MOE Joint International Research Laboratory of Animal Health and Food Safety, Engineering Laboratory of Animal Immunity of Jiangsu Province, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.
MRC-University of Glasgow Centre for Virus Research, Glasgow, UK.
Transbound Emerg Dis. 2019 Mar;66(2):842-851. doi: 10.1111/tbed.13093. Epub 2019 Jan 5.
H3N2 canine influenza virus (CIV) originated from avian species and emerged in dogs in Asia around 2005 where it became enzootic before reaching the USA in 2015. To investigate the key aspects of the evolution of H3N2 CIV regarding its emergence and adaptation in the canine host, we conducted an extensive analysis of all publicly available H3N2 CIV sequences spanning a 10-year period. We believe that H3N2 AIVs transferred to canines around 2002-2004. Furthermore, H3N2 CIVs could be divided into seven major clades with strong geographic clustering and some changed sites evidence of adaptive evolution. Most notably, the dN/dS of each H3N2 CIVs segment was higher than the correspondent of H3N2 AIVs and the U content of HA and NA was increasing over time, suggesting the idea that this avian-origin virus may be gradually adapting to the host. Our results provide a framework to elucidate a general mechanism for emergence of novel influenza viruses.
H3N2 犬流感病毒（CIV）源自禽类，并于 2005 年左右在亚洲的犬类中出现，在 2015 年到达美国之前，它已在该地区流行。为了研究 H3N2 CIV 在犬类宿主中出现和适应的进化关键方面，我们对跨度为 10 年的所有公开可用的 H3N2 CIV 序列进行了广泛分析。我们认为，H3N2 AIV 大约在 2002-2004 年转移到犬类。此外，H3N2 CIV 可分为七个主要分支，具有强烈的地理聚类，一些变化的位点表明存在适应性进化。值得注意的是，每个 H3N2 CIV 片段的 dN/dS 均高于相应的 H3N2 AIV，并且 HA 和 NA 的 U 含量随时间增加，这表明这种源自禽类的病毒可能正在逐渐适应宿主。我们的研究结果提供了一个框架，阐明了新型流感病毒出现的一般机制。
