Entomological surveillance of bluetongue in Italy: methods of capture, catch analysis and identification of Culicoides biting midges.

To elucidate the epidemiology of vector-borne diseases that can affect livestock in the Mediterranean Basin and elsewhere, it is essential to obtain a clear understanding of the life-cycle and habits of the vector insects involved. One purpose of such investigations is to provide data for an epidemiological surveillance system. As this depends heavily upon the collection of specimens in the field, it is necessary to establish the kinds of information required, and how it can be obtained. This requires, in turn, that the method (and instrument) of capture be standardised, so that all data are as complete as possible, are comparable, and are informative at many levels. Within the surveillance system for bluetongue (BT) in Italy, the National Reference Centre for Exotic Diseases (CESME: Centro Studi Malattie Esotiche) is leading an intensive and countrywide survey for Culicoides (Diptera: Ceratopogonidae) using standardised methods and protocols developed in collaboration with the Onderstepoort Veterinary Institute in South Africa. These methods have now also been implemented outside Italy in Malta, Croatia, Albania and Romania. This system includes the field protocols developed for the collection of Culicoides, the laboratory protocols developed around the insect analyses and the computer-based recording of all field data. Finally, the authors provide an 'Easy key' for the rapid identification of the principal BT vector C. imicola, and for grouping species that belong to the Obsoletus and Pulicaris vector complexes, and to the Nubeculosus and Schultzei potential vector complexes.