This report describes the characterization of Parkville virus, the etiologic agent of an outbreak of foodborne gastroenteritis, that has the morphology of a calicivirus and genetic properties that distinguish it from previously identified strains in the Sapporo/Manchester virus clade. Sequence analysis of the Parkville virus genome showed it contained the RNA-dependent RNA polymerase motifs GLPSG and YGDD characteristic of members of the family Caliciviridae with an organization identical to that reported for the Manchester virus where the capsid region of the polyprotein is fused to the RNA polymerase. Parkville virus however, demonstrates considerable sequence divergence from both the Manchester and Sapporo caliciviruses, providing the first indications that genetic diversity exists within caliciviruses of this previously homogeneous clade. On the basis of recent advances in the genetic characterization of members of the family Caliciviridae, we propose a new interim phylogenetic classification system in which Parkville virus would be included with Manchester and Sapporo virus as a separate group distinct from the small round-structured viruses (Norwalk-like viruses) that also cause diarrhea in humans
