Creutzfeldt-Jakob disease mortality in Canada, 1998 to 2013.

BACKGROUND: Human prion diseases, known collectively as Creutzfeldt-Jakob disease (CJD), are fatal, infectious neurodegenerative disorders that occur in all human populations. OBJECTIVE: To summarize national surveillance data for CJD in Canada between January 1, 1998, and December 31, 2013. METHODS: Detailed investigations were conducted of individual suspected CJD cases, with collaboration between Canadian health professionals and investigators affiliated with a central CJD surveillance registry operated by the Public Health Agency of Canada. Data were collected on the clinical profile, family history, and results of paraclinical and laboratory investigations, including post-mortem neuropathological examination. RESULTS: A total of 662 deaths from definite and probable CJD were identified in Canadian residents during the study period, comprising 613 cases of sporadic CJD (92.6%), 43 cases of genetic prion disease (6.5%), 4 cases of iatrogenic CJD (0.6%), and 2 cases of variant CJD disease (0.3%). The overall crude mortality rate for sporadic CJD was 1.18 per million per year [95% confidence interval (CI): 1.08,1.27]. Age-specific rates ranged from 0.05 [95% CI: 0.03,0.08] in persons under 50 years of age to 7.11 [95% CI: 6.20,8.11] in those aged 70 to 79. A significant net upward trend in age-adjusted rates was observed over the study period. Standardized mortality ratios, calculated for 10 individual Canadian provinces with reference to national average mortality rates, did not differ significantly from 1.0. CONCLUSION: Creutzfeldt-Jakob disease remains rare in Canada, although mortality rates vary by two orders of magnitude between older and younger age groups. The upward trend in age-standardized sporadic CJD mortality rate over the study period can be better accounted for by gradually improving case ascertainment than by a real increase in incidence.

Public health and the BSE epidemic.

Bovine Spongiform Encephalopathy was discovered in 1986 in the United Kingdom and relatively rapidly spread into its trading partners in Europe via contaminated cattle feed supplements. The practice of using the discarded bovine carcass as cattle feed supplements led to the recycling of the prion agent and the consequent generation of new point source epidemics in the recipient countries. The advent of rapid diagnostic tests and more widespread testing has led to the identification of BSE in countries not previously reporting cases and the recognition of larger numbers of infections in countries previously only reporting clinical cases. The recognition of the wider spread of BSE and the 1996 recognition of vCJD as a human disease caused by consumption of BSE agent led to international concerns regarding the threat to human health and the demand for stricter controls on human food derived from cattle. Major shifts in food safety policy have occurred as a direct result. The recommendation that risk assessments for BSE infectivity and human exposure pathways be conducted rather than reliance upon rates and simple enumeration of BSE cases is one of the most prominent changes in the basis of policy regarding human health. The movement of BSE into human populations has a wider impact than seen in food safety--surgical procedures, blood, cells, tissues and organ donation programs are all affected. The World Health Organization has recommended that 'the eradication of BSE must remain the principle public health objective of national and international animal health control authorities'. The opinions expressed in this chapter are those of the author and do not necessarily reflect the views of Health Canada. This review was written while the author was employed at the WHO.

Risk of acquiring Creutzfeldt-Jakob disease from blood transfusions: systematic review of case-control studies.

OBJECTIVE: To determine the strength of association between history of blood transfusion and development of Creutzfeldt-Jakob disease. DATA SOURCES: English and non-English language articles published from January 1966 to January 1999 were retrieved using a keyword search of Medline and Embase. These were supplemented by handsearching key journals and searching bibliographies of reviews. STUDY SELECTION: Two independent reviewers selected the relevant abstracts and articles. Articles were chosen that reported the results of case-control studies trying to identify rates of prior blood transfusion in patients with Creutzfeldt-Jakob disease and in controls. DATA EXTRACTION: Odds ratios and information on study quality were extracted from the selected articles by two independent reviewers. DATA SYNTHESIS: Five studies containing data on 2479 patients were included. Three of the five studies used medical or neurological patients as controls, the other two used population controls. Odds ratios for developing Creutzfeldt-Jakob disease from blood transfusion ranged from 0.54 to 0.89. Four of the five studies had confidence intervals that crossed 1.0. The combined odds ratio was 0.70 (95% confidence interval 0.54 to 0.89). CONCLUSIONS: Case-control studies do not suggest a risk of developing Creutzfeldt-Jakob disease from blood transfusion. Rather, a trend seems to exist towards a lower frequency of previous blood transfusion in patients with Creutzfeldt-Jakob disease than in controls. However, it is important to be aware of these studies' methodological limitations-primarily the choice of control population and reliability of recall of transfusion status.

Is Creutzfeldt-Jakob disease transmitted in blood?

Creutzfeldt-Jakob disease (CJD) has been considered infectious since the mid-1960s, but its transmissibility through the transfusion of blood or blood products is controversial. The causative agent's novel undefined nature and resistance to standard decontamination, the absence of a screening test, and the recognition that even rare cases of transmission may be unacceptable have led to the revision of policies and procedures worldwide affecting all facets of blood product manufacturing from blood collection to transfusion. We reviewed current evidence that CJD is transmitted through blood.

The epidemiology of Creutzfeldt-Jakob disease in Canada: a review of mortality data.

Creutzfeldt-Jakob disease (CJD), and particularly its transmissibility through blood and blood products, has become a focus of concern in Canada. The recent identification of new variant CJD led to a review of the Canadian mortality database to identify any clustering of CJD by age, sex, or geographic location.

Geographic and birth cohort associations of Kaposi's sarcoma among homosexual men in Canada.

The authors conducted an analysis of all 677 cases of Kaposi's sarcoma among the 3,047 cases of acquired immunodeficiency syndrome diagnosed in homosexual/bisexual men in Canada between 1980 and 1989. The proportion with Kaposi's sarcoma declined from 32.2% during 1980-1985 to 15.0% in 1989. The proportion with Kaposi's sarcoma was significantly higher in primary epidemic centers (Vancouver, Toronto, and Montreal) and in men in the 1945-1954 birth cohort independent of year of diagnosis. These data are consistent with an environmental cofactor for Kaposi's sarcoma which is likely to be a sexually transmitted agent.