Surveillance of dengue fever is mainly based on specific laboratory tests. However non-specific
systems, such as clinical surveillance, are also required. In French Guiana, we have tested a
non-specific laboratory surveillance system where different biological examinations performed
for other reasons than the diagnosis of dengue fever were analysed as methods for dengue
fever surveillance. The number of negative malaria diagnoses in Cayenne and Kourou was
found to be the best indicator of dengue fever infections in these towns. This surveillance
system appears to be very simple and reliable, and a test which could serve as an indicator that
is likely to be found everywhere.