School of Biological Sciences, The University of Hong Kong, Hong Kong SAR.
University of Guelph, Laboratory Services Division, Animal Health Laboratory, Box 3612, Guelph, ON N1H 6R8, Canada.
J Gen Virol. 2011 Jun;92(Pt 6):1391-1397. doi: 10.1099/vir.0.030155-0. Epub 2011 Feb 23.
Classification of Ontario porcine reproductive and respiratory syndrome virus (PRRSV) field isolates (n = 505) from 1999 to 2010, based on a global type 2 PRRSV ORF5 phylogenetic framework, revealed genetic diversity comparable to PRRSV in the USA, with sequences assigned to five of nine lineages (1, 2, 5, 8 and 9). Importantly, the tree topology indicated a Canadian ancestry for the highly virulent MN184-related strains that first emerged in 2001 in the USA. Mapping of the RFLP patterns onto the phylogenetic tree revealed numerous examples of different RFLP patterns located within the same phylogenetic cluster. Statistical analysis showed occurrences where similar RFLP patterns masked diverse genetic distances and instances of close genetic proximity with divergent RFLP patterns. Collectively, extensive genetic diversity prevails in type 2 PRRSV in one region of the North American swine industry, and it is not described adequately by RFLP typing, which might have value in differentiating strains at the local farm level.
1999 年至 2010 年，根据全球 2 型 PRRSV ORF5 系统发生框架，对来自安大略省的 505 株猪繁殖与呼吸综合征病毒（PRRSV）田间分离株进行分类，结果显示其遗传多样性与美国的 PRRSV 相当，序列被分为 9 个谱系中的 5 个（1、2、5、8 和 9）。重要的是，树拓扑结构表明，2001 年首先在美国出现的高致病性 MN184 相关毒株具有加拿大血统。将 RFLP 模式映射到系统发生树上，揭示了许多位于同一系统发生簇内的不同 RFLP 模式的例子。统计分析表明，存在相似的 RFLP 模式掩盖了不同遗传距离的情况，也存在与不同 RFLP 模式具有密切遗传相似性的情况。总的来说，在北美养猪业的一个地区，2 型 PRRSV 存在广泛的遗传多样性，而 RFLP 分型不能充分描述这种多样性，RFLP 分型可能有助于区分农场层面的菌株。
