The person believed to be Canada’s second-ever case of the type of Creutzfeldt-Jakob disease transmitted by BSE-infected beef is seen as unlikely to have picked it up in this country.
In a recent report, the Public Health Agency of Canada (PHAC) said the evidence in the latest probable case of variant Creutzfeldt-Jakob disease (vCJD) “strongly indicates” the victim’s risk exposure happened outside Canada.
Thus, PHAC said in its weekly communicable disease report, the evidence suggests “no negative implications for the safety of the Canadian food supply.”
CJD is one of a group of transmissible spongiform encephalopathies that includes BSE in cattle, scrapie in sheep and chronic wasting disease in deer and elk. Variant CJD is the only known zoonotic human prion disease, usually caused by dietary exposure to the misfolded proteins (prions) that cause BSE in cattle.
While Canada has confirmed 18 domestic cases of BSE in cattle since 2003, regulations have long been in place to prevent BSE transmission to people and to other animals.
Health Canada now also requires deferral of blood donors with a history of residence and/or travel in the U.K., France and Western Europe between 1980 and 1996, as well as those who got transfusions in the U.K.
With those measures in mind, plus the fact that the person in this case showed onset of vCJD symptoms starting just before immigrating to Canada early last year, “the possibility of BSE exposure in this country can essentially be ruled out as the cause of illness,” PHAC said.
The patient had no history of travel to the U.K. or Europe apart from a few visits totalling less than three months in duration, PHAC said. The victim was born in the Middle East, and also lived in several other countries before arriving in Canada, the agency added.
Furthermore, PHAC said, “based on extensive interviews with family members there is no indication that the current patient was ever a blood donor, received a blood transfusion, or underwent a surgical procedure that was not managed to prevent prion transmission.”