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From: TSS ()
Subject: Testing Changes Ordered After U.S. Mad Cow Case
Date: June 25, 2005 at 6:53 am PST


Testing Changes Ordered After U.S. Mad Cow Case
By DONALD G. McNEIL Jr.
Published: June 25, 2005
Substantial changes in the nation's mad cow testing system were ordered yesterday after British tests on a cow slaughtered in November confirmed that it had the disease even though the American "gold standard" test said it did not.

"The protocol we developed just a few years ago to conduct the tests might not be the best option today," Agriculture Secretary Mike Johanns said in making the announcement. "Science is ever evolving."

At an afternoon news conference in Washington, Mr. Johanns described serious errors in the testing in the United States on the animal, the second one found with mad cow disease, formally known as bovine spongiform encephalopathy.

But he also defended the safety of American beef, reminding reporters that the animal had been incinerated rather than being ground into hamburger, as the first one was in late 2003.

"I enjoyed beef this noon for lunch," Mr. Johanns said. "It is the safest beef in the world."

The head of the testing laboratory in Weybridge, England, who joined the news conference by telephone, said he was "pretty confident" that the incidence of mad cow disease in American herds was "very little indeed."

Of 388,000 tests in the last year, only three positive rapid tests have been found, and only this one has been confirmed.

Until yesterday, the Agriculture Department used a rapid test called an Elisa and confirmed any positives with a slower immunohistochemistry test, which it calls the "gold standard."

The Europeans and the Japanese use those tests, but routinely add a confirmatory Western blot test, which is more sensitive.

The Agriculture Department asked the English laboratory, regarded as one of the world's best, to retest the samples.

In response to questions, Dr. John Clifford, the Agriculture Department's chief veterinarian, revealed another surprise: the animal's disease strain did not closely resemble the British-style strain found in the first mad cow, which was born in Canada and raised in Washington State.

Instead, it was closer to a strain found in France - a result, another scientist said, that suggested that the infection had come from a different pool of infected feed, possibly imported from France.

Despite the Agriculture Department's assurances, critics said the dispute revealed serious flaws in the testing regimen used here for 15 years.

"All this foot-dragging has got to stop," Michael K. Hansen, a senior research associate at Consumers Union, said excitedly.

"They waited seven months to do this test?" Dr. Hansen asked. "And they didn't even bother to write up a report?"

Like other critics, Dr. Hansen called for testing all animals over 20 months old, and for bans on feeding poultry litter that has spilled cattle meal in it back to cattle, giving calves "milk replacer" made from cattle blood and letting cows eat dried restaurant "plate waste."

Dr. Hansen said the feed bans that the department refers to as its "firewall" were "more of a white picket fence."

Mr. Johanns refused to give details about the animal, other than to repeat that it was born before the 1997 ban on feeding ruminant protein to ruminants, that it was raised for beef, not dairy, and that it was too crippled to walk when it was killed.

There was "no evidence" that it was born outside the United States, Mr. Johanns said, and its brain was sampled for tests at a plant specializing in diseased and dead animals. Most beef animals are slaughtered when they are less than 3 years old.

DNA tests will be started to find the herd it was raised with, Mr. Johanns said. Normally, an infected animal's whole herd is slaughtered on the assumption that all ate the same feed.

He described several errors in the testing process in the United States:

∂The brain samples were frozen, which makes some tests harder.

∂Parts from five carcasses were temporarily mixed up.

∂No written records were kept.

Also, after the animal tested positive on two rapid Elisa tests and then negative on the slower, "gold standard" test, another "experimental" test was done that came up positive.

Mr. Johanns would not describe it, but an Agriculture Department Web site said it was an enhanced version of the "gold standard" test.

That was all the more reason further testing should have been done without delay, Dr. Hansen said.

Mr. Johanns became agriculture secretary in January.

Two weeks ago, the department's inspector general, Phyllis K. Fong, initiated a further test here - the Western blot - because of the earlier confusion. Mr. Johanns complained yesterday that it was done without his knowledge.

A lawyer for Ms. Fong's department refused to say yesterday whether she had ordered it or had the authority to do so.

Representative Henry A. Waxman, Democrat of California and a ranking member of the Government Reform Committee, who has criticized the department's testing regimen, praised the inspector general yesterday but said, "The Agriculture Department should have gotten it right in the first place."

Mr. Waxman added, "The administration's response to mad cow disease appears to be more public relations than public health.

"Today's announcement exposes the error in the administration's complacency."

Ed Loyd, an Agriculture Department spokesman, said yesterday's announcement that all positive rapid tests would now be confirmed both with the immunohistochemistry test and a Western blot "took care" of such complaints and showed that the department was not complacent.

Mr. Johanns also ordered the Agriculture Department's national laboratory in Ames, Iowa, to reassess the antibodies in its immunohistochemistry test because the British laboratory's antibodies attached to the misfolded brain proteins, called prions, that cause the disease, while the American laboratory's apparently did not.

The test is not purchased off the shelf, he said, and every laboratory must make its own.

Mr. Johanns said that the animal did not have many prions and that they were concentrated in unusual areas of the brain, so one laboratory's test might miss the infection while another caught it.

http://www.nytimes.com/2005/06/25/national/25cow.html?oref=login

TSS




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