The US Department of Agriculture has said it has been notified that an inconclusive BSE (bovine spongiform encephalopathy) test result was received on a rapid screening test used as part of its BSE surveillance programme.

"The inconclusive result does not mean we have found another case of BSE in this country. Inconclusive results are a normal component of screening tests, which are designed to be extremely sensitive so they will detect any sample that could possibly be positive," said Andrea Morgan, associate deputy administrator of the USDA's Animal and Plant Health Inspection Service (APHIS).

Morgan said tissue samples are now being sent to the USDA's National Veterinary Services Laboratories (the national BSE reference lab), which will run confirmatory testing. Results are expected within four to seven days.

"Because this test is only an inconclusive test result, we are not disclosing details specific to this test at this time," Morgan added.

The USDA said APHIS has begun internal steps to begin initial tracebacks, just in case further testing reveals a positive result. The animal did not enter the food or feed chain.

The US beef industry is still suffering trade losses as a result of a single case of BSE discovered in Washington state last December.