Preliminary Tests Confirm Mad Cow Diagnosis
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Cows feed at a ranch in Yuma, Ariz. The USDA said Monday it plans to test as many as ten times or more the 20,000 cows tested last year.
By Jon Bonné
msnbc.com
updated 3/15/2004 7:34:58 PM ET 2004-03-16T00:34:58

The U.S. Department of Agriculture will significantly increase its testing of cattle for mad cow disease this year, including tests on some 20,000 healthy older cattle, officials said Monday.

The agency will continue to focus on higher-risk animals, and will not set specific numbers, but it expects to test as many as ten times or more the 20,000 cows tested last year. The nation’s first case of bovine spongiform encephalopathy, a fatal brain disease that can be transmitted to humans, was discovered in a Washington state dairy cow last December.

“We are committed to ensuring that a robust surveillance program continues in this country,” said Agriculture Secretary Ann Veneman at a USDA briefing. “This is a fully science-based program.”

In outlining the expanded program, USDA Chief Veterinarian Ron DeHaven indicated that between 200,000 and 400,000 cattle could be checked for BSE by the end of 2005. The agency will spend about $70 million on the increased testing. Those numbers are similar to estimates reported last week .

High-risk animals include those that show signs of the disease or other nervous system maladies; those that cannot walk or have trouble walking on their own; condemned and euthanized cattle and cows that die on the farm. That could amount to 446,000 cattle this year, DeHaven said.

In addition, he said about 20,000 healthy cattle aged over 30 months would be tested, selected randomly from 40 slaughter facilities in 17 states.

However, he would not set specific figures. “It’s premature for me to set a target number or an expected number,” DeHaven said. “We’re going to test as many as we can.”

The decision largely follows the recommendations of an international advisory panel convened by Veneman in January. The panel called for U.S. testing to be "significantly extended" and recommended all-high risk cattle be tested, in addition to a random sampling of healthy but older cows.

Older cows are part of the at-risk population in most countries because the disease’s onset usually requires at least 18 months, and most cases are seen in older cattle. The European Union, for example, requires all cattle over 30 months to be tested before they enter the food supply.

However, cases in other countries have been detected in cows as young as 20 months.

'One-time effort'
The testing decision was based in part on statistical estimates that show, based on the size of the U.S. herd, testing of 201,000 samples would provide a 95 percent probability of finding the disease in one of every 10 million animals, DeHaven said. Testing of 268,000 cows would increase that to a 99 percent chance of detection at the same level. The U.S. slaughtered 37 million U.S. cattle last year.

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However, DeHaven said, "It's possible we'd collect less than 200,000 and still have a valid, scientific, statically valid sampling."

Previous testing levels, set before the discovery that the disease had spread to North America, were intended to surpass projections by the World Organization for Animal Health that testing of about 430 animals would be sufficient, as the United States was considered a "low-risk" country.

Officials were quick to note Monday that expanded testing would be a “one-time effort,” fully operational by June and running for 12 to 18 months to determine the level of BSE infection in the U.S. herd.

"After the 12 to 18 month sample collection period is over,” DeHaven said, “we will analyze the results and decide what future actions might be appropriate.”

Rapid screening procedures key
One key to expanded testing is the use of rapid screening procedures for the malformed prions, or protein strands, that cause mad cow disease.  DeHaven said his agency would soon license at least one rapid test procedure that can return results in a day or less.

Currently, tests can take up to two weeks and must be sent to the National Veterinary Services Laboratories in Ames, Iowa. Most other countries already use one of two quick test procedures. Under new regulations approved shortly after the first case was discovered Dec. 23, no carcass from a tested animal can enter the human food chain until negative results are returned.

State laboratories, including many of the 26 currently licensed to test for chronic wasting disease –- the BSE equivalent for deer -- will help process local specimens, DeHaven said. The Ames lab will continue to perform comprehensive confirmation tests using a technique known as immunohistochemistry, on any initially positive cases.

Surveillance vs. safety
Critics of the USDA's approach have called for far higher levels of testing.  While the U.S. exceeds the testing levels in some countries, it also lags far behind many of its European counterparts.  Switzerland tests about 25 percent of the 700,000 cattle it kills; France tests half of the 5.8 million it sends to slaughter.

"(The USDA) is not on the same page with our international trading partners or the American public," said Felicia Nestor, food safety project director at the Government Accountability Project. "The American public has said that they're willing to pay more to have a tested, certified BSE-free animal."

Nestor questioned whether any positive results found during the test period would prompt the USDA to take more stringent actions. "Let's say they find a couple more positive animals," she said. "Are they going to inform the public about that? Are they going to take any action at all, or are we waiting until the end of the 18 months?"

DeHaven dismissed suggestions that the United States test every cow destined for human consumption, as Japan does for the 1.1 million cows it slaughters per year. "The science just doesn’t justify or support testing every animal," he said.

To that end, he stressed that the tests were to be considered surveillance to detect the disease's presence, not a food safety measure. U.S. consumers were protected by other steps, such as the agency's consumption ban of all specified risk materials -- the brain and other neural tissue -- of animals older than 30 months, DeHaven said.

Beef industry mostly pleased with plan
Cattle industry representatives seemed mostly pleased with the USDA plan. The National Cattlemen's Beef Association said it was "confident that increased BSE testing will prove that disease risk in the United States is extremely low,” though it had some concerns about the test logistics.

American Meat Institute president J. Patrick Boyle said in a statement the proposal was "extraordinary."

The industry and the USDA have been struggling to reverse bans on U.S. beef by over 50 countries imposed after the first case was found last December. Mexico and Poland have since resumed imports. Conversely, U.S. officials have barred Canadian beef since that country's first BSE case was found last summer.

Currently, all mad cow testing in the country must be coordinated by the USDA. Despite that, some smaller meat packers have asked the agency to allow them to conduct their own tests in order to guarantee their meat free from disease. "Those proposals are actively under consideration within the department," DeHaven said Monday, but would not elaborate.

One such processor, Creekstone Farms of Arkansas City, Kan., caused a stir within the meat industry when it sought private testing. "We're not going let up at all in our campaign to get this done," John Stewart, Creekstone's CEO, said shortly before Monday's announcement.

And while the new testing plan significantly increases chances of finding the disease in higher-risk populations, some of those familiar with Europe's experiences in tracking BSE see value in broader, random sampling of healthy cattle.

Though the United States slaughters most cattle younger than Europeans do, the level of BSE in many European herds went undetected through the late 1990s because testing largely ignored healthy animals.

"All governments in Europe claimed no BSE animals are entering the food chain. When you asked them why not, they would say, 'Well, it's never been shown,'" Markus Moser, co-chief executive of Swiss firm Prionics, which makes a rapid BSE test under consideration by the USDA, said in an interview.

"It had never been shown because nobody ever looked."

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