First detection and characterization of Bovine parvovirus 2 and Bopivirus A in a neonatal calf with diarrhea in Iran through metagenomic RNA-seq.

Bovine parvovirus 2 (BoPV-2), officially classified as Ungulate copiparvovirus 1 by the ICTV, and Bopivirus A, a recently recognized picornavirus, are poorly characterized viruses sporadically reported in cattle worldwide. Here, we describe the first detection of BoPV-2 and Bopivirus A in Iran-and potentially the Middle East-through RNA-seq analysis of a diarrheic neonatal calf. Four BoPV-2 contigs (82-85% nucleotide identity; 91-100% amino acid identity) were identified, clustering within the Ungulate copiparvovirus 1 clade, while the Bopivirus sequence grouped with Chinese strains BoP8 and BoP9, supporting its classification within lineage A2. Both viruses were confirmed by phylogenetic analyses based on partial RdRp (3Dpol) and ORF regions. The concurrent detection of these viruses in a single calf suggests possible co-circulation in early-life gastrointestinal infections, highlighting the complexity of the calf virome. Notably, RNA detection of the DNA virus BoPV-2 in fecal material indicates potential intestinal replication and shedding, raising questions about its transmission dynamics. These findings expand the geographic range of BoPV-2 and Bopivirus A and underscore the value of metagenomic surveillance for uncovering under-characterized viral agents contributing to neonatal calf diarrhea.