Detection Of Porcine Circovirus Type 2 By Polymerase Chain Reaction And Sequencing Analysis Of The Isolates In Hunan And Guangxi

In this study,301 samples which were based on clinical signs for"Hot pig diseases"were detected for PCV2 by PCR. 121 samples (54 samples form Guangxi,and 67 samples from Hunan)were positive for PCV-2, and 24 porcine circovirus 2 strains of positive samples were cloned and sequenced.The complete genome of each the isolates was 1767bp in length.Comparison of complete genome sequence of the isolates in DNAStar showed that there was a 96.0%～100% identity of the complete genomic nucleotides .Analysise of the two open reading frames(ORF l and ORF2) and deduce their amino acid sequences in computer,we found that the ORF1 of the isolates showed 97.1%～100% nucleotide sequence identidy and 97.5%～99.7% amino acid identidy.The resμLt showed a high degree of homology of ORF 1 .The ORF2 of the isolates had 93.3%～99.6% nucleotide sequence identidy and 92.7%～99.6% amino acid identidy.Sequence analysis of ORF1 and ORF2 genes of 24 strains revealed that the extent of nucleotide variation was greater for the ORF2 than for the ORF 1.Phylogenetic analysis of the isolates of PCV-2 and other 17 PCV-2 and 1 PCV-1 sequences published in GenBank was obtained in Clustal w method.The result showed that the two viruses were found in different phylogenetic clusters,The 24 isolates of PCV2 were divided into two small groups,The strains were spread in small group.Comparison of nucleotide sequence confirmed that the 24 isolates were close to the isolates from France , Canada, the US and Asian..