Healthcare prevention saves lives and can even stop the spread of contagious diseases. Public health is the science and art of avoiding disease, extending life, and promoting well-being via organized efforts and educated decisions made by society, associations, both public and private, groups, and individuals. Preventive medicine focuses on the strength of individuals, organizations, and defined populations. Public health is the study and practice of protecting and promoting a community's health, such as through preventive medicine, health education, communicable disease control, sanitary measures, and environmental hazard monitoring. The goal of public health and general preventive medicine is to improve the health of communities and defined populations by promoting health, preventing disease, and managing their health. In a number of settings, these practitioners combine population-based public health abilities with knowledge of primary, secondary, and tertiary prevention-oriented clinical practice.