Study On The Biological Characteristics Of Orf Virus

This study from the Qingdao of Shandong province a sheep farm from suspected Orf disease material crust, by shearing, grinding and centrifugation after treatment in sheep testis cells were inoculated and cultured, isolated the virus, and through the morphology observation, researching of physical and chemical characteristics, animal regression experiment, virus titer determination and identification of molecular biology, confirmed that the virus was Orf virus. According to the whole genome sequence of Orfv and B2L, F1L, VIR gene published in GenBank, 3 pairs of specific primers were designed. By PCR amplification, gel recovery, recombinant plasmid transformation, positive strain screening, plasmid sequencing and so on that B2L, F1L and VIR genes were amplified, cloned and sequenced and compared the gene sequences and other published Orfv isolates from different sources to analysis.The results show that the sheep testicular cells successfully isolated a strain of ORFV, and named ORFV-Q. This isolate can cause the sheep testicular cells to produce obvious lesions, through the passage to the 11 generation, the cells began to appear pathological changes and 80%CPE time were stable at 24h and 72h after inoculation. Virus particle is elliptical, periphery of the sac membrane coated, proliferate in the cytoplasm virus on temperature, chloroform, ether were sensitive. Inoculation of strains of sheep papules, pustules and other typical symptoms of Orf, TCID50 strain 10-5.5. Gene sequence analysis showed that the separation of ORFV-Q strains of B2L gene, F1L gene and VIR gene and GenBank published strains of the sequence between the nucleotide homology respectively 96.8%~9.8.9%, 96.2%~99.9% and 94.9%~99.8%, and the separation of strains and Chinese strains isolated from Shaanxi and Hubei strain homologous relations most closely.