欧洲型PRRSV RT-PCR检测方法的建立及ORF7基因序列比较

Establishment of RT-PCR Method for Diagnosing European-type PRRSV and Sequencing and Analysis of the ORF7 Gene

根据PRRSV（LV株）ORF7基因设计一对引物，建立了欧洲型PRRSV的RT-PCR检测方法。通过对50份组织病料检测及其ORF7基因序列分析，结果表明，有4份组织病料扩增出欧洲型PRRSV576bp特异性片段，阳性率为8％，其ORF7基因序列和氨基酸推导序列与欧洲型PRRSV弱毒疫苗株（AMER-VAC-PRRS）的同源性分别在99．0％～99．7％和98．5％～100％之间，而与标准毒株（LV）的同源性分别在95．9％～96．6％和96．99，6～97．7%之间。表明该PT-PCR体系适合组织病料中欧洲型PRRSV的直接检测，同时也证实了欧洲型PRRSV在我国的存在，并且与疫苗株之间具有较高的同源性。

According to the sequence of ORF7 gene of PRRSV strain （LV）, a pair of primers were designed to establish the RT-PCR system for the detection of European-type PRRSV. Based on the system, fifty suspected tissue samples of post-weaning multisystemic wasting syndrome （PMWS） were detected and the 576 bp specific products were amplified from 4 samples with the positive rate of 8 %. Further results of sequencing showed that the nucleotide sequence and deduced amino acid homologies between the vaccine strain （AMERVAC-PRRS） and 4 detected strains were 99.0%-99.7%/6 and 98.5%-100. 0%,respectively. However, low level of homologies of nucleotide sequence （95. 9%-96. 6%） and amino acid （96. 9%- 97.7%） were found when compared 4 detected strains with standard strain（LV）. In conclusion, the RTPCR system for detecting the European-type PRRSV from tissue samples was workable and the results indicated that European-type PRRSV also existed in China.