Webster R G, Wright S M, Castrucci M R, Bean W J, Kawaoka Y
Department of Virology/Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tenn. 38101.
Intervirology. 1993;35(1-4):16-25. doi: 10.1159/000150292.
Influenza A viruses continue to emerge from the aquatic avian reservoir and cause pandemics. Phylogenetic analysis of the nucleotide sequence of all eight influenza A virus RNA segments indicate that all of the influenza viruses in mammalian hosts originate from the avian gene pool. In contrast to the rapid progressive changes in both the nucleotide and amino acid sequences of mammalian virus gene lineages, avian virus genes show far less variation and, in most cases, appear to be in evolutionary stasis. There are periodic exchanges of influenza virus genes or whole viruses between species giving rise to pandemics of diseases in humans, lower animals and birds. The periodic emergence of influenza viruses in mammalian species has been illustrated by the appearance of a new influenza virus in horses in northern China in 1989. Phylogenetic analysis of classical H1N1, avian-like H1N1 and human H3N2 viruses circulating in Italian pigs reveals that genetic reassortment is taking place between avian- and human-like viruses in the European pig population. These studies provide evidence supporting the possibility that pigs serve as a mixing vessel for reassortment between influenza viruses in mammalian and avian hosts and raise the question of whether the next pandemic of influenza will emerge in Europe!
甲型流感病毒不断从水生禽类宿主中出现并引发大流行。对甲型流感病毒所有八个RNA片段的核苷酸序列进行系统发育分析表明，哺乳动物宿主中的所有流感病毒均起源于禽类基因库。与哺乳动物病毒基因谱系的核苷酸和氨基酸序列快速渐进变化不同，禽类病毒基因的变异要少得多，而且在大多数情况下，似乎处于进化停滞状态。流感病毒基因或整个病毒在物种之间会定期交换，从而引发人类、低等动物和鸟类的疾病大流行。1989年中国北方马匹中出现一种新型流感病毒，这说明了流感病毒在哺乳动物物种中的周期性出现。对意大利猪群中流行的经典H1N1、禽源样H1N1和人类H3N2病毒进行系统发育分析发现，欧洲猪群中的禽源样病毒和人类源样病毒之间正在发生基因重配。这些研究提供了证据，支持猪作为哺乳动物和禽类宿主中流感病毒重配的混合载体的可能性，并提出了下一次流感大流行是否会在欧洲出现的问题！
