1. Boehringer Ingelheim Animal Health; Binger Strasse 173 D-55216 Ingelheim am Rhein Germany
2. Harlan Bioservice for Science; Sudkampen 31 D-29664 Walsrode Germany
3. Institute for Bacteriology and Mycology; Faculty of Veterinary Medicine; University of Leipzig; An den Tierkliniken 29 D-04103 Leipzig Germany