Surveillance of Disease: Overview

This article discusses the role and methodology of disease surveillance, which provides epidemiological data to formulate actions to control or eliminate disease hazard, one of the indispensable systems in national and global public health intelligence services. The target diseases include not only infectious diseases but also noncommunicable diseases as well as accidents and injuries. Efficacy is increasing with ever-newer diagnostic technology as well as expanding information technology. A few experiences in how surveillance has played an essential role in disease control are illustrated.