Rotavirus A (RVA) causes severe diarrhea in a wide range of young mammals including humans. RVA possesses a genome consisting of 11 segments of double-stranded RNA encoding six structural proteins (VP1-VP4, VP6 and VP7) and six nonstructural proteins (NSP1-NSP6). In a nucleotide sequence-based classification system proposed by the Rotavirus Classification Working Group (RCWG), RVA is classified into 27 G, 37 P, 17 I, 9 R, 9 C, 8 M, 18 A, 10 N, 12 T, 15 E and 11 H genotypes (for VP7, VP4, VP6, VP1, VP2, VP3, NSP1, NSP2, NSP3, NSP4 and NSP5 genes, respectively). RVAs have been isolated from a large number of animal species worldwide. However, there are few reports on RVAs in marsupial species.
To investigate the prevalence of RVA in marsupial species, we examined infection of RVA in sugar gliders (Petaurus breviceps). We obtained 28 fecal specimens of young sugar gliders that were imported from Thailand, Taiwan and Malaysia into Japan. We detected an RVA in the fecal specimen of a sugar glider from Thailand and nine RVAs in fecal specimens of sugar gliders from Taiwan by RT-semi-nested PCR. The nucleotide sequences of the VP4 and VP7 genes of these RVAs were determined by direct sequencing. RVAs in the sugar gliders from Thailand and Taiwan were classified as G27P[3] and G27P[36] genotypes (G27 and P[36] being new genotypes), respectively. To our knowledge, this is the first report on molecular characterization of RVAs in a marsupial species. We then isolated an RVA SG385 strain in a sugar glider from Taiwan and determined nucleotide sequences of all genes of this strain. All genes of SG385 strain were considered as new genotypes. These findings suggest that RVAs have evolved uniquely in marsupial species. Determination of the genotypes of SG385 strain by the RCWG is now in progress.