Public health surveillance

Public health surveillance provides the epidemiologic foundation for modern public health practice. The ongoing monitoring of disease or health trends within populations informs what public health actions are taken and reflects whether those actions are effective. Surveillance may involve monitoring of diseases and other health-related conditions as well as their antecedents, characteristics, and consequences. Surveillance can guide the local response to individual cases of disease or more broadly inform public health programmes and policies. A key function of surveillance is to identify circumstances that merit further public health scrutiny, such as groups or locations that are disproportionately affected or changes in disease occurrence or severity. General principles that underlie the practice of surveillance are essentially the same for all countries, regardless of economic development. However, in many resource-poor countries, challenges to meeting needs for population health information are heightened and include potential tensions between groups with differing interests. Public health surveillance is conducted in many ways, depending on the nature of the health event under surveillance, the nature of healthcare and information infrastructures, the population involved, resources available, and information needs. The widespread and expanding use of the internet, electronic media, communication technologies, and mobile computing have enabled innovations in public health surveillance that reach far beyond traditional methods. Although surveillance methods were originally developed as part of efforts to control infectious diseases, basic concepts of surveillance have been applied to all areas of public health.