Abstract

To date, dengue viruses ate the only arthropod-borne viruses (arboviruses) ever identified in French Polynesia. They belong to the genus Flavivirusand are transmitted by mosquitoes, principally, Aedes aegypti. Since 1944, twelve dengue outbreaks have occurred in French Polynesia, caused each time by one of the four dengue serotypes. These epidemics were either due to the introduction of a new dengue strain or to the re-emergence of a strain that has caused an outbreak in the previous years. The Institut Louis Malardé (ILM) has contributed to the local dengue surveillance effort for many decades by using more and more effective tools, the classical semi-nested RT-PCR implemented at ILM since 90's. However, efficient dengue surveillance requires the ability to quickly identify new viral introduction and new foci of dengue cases and thus, requires the constant improvement of new tools such as the faster and more sensitive real-time RT-PCR. Besides, with the increase of worldwide exchanges, French Polynesia is also threatened by the potential introduction of other emerging arboviruses. Hence, to anticipate the risk of diseases emergence, we implemented classical RT-PCR and/or real-time RT-PCR to detect the Flavivirus, Alphavirus or Phlebovirus genera. In additio, we developed specific RT-PCR detection tools against the Chikungunya and West Nile viruses, respectively members of the Alphavirus and Flavivirus genera and both of potential high risk for French Polynesia. Moreover, mosquito-spiked external positive controls were tested to further validate the use of these new tools in field-captured mosquito pools. Furthermore, non-dengue related arboviruses might have circulated undetected in French Polynesia. We have thus investigated the presence of antibodies against a range of arboviruses in the sera of people living in the 5 archipelagos of French Polynesia. The results of this serological screening will condition the implementation of additional specific RT-PCR detection tools.