BTV is non-enveloped and consists of a 3 layered protein capsid (outer-capsid, core and sub-core) surrounding a genome of ten linear segments of double-stranded RNA. The outer capsid is formed from two viral proteins, VP2 and VP5, while the inner core-particle consists of a 'core-surface' layer composed of VP7, which surrounds a sub-core shell composed of VP3. VP2 interacts with host cellsurface receptors serving as a virus-attachment protein while VP5 is involved in host-cell membrane penetration [41, 42, 43] . The outer capsid proteins are removed during cell entry, and transcriptionally active core particles are released into the cytosol where virus replication occurs [44, 45] . However, the core-particle is also infectious in its own right demonstrating that VP7 can also mediate cell attachment and membrane penetration, possibly by a distinct mechanism [46] . Other viral encoded proteins (NS1, NS2 and NS3) are also produced in infected cells where they are involved in virus replication and release of progeny virus particles [47] .