Isolation and sequence analysis of PCV2 strains from Guangdong province

In order to know the epidemic, variation and evolution of PCV2 in Guangdong province, serum samples from suspected pigs infected PCV2 in many farms of Guangdong province were used to isolate PCV2. According to the sequence of PCV2 published in GenBank, 3 pairs of primers were designed and amplified by PCR. The results showed that each of 9 genomes showed 1 767 bp in length. The homology of 9 isolates was 93.6%~99.4%, while the homology with isolates in 2012 was 94.5%~99.7%, the homology with isolates in 2011 was 94.2%~99.7%, and the homology with other isolates in GenBank was 93.2%~99.7%. The ORF2 of the 9 isolates had 89.0%~99.9% nucleotide sequence homology and 86.4%~100% amino acid homology. 5 isolates belonged to PCV2d genotype while 3 isolates belonged to PCV2b and 1 isolate belonged to PCV2a. The analysis of PCV2 genomic characteristics isolated from 2011 to 2013 found that the nucleotide sequence of PCV2 was stable, and the homology of these isolates were high with other isolates of the world.