中国北方部分地区猪圆环病毒Ⅱ型分子流行病学调查

Molecular Epidemiological Investigation of Porcine Circovirus Type 2 Infection in Some Regions in North China

目的 分析中国北方部分地区猪圆环病毒Ⅱ型(Porcine circovirus type 2,PCV2)的分子流行病学特征。方法收集2006～2008年间北京、山西、山东、河北4省(市)PCV2 DNA阳性病料共16份,分别进行PCV2 ORF1和ORF2核苷酸序列的扩增、克隆和测序,并利用分子生物学软件进行分子遗传学分析。结果本研究中的16株PCV2 ORF1、ORF2核苷酸序列及推导的氨基酸序列与参考株的同源性分别为97.1%～99.8%和98.4%～99.7%及89.6%～99.4%和88.1%～99.1%;2006～2008年间中国北方与南方以及2002～2005年间北方的PCV2流行情况基本相似,绝大多数属于1AB基因亚群;近年来,中国北方流行的PCV2(1AB基因亚群)中,有11/14集中在单独一个侧枝;在中国北京出现了2C基因亚群的PCV2野毒株,经分析可能从欧洲国家引入。结论从基因水平来讲,PCV2 1AB基因亚群是目前最高效的疫苗株,但这种局面未来可能会发生改变。

Objective To investigate the molecular epidemiological character of porcine circovirus type 2（PCV2）in some re-gions in North China.Methods Sixteen PCV2 DNA-positive materials were collected from Beijing City,Shanxi Province,Shandong Province and Hebei Province during 2006 ～ 2008,from which the nucleotides of PCV2 ORF1 and ORF2 were amplified,cloned and sequenced,and molecular genetics were analyzed by molecular biological software.Results The homologies of nucleotide and deduced amino acid sequences of PCV2 ORF1 of the 16 materials to those of reference strain were 97.1% ～ 99.8% and 98.4% ～ 99.7%,while those of PCV2 ORF2 were 89.6% ～ 99.4% and 88.1% ～ 99.1%,respectively.The epidemics of PCV2 in North and South China in 2006 ～ 2008 and those in North China in 2002 ～ 2005 were basically in agreement,most of which were caused by sub-genotype 1AB.In recent years,the sub-genotype 1AB causing 11 of 14 epidemics in North China were assembled into a separate branch.The wild PCV2 strain of subgenotype 2C appeared in Beijing,indicating a probable introduction from European countries.Conclusion At gene level,PCV2 sub-genotype 1AB was the most effective vaccine strain at present.However,the status might change in future.