Public health nursing is the practice of protecting and encouraging the health using data from nursing, social, and public health sciences. It is a systematic process by which the health and health care necessities of a population are assessed in order to identify subpopulations, families and individuals who would benefit from health promotion or WHO is in danger of sickness, injury, disability or premature death. A public health nurse’s role is to market health and prevent health problem. It focuses on teaching at-risk individuals and groups how to maintain healthy lifestyles and prevent illness by avoiding unsafe behavior or exposure.