ABSTRACT
At the beginning of this century, the leading causes of death were influenza, pneumonia, diphtheria, tuberculosis, and gastrointestinal infections. Few of us know anyone who has died of such diseases today, pointing to the revolution in medicine that has occurred in the last century. This revolution was predicated on a theory, the germ theory of disease. As early as the 17th century, van Leeuwenhoek had discovered creatures too small to be seen by the naked eye. But it was two more centuries before Pasteur and Koch developed the germ theory of disease. This theory had profound implications for the care and treatment of the sick. Lister developed aseptic techniques, resulting in drastic reductions in fatalities from operations. Sanitation substantially reduced the spread of disease. Disease prevention became a reality through the development of effective vaccines. Previously life-threatening illness could be successfully treated with the advent of antibiotics and antiviral agents. Medicine’s conquest of infectious disease has massively changed the health care challenges faced by our society. Chronic diseases and injuries from accidents, poisonings, and violence are our current health care problems. Behavioral factors, particularly habits such as smoking, dietary preferences, and alcohol use, play a major etiological role. In 1980, the Center for Disease Control of the U.S. Public Health Service estimated that 50% of mortality from the 10 leading causes of death in the United States can be traced to lifestyle behaviors (Miller, 1983).
