1. Institute of Parasitology, Centre for Infection Medicine, Faculty of Veterinary Medicine, Leipzig University, 04103 Leipzig, Germany
2. Albrecht-Daniel-Thaer Institute, Rudolf-Breitscheid-Str. 38, 04463 Groesspoesna, Germany
3. Institute of Virology, Faculty of Veterinary Medicine, Leipzig University, An den Tierkliniken 29, 04103 Leipzig, Germany