1. 1Virus Reference Department, Public Health England, London, UK
2. †Present address: Retrovirus-Host Interactions Laboratory, The Francis Crick Institute, 1 Midland Road, London, UK.
3. 2Groupe d'Etude des Interactions Hôte-Pathogène (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France
4. 3National Institute of Diagnostics and Vaccine Development in Infectious Disease, Xiamen University, Fujian, PR China
5. 4Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy