[Active surveillance for dengue and dengue hemorrhagic fever].

Dengue and dengue hemorrhagic fever are emerging as major public health problems in most tropical countries. Effective prevention and control programs will depend on improved surveillance. A new approach to active surveillance is outlined with emphasis on the interepidemic period. The objective is to develop an early warning surveillance system than can predict epidemic dengue. Virologic surveillance is the most important in an early warning system. Dengue virus transmission should be monitored to provide information on which serotypes are present, their distribution, and the type of illness associated with each serotype. Other components of the active surveillance system include fever alert and clinical surveillance for severe and fatal disease associated with viral syndrome. Individually, each component is not very sensitive, but collectively, they provide an early warning capability that allows detection of newly introduced dengue virus serotypes well in advance of epidemic transmission. With such information, emergency mosquito control can be implemented and major epidemics averted.