1. University Clinic for Swine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
2. Institute of Pathology, Department for Pathobiology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
3. Institute of Virology, Department for Pathobiology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
4. Institute of Infectious Diseases and Zoonoses, Ludwig-Maximilians-University Munich, 80539 Munich, Germany