Public health seeks to assure the conditions for people to be healthy. Public health can be distinguished from health care in several critical respects. Public health focuses on: (1) the health and safety of populations rather than the health of individual patients; (2) prevention of injury and disease rather than treatment and care; (3) relationships between the government and the community rather than the physician and patient; and (4) population based services grounded on the scientific methodologies of public health (e.g., biostatistics and epidemiology) rather than personal medical services. These critical features - populations, prevention, government and communities, and epidemiological services - are the hallmarks of public health