The clinical and pathologic picture varies, and there is no definitive clinical diagnostic test aside from neuropathologic investigation. 2 Three epidemiologic types of CJD are recognized. Worldwide, the incidence of CJD is about 1 per million population per year.
Most cases occur in people in their sixties.
There is little or no sex bias, temporal clustering or geographic variation in incidence, although familial-type disease can show local ethnic and familial clustering. Most CJD in Canada is probably sporadic, although familial disease has been reported. No cases of CJD related to the use of human growth hormone have been reported in Canada, although cadaver-derived growth hormone was used in Canada from 1965 until 1985. This program is designed to determine the risk of developing CJD as a result of receiving blood, blood products or tissue transplants and to detect any cases of vCJD that might arise in relation to the consumption of beef. CJD-SS Canada has enlisted the participation of clinicians in relevant specialties who will notify LCDC of any cases of CJD seen in their practices.