Vectorial capacity of in a new colonised area in southern mainland France.
Bluetongue disease occurred for the first time in Corsica, France in 2000. Considering the distance of this island from the mainland France and as long as its principal vector, Culicoides imicola
, was absent from the continent, bluetongue transmission risk remained low in continental France. Presence of C. imicola
was first detected in October 2004 in Var (continental France) and, since then, trapping campaigns have shown that its establishment is persistent. Thus, it is now essential to assess the risk of a bluetongue outbreak in this area. In the case of mosquito-borne diseases, the vectorial capacity is a widely and useful adopted estimate used to assess the susceptibility of an area to a particular disease. This integrated approach was applied in the Var context.
In Var, France, where Culicoides imicola
populations are established, four trapping sites were monitored every week from mid-April 2005 to mid-November 2005 with a light trap, French-type. The sites were selected according to the presence of the target animals (sheep or horses) and their geographic situation. The abundance and the parity were collected weekly and analysed in regard with local meteorological data. Expert opinions and previous published results were used to estimate others parameters of the vectorial capacity. Uncertainty and variability were taken into account by using probabilistic distributions. The vector competence of this C. imicola
’s population was tested through experimental infections under laboratory conditions.
The benefits of such an approach are analysed with the purpose of finding few sensitive parameters which could be monitored in routine.