Bluetongue: Vector surveillance in Austria in 2007.

Since the first outbreaks of bluetongue disease (BTD) were reported from The Netherlands, Germany, and Belgium in autumn of 2006, the disease is a main topic in Central Europe. The infectious disease, which originated in South Africa and from which Austria has been spared up to now, affects particularly sheep, cattle, also goats and wild ruminants - but never humans. Transmitters of the bluetongue virus (BTV, family Reoviridae, genus Orbivirus), which occurs in several 24 serotypes, are biting midges (Diptera: Ceratopogonidae) of the genus Culicoides. In Europe, Culicoides imicola, C. obsoletus, C. scoticus, C. dewulfi, C. pulicaris and, very recently, C. chiopterus have been implicated in BTV transmission. In 2007, a project on vector surveillance in Austria was started between the Federal Ministry of Health, Family and Youth (Bundesministerium für Gesundheit, Familie und Jugend; BMGFJ), the Austrian Agency for Health and Food Safety (Osterreichische Agentur für Gesundheit und Ernährungssicherheit; AGES), and the International Research Institute of Entomology at the Natural History Museum Vienna. Fifty blacklight traps have been set up spread over the whole Austrian territory and activated once per week from June to December 2007. Out of the more than 1.5 million collected Culicoides specimens, 87.3% were assigned to the Obsoletus complex, 6.7% to the Pulicaris complex, and 0.1% to the Nubeculosus complex. From these three complexes potential vectors for BTV in Central Europe are known. A percentage of 0.2% was assigned to species not belonging to any of these complexes, and 5.7% were not able to be determined to complex or species level. The highest numbers of individuals were recorded in July and August (not all traps, however, were activated in June). As from October the total amount of insects as well as the numbers of Culicoides decreased considerably.