2010年云南PRRSV分离株ORF5基因的遗传变异分析

 为了了解云南猪繁殖与呼吸综合征病毒（PRRSV）流行毒株的遗传变异情况及其与猪繁殖与呼吸综合征的分子流行病学关系，对2010年分离到的10个云南PRRSV流行毒株进行了ORF5基因序列的测定与分析。结果显示云南分离株与中国大陆首次分离株CH1a，北美代表株VR2332和欧洲型代表株LV之间的核苷酸同源性分别为93.2%-94.2%，87.4%-89.6%和62.5%-64.0%；氨基酸同源性为90.0-91.5%,87.1-88.6%和51.7-57.7%。遗传进化分析显示，云南10株分离株属于美洲型，并分为两个基因亚型。与传统毒株相比，云南分离株ORF5基因及其推导的氨基酸的变异主要以点突变为主，但关键氨基酸位点未见明显改变，表明目前云南省所流行的PRRSV仍以经典毒株为主。研究结果为云南猪繁殖与呼吸综合征的控制提供了依据。

Genetic Diversity of the ORF5 Gene of Porcine Reproductive andRespiratory Syndrome Virus Isolates from Yunnan in 2010

To insight into the molecular epidemiology of prevalent porcine reproductive and respiratory syndrome virus (PRRSV) in Yunnan, in the present study the ORF5 gene of 10 PRRSV isolates from Yunnan clinical samples collected in 2010 were sequenced and analyzed. Nucleotide and amino acid homology analyses were carried out on 10 isolates and representative strains of the North American genotype, European genotype and some Chinese isolates. Results revealed that these isolates shared 93.2%-94.2% identification at nucleotide level and 90.0%-91.5% amino acid level with CH 1a that was isolated in mainland of China in 1996, 87.4%-89.6% and 87.1%-88.6% with VR 2332 the prototypical North American PRRSV, 62.5%-64.0% and 51.7%-57.7% with Lelystad virus (LV) the representative strain of European genotype. Phylogenetic analyss revealed that all 10 isolates belong to the North American genotype and were further divided into two different sub genotypes. Compared with classical PRRSV strains, the ORF5gene had a few site mutations but no deletion. Our study suggests that the PRRSV in Yunnan belongs to the  strains, which provides a guide for control and prevention of this disease.