Identification and biochemical characterization of a novel porcine circovirus associated with porcine respiratory and diarrheal diseases

作者：Xianhui Liu, Lin Wang, Xinming Zhang, Yilong Liu, Yixuan Li, Zan Li, Zhi Geng, Leyi Zhang, Yanling Liu, Pengshuai Liang, Yuhui Dong, Zheng Xu, H. Zhang, Changxu Song · 发表于：Microbiology Spectrum · 年份：2025 · DOI：10.1128/spectrum.02299-25 · 被引用次数：15 · 研究领域：Animal Virus Infections Studies、Virus-based gene therapy research、Viral Infections and Immunology Research

ABSTRACT Eukaryotic circular Rep encoding single-stranded DNA (CRESS DNA) viruses exhibit high genomic diversity. Four species of circoviruses within the genus Circovirus have been identified in pigs, including the non-pathogenic porcine circovirus type 1 (PCV1), and the pathogenic PCV2, PCV3, and PCV4. In this study, a novel single circular DNA virus was identified in pigs suffering from respiratory, diarrheal, and reproductive failure diseases. The viral Rep and Cap showed low amino acid sequence identities to the four PCV species, with the highest identity of 26.2% to PCV2 Rep and 20.8% to PCV4 Cap. The classification of CRESS DNA viruses primarily relies on Rep, and biochemical analyses of the viral Rep confirm its classification as a CRESS DNA virus. Thus, it was tentatively named porcine circovirus type 5 (PCV5). This tentative designation reflects its host and genomic organization; however, phylogenetic analysis indicates that it clusters outside the family Circoviridae and is most closely related to the fur seal faces-associated circular DNA virus (FSfaCV). The positive detection rate for PCV5 in tested samples was 54.4% (294 out of 540), with 24.3% (17 out of 70) of pig farms in China testing positive for the virus. A close correlation between the copy number of PCV5 and the severity of infectious diseases was observed. Moreover, a PCV5 virus-like particles (VLPs)-based enzyme-linked immunosorbent assay, which was developed, also elucidated that PCV5 has been circula...