The control of communicable disease, the essence of traditional public health, is not the same as the internal medicine subspecialty of infectious disease treatment. This subspecialty is concerned with the treatment of individual patients infected with viral and bacterial organisms, and the training is oriented to individual patients, not the community. In contrast, disease control is concerned with the prevention of the spread of diseases in the community rather than the treatment of individual patients.

Disease control was the core of public health until the last polio epidemics in the 1950s. With the development of antibiotics and effective immunizations, the public lost its fear of communicable diseases, undermining public support for disease control in the general populace and in schools of public health. Since the 1960s, public health has become a broad umbrella, encompassing every cause from nuclear war to controlling cholesterol levels. This loss of focus has weakened the disease control programs in most health departments. The diminished support for disease control is exacerbated by the burden of indigent medical care. Although indigent medical care is a critical community service, it is so expensive and demanding that it saps the resources of the much smaller preventive programs.