King Seetha Jaganathan, Ooi Peck Toung, Phang Lai Yee, Allaudin Zeenathul Nazariah Binti, Loh Wei Hoong, Tee Chiou Yan, How Shiao Pau, Yip Lai Siong, Choo Pow Yoon, Lim Ban Keong
Department of Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, UPM, Serdang, Selangor, 43400, Malaysia.
Asia-Pacific Special Nutrients Sdn. Bhd, Lot 18B, Jalan 241, Section 51A, Petaling Jaya, Selangor, 46100, Malaysia.
BMC Vet Res. 2017 Jan 5;13(1):3. doi: 10.1186/s12917-016-0933-z.
Porcine reproductive and respiratory syndrome (PRRS) is one of the most expensive diseases of modern swine production & results in annual economic losses and cost the industry over 600 million USD in U.S. alone and billions of dollars worldwide. Two atypical PRRS cases were observed in 2013 and 2014 characterized by late-term abortion, fever and sudden increase in sow mortality which persisted for a prolonged period of time.
Lungs, lymph nodes and other samples were collected for disease investigation. Sequencing of the viral envelope glycoprotein (ORF5) and nucleocapsid protein (ORF7) of PRRSV was done using the BigDye Terminator v3.1 cycle sequencing kit chemistry. The phylogenetic tree was constructed by using the Maximum Likelihood method, generated by Mega 6.06®.
Analysis of the ORF5 and ORF7 showed high degree of sequence homology to PRRSV parent vaccine strain VR-2332, RespPRRSV and other mutant/chimeric virus strains.
Our study suggests that recombination events between vaccine strains and field isolates may contribute to PRRSV virulence in the field.
猪繁殖与呼吸综合征（PRRS）是现代养猪生产中代价最为高昂的疾病之一，会导致年度经济损失，仅在美国该行业每年就损失超过6亿美元，在全球则达数十亿美元。2013年和2014年观察到两例非典型PRRS病例，其特征为晚期流产、发热以及母猪死亡率突然上升，且这种情况持续了很长一段时间。
采集肺、淋巴结和其他样本用于疾病调查。使用BigDye Terminator v3.1循环测序试剂盒化学方法对PRRSV的病毒包膜糖蛋白（ORF5）和核衣壳蛋白（ORF7）进行测序。通过Mega 6.06®生成的最大似然法构建系统发育树。
对ORF5和ORF7的分析表明，其与PRRSV亲本疫苗株VR - 2332、RespPRRSV以及其他突变/嵌合病毒株具有高度的序列同源性。
我们的研究表明，疫苗株与田间分离株之间的重组事件可能导致PRRSV在田间的毒力。
