[The explicative models of infectious diseases in Canada in the 19th Century]

Until the last third of the 19th Century in Canada, physicians looked for the causes of infectious diseases and adopted explicative models associated to airist theories, climatic variations and the physical environment. Rarely did they mention the social environment. Yet, the interpretation of disease plays a fundamental role in the elaboration of preventive measures. Consequently, Canadian physicians adopted a naturalist approach based on local sanitation rather than a social approach of the disease. This reinforced the concept of "predisposing causes". By examining local conditions and, to a lesser extent, the living conditions of Quebec's population, the pre-bacteriologist theories prepared the way for the intervention of modern hygienists.