[1] Ist Super Sanita, Dept Infect Parasit & Immunomediated Dis, I-00161 Rome, Italy
[2] Univ Naples Federico 2, Dept Anim Pathol & Hlth, I-80137 Naples, Italy
[3] Univ Catanzaro Magna Graecia, Sch Vet Med, Catanzaro, Italy
[4] Ist Super Sanita, SIDBAE, I-00161 Rome, Italy
[5] UPVM, ENVA, INRA, AFSSA,UMR 956, F-94700 Maisons Alfort, France