Evolutionary dynamics and codon bias analysis of canine circovirus: Insights into global spread and host adaptability.

Abstract

Circoviruses are relatively new pathogens, and new circoviruses are constantly being discovered, with a growing range of hosts. Recently, canine circovirus (CanineCV) was reported to infect cats and badgers, further broadening its host range. Previous studies on the evolution and dissemination of CanineCV were fragmented. Here, when conducting a metagenomic analysis of shelter dogs, we identified a canine circovirus positivity rate of 32.4% and obtained three new viral strains. Furthermore, we integrated publicly available viral sequences and employed multiple bioinformatic software tools to analyze the evolution, codon usage bias, recombination, origin, spatiotemporal distribution and host adaptability of CanineCV. In this study, CanineCV could be divided into five distinct phylogenetic clades, named as China-I, China-II, Cosmopolitan, EA, and SEA clades. The extensive inter-clade recombination was observed, which plays an important role in viral evolution, while based on existing sequence information, CanineCV most likely originated in Norway from Vulpes vulpes in 1950.7. Notably, CanineCV exhibits greater adaptability to human hosts compared to previously documented hosts, as indicated by host adaptability indices, suggesting that this virus may possess zoonotic potential. In summary, our study elucidates the phylogeography and evolutionary dynamics of CanineCV and underscores the importance of investigating its potential for zoonotic transmission.