Genetic Evolution of F1L, B2L, and GIF of Orf Virus in Four Clinical Samples

  Objective   Molecular epidemiology of the Orf virus (ORFV) in the diseased sheep and goats from farms in Fujian Province in 2021 were studied.

  Method  The ORFV genes, F1L, B2L, and GIF, from 4 clinical samples of the diseased animals were confirmed positive by PCR prior to cloning for sequence determination. The data were uploaded to GenBank for a comparative analysis using bioinformatics software.

  Result   The nucleotide sequence similarities were 98.0%–98.8% on F1L , 98.4%–99.5% on B2L, and 97.2%–99.6% on GIF; those related to the domestic epidemic strains, 97.4%–99.4% on F1L, 97.4%–99.9% on B2L, and 95.7%–99.0% on G1F; those related to the foreign epidemic strains, 97.5%–98.6% on F1L, 97.9%–98.9% on B2L, and 95.6%–98.0% on G1F; those related to the German D1701 attenuated strain, 96.5%–96.8% on F1L, 98.0%–98.7% on B2L, and 96.0%–96.4% on G1F; and those related to the NZ2 reference strain, 97.7%–98.1% on F1L, 97.5%–98.1% on B2L, and 95.9%–96.1% on G1F. The phylogenetic tree showed the ORFVs closely related to the strains from Jilin (NA17, SY17, and CL18), Fujian (SJ1), and India (MP), but remotely with OV-IA82 from the USA, D1701 attenuated strain from German, NZ2 reference strain from New Zealand, and the vaccine strain from China. It appeared that the current epidemic strain might be a recombination of Fujian, Jilin GZ18, and Indian MP strains.

  Conclusion  The sequences of B2L, F1L, and GIF from the 2021 clinical specimens were uploaded to GenBank database enriching its collection. This study characterized the ORFVs found in the sheep and goats infected by the epidemic and facilitated further studies in the disease control and prevention.