The recent outbreak of the Chikungunya virus in the Indian Ocean and more precisely the epidemic in Réunion Island has shown the difficulties to control it by anti-vector methods due to the lack of knowledge on the mosquito vectors.
The Chikungunya virus is known to be enzootic and epidemic throughout much of Africa, whereas in Asia it is only epidemic. In Réunion Island it has been shown that the major vector of this disease was Aedes albopictus. The purposes of the Entomochik project are to study the biology and genetic of the vectors, to better understand the virus-vector relationships and finally to model the entomological risks of emerging arboviruses transmitted by Aedes mosquitoes in Réunion Island.
This 2007- 2009 project has been divided into four workpackages.

WP1 is dedicated to the study of the biology of Ae. albopictus. Different experiments will be conducted in field and laboratory conditions in relation to the environmental constrains. Indeed, the population dynamic, the biology of immature stages and adults, the behaviour, the trophic preferences, the longevity and dispersion will be assessed.

WP2 is axed on the molecular phylogeography and genetics of populations, for studying 1) the history of introductions of Ae. albopictus in Réunion Island and 2) the genetic structure of populations linked to the geographical and ecological criteria at the micro and macro scales.

WP3 assesses the vector competence of Ae. albopictus with different strains of Chikungunya and Dengue. The underlying molecular mechanisms of the transmission will be studied. Several vector populations collected from the Island of the south west part of the Indian Ocean and from other parts of the world will also be tested. The vertical transmission efficiency and its mechanisms will also be studied.

WP4 includes the spatialization of the data obtained through a geographical information system and bases of geo-referenced data and the modelling of the observed phenomenon. Two different types of models will be developed: 1) models focusing on the distribution, biology and dynamic of populations of Ae albopictus linked to the environmental conditions; 2) multi-agent system models including the spatiality, the environmental conditions and the human-vector interactions.

Four different partners with complementary competences are part of this project: IRD based in Montpellier and in Réunion Island (Saint Pierre), DRASS based in Réunion Island (Saint Denis), Institut Pasteur based in Paris and UMR PVBMT (CIRAD - Université de la Réunion) based in Saint Pierre. PI is D Fontenille, IRD, who has a huge experience both in arbovirus vectors and project management.
The EntomoChik project will allow us to better understand factors implicated in the emergence of Chikungunya disease and to develop models to predict the entomological risk for arboviruses emergence. Furthermore, our results will improve our knowledge on the biology and vector competence of Ae. albopictus, which have been poorly studied. These data will be very useful for other projects linked to human epidemiology, animal reservoirs, social aspects and human behaviours, and also on new vector control initiatives (new insecticides, traps, genetic control). Finally this project will reinforce the medical entomology skills in the Indian Ocean, thanks to workshops, Master and scientists training.

Work package 3: Relations between virus-vector (CHIKV & DENV) in Ae. albopictus & Ae. aegypti populations

Work package 4: Modelisation of the entomological risk

I- Ecology and repartition of Ae albopictus in La Réunion and in the SWIO islands

Breeding sites of Ae albopictus in the SWIO islands

Coconut shelves (Madagascar)	Water container (Mayotte)
Palm leaf (Mayotte)	Flower plates (Réunion)

Delatte, H., Dehecq, J. S., Thiria, J., Domerg, C., Paupy, C. & Fontenille, D. (2008). Geographic distribution and developmental sites of Aedes albopictus (Diptera: Culicidae) during a chikungunya epidemic event. Vect Borne Zoo Dis 7, 1-11.
Corresponding author: delatte@cirad.fr