Sentinel birds in wild-bird resting sites as potential indicators for West Nile virus infections in Germany

West Nile virus (WNV) is a mosquito-transmitted flavivirus with wild birds as its natural hosts. Ravens, falcons and jays are highly susceptible for WNV and develop deadly encephalitis, while other bird species undergo only subclinical infections. Migratory birds are efficient vectors for geographic spreading of WNV. Until now, WNV infections have not been diagnosed in Germany, but infections in humans and horses have occurred recently in Austria, Hungary and Italy. To investigate potential WNV introduction by infected wild birds, we have monitored the serological status of ducks in three national sentinel stations. No WNV-positive reactions were found, whereas sera from coots from northern Iran were positive.