1. Department of Biomedical Sciences, University of Sassari, Sassari, Italy
2. Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d’Aosta, Turin, Italy
3. Istituto Zooprofilattico Sperimentale del Lazio e della Toscana M. Aleandri, Pisa, Italy
4. Department of Veterinary Medicine, University of Sassari, Sassari, Italy