CMAJ 1997;157:1329
© Canadian Medical Association
Stanley Prusiner, recipient of the 1997 Nobel Prize in Medicine and Physiology, postulated in 1982 that the causative agent of scrapie was not a microbe but an infectious protein particle, or "prion." This was a true paradigm shift, perhaps the most important one in medicine this century. Prusiner's work received increased attention with the emergence of "mad cow disease" and the first reports of new variant CreutzfeldtJakob disease (vCJD). Estimates of the total number of people infected with vCJD range from a few dozen to possibly millions. In this issue Neil Cashman of the Montreal Neurological Institute provides a "primer" to guide readers through the disquieting territory of prion diseases (page 1381).
CJD has a long incubation period -- up to 30 years -- during which it is asymptomatic. There is no diagnostic test. Is it transmissible during this period? More specifically, can it be spread through the blood supply? Maura Ricketts of the Laboratory Centre for Disease Control (LCDC) reports that no cases of blood-borne transmission have been reported and that this risk must be considered theoretical (page 1367). Nonetheless, as Ricketts points out, methodologic difficulties with epidemiologic studies, together with recent evidence from animal experiments that blood and its fractions can be a vehicle for transmission, may leave us with nagging doubts.
As Elizabeth Stratton of the LCDC reports in our Public Health column, 390 Canadians died of CJD between 1979 and 1995 (page 1405). In July 1995 the Canadian Red Cross Society became aware that a blood donor had subsequently been diagnosed with CJD. Having underestimated the prevalence of HIV infection in 1982 the Red Cross did not wish to make a similar mistake. In the face of uncertainty it recommended that all recipients of blood products associated with donors in whom CJD is later diagnosed be notified and counselled. This is a difficult task: the science is far from clear, and the ethical and legal issues are ill defined. Timothy Caulfield and colleagues provide a thoughtful analysis of the issues and conclude that individual notification is not justified (page 1389).
Hip fracture in people over 50 is surprisingly common. Annual incidence rates are roughly 5 per 1000 for women and 2 per 1000 for men. Emmanuel Papadimitropoulos and colleagues used population projections to calculate the burden of this disease over the next 4 decades (page 1357). Assuming no change from current rates, the increase in the rate of hip fracture will be far greater than in previous estimates.
Physicians are sometimes asked to make their patient lists available to researchers or to ask patients to participate in clinical research. Moreover, physicians may be offered a finder's fee for each patient who is eventually enrolled. We receive more than a few manuscripts each year reporting on studies in which this recruitment practice has been used. Is it ethical? In our view, it is not. Associate Editor Ken Flegel explores the rationale for this stance and proposes new guidelines for physicians and researchers (page 1373).--JH
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