Aug 2026· Virulence· Vol 17· 0 citations· 30 references
Medicine
TL;DR
The evidence of PRRSV 1 and PRRSV 2 concurrent circulation in the single sow farm in China is provided, which highlights the ongoing evolution of both Chinese PRRSV species and underscores the urgent need for enhanced surveillance and updated control strategies.
Abstract
ABSTRACT Porcine reproductive and respiratory syndrome virus (PRRSV) remains a major threat to the swine industry globally. In China, the dominance of PRRSV 2 is complicated by the emergence and co-circulation of genetically distinct strains, including a rising number of PRRSV 1 cases. In this study, the concurrent circulation of PRRSV 1 and PRRSV 2 was identified, and two novel strains AHB1 and Chah2022 were isolated from a single sow farm experiencing reproductive failure. Genetic analysis revealed that AHB1 shared 81.6%-83.6% nucleotide identity with subtype 1 strains of PRRSV 1 and clustered within a new evolutionary branch, characterized by a continuous 54-amino acid deletion in nsp2 and 1-amino acid deletion in the GP3-GP4 overlap region. In contrast, Chah2022 was identified as a recombinant virus with NADC30-like (lineage 1) and highly pathogenic PRRSV-like (lineage 8) strains. Pathogenicity assessment in nursery piglet model demonstrated that both AHB1 and Chah2022 had established systemic and persistent infections, although with low or moderate clinical signs. Our findings provide the evidence of PRRSV 1 and PRRSV 2 concurrent circulation in the single sow farm in China, which highlights the ongoing evolution of both Chinese PRRSV species and underscores the urgent need for enhanced surveillance and updated control strategies.
Porcine reproductive and respiratory syndrome virus (PRRSV) poses a significant threat to the global swine industry. In this study, the genetic diversity, evolutionary dynamics, and key antigenic characteristics of the PRRSV-1 GP5 gene in China were systematically investigated. A total of 114 Chinese PRRSV-1 GP5 sequences, isolated between 1999 and 2024, were analyzed alongside global reference strains. The nucleotide and amino acid sequence similarities ranged from 60.03% to 100% and from 48.72% to 100%, respectively, with mutation and deletion hotspots concentrated in the N-terminal hypervariable region. Phylogenetic analysis further classified the Chinese strains into four major lineages: Amervac-like, BJEU06-1-like, HKEU16-like, and NMEU09-1-like. Notably, a preliminary phylogenetic observation indicated that several recent Chinese PRRSV-1 isolates clustered topologically close to PRRSV-2 strains. However, as this finding is based solely on a single-gene tree and has not been validated by formal tests for convergent evolution, homoplasy, or selection pressure, it should be interpreted with caution and warrants further investigation using whole-genome data. A Bayesian evolutionary analysis estimated the evolutionary rate at 1.94 × 10−3 substitutions per site per year and the time to the most recent common ancestor at approximately 1910. No statistically significant recombination events were identified within the GP5 gene. The transmembrane topology of GP5 was highly conserved, whereas B-cell linear epitopes were enriched in the N-terminal extracellular region. This study establishes a useful molecular foundation for understanding PRRSV-1 evolution in China and offers valuable insights for the development of broad-spectrum vaccines and effective control strategies.
Fang Liang, Tian-Yuan Nie, Pei-Xiu Lin et al.· Microorganisms· 0 citations
Porcine reproductive and respiratory syndrome (PRRS) causes severe reproductive losses in pregnant sows and piglets, resulting in substantial economic impact on the swine industry worldwide. However, due to the significant genetic diversity and rapid evolutionary changes of the pathogen, continuous surveillance and detailed genetic analysis of circulating strains are essential. The current study aimed to evaluate the genetic diversity of the hypervariable (HV) region of non-structural protein 2 (nsp2) among North American PRRSV strains isolated from swine farms in Vietnam. Phylogenetic analysis and multiple sequence alignment were conducted to determine subtype classification and assess genetic variability. A total of 48 field isolates were obtained, of which 12.5% belonged to classical NA-PRRSV, 16.6% to NADC30-like and 70.9% to HP-PRRSV, primarily distributed across sublineages 1.4, 5.1, 8.7 and 8.9. Amino acid comparisons found multiple insertions, deletions and substitutions at various positions within the hypervariable region of nsp2. The study revealed substantial genetic variation in the HV region of nsp2 among NA-PRRSV field strains, largely associated with recombination and immune escape. These findings highlight epidemiological risks to vaccine efficacy and underscore the need for continuous molecular surveillance to support effective PRRSV control in Vietnam.
