Metagenomic identification and sequence analysis of a Teschovirus A-related virus in porcine feces in Japan, 2014-2016.

Porcine Teschoviruses (PTVs) are associated with polioencephalomyelitis and various diseases, including reproductive and gastrointestinal disorders, of pigs and wild boars, and are also detected in the feces of healthy pigs. The genus Teschovirus contains a single species Teschovirus A that currently includes 13 serotypes. In the present study, we identified novel PTVs that are distantly related to Teschovirus A and were found in fecal samples of pigs with or without diarrhea in Japan. Phylogenetic analysis of amino acid (aa) sequences of the complete coding region revealed that these newly identified viruses did not cluster with any strains of PTVs or other strains within the picornavirus supergroup 1, suggesting that the viruses may not belong to Teschovirus A or any genus of the family Picornaviridae. These novel PTVs share a type IV internal ribosomal entry site and conserved characteristic motifs in the coding region, yet exhibit 62.2-79.0%, 86.6-92.8%, 77.1-81.0%, and 84.3-86.7% aa identities to PTV strains in P1, 2C, 3C, and 3D regions, respectively. In contrast, PTV 1-13 strains of the Teschovirus A share 76.5-92.1%, 88.1-99.7%, 93.2-100%, and 95.8-100% aa identities in the P1, 2C, 3C, and 3D, respectively, within the species. These data imply that the newly identified viruses belong to teschoviruses, and may represent a novel species in the genus Teschovirus.