[Epidemiologic surveillance of dengue fever: non specific alert system in the hospital milieu in Cayenne].

A retrospective study was carried out in the General Hospital of Cayenne, the main city in French Guiana, where malaria is endemic and dengue fever constitutes a permanent threat. The aim of this study was to test an alert system for epidemic outbreaks of dengue fever. Patients attending the emergency ward and for whom a search of Plasmodium was prescribed were included. In 90% of cases, patients were febrile, presenting clinical symptoms compatible with malaria or dengue fever-like syndrome. The period of survey covered 39 months (January 1996 to March 1999). Three indices were studied; two non specific: EMN (Emergency Malaria Negative--UPN in French): number of negative malaria blood tests for patients having consulted the emergency ward; EMNT (Emergency Malaria Negative Thrombopenia--UPNT in French): UPN with platelets < 150.000; and one more specific; number of hospitalised dengue fever cases according to data from a hospital programme on medical systems information. EMN weekly follow-ups led to three epidemic alerts, two of which turned out to be crucial for dengue. Accounting for thrombopenia (EMNT) reinforced the specificity. This simple and reactive alert system should incite increased serological and virological surveillance and contribute to precocious antivectorial control measures in districts where several dengue fever cases are suspected.