Refining Lineage Classification and Updated RFLP Patterns of PRRSV‐2 Revealed Viral Spatiotemporal Distribution Characteristics in China in 1991–2023

Abstract

Porcine reproductive and respiratory syndrome virus (PRRSV) is a significant infectious disease impacting the global swine industry. Due to high frequency of viral mutation and recombination, PRRSV exhibits complex genetic diversity; however, its lineage classification, restriction fragment length polymorphism (RFLP) patterns, and spatiotemporal distribution have not been systematically analyzed in China. In this study, we sequenced PRRSV‐2 open reading frame (ORF)5 sequences from clinical samples ( n = 364) and retrieved all the available PRRSV‐2 ORF5 sequences in China in 1991–2023 from GenBank ( n = 5773). Systematically analysis revealed that PRRSV‐2 strains in China were classified into five lineages (L1, L3, L5, L8, and L9) and eight sublineages (L1A‐L1C, L5A, L5B, L8C, L8E, and L9B), the L8E and L1C PRRSV‐2 were widely distributed across almost all provinces in China, the L1C and L1A strains were increasing and gradually replacing L8 as dominant epidemic strains, and L1B PRRSV‐2 in China was analyzed for the first time. The L3 PRRSV‐2 has a trend of spreading gradually from the southern to the northern provinces, which needs to be paid attention to the monitoring and prevention of PRRSV‐2. Meanwhile, PRRSV‐2 strains in China were classified into 112 different RFLP patterns. RFLP 1‐4‐4 PRRSVs were detectable in China, which accounted for 12.71% of all Chinese PRRSV‐2 strains. Although they are different from the RFLP 1‐4‐4 L1C variant in the United States, it is necessary to enhance surveillance of the RFLP 1‐4‐4 L1C PRRSVs. These results contributed the understanding of genetic diversity and spatiotemporal distribution of PRRSV‐2 in China and provide important references for future PRRSV‐2 monitoring and control in China.

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