On Friday, USDA received an inconclusive-positive result from a rapid bovine spongiform encephalopathy screening test that USDA inspectors conducted as part of its enhanced screening program. USDA did not disclose the type of bovine or the location of where the sample was collected. USDA is conducting confirmatory tests at the National Veterinary Services Laboratories in Ames, Iowa, using an immuno-histochemistry test. In addition, USDA's Agricultural Research Service is also conducting a Western blot test. The results of those tests will be available this week.

"This inconclusive result does not mean we have found a new case of BSE,” USDA Animal and Plant Health Inspection Service's chief veterinary medical officer Dr. John Clifford said in a prepared statement. “Inconclusive results are a normal component of most screening tests, which are designed to be extremely sensitive so they will detect any sample that could possibly be positive. In addition, this animal did not enter the human food chain or the animal feed chain.”

Clifford continued: "I want to emphasize that human and animal health in the United States are protected by a system of interlocking safeguards and that we remain very confident in the safety of U.S. beef. The most important of these safeguards is the ban on specified risk materials from the food supply and the Food and Drug Administration's feed ban. And by any measure, the incidence of BSE in this country is extremely low. Our enhanced surveillance program is designed to provide information about the level of prevalence of BSE in the United States, while these interlocking safeguards continue to protect our food supply.”

In December 2003, the United States reported its first case of BSE in a cow in the state of Washington. In June 2004, the United States began an enhanced surveillance program to determine the BSE status in the U.S. beef herd. The program involved the use of rapid, qualitative screening tests on high-risk cattle – primarily older cattle and non-ambulatory cattle. The rapid screening tests reported several false positives, prompting USDA to slightly alter the way in which it reports positive screening test results to the public. Under current procedures, a positive screening test must be repeated before information is released to the public.

Clifford added: "We are extremely gratified that since June 2004, all sectors of the cattle industry have cooperated in this program by submitting samples from more than 640,000 animals from the highest risk populations and more than 20,000 from clinically normal, older animals, as part our enhanced BSE surveillance program. To date, only one of these highest risk animals has tested positive for the disease as part of the surveillance program."