两株猪繁殖与呼吸征病毒的分离鉴定及遗传变异分析

从广东省发病猪场采集的组织和血清中分离到两株PRRSV,病料经RT-PCR检测为阳性,通过Marc-145细胞进行传代,可产生明显细胞病变,通过间接免疫荧光可检测到荧光信号,两株病毒分别命名为ZH-GD株和ZS-GD株。对两株病毒的ORF5和Nsp2高变区进行序列测定和分析,结果表明,PRRSV ZH-GD株和ZS-GD株的核苷酸序列与欧洲型代表株LV株间的相似性相对较远,与美洲株经典毒株VR-2332间的相似性分别为88.6%和88.1%,与中国经典美洲毒株CH-1a间的相似性分别为94.4%和93.0%。在Nsp2上有30个氨基酸的缺失,与JXA1、XH-GD等高致病性变异株的Nsp2缺失位置一致。分离的两株PRRSV均属于美洲型的变异株PRRSV。

Isolation and Identification of Two Strains of Porcine Reproductive and Respiratory Syndrome Virus and Genetic Variation Analysis

Two strains of porcine reproductive and respiratory syndrome virus were isolated from tissue and serum from some Guangdong pig farms and shown PRRS positive in RT-PCR testing by Marc-145.The two strains of virus can passage stably and cause typical cytopathic effect,and fluorescence signal was detected by IFA,were named ZH-GD strain and ZS-GD strain.The analysis of variable region sequences of ORF5 and Nsp2 of two strains of virus showed that,PRRSV ZH-GD strain and ZS-GD strain were far to Europe strain LV,the homology of nuclear nucleotide sequence were 50.9% and 49.2%,and the homology with VR-2332 strain were 88.6% and 88.1%,with classic American CH-1a strain were 94.4 % and 93.0%.And there were 30 amino acids deletion in Nsp2.It shared the same deletion with JXA1,XH-GD and other highly pathogenic variant.Thus,the two strains of PRRSV belonged to variants of American type.