Changing clinical and biological manifestations of dengue during the dengue-2 epidemic in French Polynesia in 1996/97 - description and analysis in aprospective study

In August 1996 dengue-2 virus was detected in French Polynesia for the firs t time since 1976. A prospective study was conducted from November 1996 to April 1997. Each time one of 7 physicians suspected dengue, the patient was enrolled and epidemiological, clinical and biological data were recorded. Dengue diagnosis was confirmed by virus isolation and IgM detection. The ai ms of this study were to find clinical and biological predictive factors co nstituting a specific profile of dengue (DF) and dengue haemorrhagic fever (DHF/DSS) and to assess the possibility of diagnosing dengue at primary hea rth care level using clinical criteria and basic laboratory parameters. Of 298 clinically suspect cases, 196 (66%) were confirmed as dengue. The assoc iation of macular rash, pruritis, low platelet count and leukopenia was sta tistically predictive of dengue but not clinically, since these four signs occur in many other viral infections. As the prevalence of clinical and bio logical manifestations varied over time in our study, a specific profile us eful for dengue diagnosis cannot be defined. With six cases of DHF, the mor bidity of this dengue-2 outbreak was very low despite the sequential infect ion scheme DEN-3/DEN-2. The clinical expression of dengue could depend on a specific virus strain circulating in a specific population in a particular place, with varying virulence over time.