Metagenomic Identification of a Novel Zoonotic Gemykibivirus in a Diarrheic Pig in China

Gemykibiviruses are circular, replication-associated protein (REP) encoding single-stranded DNA (ssDNA) viruses classified within the genus Gemykibivirus of the family Genomoviridae. In recent years, several gemykibiviruses have been detected in humans presenting with clinical symptoms, such as encephalitis, respiratory illness, sepsis, pericarditis, diarrhea, and multiple sclerosis. However, the presence of gemykibiviruses in other animal hosts, as well as the evolution of the Gemykibivirus genus, remains poorly understood. In this study, we identified a novel gemykibivirus from a diarrheic pig in China using metagenomic sequencing, which we designated as pGkV. The pGkV genome comprises 2200 nucleotides and encodes two key proteins as follows: the capsid-associated protein (CAP) and the REP. Phylogenetic analyses revealed that pGkV clusters within the zoonotic gemykibivirus (ZooGkV) clade, which includes nearly all gemykibivirus species recently identified in humans. Mutation and haplotype analyses revealed that pGkV is closely related to an avian gemykibivirus, while its CAP and REP proteins are identical to those of a human gemykibivirus, underscoring its potential zoonotic capability. Furthermore, recombination signals were detected among Zoo-GkVs, suggesting that recombination may contribute to the emergence of novel gemykibivirus strains. The identification of pGkV provides new insights into the evolution and cross-species transmission of gemykibiviruses.