Identification of a novel Picornavirales virus distantly related to posavirus in swine feces.

De novo assembly of metagenomic sequencing reads from feces from a clinically normal pig identified two approximately 9 kb contigs which each consisted of a single large open reading frame. While one contig encoded a predicted 2990 amino acid protein with 83 % identity to the recently described posavirus 1, the other contig encoded a predicted 2942 amino acid protein with only 25 % identity limited to the genomic region encoding the RNA-dependent RNA polymerase (RdRp) of posavirus 2. Besides RdRp, search of the conserved domain database identified domains associated with picornavirus capsid proteins but failed to identify picornaviral helicase and proteinase domains. In addition, a domain representing a family of Mycoplasma and Ureaplasma immunoglobulin-blocking virulence proteins was identified near the 5'-terminus. Phylogenetic analysis found a distant relationship between this novel virus, provisionally named posavirus 3, to the unclassified posaviruses and fisavirus which are proposed to represent different genera in a novel family of the Picornavirales.