野鼠中猪圆环病毒2型毒株的分离鉴定及其基因变异情况分析

Isolation and genetic analysis of porcine circovirus 2 strain isolatedfrom the wild mice

湖南省某规模化猪场妊娠母猪发生由PCV2感染引起的繁殖障碍,为了解猪场周围野鼠PCV2感染及其基因变异情况,本研究采用PCR法检测从该场采集的猪血液及该场周边的野鼠组织样品中是否存在PCV2核酸;扩增PCV2阳性样品全基因组并测序,分析鼠源和猪源PCV2全基因组的同源性与遗传进化关系,对野鼠源PCV2(HNRCV株)进行分离与鉴定。结果表明,该场母猪和周边野鼠存在PCV2感染,且猪源和野鼠源PCV2全基因组序列(1767 bp)的同源性为100%;同源性与遗传进化分析结果表明,湖南HNRCV分离株与美国毒株22625-33的同源性最高(99.89%),同属于PCV2d,且Cap基因的同源性为99.72%;在野鼠组织中成功分离出HNRCV株,并且该分离株可在PK-15细胞中增殖。本研究结果提示,野鼠在猪场中PCV2的流行与传播发挥着重要作用,为PCV2的防控提供科学依据。

Reproductive abnormalities caused by porcine circovirus 2(PCV2)infection were observed in sows within a large-scale pig farm situated in Hunan Province.To understand the biology of the infection and identify genetic mutations in PCV2 in wild mice around the pig farm,we evaluated the presence of PCV2 nucleic acid in the blood samples collected from the pigs on the farm and the tissue samples from the wild mice around the farm using polymerase chain reaction(PCR).The whole genome of PCV2-positive samples was amplified and sequenced;furthermore,the whole genomes of PCV2 of murine and porcine origins were analyzed for sequence homology and genetic evolutionary relationships.Finally,PCV2(HNRCV strain)from wild mice was isolated and identified.PCV2 infections in sows on the farm and wild mice in the neighborhood were found,and the homology of the whole genome sequences of PCV2(1767 bp)detected in pigs and wild mice was 100%.The results from the analyses of sequence homology and genetic evolutionary relationships indicated that the isolated HNRCV strain from Hunan Province exhibited the highest level of homology(99.89%)with the U.S.strain 22625-33.The PCV2d genotype served as the foundation for both these strains and a notable 99.72%homology was evident within the Cap gene.The HNRCV strain was successfully isolated from the wild mouse tissue samples and could proliferate in PK-15 cells.The results of this study suggest that wild mice play an important role in the prevalence and transmission of PCV2 in pig farms,thus providing a scientific basis for the prevention and control of PCV2.