T. Le-thi, Van-Anh Huynh-Nguyen, Tram-Anh Bui-Nguyen et al.· Acta Veterinaria Hungarica· 0 citations
Porcine reproductive and respiratory syndrome virus (PRRSV) continues to pose a major challenge to swine production in Vietnam because of its rapid evolution and genetic diversity. Here, we analyzed 69 PRRSV-positive samples collected from 20 provinces in Vietnam between 2021 and 2026 using ORF5 gene sequencing to characterize the genetic diversity of circulating strains. Phylogenetic analysis demonstrated the co-circulation of multiple PRRSV-2 lineages (L1, L3, L5, L8, and L10), together with a limited presence of PRRSV-1, indicating a genetically diverse PRRSV population within the analyzed diagnostic samples. Among the PRRSV-2 strains, lineage 8 (L8), particularly sub-lineage L8E, was the most frequently detected, whereas lineage 10 (L10) accounted for 24.6% of the sequenced isolates and was detected only in samples collected from 2023 onwards. Independent maximum-likelihood phylogenetic and pairwise ORF5 distance analyses showed that the Vietnamese L10 strains formed a distinct monophyletic cluster within lineage 10. Analysis of the GP5 protein identified amino acid variation in previously described antigenic regions, providing descriptive information on the genetic diversity of circulating Vietnamese PRRSV strains. Collectively, these findings provide updated insights into the molecular epidemiology of PRRSV in Vietnam and highlight the value of continuous molecular surveillance for monitoring the emergence and distribution of PRRSV lineages.
Mai Tuan Anh Nguyen, Thi Chau Giang Tran, Thi Thu Hang Vu et al.· The Veterinary Journal· 0 citations
Abstract Porcine reproductive and respiratory syndrome virus (PRRSV) is a major pathogen that poses a serious threat to the global pig industry. North Central Vietnam, comprising six provinces, is one of the country’s largest pig-breeding regions; however, the information of molecular characterization of this virus circulating in this area have been limited. To address this gap, 130 samples were collected from these provinces between 2023 and 2024. The results showed a PRRSV-positive rate of 23.07% (30/130). Molecular characterizations of PRRSV were further analyzed based on sequences of the ORF5 and NSP2 hypervariable regions (HVRs), in comparison with reference strains from Vietnam and other countries downloaded from GenBank (NCBI). Phylogenetic analysis revealed that the sequenced strains belonged to PRRSV-2 (lineages 1, 5, and 8). Specifically, 28 PRRSV-2 strains were selected for ORF5 analysis and classified into sublineage 8.7 (HP-PRRSV), sub-lineage 5.1 (classical PRRSV), and the newly identified sub-lineage 1.8 (NADC30-like). The NSP2 HVRs of the identified strains showed amino acid identities ranging from 38.63% to 100%, while ORF5 identities ranged from 80.3% to 100%. Sequence analysis of ORF5 indicated that GP5 mutations were mainly concentrated in HVR1, HVR2, and virulence-associated sites. In summary, the detection of NADC30-like PRRSV for the first time in Vietnam is important, indicating that this HP-PRRSV and classical PRRSV strains reported previously are currently co-circulating among the pig population in North Central Vietnam. Additionally, these findings suggest that PRRSV strains in Vietnam are undergoing substantial genomic divergence.
A. D. Truong, Thi Thanh Ha Tran, Van Hiep Dang et al.· Acta Veterinaria· 0 citations
This study highlights the S32 site in the PRRSV GP5 protein as an important factor influencing virus propagation, neutralization, cell tropism and pathogenicity in piglets, and suggests that targeting this residue could lead to the development of more effective PRRSV vaccines.
Xing-Dong Zhou, Xiao-Hui Zhang, E. Kan et al.· Virulence· 0 citations
Background/Objectives: Porcine reproductive and respiratory syndrome virus type 2 (PRRSV-2) remains the predominant genotype circulating in China and continues to evolve through mutation and recombination. Although NSP1 is recognized as a multifunctional nonstructural protein involved in immune regulation, its genetic variation among PRRSV-2 strains circulating in China has not been comprehensively characterized. Methods: In this study, 425 complete NSP1 sequences, primarily representing PRRSV-2 strains circulating in China, were analyzed, and 48 representative strains were selected for pairwise percent-identity visualization. Results: Pairwise nucleotide identity among the 48 representative strains was found to range from 80.1% to 100.0%, with the lowest value detected between AHBZ and SD-R, whereas pairwise amino-acid identity ranged from 79.6% to 100.0%, with the lowest value detected between AHBZ and HNhx. Among the 425 aligned amino-acid sequences, 290 variable sites and 93 completely conserved sites were identified. The broad-lineage distribution was composed of Lineage 1 (n = 79), Lineage 3 (n = 4), Lineage 5 (n = 21), and Lineage 8 (n = 321). A global FEL dN/dS of approximately 0.2979 was estimated from 379 non-recombinant unique haplotypes, and seven high-confidence candidate positively selected sites—42, 239, 255, 302, 367, 370, and 378—were supported by MEME, FEL, and FUBAR. A descriptive lineage-biased pattern concentrated in Lineage 5 was observed for NSP1β Val19Ile, corresponding to full-length NSP1 V199I. Eight candidate recombination events were identified using RDP4, and six representative events were further examined using SimPlot. Conclusions: Overall, NSP1 was found to be under predominant purifying selection while retaining localized variability, lineage-biased residue patterns, and candidate recombination signals that should be interpreted cautiously and validated experimentally.
Tian-Yuan Nie, Jiaman Li, Si-Qi Ye et al.· Genes· 0 citations
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