1. Karolinska InstitutetDepartment of Microbiology, Tumor and Cell Biology, Stockholm, Sweden
2. Swedish Institute for Communicable Disease ControlDepartment of Diagnostics and Vaccinology, Solna, Sweden
3. Viral Pseudotype UnitUniversity of Kent, Kent, UK
4. Reparto di Virologia, Istituto Zooprofilattico Sperimentale della Lombardia ed Emilia Romagna, Brescia, Italy
5. National Veterinary InstituteSwedish University of Agricultural Sciences, Uppsala, Sweden
6. Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden