1. Institute of Microbiology and Epizootics, Centre of Infection Medicine; Department of Veterinary Medicine, Freie Universität Berlin; Berlin Germany 14163
2. Institute of Microbiology; University of Veterinary Medicine; Vienna Austria A-1210
3. Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine; China Agricultural University; Beijing China 100193
4. Institute of Farm Animal Genetics; Friedrich-Loeffler-Institut; Neustadt-Mariensee Germany 31535