According to the WHO definition of improved environmental sanitation, epidemic prevention, based on the principles of personal hygiene and health education, disease prevention, early diagnosis and treatment of medical and nursing services for the organization, Further all residents of the community sufficient to maintain the health and living standards aimed at ensuring the development of social institutions, and through the efforts of a community that is committed preventing disease and prolong life, and the promotion of health and human devise efficient science and technology. This means that in the public health may knock.