【摘要】 在过去的两个时间段内,作者从我国西北地区的15个猪场分离出32个病原样品,通过基因分子检测和测序分析以确定猪繁殖与呼吸综合征病毒(PRRSV)的感染和PRRSV的基因型。结果显示,PRRSV阳性检出率为35.9%,2007-2008年和2009-2010年的平均发病率分别为46.5%和29.3%。依据GP5完整基因的核苷酸序列所做的遗传进化树分析表明,所有的32株PRRSV田间流行株的基因型都属于北美洲型,且属于高致病性的PRRSV亚型。分离自新疆的毒株形成一个相对密切的基因分支,与以BJ0706株为代表的分子进化中间型的其他分离株也有较为密切的进化关系。此外,通过比较2007-2008年和2009-2010年分离自同一养猪场的毒株,发现16个分离株中15株表现相同的氨基酸突变,即V29→A29和N34→S34。调查结果表明,自2007年到2010年间PRRSV在我国西北地区和其他地区相继出现,而且显示一定的地域特征。同时,2009年之后的分离株在GP5基因上出现新的氨基酸突变。更多还原

【Abstract】 The 32 field-isolated tissue or serum samples were collected from aborted fetuses or pigs with respiratory disease from 15 herds,twice over 2 years.Porcine reproductive and respiratory syndrome virus(PRRSV) infection was determined and virus strains were classified with PCR method to the virus-specific sequences and the sequencing of GP5.The 35.9% of animals were PRRSV-positive,and the average prevalence from 2007 to 2008 and from 2009 to 2010 were 46.5% and 29.3%,respectively.To further investigate the genetic divergence of PRRSV samples,32 strains were included for GP5 sequencing and analysis,and the phylogenetic tree was also calculated using complete GP5 amino acid sequences.All PRRSV were the NA genotype and belonged to the highly pathogenic HP-PRRSV subgenotype.Isolates from Xinjiang region formed a tightly clustered branch and were closely related to an evolutionary intermediate subgroup isolate.Virus sequences from 2007 to 2008 were compared with those from 2009 to 2010 from the same herd.The results showed that new mutations were found in isolates after 2009 and focused on nucleotides in the GP5antibody decoy epitope,and PRRSV strains in north-western China from 2007to 2010were similar to those from other regions of China,with some regional characteristics.更多还原