Molecular Characterization of a New G (VP7) Genotype in Group B Porcine Rotavirus

Rotaviruses (RVs), a common cause of viral gastroenteritis in humans and animals, are classified into 9 established groups/species (RVA–RVI). Although RVB has been found in several countries, genetic variation among RVB field strains remains poorly characterized. RVB strains can be classified into G genotypes based on a nucleotide (nt) homology that exceeds a cutoff value of 80% for the gene that encodes the structural protein VP7. In this study, we determined the VP7 nt and deduced amino acid sequences of one RVB strain (RB62) identified in a diarrheic fecal sample obtained from a piglet in Brazil in 2012. Comparative analysis of this strain and the strains of the other 21 previously identified VP7 ge­notypes showed that the highest nt identity (71.2%) was found with the porcine PB-70-H5 strain within the G4 genotype. However, when compared with the nonclassified Vietnamese RVB G genotype 14177_18 strain, the nt sequence identity was of 82.9%. These results led us to conclude that the Brazilian strain BR62 and the Vietnamese strain 14177_18 belong to a novel G genotype (G22).