The Canadian Food Inspection Agency raised the possibility of a new case of bovine spongiform encephalopathy, or BSE, early Thursday after preliminary tests finished Wednesday showed positive results.

Less than 24 hours earlier, the U.S. Department of Agriculture said it would re-open the U.S. border to nearly all Canadian exports of beef and live cattle beginning March 7, after a 19-month ban.

The CFIA released few details about the suspected new mad cow case, and said final test results would not be available for three to five days, the Canadian Broadcasting Corp. said.

Officials said they usually do not release preliminary test findings, but found Wednesday's situation unique.

"Given the unique situation created by the United States' border announcement ... it was decided that the most prudent action would be to publicly announce the available information and provide stakeholders with a full understanding of the current situation," the agency said.