宁夏地区新城疫分子流行病学特点分析

Molecular Epidemiology Analysis on Newcastle Disease Outbreaks in Ningxia

试验对2005～2006年从宁夏地区分离到的6株新城疫病毒进行遗传学特性研究,采用RT-PCR扩增了分离株F基因主要功能区片段并进行序列测定,序列分析表明6株分离株扩增片段的长度均为535bp,与预期扩增片段长度大小一致。裂解位点的氨基酸组成均为112R-R-Q-K-R-F117,具有强毒株的典型分子特征。通过构建新城疫病毒F基因的遗传进化树,表明6株宁夏分离株在分类地位上均属于基因Ⅶd亚型,与我国近年来新城疫病毒主要流行优势基因型一致,同时表明在宁夏地区至少有2个不同来源的毒株同时流行。

Six isolates of Newcastle disease virus obtained from Ningxia from 2005 to 2006 were characterized genotypically. The main functional region of the F gene comprising 535 nucleotides was amplified by RT-PCR and sequenced. The amino acid sequence of the fusion protein cleavage site in all six isolates was 112R-R-Q-K-R-F117, which is a typical sequence of velogenic strains. A phylogenetic tree based on nucleotides 47 to 435 of the F gene was constructed. Phylogenetic analysis showed that all the isolates were of the genotype Ⅶd virus,which was a predominant genotype responsible for most outbreaks of Newcastle disease in China in recent years. At the same time,at least two strains with different source may result in outbreak of Newcastle disease in Ningxia.