Isolation and Identification of Orf Virus from Jiangsu Province and Phylogenetic Analysis of Their B2L Gene

The study was aimed to investigate prevalence of Orf virus (ORFV) in Jiangsu province in recent years and control Orf better. A total of 121 tissue samples were collected in some farms from 2013 to 2015 and subjected to PCR detection, viral isolation and phylogenetic analysis of B2L gene. Four samples were ORFV positive by PCR. The viruses were isolated by passaging in ovine fetal turbinate (OFTu) cells and MDBK cells, and were named as ORFV/Ovis/XZ/Jiangsu/2015/China, ORFV1/Ovis/DT/Jiangsu/2015/China, ORFV2/Ovis/DT/Jiangsu/2015/China and ORFV/Ovis/SL/Jiangsu/2015/China,respectively. The B2L gene was amplified and sequenced for the phylogenetic study. The nucleotide homology of these 4 strains was 98.5% to 100.0%. ORFV/Ovis/XZ/Jiangsu/2015/China, ORFV1/Ovis/DT/Jiangsu/2015/China and ORFV2/Ovis/DT/Jiangsu/2015/China, gathered into a cluster with SC-JY, GX-YB, JS-FX isolates and the nucleic acid homology of these strains was 97.8% to 100%. ORFV/Ovis/SL/Jiangsu/2015/China gathered into a cluster with LiaoNing, HuB and Gansu isolates, the nucleic acid homology was 98.8% to 98.9%. The nucleic acid homologies of 4 strains and ORFV strain China vaccine was 96.8% to 98.1%. The result showed that the ORFVs in Jiangsu province might be from different source. For controlling the spreading of this virus, it was necessary to carry out deep epidemiological survey in Jiangsu province.