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From: TSS ()
Subject: Latest test for mad cow is negative HOUSTON CHRONICLE
Date: August 4, 2005 at 6:09 am PST

Aug. 3, 2005, 11:15PM

Latest test for mad cow is negative
Markets largely ignore newest case of suspect animal
By DAVID IVANOVICH
Copyright 2005 Houston Chronicle Washington Bureau
WASHINGTON - The U.S. Agriculture Department on Wednesday declared a cow suspected of having mad cow disease free of the brain-devouring illness.


USDA officials had raised the specter of a third case of mad cow disease last week when they revealed that tests conducted on samples taken from a 12-year-old cow had produced unsettling results.

On Wednesday, USDA officials announced that further tests — conducted at the agency's laboratory in Ames, Iowa, as well as the world's foremost mad cow testing facility in Weybridge, England — had proven negative for the disease.

"Needless to say, we are very pleased with these results," said John Clifford, USDA's chief veterinarian.

While the USDA's announcement was good news for the nation's cattle industry, the markets have largely ignored this latest roller-coaster ride as regulators tried to determine whether an animal was really infected with the dread disease.

The cow in question was killed last April, after suffering complications while giving birth.

Meat from the animal in question did not enter the human food chain. The cow's remains were burned and buried.

Regulators have not said where the cow lived, although they believe it had been raised in the United States. The farm where it was found was never placed under quarantine.

The cow was one of more than 426,000 head of cattle tested for bovine spongiform encephalopathy, better known as mad cow disease, since June 2004. That's when the government launched its current program to screen for the disease in the wake of the nation's first confirmed case of mad cow.


Brain sample taken
As part of that surveillance program, a private veterinarian took a brain sample from the cow for testing. This sample was stored in a preservative known as formalin, an acceptable protocol at the time.

Current rules would require a vet to keep such a sample on ice and ship it to the USDA for testing within 48 hours. USDA officials didn't learn of the sample until last week because the vet "simply forgot to send it in."

The preservative rendered the sample fit for only one kind of test, known as the immunohistochemistry, or IHC, test. It also precluded technicians from using two other methods to test for the disease, the "rapid" screening test and the Western blot method.

Until recently, that wouldn't have seemed like a problem. USDA officials considered the IHC test the "gold standard" of mad cow testing.

But then a Texas cow that had tested negative for the disease using that procedure was confirmed to have had the disease after scientists took another look using the Western blot method.


Only method available
Using the only method available to them, USDA officials conducted an IHC test on the sample from the cow that died in April. The result was puzzling. It showed some of the telltale signs for the disease, but the patterns were not consistent with those found in animals known to have the disease.

So experts conducted more tests, again using the IHC method.

"We couldn't use Western blot or the rapid test, but what we could do is slice up and test every bit of the sample that we could access and get our counterparts in England to do the same," USDA spokesman Jim Rogers said.

The results were negative. USDA officials concluded that the initial confusing test has been marred by contamination, mishandling or another problem.

"You have to expect a certain amount, in any sort of scientific study, of static," Rogers said.


'That's why you retest'
"You're going to run across results that aren't what you expect and aren't right. And so that's why you retest," he said.

But Michael Hansen, a senior research associate with Consumers Union, said he was happy the test came back negative but said the handling of this case demonstrates "all sorts of bungling."

"How can a brain sit for months that was going to be sampled and be put in formalin, which precludes you from doing the more sensitive tests?" Hansen asked.

Cattle futures in Chicago have moved up 2.5 percent since July 27, when the USDA warned it might have another case.


'People kind of yawned'
Last week, "people kind of yawned," said John Harrington, chief livestock analyst for DTN, a commodity market reporting service in Hastings, Neb. When the results were announced Wednesday morning, "I think they yawned also. It was good news but not really good enough to be a market factor."

The USDA's announcement was enough to convince Bill Hyman, executive director of the Independent Cattlemen's Association of Texas.

"It shows the testing procedure works," Hyman said.

david.ivanovich@chron.com

http://www.chron.com/cs/CDA/ssistory.mpl/business/3295454

Greetings list members,

>>Using the only method available to them, USDA officials conducted an IHC test on the sample from the cow that died in April. The result was puzzling. It showed some of the telltale signs for the disease, but the patterns were not consistent with those found in animals known to have the disease.<<


>>So experts conducted more tests, again using the IHC method.<<

>>"We couldn't use Western blot or the rapid test, but what we could do is slice up and test every bit of the sample that we could access and get our counterparts in England to do the same," USDA spokesman Jim Rogers said.<<

>>The results were negative. USDA officials concluded that the initial confusing test has been marred by contamination, mishandling or another problem.<<

WITH the 2 Texas mad cow blunders, the one they did not test at all, and then the positive, positive, secret positive, inconclusive, negative, and finally confirmed positive by Weybridge by WB. WITH test 2 Texas mad cows and then this blunder here where the sampling was marred with not only contamination, mishandling and or whatever the other problem was and the fact that the preservative rendered the sample fit for only one kind of test and that the WB could not confirm what the Honorable Phyllis Fong confirmed by ordering a WB confirmation, my question to the experts on BSE testing here on this list is, IS there a chance that this test could be flawed and be positive still due to the incompetence of everyone involved here? i will never believe that this sample just sat up on a shelf and was forgot about and then accidentally put in preservative as to destroy any hopes of confirmation by WB, while all the time the 2nd TEXAS MAD COW blunder was going on. this is totally fiction. but again, what are the chances, considering WB was not done, can never be done, what are the chances that this cow in question was positive for mad cow disease, but no confirmation could be made due to the fact the WB could not be done? WE know that the IHC could not detect the TEXAS mad cow, so why should we be so sure the IHC was correct in the negative reading here without WB???

maybe roland, prionics or bio-rad or someone will hopefully comment.

thank you,

kind regards,

terry




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