Infectious disease surveillance in China.

A national system of infectious disease surveillance was established in 1959 in China. Now it consists of three subunits, namely, national disease reporting system (NDRS), nationwide disease surveillance points (DSPs), and surveillance network for specific infectious diseases. There are 35 notifiable infectious diseases, which are divided into Classes A, B, and C. The functions of the surveillance include explaining the natural history of infectious diseases, describing the distribution of case occurrence, triggering disease-control effort, monitoring epidemic of infectious diseases during natural disasters, predicting and controlling epidemics and providing the base of policy adjustment.