Dennehy John J
Biology Department, Queens College of the City University of New York, Queens, New York and The Graduate Center of the City University of New York, New York, New York.
Ann N Y Acad Sci. 2017 Feb;1389(1):124-146. doi: 10.1111/nyas.13304. Epub 2016 Dec 30.
The cross-species transmission of viruses into new host populations, termed virus emergence, is a significant issue in public health, agriculture, wildlife management, and related fields. Virus emergence requires overlap between host populations, alterations in virus genetics to permit infection of new hosts, and adaptation to novel hosts such that between-host transmission is sustainable, all of which are the purview of the fields of ecology and evolution. A firm understanding of the ecology of viruses and how they evolve is required for understanding how and why viruses emerge. In this paper, I address the evolutionary mechanisms of virus emergence and how they relate to virus ecology. I argue that, while virus acquisition of the ability to infect new hosts is not difficult, limited evolutionary trajectories to sustained virus between-host transmission and the combined effects of mutational meltdown, bottlenecking, demographic stochasticity, density dependence, and genetic erosion in ecological sinks limit most emergence events to dead-end spillover infections. Despite the relative rarity of pandemic emerging viruses, the potential of viruses to search evolutionary space and find means to spread epidemically and the consequences of pandemic viruses that do emerge necessitate sustained attention to virus research, surveillance, prophylaxis, and treatment.
病毒跨物种传播到新宿主群体，即所谓的病毒出现，是公共卫生、农业、野生动物管理及相关领域的一个重大问题。病毒出现需要宿主群体之间存在重叠，病毒基因发生改变以允许感染新宿主，以及适应新宿主从而使宿主间传播可持续，所有这些都属于生态学和进化领域的范畴。要理解病毒如何以及为何出现，就需要对病毒生态学及其进化方式有深入的了解。在本文中，我探讨了病毒出现的进化机制以及它们与病毒生态学的关系。我认为，虽然病毒获得感染新宿主的能力并不困难，但通向病毒在宿主间持续传播的有限进化轨迹以及生态库中突变崩溃、瓶颈效应、种群统计随机性、密度依赖性和基因侵蚀的综合作用，将大多数出现事件限制为死胡同式的溢出感染。尽管大流行新兴病毒相对罕见，但病毒探索进化空间并找到流行传播方式的潜力以及确实出现的大流行病毒的后果，使得有必要持续关注病毒研究、监测、预防和治疗。
