Dengue-like syndrome is defined as a sudden onset of fever ≥38.5°C, accompanied by one or more nonspecific symptoms (musculoskeletal pain, headache, fatigue, retroorbital pain, maculopapular rash, gastrointestinal symptoms) in the absence of any other identifiable infectious cause.

In 2008, a protocol for enhanced surveillance of DLS was implemented in close collaboration with the laboratory at the Mayotte Hospital Center (CHM). For any patient presenting with a clinical picture of SDL, physicians are encouraged to order, after ruling out malaria, systematic testing for the four infections—chikungunya, dengue, Rift Valley fever, and leptospirosis—using molecular biology or serology.

This epidemiological update provides an overview of the main diseases involved: dengue, chikungunya, Rift Valley fever, and leptospirosis.