NEWS: Third Cow Tested for Mad Cow Disease - Washington Post 07/28/0

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*washingtonpost.com* <http://www.washingtonpost.com/> Thursday,

July 28, 2005; 4:29 AM

 

 

 

*Possible Case of Mad Cow Investigated*

 

 

 

By LIBBY QUAID

 

 

The Associated Press

 

 

 

WASHINGTON -- A cow being tested for mad cow disease never entered the

food supply, the government says.

 

 

 

The animal had complications while giving birth and died on the farm

where it had lived, the Agriculture Department's chief veterinarian said

Wednesday.

 

 

 

Unlike in the two confirmed cases of mad cow disease, this cow did not

go to a slaughterhouse or feed mill. It was burned and buried after a

local veterinarian removed brain tissue for testing, John Clifford said.

 

 

 

"There is absolutely no risk to human or animal health from this

animal," he said. "Regardless of the outcome of further testing, I want

to emphasize that human and animal health in the United States are

protected by a system of interlocking safeguards."

 

 

 

Testing indicated the disease may have been present in the cow. The

department is conducting further tests at its laboratory in Ames, Iowa,

and is sending tissue to be tested by the internationally recognized

laboratory in Weybridge, England.

 

 

 

Results should come in the next week, Clifford said.

 

 

 

The cow probably was born in the United States and was at least 12 years

old, Clifford said. That means it was born before 1997, when the U.S.

and Canada banned the practice of adding ground-up cattle remains to

cattle feed.

 

 

 

The only way cows are known to get the disease is by eating brain and

nerve tissue of already-infected cows.

 

 

 

Clifford said the department knows the location of the farm but is not

disclosing it. Also, there is no quarantine now on the farm.

 

 

 

The two U.S. cases were confirmed in a Texas cow last month and in a

Canadian-born cow in December 2003 in Washington state. Both cows also

were born before the feed ban.

 

 

 

The brain-wasting disease is known scientifically as bovine spongiform

encephalopathy, or BSE. The consumption of meat products contaminated

with BSE is linked to about 150 human deaths from a fatal disorder

called variant Creutzfeldt-Jakob disease. Most of the deaths were in the

Britain, where there was an outbreak in the 1980s and 1990s.

 

 

 

Of the 96 million U.S. cattle, the government has tested more than

419,000 for mad cow disease.

 

 

 

Testing options are limited for the latest animal infected. The brain

sample was preserved with formalin, making it unsuitable for all but one

type of testing: immunohistochemistry, or IHC.

 

 

 

That test returned conflicting results on the Texas cow.

 

 

 

"It is possible for an IHC test to yield differing results depending on

the slice of tissue that is tested," Clifford said. "Therefore,

scientists at our laboratory and at Weybridge will run the IHC test on

additional slices of tissue from this animal to determine whether or not

it was infected."

 

 

 

Two additional tests, rapid screening and Western blot, were used in the

Texas and Washington state cases.

 

 

 

While testing in Ames has indicated mad cow disease may be present, the

sample did not look like a typical case of BSE, Clifford said. He said

it did not have the normal distribution of prions, the misfolded mad cow

proteins that kill brain cells and leave spongy holes behind.

 

 

 

The animal died in April, but the veterinarian who removed the brain

forgot to send in the sample until last week, Clifford said.

 

 

 

"While that time lag is not optimal, it has no implications in terms of

the risk to human health," he said. "The carcass of this animal was

destroyed."

 

 

 

In the time since the suspect cow's death, the department has changed

its rules and no longer allows tissue to be preserved in formalin.

Samples now must be shipped immediately, while they are fresh.

 

 

 

Clifford said the possibility of a new case should not hinder efforts to

persuade Japan to lift a ban on U.S. beef imposed after the Washington

state case. Japan, which purchased $1.5 billion in beef in 2003, agreed

to lift its ban last fall but still has not done so.

 

 

 

The U.S. lifted a ban on Canadian cattle last week after a legal battle

with a western ranchers' group. A federal appeals court allowed Canadian

shipments to resume, although the ranchers' lawsuit is still pending.