Isolation and characterization of a novel reovirus from white bream Blicca bjoerkna

During a fish health inspection in the Viennese waterway 'Old Danube', a virus was isolated exclusively from white bream Blicca bjoerkna (L.) (formerly Abramis bjoerkna L.), one of the most abundant cyprinids present and not known as a host species for this virus. The virus preferentially replicated in cultures of the epithelioma papulosum cyprini cell line where focal plaques of infection developed slowly. Examination of infected cell cultures by electron microscopy revealed non-enveloped 60 to 70 nm icosahedral virions that had characteristic multiple segregated protrusions of their outer capsid. A partial RNA-dependent RNA polymerase gene sequence was obtained and a BLAST search indicated 76% identity to golden shiner reovirus and grass carp reovirus. These results suggested that the virus belonged to the genus Aquareovirus (Family Reoviridae). Phylogenetic analysis placed the isolated virus within a clade of the species Aquareovirus C species. Accordingly, the virus was tentatively designated as white bream reovirus (WBRV) strain A-127/06 within the species Aquareovirus C.