Abstract
Reports of disease clustering are becoming ever more common, and there is increasing pressure on public health agencies to respond rapidly and appropriately to these reports. We investigated a cluster of five cases of MS occurring in a small multidisciplinary hospital department. Data were collected by a variety of methods, including measurement and description of the workplace, completion of survey instruments by department staff, and construction of case histories of persons with MS. The results indicated that the department comprised a high-risk population and that only one case of MS could have any possible etiologic significance. Investigators should consider a number of factors when evaluating disease clusters, including the accuracy of diagnosis, the induction period and cause of the disease, and possible biases in the population at risk. Additionally, boundaries should not encircle the cases that led to identification of the cluster and should reflect environmental significance.
Abrégé
Les rapports sur les agrégats de cas sont de plus en plus courants, et de plus en plus de pressions s’exercent sur les services de santé publique pour qu’ils répondent rapidement et comme il faut à ces rapports. Nous avons étudié un agrégat de cinq cas de sclérose en plaques survenus dans un petit service hospitalier, pluridisciplinaire. Les données ont été recueillies à l’aide de diverses méthodes, notamment la mesure et la description du lieu de travail, les réponses du personnel à des questionnaires et les dossiers d’observation médicale des personnes atteintes par la sclérose en plaques. Les résultats ont révélé que le service comprenait une population à risque élevé et qu’un seul cas pourrait avoir n’importe quelle explication causale. Les enquêteurs devraient prendre en considération un ensemble de facteurs lorsqu’ils évaluent des agrégats de cas, notamment l’exactitude du diagnostic, la période d’induction et la cause de la maladie, ainsi que les biais possibles dans la population à risque. En outre, il ne faut pas se circonscrire aux cas qui ont permis l’identification de l’agrégat mais prendre en compte l’ensemble de l’environnement.
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