Origins and Evolutionary Dynamics of H3N2 Canine Influenza Virus
Origins and Evolutionary Dynamics of H3N2 Canine Influenza Virus
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DOI：
10.1128/jvi.03395-14
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发表时间：
2015-05-01
影响因子：
5.4
通讯作者：
Murcia, Pablo R.
中科院分区：
文献类型：
--
作者：
Zhu, Henan;Hughes, Joseph;Murcia, Pablo R.
甲型流感病毒（iav）主要存在于野生鸟类中，尽管禽类iav经常外溢感染到哺乳动物中，但只有少数病毒在哺乳动物宿主中建立。2005年前后，亚洲出现了一种新的源自禽类的H3N2犬流感病毒（CIV），目前正在中国和韩国的犬群中传播，也可能在泰国传播。文明的出现为人畜共患感染和种间传播提供了新的机会。我们检测了14,764个完整的IAV基因组，以及自首次分离到2013年以来公开获得的所有CIV基因组。我们表明，文明可能早在1999年就起源于欧亚和北美鸟类IAV谱系之间的片段重组。我们还发现了氨基酸的变化可能在文明的出现中发挥了作用，其中一些以前没有在其他跨物种跳跃中被发现。CIV的进化速度低于H3N2人类流感病毒，病毒系统发育表现出与本地高水平传播相适应的地理结构。我们检测到多个亚型内和异亚型重配事件，包括获得先前被忽视的H5N1禽流感病毒的NS片段。总之，我们的研究结果提供了对禽病毒在哺乳动物中建立自身所需的适应性变化的见解，并强调了狗作为具有人畜共患病和/或大流行潜力的病毒可能起源的中间宿主的潜在作用，特别是估计有7亿狗的种群。甲型流感病毒在人类和动物中传播。这种多宿主生态具有重要意义，因为过去的大流行是由携带人类和动物源基因片段的iav引起的。适应性进化是跨物种跳跃的核心，这就是为什么理解形成甲型流感病毒基因组的进化过程是阐明病毒出现机制的关键。一种源自禽类的犬流感病毒（CIV）最近在犬类中出现，并正在亚洲蔓延。我们重建了文明的进化历史，并表明它起源于欧亚和北美的鸟类谱系。我们还发现了可能导致跨物种跳跃的突变。最后，我们提供了CIV与其他流感病毒（包括H5N1禽流感病毒）之间多次重组事件的证据。这是一个值得关注的问题，因为全球有大量的狗，人类高度暴露在这些狗的环境中。
Influenza A viruses (IAVs) are maintained mainly in wild birds, and despite frequent spillover infections of avian IAVs into mammals, only a small number of viruses have become established in mammalian hosts. A new H3N2 canine influenza virus (CIV) of avian origin emerged in Asia in the mid-2000s and is now circulating in dog populations of China and South Korea, and possibly in Thailand. The emergence of CIV provides new opportunities for zoonotic infections and interspecies transmission. We examined 14,764 complete IAV genomes together with all CIV genomes publicly available since its first isolation until 2013. We show that CIV may have originated as early as 1999 as a result of segment reassortment among Eurasian and North American avian IAV lineages. We also identified amino acid changes that might have played a role in CIV emergence, some of which have not been previously identified in other cross-species jumps. CIV evolves at a lower rate than H3N2 human influenza viruses do, and viral phylogenies exhibit geographical structure compatible with high levels of local transmission. We detected multiple intrasubtypic and heterosubtypic reassortment events, including the acquisition of the NS segment of an H5N1 avian influenza virus that had previously been overlooked. In sum, our results provide insight into the adaptive changes required by avian viruses to establish themselves in mammals and also highlight the potential role of dogs to act as intermediate hosts in which viruses with zoonotic and/or pandemic potential could originate, particularly with an estimated dog population of similar to 700 million.IMPORTANCEInfluenza A viruses circulate in humans and animals. This multihost ecology has important implications, as past pandemics were caused by IAVs carrying gene segments of both human and animal origin. Adaptive evolution is central to cross-species jumps, and this is why understanding the evolutionary processes that shape influenza A virus genomes is key to elucidating the mechanisms underpinning viral emergence. An avian-origin canine influenza virus (CIV) has recently emerged in dogs and is spreading in Asia. We reconstructed the evolutionary history of CIV and show that it originated from both Eurasian and North American avian lineages. We also identified the mutations that might have been responsible for the cross-species jump. Finally, we provide evidence of multiple reassortment events between CIV and other influenza viruses (including an H5N1 avian virus). This is a cause for concern, as there is a large global dog population to which humans are highly exposed.