TSEs: Dealing with Uncertainty

Transmissible spongiform encephalopathies (TSEs) returned to the front burner with the announcement on May 20, 2003, by Canadian authorities of a case of bovine spongiform encephalopathy (BSE)—or mad cow disease—in a cow in Alberta.

The U.S. Dept. of Agriculture responded by banning any imports from Canada of products from any ruminant. With the U.S. ban still in place in early July, journalists reported that Canadian officials had begun to question the viability of the highly integrated market t…