1. Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 268, 8057 Zurich, Switzerland
2. Cantonal Veterinary Office Ticino, Via Dogana 16, 6500 Bellinzona, Switzerland
3. Department of Veterinary Medical Sciences, University of Bologna, Via Tolara di Sopra, 43, 40064 Ozzano dell'Emilia, Bologna, Italy