1. Unit Porcine Health Management, Department of Reproduction; Obstetrics and Herd Health; Faculty of Veterinary Medicine; Ghent University; Salisburylaan 133 Merelbeke 9820 Belgium
2. Intervet International; MSD Animal Health; Wim de Körverstraat 35 Boxmeer 5831 The Netherlands
3. Department of Pathology; Bacteriology and Avian Diseases; Faculty of Veterinary Medicine; Ghent University; Salisburylaan 133 Merelbeke 9820 Belgium