Vaccines and hormones were imported from the U.K. and other BSE-infected countries in 1992 and 1999, according to the report. But the greatest risk of variant Creutzfeldt-Jacob infection in Canadians is from British beef products imported at the height of the epidemic, including baby food, according to the report. Several children's vaccines were produced in the U.K. using bovine materials at the peak of the BSE epidemic and were not recalled. Data on the possible importation of these vaccines was not available to the researchers. 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. Live pigs have been imported from Britain. 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.