Objective: This study investigates the molecular epidemiology of orf virus (ORFV) in the Fujian province in 2024, with the goal of gaining insights that can enhance disease prevention and control strategies.
Methods: This experimental study was conducted from January 2024 through March 2024. The samples, showing suspected orf lesions, tested positive for ORFV via PCR. The ORFV059 (F1L) and ORFV011 (B2L) genes from these samples were cloned and sequenced.
Results: Analysis identified 3 ORFV strains: FJ-2401, FJ-2402, and FJ-2403. For the F1L gene, nucleotide sequence identity ranged from 95.7% to 99.6%, and amino acid identity ranged from 95.0% to 99.7% compared to the reference strain. These strains were closely related to others from Fujian, Guangzhou, and India but differed from the NZ2 reference strain, the German D1701 weak strain, and Chinese vaccine strains, which were in separate branches. For the B2L gene, nucleotide identity ranged from 97.4% to 99.6%, and amino acid identity ranged from 97.1% to 100%. Evolutionary analysis indicated potential recombination events with strains from Fujian, Jilin, and India. The B2L gene showed distinct branching from the German D1701 weak strain, Fujian GO strain, and Chinese vaccine strains, suggesting that current vaccines might be inadequate.
Conclusions: Viruses are constantly evolving, and currently available commercial vaccines may not provide sufficient protection against emerging ORFV strains. This underscores the urgent need for updated vaccines and improved management strategies.
Clinical relevance: The study reveals significant genetic diversity and potential recombination in ORFV strains in Fujian, highlighting their divergence from known references.
Keywords: B2L gene; F1L gene; Fujian province; evolutionary analysis; orf virus.