Ten years of entomological surveillance for bluetongue in Sicily

The Bluetongue (BT) or catarrhal Fever of the sheep is a not contagious viral pathology, belonging to the A list of the   Office International des Epizooties (OIE).  This disease  is transmitted to the vertebrate hosts through insects of the genus Culicoides (Diptera:  Ceratopogonidae). The spreading and the intensity of the infections of bluetongue are strongly related to the distribution and abundance of the Culicoides. The first case of outbreak of BT in Sicily verified in October 2000 in the province of Palermo in  some sheep; after that episode, other Sicilian provinces were also involved in epidemic.  In Italy monitoring and surveillance of BT was ruled by the O.M. of may 11^th 2001. In concomitance with the first hotbeds, with the collaboration of the National Reference Centre for Exotic Diseases of Institute Zooprofilattico Sperimentale dell’Abruzzo e Molise, an entomological surveillance plan started, that  included at the beginning  the monitoring of the whole island for the presence of Culicoides spp and C. imicola (Kieffer, 1913) and subsequently a plan of surveillance using fixed traps in each Sicilian province activated weekly, in order to build up the distribution maps and the preventive risk maps of the various species of Culicoides.  The captures were carried out in sheep, goats and cattle farms. In Sicily C. imicola has never been particularly abundant or widely distributed; nonetheless Sicily was one of the first regions to show an epidemic of BT, these data together with  BTV isolation in other species of Culicoides suggests that in Sicily the role of the carrier is not to be attributed only to C. imicola. The data reported in this work include the results of the examination of catches carried out within ten years, from 2002 to 2012 to assess the presence of several species of Culicoides in relation to  the different seasons. Were identified Culicoides belonging to the following species/complex: C.imicola, C.obsoletus complex, C.pulicaris, C.newsteadi, C.circumscriptus, C.gejgelensis, C.paulae, C.subfascipennis, C.tauricus, C.agathensis, C.monoculicoides, C.fascipennis, C.punctatus, C.nubeculosis, C.Schultzei. The found species were mostly present all months of the year, though, in the winter months, the prevalence of some of them was zero or very near to zero. As concerns C. imicola,  we observed high prevalence in the autumn months of September-November, reaching the peak of activity during the month of October. The data give a general picture on the prevalence of the various species of Culicoides in Sicily suggesting as these species may be implicated on the transmission of Bluetongue virus.