[Challenges in public health for the new century].

The history of public health has followed different trends, depending on the prevailing theories of disease causality and the interventions that these suggest. From the concern with miasmas to the germ theory, to the stress on lifestyles and the current interest on the linkages between health, economic welfare, and social status, the proposed policies are contingent on how health and disease are conceptualized and explained. Ironically, now that there is increasing evidence on the socio-economic determinants of health, interventions continue to focus on specific target groups or disease categories, as well as on the medical sector.