Dengue is a viral disease transmitted to humans by hematophagous mosquitoes of the genus Aedes. The infectious agent is dengue (DEN) virus, a member of the Flaviviridae family (genus flavivirus). DEN virus can be classified into four serologically defined groups (DEN-1, 2, 3, 4). The dengue that is essentially present in tropical areas of the Asian, Oceanien, African and American continents, affects several millions of people every year with a high mortality in children. It is, at present, the most frequent viral mosquito-borne disease. Dengue in its classical form is a febrile syndrome resembling flulike illness. However, it can also lead to haemorraghic syndroms and to a hypovolemic shock which often proves fatal. Dengue pathogenesis is still not well understood and no factor predicative of the evolution of the disease is recognised. In the absence of a vaccine, treatment of this spreading disease remains only symptomatic.