A G4P[13] Porcine Rotavirus a Strain with Genomic Features Suggestive of Reassortment: Isolation, Genomic Characterization, and Pathogenicity in Piglets

Porcine rotavirus A (PoRVA) is an important cause of diarrhea in neonatal piglets, resulting in significant economic losses in the swine industry. In this study, a PoRVA strain, designated QY, was isolated from diarrheic piglets and systematically characterized. The virus was propagated in MA104 cells and identified by immunofluorescence assay and transmission electron microscopy, showing typical cytopathic effects and spherical particles of approximately 70 nm. Whole-genome sequencing and phylogenetic analysis revealed that QY was a G4P[13] strain with a genotype constellation of G4–P[13]–I1–C1–M1–R1–A8–N1–T1–E1–H1. Several genome segments showed close phylogenetic relationships with human- or bat-associated RVA strains, a pattern consistent with a possible reassortment history of QY. Experimental infection showed that QY caused watery diarrhea, intestinal lesions, and viral shedding in neonatal piglets under the experimental conditions used in this study. High viral loads were detected in small intestinal tissues, accompanied by villous atrophy and epithelial degeneration. These findings provide new insights into the genetic diversity and evolution of PoRVA and further characterize the pathogenicity of the G4P[13] QY strain in neonatal piglets.