Study On The E2 Gene Nucleotide Sequences And Pathogenicity Of Prevalent Field Strains Of Hog Cholera Virus

The E2 gene nucleotide sequences of field strains of hog cholera virus (HCV)collected from Linxia and Lintao of Gansu province were amplified by reversetranscription (RT) and nested polymerase chain reaction (nPCR), and then, the'amplified fragments were cloned and sequenced. Tl1e nucleotide sequel1ces a11dthe deduced arnino acid sequences of the two strains and C-strain from spleentissue (C-ST) of rabbit were compared and analyzed by Goldkey software. Thefurther study of the two strains genetic relativity was done by Phylogenetic treeconstructed on the base of analyzing the dataset of E2 gene with con1putersoftware. Meanwhile, the pathogenicity of the 3 strains (GSLT GSLX, NXYC)was studied from the clinical symptoms and morphopathology by established thepathological model of hog cholera. The result 'revealed that, (l) 'I'he homology ofthe nucleotide sequences and the deduced an1ino acid sequences between GSLTand GSLX were very high and tl1ey were all classified subgroup 2.l i11 thePhylogenetic tree, and the homology betweell tIle two strains and C-ST were lowand they were classified different subgro[lp (the C-ST was classified subgroupl. l ). The neutral antigenic deter111ina11ts i11 tlle glycoproteil1 antige11ic dolnaills ofE2 were certainly different froln amino acid properties which may effect onneutral titre of C-strain of HCV to tl1e prevalent field virus. (2) NXYC, GSLTGSLX were strains of middle degree virulence, they all have pathogenicity andcan lead to subacute or cl1ro11ic l1og cl1olcra. (3) 'I'l1e patholnorpl1ologicaI lesionsin affected pigs caused by the 3 t1eld strains are no more than acute hog choleraand the brain (cerebrum, cerebellum), lymphoid tissues and kidney were theirtarget organs. (4) The feature of pathomorphological changes caused by the 3prevalent field strains are non-suppurative meningoencephalitis, hyperplasticglomerulonephritis, proliferation and necrotic of imlnuno-organs, endotheliosis ofsmall blood vessels and lymphocyte and eosinophilic granulocyte infiltration inmany tissues.