Coinfection caused by various genotypes of porcine epidemic diarrhea virus (PEDV) is a new disease situation. We previously reported the coexistence of PEDV strains containing different ORF3 genotypes in China. In this study, the PEDV strains 17GXCZ-1ORF3d and 17GXCZ-1ORF3c were isolated and plaque-purified from the same piglet, which had a natural large deletion at the 172–554 bp position of the ORF3 gene or possessed a complete ORF3 gene, respectively. Meanwhile, 17GXCZ-1ORF3d had >99% nt identity with 17GXCZ-1ORF3c in the 5′UTR, ORF1a/1b, S, E, M, N and 3′UTR regions but only demonstrated low nucleotide identities (80.5%) in the ORF3 gene. To elucidate the pathogenicity, 7-day-old piglets were infected. Piglets infected with these two PEDV strains exhibited severe clinical signs and shed the virus at the highest level within 96 hpi. Compared with the piglets inoculated with the 17GXCZ-1ORF3c strain, the piglets inoculated with the 17GXCZ-1ORF3d strain had higher mortality rates (75% vs. 50%), an earlier onset of clinical signs with a significantly higher diarrhea score, lower VH:CD ratios and a higher percentage of PEDV-positive enterocytes. This study is the first to report PEDV coinfections with different ORF3 genotypes, and a PEDV strain with a large deletion in the ORF3 gene might have the advantage of a potential genetic marker, which would be useful during vaccine development.

Newcastle disease is an important poultry disease that also affects Columbiform birds. The viruses adapted to pigeons and doves are referred to as pigeon paramyxoviruses 1 (PPMV-1). PPMV-1 are frequently isolated from pigeons worldwide and have the potential to cause disease in chickens. The complete genomes of 18 PPMV-1 isolated in China during 2012–2018 were sequenced by next-generation sequencing (NGS). Comprehensive phylogenetic analyses showed that five of the viruses belong to sub-genotype VI1.2.1.1.2.1 and 13 isolates belong to sub-genotype VI.2.1.1.2.2. The results demonstrate that these sub-genotypes have been predominant in China during the last decade. The viruses of these sub-genotypes have been independently maintained and continuously evolved for over 20 years, and differ significantly from those causing outbreaks worldwide during the 1980s to 2010s. The viral reservoir remains unknown and possibilities of the viruses being maintained in both pigeon farms and wild bird populations are viable. In vivo characterization of the isolates’ pathogenicity estimated mean death times between 62 and 114 h and intracerebral pathogenicity indices between 0.00 and 0.63. Cross-reactivity testing showed minor antigenic differences between the studied viruses and the genotype II LaSota vaccine. These data will facilitate PPMV-1 epidemiology studies, vaccine development, and control of Newcastle disease in pigeons and poultry.

Porcine Teschovirus (PTV) is a highly prevalent pathogen within swine populations, primarily associated with encephalitis, diarrhea, pneumonia, and reproductive disorders in pigs, thereby posing a significant threat to the sustainable development of the pig farming industry. In this study, a novel strain of PTV was isolated from the feces of a pig exhibiting symptoms of diarrhea, utilizing PK-15 cell lines. The structural integrity of the viral particles was confirmed via transmission electron microscopy, and the viral growth kinetics and characteristics were evaluated in PK-15 cells. High-throughput sequencing facilitated the acquisition of the complete viral genome, and subsequent phylogenetic analysis and full-genome alignment identified the strain as belonging to the PTV 2 genotype. Further investigation revealed that infection with the PTV-GXLZ2024 strain induces phosphorylation of the eukaryotic translation initiation factor 2α (eIF2α) in PK-15 cells, indicating activation of the unfolded protein response (UPR) through the PERK pathway, with minimal involvement of the IRE1 or ATF6 pathways. Notably, ATF4 protein expression was progressively downregulated throughout the infection, while downstream CHOP protein levels remained unchanged, indicating an incomplete UPR induced by PTV-GXLZ2024. Furthermore, PERK knockdown was found to enhance the replication of PTV-GXLZ2024. This study provides critical insights into the molecular mechanisms underlying PTV pathogenesis and establishes a foundation for future research into its evolutionary dynamics and interactions with host organisms.

