Detection and characterization of bopiviruses in domestic and wild ruminants

Highly divergent picornaviruses (PVs) classified in the genus Bopivirus have been recently discovered on faecal samples from sheep and goats in Hungary and from fallow and red deer in Australia. In this study, we investigated the epidemiology of these novel viruses in domestic and wild ruminants from Northwestern Italian Alps by testing archival faecal samples collected from 128 sheep, 167 goats, 61 red deer (Cervus elaphus), 77 roe deer (Capreolus capreolus), 43 chamois (Rupicapra rupicapra) and 32 Alpine ibex (Capra ibex). Bopivirus RNA was detected in a total of 19 animals, including 14 sheep (10.9%), 2 red deer (3.3%), 1 roe deer (1.3%), 1 chamois (2.3 %) and 1 Alpine ibex (3.3 %), but not in goats. Upon sequence analysis of the 3D(RdRp) region, the sequences generated from chamois, roe deer, Alpine ibex and ovine faecal samples showed the highest nucleotide identity (96.8-100%) to bopiviruses detected in goats and sheep from Hungarian farms, whereas strains found in red deer displayed the closest relatedness (90.8%-91.2%) to bopiviruses identified in fallow and red deer in Australia. The nearly complete genome sequence of strains 12/2020/ITA (ON497046) and 14-73/2020/ITA (ON497047) detected in an Alpine ibex and in a sheep, respectively, was determined by combining a modified 3'-RACE protocol with Oxford Nanopore Technologies sequencing platform. On phylogenetic analysis based on the complete polyprotein, both strains segregated into the candidate species Bopivirus B along with ovine and caprine strains detected in Hungary (90.0-94.6% nucleotide and 94.6-98.0% amino acid identities). The findings of this study expand the host range of these novel viruses and hint to a possible virus circulation between domestic ruminants and wild animals.