高致病性PRRSV变异株与经典株混合感染的研究

Study on Co-infection of Highly Pathogenic PRRSV and Classical PRRSV

应用RT-PCR技术对来自广东省某猪场患有明显呼吸道临床症状和高热死亡的仔猪肺脏组织进行检测,结果初步鉴定为PRRSV高致病性变异株(YGhp株)与经典株(YGcl株)混合感染。进一步对2个毒株的NSP2基因进行序列分析,结果发现YGhp株与VR-2332、JXA1和Lelystad株的核苷酸同源性分别为75.1%、99%和35%,而YGcl株与上述毒株的同源性分别为99%、77.7%和34.5%,表明YGhp株为高致病性变异株,YGcl株为经典株,均属美洲型。高致病性PRRSV变异株与经典株混合感染属非常罕见。

Lung tissue of piglets died of obvious respiratory syndrome and high fever was subjected to RTPCR analysis. The result showed that a highly pathogenic PRRSV （YGhp） and a classical PRRSV （YGcl） co-existed in the same specimen. Sequencing their NSP2 genes demonstrated that the PRRSV strain YGhp shared 75.1%, 99% and 35% nucleotide acid identities with VR-2332, JXA1 （highly pathogenic） and Lelystad strains,respectively, while for YGcl strain it was 99%, 77. 7% and 34. 5%, respectively. The YGhp strain belonged to a highly pathogenic PRRSV and YGcl to a classical one, both being PRRSV American genotypes. As far as we know, co-infection with highly pathogenic and classical PRRSV has been rarely reported.