Organised efforts focused on the health of defined populations in order to promote and maintain or restore health, to reduce the amount of disease, premature death and discomfort and disability due to disease. Programs, services and institutions here emphasize the prevention of disease and the health needs of the population as a whole. Among a broad scope of disciplines, various knowledge and skills are used, such as bio-statistics, epidemiology, planning, organisation, management, financing and evaluation of health programs, environmental health, application of social and behavioural factors in health and disease, health promotion, health education and nutrition. (IIME 2002)