Nguyen V G, Kim H K, Moon H J, Park S J, Chung H C, Choi M K, Park B K
Department of Veterinary Medicine Virology Laboratory, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea; Department of Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Hanoi University of Agriculture, Hanoi, Vietnam.
Transbound Emerg Dis. 2014 Dec;61(6):537-45. doi: 10.1111/tbed.12058. Epub 2013 Jan 22.
Understanding viral transmission is an important factor for the effective prevention one of the most devastating swine diseases, porcine reproductive and respiratory syndrome. Focusing on molecular epidemiology of type 1 PRRSV, this study analysed a large ORF5 dataset collected worldwide from 1991 to 2012 using a coalescent-based Bayesian Markov chain Monte Carlo approach. The results suggested that the virus diversified into unique subpopulations in Russia & Belarus and Italy approximately 100 years ago. Previously unreported consecutive diffusions of the virus were identified, which showed that some countries, such as Spain and Germany, acted as distribution sources to some extent. This study also provided statistical evidence for the existence of an ORF5-based phylogeographical structure of type 1 PRRSV, in which the virus tended to cluster by geographical locations more tightly than expected by chance. In contrast to this tight geographical structure, the evolution of the ORF5 gene, based on mapping of non-synonymous/synonymous substitutions, was best described by a non-homogeneous process that could be implicated as a mechanism for viral immune evasion.
了解病毒传播是有效预防最具毁灭性的猪病之一——猪繁殖与呼吸综合征的一个重要因素。本研究聚焦于1型猪繁殖与呼吸综合征病毒（PRRSV）的分子流行病学，采用基于溯祖理论的贝叶斯马尔可夫链蒙特卡罗方法，分析了1991年至2012年期间在全球范围内收集的大量开放阅读框5（ORF5）数据集。结果表明，该病毒大约在100年前在俄罗斯、白俄罗斯和意大利分化为独特的亚群。研究发现了此前未报道的病毒连续扩散情况，这表明西班牙和德国等一些国家在一定程度上充当了传播源。本研究还为1型PRRSV基于ORF5的系统地理学结构的存在提供了统计证据，在该结构中，病毒倾向于按地理位置聚集，其紧密程度高于随机预期。与这种紧密的地理结构形成对比的是，基于非同义/同义替换图谱的ORF5基因进化，最适合用一个非均匀过程来描述，这可能是病毒免疫逃逸的一种机制。
