A second rapid bovine spongiform encephalopathy test and confirmatory Western blot test confirmed the latest United States BSE find, according to USDA's Chief Veterinarian John Clifford. (View Clifford's statement)
The latest case is from an Alabama beef cow. Clifford says based on dentition the animal is an older animal, "upwards of 10 years of age." This would indicate that this animal would have been born prior to the implementation of the Food and Drug Administration's 1997 feed ban. Older animals are more likely to have been exposed to contaminated feed circulating before the FDA's 1997 ban on ruminant-to-ruminant feeding practices, which scientific research has indicated is the most likely route for BSE transmission.
The sample was from a non-ambulatory animal. Clifford says that the sample was collected by a private veterinarian who treated the animal one day and euthanized the animal the next. The animal was buried on the Alabama farm after the vet took the sample. When questioned about its origin, Clifford says, "I cannot say if it is of U.S. or Canadian origin. It's only been at the particular location for less than a year."
The find sets into motion an epidemiological investigation about the whereabouts of herd mates and offspring of the animal in question. Clifford did not say the amounts of records available on the animal, except for the fact that it has been on the farm for less than a year.
No further tests being run
The find is the third BSE find in the United States, the second under the enhanced surveillance program. To date over 650,000 high-risk animals have been tested for the disease.
USDA considers an animal positive for BSE if either of the two confirmatory tests returns a positive result. In this instance, the inconclusive result from the contract lab in Georgia was confirmed through a second rapid test at the Ames, Iowa National Veterinary Services Laboratories. Now, the Western blot test has returned a positive result, and that is sufficient for USDA to confirm this animal to be positive for BSE.
Now that USDA uses two confirmatory tests - immunohistochemistry and Western blot - it does not plan to send samples to Weybridge, England for additional tests. The IHC results, what was once recognized as the "gold standard" in BSE testing, are still pending and USDA says it will release those results as soon as they are available, which is expected later this week.
The first domestic BSE find - a cow from Texas - received an inconclusive finding on a rapid screening test, a negative on an IHC but a positive on the Western blot. The Western blot test also takes days less to run compared to the IHC.
Find not expected to disrupt trade negotiations
Korea is expected to resume beef trade with the United States in the upcoming weeks and Japan has sent questions to the United States to clarify procedures before resuming trade itself.
Clifford says USDA does not anticipate the latest find to impact ongoing negotiations. "Japan themselves has had 20 plus cases of BSE. We believe their product is safe and feel they should feel the same about ours," he says.