Syndromic surveillance is the analysis of medical data to detect or anticipate disease outbreaks. Syndromic surveillance can include fevers of unknown origin, clinically diagnosed cases, school absenteeism, over-the-counter drug sale records etc.

Vector control response based on syndromic surveillance in the form of clinical diagnosis can result in vector control measures being implemented weeks to months earlier than vector control response based on dengue cases confirmed by laboratory diagnostic tests.

The local potential for implementing vector control in response to clinically diagnosed dengue cases needs to be evaluated based on: 1) the proportion of clinically diagnosed cases that are confirmed by laboratory tests as dengue; and 2) the typical time-lag between clinical diagnosis and laboratory confirmation.

Vector control response based on clinical diagnosis is most appropriate under a scenario with a high percentage of clinically diagnosed cases being laboratory-confirmed as dengue and a slow turn-around time for laboratory confirmation.