Table_1_Has avian influenza virus H9 originated from a bat source?.docx

Influenza A viruses are important pathogens that can cause diseases with high mortality in humans, animals, and birds; and wild birds are considered the primary reservoir of all subtypes in nature. After discovering the H9 influenza A viruses in bats, questions arose about their potential to serve as an additional natural reservoir and about the priority of the viral origin: Did the virus initially circulate in bats and then transmit to birds or vice versa? Influenza A viruses of the H9 subtype are of particular interest because fatal infections of humans caused by H5, H7, and H10 influenza viruses contained RNA segments from H9 viruses. Recently, a novel subtype of influenza A virus (H19) was reported and it was closely related to the H9 bat influenza A virus by its hemagglutinin structure. The genome of novel H19 has revealed a mixed characteristic genomic signature of both avian and bat influenza viruses. The time to most recent common ancestor (TMRCA) estimates have shown that the divergence time between the bat and avian H9-similar influenza virus occurred approximately at the end of the XVIII century. This article discusses the evolution and possible origin of influenza viruses of the H9 subtype isolated from bats and birds. The obtained data, along with the known data, suggest that the primary reservoir of the H9 influenza virus is wild birds, from which the virus was transmitted to bats. We hypothesize that the novel H19 could be a descendant of an intermediate influenza virus that was in the transition stage of spillover from avian to bat hosts.

流感A型病毒是重要的病原体，能够在人类、动物和鸟类中引起高死亡率疾病；在自然界中，野生鸟类被认为是所有亚型的原始宿主。在蝙蝠中发现H9流感A型病毒后，引发了关于其作为额外自然宿主潜力的疑问，以及病毒起源的优先级：病毒最初是在蝙蝠中循环并传播给鸟类，还是相反？H9亚型的流感A型病毒特别引人关注，因为由H5、H7和H10流感病毒引起的致命感染中包含有来自H9病毒的RNA片段。最近，报道了一种新型的流感A型病毒（H19），其血凝素结构与蝙蝠中的H9流感A型病毒密切相关。新型H19的基因组揭示了鸟类和蝙蝠流感病毒混合的基因组特征。最近共同祖先（TMRCA）的估计表明，蝙蝠和鸟类中H9相似流感病毒的分化时间大约发生在18世纪末。本文讨论了从蝙蝠和鸟类中分离出的H9亚型流感病毒的进化及其可能的起源。获得的数据与已知数据相结合，表明野生鸟类是H9流感病毒的主要宿主，病毒从中传播到蝙蝠。我们假设新型H19可能是介于鸟类和蝙蝠宿主过渡阶段的中间型流感病毒的子代。