1. Dipartimento di Patologia Animale, Facolta' di Medicina Veterinaria, Universita' di Torino, Grugliasco, Torino, Italy
2. Department of Clinical Science, Kansas State University, 1800 Denison Ave, Manhattan, KS, USA;
3. Clinica Veterinaria Malpensa, Samarate, Varese, Italy
4. Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, Uppsala, Sweden