[1] Univ Liege, Dept Malad Infect & Parasitaires, Fac Med Vet, Epidemiol & Anal Risques Appl Sci Vet, B-4000 Liege, Belgium
[2] Univ Liege, Fac Med Vet, Dept Malad Infect & Parasitaires, Virol & Pathol Malad Virales, Liege, Belgium
[3] Ctr Etud & Rech Vet & Agrochim, Dept Virol, B-1180 Brussels, Belgium
[4] Univ Liege, Fac Med Vet, Clin Anim Prod, Liege, Belgium
[5] INRA, UE 1277, Plate Forme INfect Expt, F-37380 Nouzilly, France