Kim Seung-Chai, Jeong Chang-Gi, Park Gyeong-Seo, Park Ji-Young, Jeoung Hye-Young, Shin Go-Eun, Ko Mi-Kyeong, Kim Seoung-Hee, Lee Kyoung-Ki, Kim Won-Il
College of Veterinary Medicine, Jeonbuk National University, 79 Gobong-ro, Iksan, Jeonbuk, 54596, Republic of Korea.
Animal and Plant Quarantine Agency, 177 Hyeoksin 8-ro, Gimcheon, 39660, Korea.
Arch Virol. 2021 Oct;166(10):2803-2815. doi: 10.1007/s00705-021-05169-w. Epub 2021 Aug 10.
Porcine reproductive and respiratory syndrome virus (PRRSV) is the most important pathogen in the Korean swine industry. Despite efforts including improved biosecurity and vaccination protocols, the virus continues to circulate and evolve. Based on phylogenetic analysis of open reading frame 5 (ORF5), Korean PRRSVs are known to form not only globally circulating lineages but also country-specific lineages (Lin Kor A, B, and C). To understand the recent epidemiological status of PRRSV in Korea, a total of 1349 ORF5 sequences of Korean PRRSV isolates from 2014 to 2019 were analyzed. Phylogenetic analysis was conducted using the maximum-likelihood method, and temporal changes in the relative prevalence of lineages were investigated. The analysis showed that PRRSV1 and PRRSV2 were both highly prevalent throughout the years examined. Among the PRRSV1 isolates, subgroup A (90.1%) and vaccine-like subgroup C (9.0%) composed most of the population. For PRRSV2 isolates, vaccine-like lineage 5 (36.3%) was dominant, followed by Lin Kor B (25.9%), Kor C (16.6%), lineage 1 (11.6%), and Kor A (9.1%). The PRRSV2 lineage 1 population increased from 2014 (1.8%) to 2019 (29.6%) in Korea due to the continual spread of sublineage 1.8 (NADC30-like) and introduction of sublineage 1.6 into the country. Additional genetic analysis, including analysis of non synonymous and synonymous mutations, revealed evidence of diversification and positive selection in immunologically important regions of the genome, suggesting that current vaccination is failing and promoting immune-mediated selection. Overall, these findings provide insights into the epidemiological and evolutionary dynamics of cocirculating viral lineages, and constant surveillance of PRRSV occurrence is needed.
猪繁殖与呼吸综合征病毒（PRRSV）是韩国养猪业中最重要的病原体。尽管采取了包括改善生物安全措施和疫苗接种方案在内的各种措施，但该病毒仍在持续传播和进化。基于开放阅读框5（ORF5）的系统发育分析，已知韩国的PRRSV不仅形成全球流行谱系，还形成特定国家的谱系（林科A、B和C）。为了解韩国PRRSV的近期流行病学状况，对2014年至2019年期间韩国PRRSV分离株的1349个ORF5序列进行了分析。采用最大似然法进行系统发育分析，并研究了谱系相对流行率的时间变化。分析表明，PRRSV1和PRRSV2在整个研究年份中均高度流行。在PRRSV1分离株中，A亚组（90.1%）和疫苗样C亚组（9.0%）构成了大多数群体。对于PRRSV2分离株，疫苗样谱系5（36.3%）占主导地位，其次是林科B（25.9%）、科C（16.6%）、谱系1（11.6%）和科A（9.1%）。由于1.8亚谱系（NADC30样）的持续传播以及1.6亚谱系传入韩国，韩国PRRSV2谱系1群体从2014年的1.8%增加到2019年的29.6%。包括非同义突变和同义突变分析在内的进一步基因分析揭示了基因组免疫重要区域多样化和正选择的证据，表明当前的疫苗接种未能奏效并促进了免疫介导的选择。总体而言，这些发现为共循环病毒谱系的流行病学和进化动态提供了见解，需要持续监测PRRSV的发生情况。
