PDF(Pubmed)
Abstract：
BACKGROUND: The wide diversity of porcine reproductive and respiratory syndrome virus (PRRSV) strains combined with incomplete heterologous cross-protection complicates the management of the disease at both the herd and the regional levels. The objectives of this study were to describe the spatial and temporal distribution of various PRRSV genetic clusters infecting pig sites in Quebec, Canada, and to compare PRRSV regional diversity of wild-type sequences over the years.
METHODS: A retrospective surveillance-based study was conducted on all pig sites which had PRRSV ORF5 sequences from field submissions transferred into the Laboratoire d\'épidémiologie et de médecine porcine database from January 1, 2010 to December 31, 2019. A maximum likelihood phylogenetic tree inferred from multiple sequence alignment was used to identify genetic clusters. For each wild-type cluster gathering ≥ 15 sequences, the number of pig sites in which the cluster was detected per administrative region and per year were displayed on bubble charts and the spatiotemporal distribution of pig sites was illustrated using pie chart maps. A molecular analysis of variance was performed to compare PRRSV wild-type sequence diversity according to the administrative region for each year.
RESULTS: A total of 32 wild-type clusters gathering 1653 PRRSV2 sequences from 693 pig sites were described. Each cluster was detected on up to 132 pig sites and 7 administrative regions over the 10-year period. Annually, the mean (min-max) number of wild-type clusters detected in at least one pig site reached 24 (17-29). Some clusters remained localized on a few sites over time whereas others were widespread over the territory during a few or many years. For each year, regional differences were also observed in PRRSV diversity of wild-type sequences.
CONCLUSIONS: The differences observed in both the spatiotemporal distributions of PRRSV clusters and in the regional diversity of wild-type sequences highlight the importance of ongoing provincial surveillance to improve collective PRRS management strategies.
METHODS: A retrospective surveillance-based study was conducted on all pig sites which had PRRSV ORF5 sequences from field submissions transferred into the Laboratoire d\'épidémiologie et de médecine porcine database from January 1, 2010 to December 31, 2019. A maximum likelihood phylogenetic tree inferred from multiple sequence alignment was used to identify genetic clusters. For each wild-type cluster gathering ≥ 15 sequences, the number of pig sites in which the cluster was detected per administrative region and per year were displayed on bubble charts and the spatiotemporal distribution of pig sites was illustrated using pie chart maps. A molecular analysis of variance was performed to compare PRRSV wild-type sequence diversity according to the administrative region for each year.
RESULTS: A total of 32 wild-type clusters gathering 1653 PRRSV2 sequences from 693 pig sites were described. Each cluster was detected on up to 132 pig sites and 7 administrative regions over the 10-year period. Annually, the mean (min-max) number of wild-type clusters detected in at least one pig site reached 24 (17-29). Some clusters remained localized on a few sites over time whereas others were widespread over the territory during a few or many years. For each year, regional differences were also observed in PRRSV diversity of wild-type sequences.
CONCLUSIONS: The differences observed in both the spatiotemporal distributions of PRRSV clusters and in the regional diversity of wild-type sequences highlight the importance of ongoing provincial surveillance to improve collective PRRS management strategies.
摘要：
背景：猪繁殖与呼吸综合征病毒（PRRSV）毒株的广泛多样性与不完全的异源交叉保护相结合，使疾病在畜群和区域水平上的管理复杂化。这项研究的目的是描述各种PRRSV遗传簇在魁北克感染猪地点的时空分布，加拿大,并比较多年来PRRSV野生型序列的区域多样性。
方法：从2010年1月1日至2019年12月31日，对所有猪场进行了一项基于回顾性监测的研究，这些猪场将来自现场提交的PRRSVORF5序列转移到猪实验室数据库中。从多个序列比对推断的最大似然系统发育树用于识别遗传簇。对于每个野生型簇收集≥15个序列，在气泡图上显示了每个行政区和每年检测到集群的猪场数量，并使用饼图说明了猪场的时空分布。进行了方差分析，以根据每年的行政区域比较PRRSV野生型序列多样性。
结果:描述了总共32个来自693个猪位点的1653个PRRSV2序列的野生型簇。在10年内，在多达132个养猪场和7个行政区检测到每个集群。每年,在至少一个猪站点中检测到的野生型簇的平均（min-max）数量达到24（17-29）。随着时间的流逝，一些集群仍然位于一些站点上，而其他集群则在几年或许多年内在该领土上广泛分布。每年,在野生型序列的PRRSV多样性中也观察到了区域差异。
结论：在PRRSV簇的时空分布和野生型序列的区域多样性中观察到的差异突出了正在进行的省级监测对于改善集体PRRS管理策略的重要性。
方法：从2010年1月1日至2019年12月31日，对所有猪场进行了一项基于回顾性监测的研究，这些猪场将来自现场提交的PRRSVORF5序列转移到猪实验室数据库中。从多个序列比对推断的最大似然系统发育树用于识别遗传簇。对于每个野生型簇收集≥15个序列，在气泡图上显示了每个行政区和每年检测到集群的猪场数量，并使用饼图说明了猪场的时空分布。进行了方差分析，以根据每年的行政区域比较PRRSV野生型序列多样性。
结果:描述了总共32个来自693个猪位点的1653个PRRSV2序列的野生型簇。在10年内，在多达132个养猪场和7个行政区检测到每个集群。每年,在至少一个猪站点中检测到的野生型簇的平均（min-max）数量达到24（17-29）。随着时间的流逝，一些集群仍然位于一些站点上，而其他集群则在几年或许多年内在该领土上广泛分布。每年,在野生型序列的PRRSV多样性中也观察到了区域差异。
结论：在PRRSV簇的时空分布和野生型序列的区域多样性中观察到的差异突出了正在进行的省级监测对于改善集体PRRS管理策略的重要性。
