εταιρικά νέα για Front Vet Sci | New Human-Porcine Reassortant G9P[23] Porcine Rotavirus Emerges in Central China[23]

On December 19, 2025, a joint research team from Nanyang Normal University and the Harbin Veterinary Research Institute of the Chinese Academy of Agricultural Sciences published a new study on porcine rotavirus in the journal *Frontiers in Veterinary Science*.

This study successfully isolated and sequenced the entire genome of a newly emerging G9P[23] porcine rotavirus in central China, named HN240916, and revealed the presence of cross-species gene recombination between pigs and humans in its genome, providing important scientific evidence for the prevention and control of porcine rotavirus and vaccine development in my country.

Research Highlights

· First Isolation and Identification: G9P[23] porcine rotavirus was successfully isolated from diarrheal piglets in a large-scale pig farm in Henan Province and systematically identified.

· Whole Genome Analysis: The whole genome sequence of this strain was reported for the first time, with the genotype G9-P[23]-I5-R1-C1-M1-A8-N1-T1-E1-H1. • Evidence of cross-species recombination: The NSP3 and NSP5 genes of this strain are highly homologous to human rotavirus, suggesting that it is a porcine-human recombinant virus.

• Antigenic variation analysis: Multiple amino acid variations exist in the key antigenic proteins VP7 and VP4, which may affect the protective efficacy of existing vaccines.

• Epidemiological significance: This study fills a gap in the systematic surveillance of porcine rotavirus in central China, highlighting the need to strengthen the surveillance of novel recombinant strains.

Although G9P[23] strains have been reported in my country previously, whole-genome information is insufficient, especially systematic studies in the central region.

This study investigates a case of piglet diarrhea in Henan Province against this backdrop, successfully isolating a representative G9P[23] strain and completing a deep whole-genome analysis.

Introduction

Rotaviruses are the main pathogens causing viral gastroenteritis in infants and young animals, bringing dual pressures to public health and the livestock economy. Porcine rotavirus is particularly prone to causing severe diarrhea in piglets, often co-infecting with other viruses, exacerbating the condition and causing economic losses. In recent years, the global spread of G9 porcine rotavirus has been increasing, and it is also prone to cross-species transmission and gene recombination, becoming a new focus of zoonotic disease prevention and control.

Research Results

1. Virus Isolation and Identification:

A PoRV strain, HN240916, was successfully isolated through MA104 cell culture. Verification by RT-PCR, indirect immunofluorescence (IFA), and transmission electron microscopy (TEM) confirmed that this strain exhibits typical rotavirus morphology (approximately 70 nm in diameter, with a rotavirus-like structure). It induced significant cytopathic effects (CPE) in cells and maintained stable replication capacity after 20 consecutive passages.

Figure 1. Isolation, identification, and growth curve of HN240916 virus.

2. Genomic characteristics:

Whole-genome sequencing revealed that nine of the eleven gene fragments in strain HN240916, including VP1-VP4, VP6, NSP1-NSP2, and NSP4, were highly homologous to porcine rotavirus. The NSP3 gene showed 96.68% homology with the 2001 Chinese human rotavirus strain LL4260, and the NSP5 gene showed 98.65% homology with the 2008 human rotavirus strain E931, confirming it as a porcine-human cross-species recombinant strain.

Table 1. Highest nucleotide sequence homology between HN240916 and other known RV strains.

3. Phylogenetic analysis:

The VP7 gene clustered in the G9 genotype porcine strain branch, and was most closely related to the 2023 Chinese SC/06041 strain; the VP4 gene belonged to the P[23] genotype, and was highly similar to the 2023 Chinese HeN/10437 strain; the NSP3 and NSP5 genes clustered in the human rotavirus T1 and H1 genotype branches, respectively, further confirming the occurrence of recombination events.

Figure 2. Phylogenetic tree based on VP7 (A), VP4 (B), NSP3 (C), NSP5 (D), VP1–VP3, VP6, NSP1–NSP2, and NSP4 (E).

4. Epitope Variations:

Partial amino acid variations exist in the 7-1 and 7-2 epitopes of the VP7 protein, and multiple mutations occur at sites in the VP5 and VP8 domains of the VP4 protein. These variations may affect the neutralizing antibody efficacy induced by existing vaccines.

Figure 3. Comparison of VP7 and VP4 (VP5* and VP8*) antigenic epitopes of HN240916-P5 strain with other reference PoRV strains.

Summary

This study not only successfully isolated and systematically identified the first G9P[23] porcine rotavirus strain in central China, but also revealed its cross-species recombination characteristics and antigenic variation potential through whole-genome analysis. This provides important data support for molecular epidemiological research on porcine rotavirus in my country, and also provides a scientific basis for future vaccine development and prevention and control strategies.