1. Section of Clinical, Allergological and Venereological Dermatology Department of Medicine University of Perugia 06156 Perugia Italy
2. Department of Veterinary Medical Sciences Alma Mater Studiorum University of Bologna Bologna Italy
3. Laboratory of Histopathology and Electron Microscopy Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche ‘Togo Rosati’ Perugia Italy