Characteristics of a new reovirus from channel catfish (Ictalurus punctatus)

The characteristics of a reovirus (CRV) recently isolated from channel catfish (Ictalurus punctatus) were examined following purification of virions from infected cell cultures. Virions had double capsids, the inner and outer with diameters of 55 nm and 75 nm respectively. Complete virions had a density of 1.36 g/ml in CsCl gradients and contained seven polypeptides of 132 000, 130 000, 110 000, 68 000, 56 000, 43 000 and 32 000 mol. wt. The nucleic acid labelled with [5-3H]uridine had a density of 1.56 g/ml in Cs2SO4 gradients, which suggested that it is double-stranded RNA. The genome was composed of 11 segments that ranged in mol. wt. from approximately 0.4 X 10(6) to 2.5 X 10(6). Serum cross-neutralization comparisons of CRV to reoviruses isolated from chum salmon (Oncorhynchus keta) and golden shiners (Notemigonus crysoleucas) indicated that each was distinct although some crossreactions were observed. These viruses seem to represent three serotypes of a new genus within the family Reoviridae.