Epidemiological and evolutionary analysis of canine circovirus from 1996 to 2023.

BACKGROUND: Canine circovirus (CanineCV), a non-enveloped virus with a circular DNA genome, has been identified in various avian and mammalian species, including domestic and wild canids. This study aimed to comprehensively analyze the prevalence of CanineCV across diverse animal species in 11 provinces of China. RESULTS: A total of 1,666 serum samples were collected, revealing a 5.82% prevalence of CanineCV in dogs, with the highest rates being observed in southern and eastern China. Phylogenetic analysis of 266 global CanineCV genomes sourced from the NCBI identified six distinct genotypes, elucidating the complex dynamics of their evolution. Evidence suggested a potential bat origin for CanineCV, with positive selection and high rates of evolution being observed. Recombination analysis revealed dynamic genetic exchange, highlighting the intricate nature of CanineCV evolution. Mutational analysis identified key amino acid substitutions likely to influence the virus's adaptation. Additionally, glycosylation, palmitoylation, and SUMOylation sites were predicted, shedding light on crucial functional properties of the virus. CONCLUSIONS: This study provides a global perspective on the origin, genetic diversity, and evolutionary dynamics of CanineCV. Understanding these factors is crucial for elucidating its epidemiology and potential health risks.

3Cpro of foot-and-mouth disease virus antagonizes the interferon signaling pathway by blocking STAT1/STAT2 nuclear translocation.

UNLABELLED: Foot-and-mouth disease virus (FMDV) causes a highly contagious, debilitating disease in cloven-hoofed animals with devastating economic consequences. To survive in the host, FMDV has evolved to antagonize the host type I interferon (IFN) response. Previous studies have reported that the leader proteinase (L(pro)) and 3C(pro) of FMDV are involved in the inhibition of type I IFN production. However, whether the proteins of FMDV can inhibit type I IFN signaling is less well understood. In this study, we first found that 3C(pro) of FMDV functioned to interfere with the JAK-STAT signaling pathway. Expression of 3C(pro) significantly reduced the transcript levels of IFN-stimulated genes (ISGs) and IFN-stimulated response element (ISRE) promoter activity. The protein level, tyrosine phosphorylation of STAT1 and STAT2, and their heterodimerization were not affected. However, the nuclear translocation of STAT1/STAT2 was blocked by the 3C(pro) protein. Further mechanistic studies demonstrated that 3C(pro) induced proteasome- and caspase-independent protein degradation of karyopherin α1 (KPNA1), the nuclear localization signal receptor for tyrosine-phosphorylated STAT1, but not karyopherin α2, α3, or α4. Finally, we showed that the protease activity of 3C(pro) contributed to the degradation of KPNA1 and thus blocked STAT1/STAT2 nuclear translocation. Taken together, results of our experiments describe for the first time a novel mechanism by which FMDV evolves to inhibit IFN signaling and counteract host innate antiviral responses. IMPORTANCE: We show that 3C(pro) of FMDV antagonizes the JAK-STAT signaling pathway by blocking STAT1/STAT2 nuclear translocation. Furthermore, 3C(pro) induces KPNA1 degradation, which is independent of proteasome and caspase pathways. The protease activity of 3C(pro) contributes to the degradation of KPNA1 and governs the ability of 3C(pro) to inhibit the JAK-STAT signaling pathway. This study uncovers a novel mechanism evolved by FMDV to antagonize host innate immune responses.

Genetic characterization of Sus scrofa papillomavirus type 1 from domestic pigs in Guangxi Province, China.

Sus scrofa papillomatosis (SsP) is a tumour caused by Sus scrofa papillomaviruses (SsPVs). To investigate the presence of SsPVs in China, 354 domestic pig skin samples collected from Guangxi Province were examined for SsPV DNA by PCR. Three SsPV1s (GX12, GX14, and GX18) were identified with a prevalence of 0.847% (3/354). Sequence analysis showed that L1 of SsPV1/GX12 and SsPV1/GX14 had 99.7% and 99.6% nucleotide identify with the reference SsPV1a, respectively. Phylogenetic and evolutionary analyses showed that SsPV1/GX12 and SsPV1/14 clustered into SsPV1a and that SsPV1/GX18 clustered into SsPV1b. Compared with other SsPV L1 and L2 proteins, we found that the SsPV1/GX18 and SsPV1b strains shared the same unique substitutions, and SsPV1/GX12, SsPV1/GX14, and SsPV1a shared almost identical amino acid sequences. This study reports the first detection of SsPV DNA in China based on whole genome information and provides a scientific basis for the development of SsPV pathogenic biology, epidemiology, and prevention, as well as control technology research.

The detection of canine circovirus in Guangxi, China.

Since the first description of canine circovirus (CanineCV)-associated infection, there have been several reports on the distribution of the disease in worldwide. To investigate the prevalence and genetic diversity of CanineCV in China, we conducted PCR screening of 1226 dog serum samples collected from different regions in mainland China between 2014 and 2016. CanineCV DNA was found in 81/926 serum samples from Guangxi Province. Furthermore, 25 full-length genomes of CanineCV from positive samples were sequenced and compared with CanineCV sequences in the GenBank database. Pairwise analysis showed that the determined genome sequences shared 84.9%-100% identity among themselves and 81.4%-90.5% with the other 28 sequences. Phylogenetic analysis revealed that the 52 viral genome sequences could be divided into two genotypes (CanineCV-1 and CanineCV-2). Analysis of the amino acid sequences of the capsid protein revealed the existence of 9 major regions of variation. The present work contributes to the understanding of CanineCV molecular epidemiology.