1. Department of Public Health and Animal Sciences, Faculty of Veterinary Medicine, Valenzano (Bari), Italy
2. Istituto Zooprofilattico Sperimentale di Lombardia ed Emilia Romagna, via A. Bianchi 9, 25124 Brescia, Italy
3. Centro Nacional de Biotecnologia, Department of Molecular and Cell Biology, Campus Universidad Autonoma, Cantoblanco (Madrid), Spain