The risk from imported blood, tallow, gelatin, semen, embryos and milk products is uncertain but food supplements pose a risk, according to the report. Further investigation is needed, it suggests. Pigs and poultry have been shown to be susceptible to BSE in experiments, although there have been no confirmed cases. Last month, U.S. officials seized a flock of sheep feared infected with a version of mad cow disease, the first such seizure of its kind of any U.S. farm animals. Canada currently has scrapie, which affects sheep, and chronic wasting disease, which affects elk and deer.
Animals have to be killed to look for lesions on the brain for diagnosis.
A blood test has recently been developed but while it is being used on a large scale in Europe, its accuracy is still under study. Researchers know very little about these diseases, said the University of Alberta's Price. They can't even be sure that BSE causes variant Creutzfeldt-Jacob in humans. There is certainly not enough evidence to justify slaughtering millions of cattle, he said. There are greater risks to worry about, he added, citing E. coli, a virulent strain of botulism.