中国高致病性猪繁殖与呼吸综合征病毒的起源-外文翻译.doc

毕 业 设 计（论 文）外 文 参 考 /a 资 料 及 译 文 译文题目：中国高致病性猪繁殖与呼吸综合征病毒的起源 学生姓名： 杨力元 学 号： 0710110121 专 业： 动物医学 所在学院： 动物科学与技术学院 指导教师： 张志成 职 称： 讲师 2011 年 3 月 9 日 Origin of Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus, China A highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV), which affected 2 million pigs, emerged in early 2006 in the People’s Republic of China. The disease was characterized by high fever (41°C), high illness rates (50%–100%), and high death rates (20%–100%) for pigs of all ages . A number of HP-PRRSVs have been isolated from 2006 through 2009 from infected pigs in different provinces of China and confirmed to be the causative agent of the new outbreaks . These HP-PRRSVs have a deletion of 30 amino acids in nonstructural protein 2 (NSP-2). However, the evolutionary origin and path of the HP-PRRSV remain unknown. We analyzed the full-length sequences of 67 PRRSVs: 35 HP-PRRSVs (HuN4 and LNSY-08-1 isolated in our laboratory and 33 viruses isolated in other laboratories), 28 classic PRRSVs (18 viruses isolated from China and 10 viruses representing other Asian countries and North America), and 4 commercially available attenuated live PRRSV vaccine viruses. Except for the 2 viruses we isolated (HuN4 and LNSY-08-1), the full-length sequences of the other 65 viruses were obtained from GenBank.Nucleotide and deduced amino acid sequences of these PRRSVs were aligned and compared by using previous methods . Whole genome-based phylo-genetic analysis showed that these 67 PRRSVs could be divided into 4 subgroups . Ten classic PRRSVs from China, together with the North American prototype virus VR-2332 and the vaccine virus RespPRRS/Repromodified live vaccine, were classified into subgroup 1. The first Chinese isolate, CH-1a, and its 3 derivatives (CH2002, CH2003, and CH2004) were classif