基因Ⅵ型新城疫病毒时空传播动态研究

Spatial-temporal Transmission Dynamics of GenotypeⅥNewcastle Disease Virus

新城疫病毒(Newcastle disease virus,NDV)是禽类最重要的疫病病原之一,其中基因Ⅵ型NDV在鸽群广泛流行,给养鸽业造成了严重的经济损失。为深入了解基因Ⅵ型NDV在世界不同地理区域和宿主间的传播动态,本研究通过病毒分离鉴定、高通量测序、完整F基因系统发育树构建和贝叶斯系统动力学等方法进行综合分析,结果获得4株广西NDV分离株,均为基因Ⅵ型。进一步的时空分析显示,基因Ⅵ型NDV最近的共同祖先时间为1972年(95%置信区间:1965~1978),估计进化速率为1.43×10^(-3)substitution/site/year(95%置信区间:1.27×10^(-3)~1.59×10^(-3));意大利是欧洲基因Ⅵ型NDV早期的外溢传播中心,该病毒从欧洲传播至我国,随后华东和华南成为我国的主要传播中心;病毒存在从鸽(Columba livia)到野鸟和鸡(Gallus gallus)、从野鸟到鹌鹑(Coturnix coturnix)等的跨物种传播,但病毒传播最重要的宿主是鸽。分析结果表明基因Ⅵ型NDV正快速进化,有作为突变库的潜在威胁。基于“One Health”理念,应在全球范围内加强主动监测,改善家禽管理策略,避免不同家禽之间及不同家禽与野鸟之间的直接和间接接触。这些信息有助于了解基因Ⅵ型NDV的起源、传播与进化,为制定相应防控策略提供科学依据。

Newcastle disease virus(NDV)is one of the most important infectious disease pathogens in poultry.The genotypeⅥNDV is widely prevalent in pigeon flocks,causing significant economic losses to pigeon industry.In order to better understand the transmission dynamics of genotypeⅥNDV in different geographical regions and hosts in the world,the isolation and identification,next-generation sequencing,construction of complete F gene phylogenetic tree,and Bayesian systematic dynamics analysis of the NDV were performed.The results indicated that four NDV isolates in Guangxi were obtained,and all of them were genotypeⅥ.Further spatial-temporal analysis showed that the time to the most recent common ancestor of genotypeⅥNDV was 1972(95%CI:1965~1978),and the average evolutionary rate was 1.43×10^(-3) substitution/site/year(95%CI:1.27×10^(-3)~1.59×10^(-3)).Italy was the early spillover transmission center of genotypeⅥNDV in Europe,and the virus was transmitted to China from Europe,and then East China and South China became the main transmission centers in China.The most important host for virus transmission is pigeons,but cross-species transmission from pigeons(Columba livia)to wild birds and chickens(Gallus gallus),and from wild birds to quails(Coturnix coturnix)is also present.The results show that the genotypeⅥNDV is evolving rapidly and has a potential threat as a mutation reservoir.Based on the concept of“One Health”,active surveillance should be strengthened worldwide,and poultry management strategies should be improved to avoid direct and indirect contact between different poultry and between different poultry and wild birds.These data will help us to understand the origin,transmission and evolution of genotypeⅥNDV,and provide scientific basis for the development of corresponding prevention and control strategies.