Department of Virology, Erasmus Medical Centre, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
Vaccine. 2012 Jun 22;30(30):4419-34. doi: 10.1016/j.vaccine.2012.04.049. Epub 2012 Apr 24.
Human influenza viruses have their ultimate origin in avian reservoirs and may adapt, either directly or after passage through another mammalian species, to circulate independently in the human population. Three sets of barriers must be crossed by a zoonotic influenza virus before it can become a human virus: animal-to-human transmission barriers; virus-cell interaction barriers; and human-to-human transmission barriers. Adaptive changes allowing zoonotic influenza viruses to cross these barriers have been studied extensively, generating key knowledge for improved pandemic preparedness. Most of these adaptive changes link acquired genetic alterations of the virus to specific adaptation mechanisms that can be screened for, both genetically and phenotypically, as part of zoonotic influenza virus surveillance programs. Human-to-human transmission barriers are only sporadically crossed by zoonotic influenza viruses, eventually triggering a worldwide influenza outbreak or pandemic. This is the most devastating consequence of influenza virus cross-species transmission. Progress has been made in identifying some of the determinants of influenza virus transmissibility. However, interdisciplinary research is needed to further characterize these ultimate barriers to the development of influenza pandemics, at both the level of the individual host and that of the population.
人类流感病毒的终极起源是禽类宿主，它们可能会直接适应，或者在经过其他哺乳动物物种后适应，从而在人类中独立传播。一种人畜共患流感病毒要成为人类病毒，必须跨越三组障碍：动物到人类的传播障碍、病毒与细胞的相互作用障碍以及人与人的传播障碍。对允许人畜共患流感病毒跨越这些障碍的适应性变化进行了广泛研究，为改善大流行准备工作提供了关键知识。这些适应性变化中的大多数都将病毒获得的遗传改变与特定的适应机制联系起来，这些机制可以作为人畜共患流感病毒监测计划的一部分，通过遗传和表型进行筛选。人畜共患流感病毒只是偶尔跨越人与人的传播障碍，最终引发全球流感爆发或大流行。这是流感病毒跨物种传播最具破坏性的后果。在确定流感病毒传播能力的一些决定因素方面已经取得了进展。然而，需要开展跨学科研究，以进一步描述个体宿主和人群中流感大流行发展的这些最终障碍。
