The interchange of disease and health between the Old and New Worlds.

A review of the five centuries since Columbus discovered America helps us understand the mutual contributions of the Old and the New Worlds to the history of diseases and their treatment. It also shows the consequences of this "mutual discovery" as they are currently emerging in the fields of health, culture, and the environment. To evaluate the multiple aspects of the interchange between the Old and New Worlds, this paper discusses the following: the causes of the rapid decline of the original American populations; the diffusion of communicable diseases between the two civilizations; the health consequences of nutritional changes on both sides of the Atlantic; drug addictions, as they developed through the centuries and as they exist today; the ways diseases were and are evaluated, prevented, diagnosed, and treated; and the mutual impact of different models of health services. Arguing that a major global change following the discovery of America was the transition from isolation of the two worlds to communication, and, more recently, to global interdependence, the paper also discusses some problems of bioethical relevance and the possible impact of new epidemics. Finally, it suggests that a critical analysis of the past may help stimulate future cooperation and solidarity.