1. Field Station for Epidemiology; University of Veterinary Medicine Hannover, Foundation; Bakum Germany
2. Veterinary Epidemiology and Public Health Group; The Royal Veterinary College; Hatfield Hertfordshire UK
3. Institute for Biometry, Epidemiology & Information Processing; WHO Collaborating Centre for Research and Training in Veterinary Public Health; University of Veterinary Medicine Hannover, Foundation; Hannover Germany
4. Department of Pathobiology; Institute of Bacteriology, Mycology and Hygiene; University of Veterinary Medicine; Vienna Austria