Porcine rotavirus (PoRV) has emerged as a primary pathogen causing viral diarrhea in pigs, resulting in significant economic losses. This study was conducted to systematically characterize the epidemiology and genotypic characteristics of PoRV in Guangxi, China. A total of 870 diarrheic pig samples were collected from Guangxi during 2020–2025. The qRT-PCR results indicated an overall PoRV-positive rate of 41.38% (360/870), and the annual positivity rate showed an overall upward trend. The genetic evolutionary analysis of the VP4, VP6, and VP7 genes indicated that PoRV predominantly belonged to the A group and the predominant P genotype observed was P[13] (76.83%), while the G genotypes were G5 (36.56%) and G9 (33.33%). The most prevalent genotype combinations were G9P[13]I5 and G5P[13]I5. CH-GXGL-PoRV-3151-2021, a PoRV strain isolated from positive samples, was identified via RT-PCR, qRT-PCR, whole-genome sequencing, and IFA. This strain was assigned the 11-segment genotype constellation G9-P[23]-I5-R1-C1-M1-A8-N1-T1-E1-H1 based on whole-genome sequencing. NSP1 and NSP2 showed high similarity to human rotavirus strains, whereas VP1–VP4, VP6, VP7, and NSP3–NSP5 showed high similarity to porcine rotavirus strains. This study indicates the widespread circulation of PoRV in Guangxi, with multiple G genotypes, including G9, G5, G4, G3, G2, and G26, being detected. The isolated G9P[23]I5 strain exhibits the same genotype as the strains that have become increasingly prevalent in recent years. This strain may represent a possible reassortant between porcine and human rotaviruses. This study offers significant insights into the epidemiology of PoRV and the prevalent genotypes in Guangxi, thereby supporting the development of targeted prevention strategies and novel vaccines.

Enterovirus G (EV-G) is an important enteric pathogen widely circulating in swine populations and is characterized by considerable genetic diversity and recombination potential. In recent years, recombinant EV-G strains carrying exogenous papain-like cysteine protease (PLCP) gene insertions have been increasingly reported; however, their genotype distribution and molecular characteristics in major pig-producing regions remain poorly understood. In this study, 356 clinical samples collected from Guangxi, southern China, between 2020 and 2025 were screened for EV-G, and 13 representative strains were subjected to whole-genome sequencing and sequence analysis. The overall EV-G positivity rate in Guangxi was 20.51% (73/356). Phylogenetic analysis showed that the 13 Guangxi EV-G strains were mainly classified into three genotypes, G1, G2, and G8, with G1 being the predominant genotype. Notably, PLCP gene insertions of 573–642 nt were identified at the 2C/3A junction in seven strains belonging to three distinct genotypes, G1, G2, and G8, demonstrating the cross-genotype distribution of PLCP insertions within a single geographic region. Phylogenetic analysis of the PLCP sequences demonstrated that all Guangxi-derived PLCP sequences clustered within the EV-G-PLCP clade and were clearly separated from the torovirus PLCP clade. Recombination analysis retained three potential recombination events with clearer combined support from RDP4 and SimPlot analyses, involving Guangxi strains GX3008, GX3022, and GX4292. Selection pressure analysis showed that the VP1 gene was overall under negative selection. Collectively, these findings demonstrate the co-circulation of multiple EV-G genotypes, the cross-genotype distribution of PLCP insertions, and the presence of potential recombination events in Guangxi. This study provides new evidence for understanding the genetic diversity, genomic plasticity, and regional molecular characteristics of EV-G, and also provides an important basis for future PLCP-related functional studies and continued EV-G surveillance.