Detection and molecular characterization of sapoviruses in dogs

Caliciviruses are important human and animal pathogens. Novel caliciviruses have been identified recently in dogs, raising questions about their pathogenic role and concerns regarding their zoonotic potential. By screening stool samples of young or juvenile dogs using RT-PCR assays, sapoviruses (SaVs) were found in 7/320 (2.2%) samples of animals with acute gastroenteritis while they were not detected in healthy animals (0/119). The sequence of a nearly 3 kb portion at the 3′ end of the genome, encompassing the RNA-dependent RNA polymerase (RdRp), the capsid region (ORF1) and the ORF2 were determined for three strains. A distinctive genetic feature in canine SaVs was a 4-nucleotide (nt) interval between the ORF1 and ORF2. Two strains (Bari/4076/07/ITA and Bari/253/07/ITA) were very closely related in the RdRp and capsid regions to the strain AN210D/09/USA (90.4–93.9% nt), while strain Bari/5020/07/ITA displayed only 71.0–72.0% nt identity to this group of canine SaVs and 76.0% to strain AN196/09/USA. Overall, these findings indicate that the canine SaVs detected in Italy may represent distinct capsid types, although all currently known SaVs segregate into the novel proposed genogroup, tentatively named as GXIII.