1. Clinic for Ruminants, Vetsuisse Faculty, University of Bern , Bremgartenstrasse 109a, 3012 Bern , Switzerland
2. Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern , Länggassstrasse 122, 3012 Bern , Switzerland
3. Veterinary Public Health Institute, Vetsuisse Faculty, University of Bern , Schwarzenburgstrasse 161, 3097 Liebefeld , Switzerland