1. Department of Veterinary Medicine, Institute of Microbiology and Epizootics, Centre for Infection Medicine, Free University of Berlin, Berlin, Germany
2. Institute for Microbiology, University of Veterinary Medicine, Hannover, Germany
3. Sanofi-AventisGmbH, Berlin, Germany
4. German Federal Institute for Risk Assessment (BfR), Berlin, Germany
5. Robert Koch Institute, Berlin, Germany