Sequencing And Analysis Of E2 Gene Of CSFV Gansu Epidemic Strain

Classical Swine Fever virus(CSFV) is the most important virus that affect theswine industry nowadays. Epizootic and spread of CSFV have rised serious threat andsignificant economic impact on the swine industry worldwide.In order to controlCSFV effectively and reduce the economy loss, We study the genetic mutation andmolecular detection method.In this study the E2 genes of CSFV strains isolated from Gansu was amplifiedby reverse transcriiption polymerase chain reaction (RT-PCR). The E2 gene fragmentswhich contain 1100 base pair in length and encode 367 amino acid residues werecloned and sequenced. Comparison of E2 seqences between Gansu strain and Alfortstrain,Shimen strain,C strain,AY027672,AY554397 using DNAStar sofitware werecarried out, the result showed that the homology between Gansu strain and Alfort was84.5% for nucleotide sequence and 91.3% for deduced amino acid sequence. Thehomology between Gansu strain and Shimen was 84.1% for nucleotide sequenceand 90.4% for deduced amino acid sequence. The homology between Gansu strainand C strain was 83.3% for nucleotide sequence and 89.3% for deduced amino acidsequence. The homology between Gansu strain and AY027672 was 95.8% fornucleotide sequence and 97% for deduced amino acid sequence. The homologybetween Gansu strain and AY554397 was 96.1% for nucleotide sequence and 97.8%for deduced amino acid sequence.Phylogenetic tree among Gansu strain and otherCSFV strains published were obtained by analyzing nucleotide sequences of E2 gene.The Phylogenetic tree revealed that CSFV epidemic strain from Gansu wassignificantly genetic divergent from strains in recent years.A RT-PCR method for detection of CSFV was developed and an epidemicinvestigation of CSF in some of pig farms were carried out using this RT-PCRmethod. The result indicated that the positive rate of CSF was 53.3%(8/15), indicatingthe CSF prevalence in pig farms.