Chikungunya and dengue autochthonous cases in Europe, 2007-2012.

A large number of autochthonous cases of dengue fever (2237) and chikungunya fever (231) occurred in Europe (Italy, France, Croatia, Madeira) during the period covered by our analysis (2007-2012). In all dengue outbreaks, the circulating strain, identified by means of molecular analysis, was the DENV-1 strain. Dengue and chikungunya are infectious diseases that often result in hospitalizations and are associated with high public health costs. The dengue epidemic on the island of Madeira resulted in 122 hospitalizations. Only one death (from chikungunya) occurred but long-term sequelae were described after the chikungunya outbreak in Emilia-Romagna, Italy. Vector control is key to reducing the impact of these diseases. During the chikungunya outbreak in Italy and the dengue outbreak in Madeira, appropriate measures for the control of mosquitoes (Aedes aegypti and Aedes albopictus) were effectively implemented. The effectiveness of these measures (reducing the number of breeding sites, application of pesticides and insecticides, public health education) was shown in the context of these real-life outbreaks. All the pre-requisites for autochthonous transmission of both dengue virus and chikungunya virus (vectors, viremic returned travellers, climatic conditions) are present in Europe. Constant surveillance is imperative.