[1] Swedish Univ Agr Sci, OIE Collaborat Ctr Applicat Biotechnol Based Meth, Natl Vet Inst & Fac Vet Med & Anim Sci, Dept Virol,Joint R&D Div, S-75189 Uppsala, Sweden
[2] Uppsala Univ, Dept Med Sci, Sect Virol, S-75185 Uppsala, Sweden
[3] Swedish Inst Infect Dis Control, Dept Virol, S-17182 Solna, Sweden