BSE test negative, but other incidents likely, officials say

AMES, IOWA- As the United States Department of Agriculture (USDA) proclaims a cow suspected of carrying bovine spongiform encephalopathy (BSE) free of the brain-wasting illness, a veterinary leader predicts the scare will not be the last.

BSE Watch 2004

While the news relieves stakeholders alarmed by "inconclusive" test results publicized Nov. 18 by the USDA's Animal and Plant Health Inspection (APHIS), Dr. Lyle Vogel, director of the American Veterinary Medical Association's Scientific Activities Division, anticipates similar incidents, if not positive ones, down the road.

It's a matter of odds, he says. Government efforts to enhance the safety of the nation's food supply call on APHIS to test roughly 7,000 samples a week for BSE, totaling a reported 121,000 animal tested since July.

"We're of course relieved that this latest case was negative, but I would be surprised if this program did not identify a positive," Vogel says. "They're targeting the high-risk animals, the ones that show illness, are non-ambulatory or disabled. They're in a category we would expect to see BSE in if it did occur in the United States again."

The process

The latest scare involved three rapid screening tests, which returned inconclusive for BSE. Alerted to the discrepancy, National Veterinary Services Laboratories (NVSL) in Ames, Iowa, performed immunohistochemistry (IHC) tests on the sample. The IHC tests, described as "internationally recognized gold-standard tests for BSE," returned negative, APHIS Deputy Administrator John Clifford says.

"Screening tests are designed to be extremely sensitive and false positives are not unexpected," Clifford says in a Nov. 23 release reporting the negative results.

Industry effect

Clifford's news offers relief to a U.S. beef industry still recuperating from the country's first and only direct encounter with BSE. In December 2003, the disease was discovered in a Canadian-born Holstein dairy cow in Washington. The United States since has instituted a beef ban but at presstime, was considering reopening cattle trade with Canada.

The proposed rule soon will be published for public comment, Vogel says.

"Although we at AVMA have no direct in involvement, we've examined the safeguards that USDA and FDA have put in place to guard against BSE," he says. "We're quite satisfied with the current state of them and believe they're adequate to protect human health."