Antigenic and molecular characterization of bovine rotaviruses isolated in Japan.

Japanese bovine rotavirus isolates, which fall into two different serotypes, were shown to belong to subgroup I and to have long RNA electrophoretypes. This study confirmed the distinction of two serotypes on the basis of a greater than 20-fold difference in neutralization titres between the homologous and heterologous reactions; however, significant one-way cross-neutralization was observed between one of the strains with bovine serotype 2 and antisera to strains with bovine serotype 1 (serotype 6 according to the unified serotyping system). When 32P-labelled transcription probes prepared from Japanese strains as well as a prototype NCDV strain were hybridized with genomic double-stranded RNA from these bovine strains and from prototype human strains, a high level of homology was observed among bovine rotavirus strains; but this level of homology was not found between bovine strains and any of the prototype human strains. These results suggest that bovine rotavirus strains belong to a single genogroup that is distinct from any of the human genogroups previously identified by RNA-RNA hybridization.