Genomic characterization of swine caliciviruses representing a new genus of Caliciviridae

This study reports the molecular characterization of novel caliciviruses, the St-Valérien-like viruses, which were isolated from pig feces in the province of Quebec, Canada between 2005 and 2007. The genomes of St-Valérien-like viruses contain 6409 nucleotides and include two main open reading frames (ORFs). ORF1 encodes the non structural (NS) polyprotein and the major capsid protein (VP1) while ORF2 encodes the putative basic minor capsid protein. Typical conserved amino acid motifs predict a gene order reminiscent of calicivirus genomes. Phylogenetic, pairwise homology, and distance analyses performed on complete genomic sequences and partial amino acid sequences from the NTPase, polymerase, and major capsid protein segregated the St-Valérien-like viruses in a unique cluster sharing a common root with the Tulane virus and the noroviruses. Based on the genomic analyses presented, the St-Valérien-like viruses are members of a new genus of Caliciviridae for which we propose the name Valovirus.