Entomological survey on vectors of Bluetongue virus in Northrhine-Westfalia (Germany) during 2007 and 2008

The entomological monitoring programs done on 19 farms all over Northrhine-Westfalia (Germany) in the years 2007 and 2008 showed that the species Culicoides obsoletus and C. pulicaris are the most common ones and that both act as vectors of the bluetongue-virus of the serotype 8. Especially the species C. obsoletus was found all over the year and also inside or close to stables during the winter months. Therefore, there exists no midge-free period that would interrupt the transmission cycle of bluetongue virus. This makes it necessary that vaccination programs and insecticidal treatment have to consider this and must be preceded even in winter months. From the fact that there was no northward migration of southern Culicoides species (e.g., Culicoides imicola), apparently, globalization and its intense transportation of animals, plants, and other goods is the reason of this BTD outbreak in Central Europe. This conclusion needs urgently special attention on other luring epidemics in the near future.