A novel parvovirus circulating in canine populations and sporadically detected in human oropharyngeal samples

ABSTRACT Most human pathogens, while originating from animals, have crossed species barriers to infect humans, often leading to outbreaks of new infectious diseases. Despite significant efforts, the mechanisms, timing, and locations of these emerging diseases remain largely uncertain. Here, using a viral metagenomic approach, we discovered a novel canine-associated parvovirus in human oropharyngeal secretions. Molecular screening revealed the presence of this parvovirus in different canine tissues, including 24 of 108 pharyngeal lymph node samples. Further molecular investigation showed that the virus was detected in the oropharyngeal secretions of pet dogs and in human samples that were not linked to these animals. This parvovirus was therefore named human-canine associated parvovirus 1 (HCAPV-1). Nine complete genomes of HCAPV-1 were acquired through next-generation sequencing, combining Sanger sequencing. Genomic and phylogenetic analyses indicate that these nine strains of HCAPV-1 belong to the genus Protoparvovirus and form a distinct clade, with their closest relatives being newlaviruses from foxes. Amino acid substitutions have been characterized in the capsid proteins of the variants of HCAPV-1, which potentially alter their infection patterns. Potential genomic recombination was also observed in HCAPV-1. Taken together, our findings reveal the presence of a novel parvovirus in both canine and human samples, highlighting the need to investigate its host range and transmission dynamics. IMPORTANCE This study identified a novel parvovirus, human-canine associated parvovirus 1 (HCAPV-1), which was detected in human oropharyngeal secretions and various canine tissues, suggesting that its host range may extend beyond a single species. Phylogenetic analysis revealed that HCAPV-1 forms a distinct clade within the genus Protoparvovirus , closely related to newlaviruses from foxes. Amino acid substitutions observed in the capsid proteins of HCAPV-1 variants indicate genetic divergence, warranting further investigation into their potential implications for host interactions. Recombination events may have contributed to its emergence. This finding highlights the importance of continued surveillance in settings where humans and companion animals coexist and underscores the need for further research to clarify the ecological and host-range characteristics of such viruses.