Pathogenicity And Sequence Analysis Of E2 Gene Of CSFV In Xinjing

Nine clinically pathological samples of classical swine fever were successfiully detected with three different methods such as fluorescent staining, electro microscopy , indirect ELISA respectively. The results showed that the methods of fluorescent staining and indirect ELISA were the same sensitivity , which were more sensitive than the second method mentioned above. The two positive pathological samples were screened and selected for RT-PCR amplification. In order to characterize the genetic variation of E2 protein gene of different wild strains of classical swine fever virus , the homology of the sequence was reported and registered in Genbank or EMBL of chinese strain of CSFV and was analyzed and compared respectively. According to the property of the virus, the hypervariable region of E2 protein gene of CSFV was analyzed and selected for PCR amplification . The total RNA was extracted from the tissues of infected animals by single step method of acid guanidinium thiocyanate-phenol-chloroform extraction and was used for reverse transcription. The 272bp cDNA fragments which were amplified from the product of RT were sequenced and analysed. The homology of hypervariable regions of E2 gene of wild strain of CSFV in Xin Jiang was 82.8% compared with Chinese strain of CSFV. The homology of amino acid sequence was 88.3% compared with the Chinese CSFV strains mentioned above. The results signified that the marked genetic variation of this region of 32 E2 gene had happened. It might be the reason that caused the happen of CSF in the south of Xin Jiang. We had also successfully infected three 40-day-old piglets with the clinical samples and systematically observed the clinical symptoms and pathological changes. The artificial infected experiment showed that the wild strain of CSFV in Xin Jiang was medium or strong virulent. The pathology was studied with the techniques of physicochemistry and immunochemistry. The specific nucleotide fragment was also successfully amplified from samples of artificial infected piglets.These results provided a solid foundation for further study of molecular epidemiology ,diagnosis and control of CSF in Xin Jiang.