Zhdanov Vladimir P, Kasemo Bengt
Sections of Nano and Biological Physics and Chemical Physics, Department of Physics, Chalmers University of Technology, Göteborg, Sweden; Boreskov Institute of Catalysis, Russian Academy of Sciences, Novosibirsk, Russia.
Sections of Nano and Biological Physics and Chemical Physics, Department of Physics, Chalmers University of Technology, Göteborg, Sweden.
Biosystems. 2020 Dec;198:104241. doi: 10.1016/j.biosystems.2020.104241. Epub 2020 Sep 5.
Some infections, including e.g. influenza and currently active COVID 19, may be transmitted via air during sneezing, coughing, and talking. This pathway occurs via diffusion and gravity-induced drift of single virions and respiratory droplets consisting primarily of water, including small fraction of nonvolatile matter, and containing virions. These processes are accompanied by water evaporation resulting in reduction of the droplet size. The manifold of information concerning these steps is presented in textbooks and articles not related to virology and the focus is there frequently on biologically irrelevant conditions and/or droplet sizes. In this brief review, we systematically describe the behavior of virions and virion-carrying droplets in air with emphasis on various regimes of diffusion, drift, and evaporation, and estimate the rates of all these steps under virologically relevant conditions. In addition, we discuss the kinetic aspects of the first steps of infection after attachment of virions or virion-carrying droplets to the epithelium, i.e., virion diffusion in the mucus and periciliary layers, penetration into the cells, and the early stage of replication. The presentation is oriented to virologists who are interested in the corresponding physics and to physicists who are interested in application of the physics to virology.
一些感染，例如流感和目前流行的新冠病毒感染，可能在打喷嚏、咳嗽和说话时通过空气传播。这种传播途径是通过单个病毒粒子以及主要由水组成（包括一小部分非挥发性物质且含有病毒粒子）的呼吸道飞沫的扩散和重力诱导漂移发生的。这些过程伴随着水的蒸发，导致液滴尺寸减小。关于这些步骤的大量信息在与病毒学无关的教科书和文章中有所呈现，并且重点常常放在生物学上不相关的条件和/或液滴尺寸上。在这篇简短的综述中，我们系统地描述了病毒粒子和携带病毒粒子的液滴在空气中的行为，重点关注扩散、漂移和蒸发的各种状态，并在病毒学相关条件下估计所有这些步骤的速率。此外，我们讨论了病毒粒子或携带病毒粒子的液滴附着到上皮细胞后感染的第一步的动力学方面，即病毒粒子在黏液和纤毛周围层中的扩散、侵入细胞以及复制的早期阶段。本文是为对相应物理学感兴趣的病毒学家以及对物理学在病毒学中的应用感兴趣的物理学家撰写的。
