadian beef after May 2003 when a BSE infected cow was found in Alberta.

Japan, which has had 20 cases of mad cow disease despite a policy that requires testing of all cattle slaughtered for human consumption, closed its borders to U.S. beef after December 2003 when the Washington state mad cow was discovered. That cow was later found to have originated in Canada.

The disease has thrown the beef industry in both the U.S. and Canada into turmoil.

An "industry in crisis" was the resounding theme of testimony given at a USDA roundtable on BSE held Thursday at the University of Minnesota in St. Paul. The roundtable discussion of U.S. beef safety and the economics of BSE on the industry brought together more than 200 attendees including USDA experts, producers, packers, other industry groups and academics.

Secretary Johanns opened the discussion by explaining the critical importance of the cattle and beef embargo to the U.S. beef industry and its potential impact. Each day the border remains closed to Canada there is an increased possibility that these changes will become permanent, he said.

Johanns noted that one of the most recent victims of the embargo, Packerland Packing, in Gering, Nebraska, announced last week that they were closing their doors for good and laying off more than 200 workers.

Johanns said it is difficult to ban trade with Canada while trying to open markets abroad. "It is difficult to ask Japan to treat us one way when we are treating another major trading partner another way,” he said.


Veterinarian Dr. Ron DeHaven leads the USDA's Animal and Plant Health inspection Service. (Photo courtesy USDA)
APHIS Administrator Ron DeHaven, who was the agency's chief veterinary officer when the first U.S. case of BSE was found, told the roundtable that Canadian preventive measures are virtually identical to those in the United States.

“The risk of BSE transmission in the U.S. and Canada is extremely low,” DeHaven said, noting that "USDA is fully confident that American and Canadian cattle are equally protected from BSE."

But others are not so sure.

News stories May 31 on Dow Jones Newswires and June 1 in the "Wall Street Journal" revealed an internal USDA document called a "decision memorandum" from October 2003, in which top USDA officials reversed a May 2003 ban on imports of certain Canadian processed and rendered beef products, including ground beef, that could have potentially contained the BSE infective agent.

The memo stated that the expansion of imports requested by the National Food Processors Association and others, “increases the possibility that higher risk product ... may be imported into the United States,” and warned that the decision would be a “significant change in policy without opportunity for public comment.”

Bill Bullard, CEO of R-CALF United Stockgrowers of America, said the memo shows that USDA has not adhered to sound scientific principles, but rather has been basing critical decisions on inappropriate considerations, including pressure from the meat processing and packing industries.