The Fluid Dynamics of Respiratory Disease Transmission

致命病毒（如甲型H1N1流感、严重急性呼吸系统综合症）和细菌（如肺结核）感染的出现和爆炸性传播是一个全球关心的问题，对人类和经济造成巨大后果。人口和网络疾病模型可以深入了解这些公共卫生威胁的传播，并指导旨在减轻这些威胁的政策。在这些模型中，接触的中心概念极大地影响了疾病流行的结果，但其定义仍然模糊不清。这个项目通过发展我们对呼吸系统疾病传播的流体动力学的理解，澄清了接触的概念。本文将越来越复杂的数学模型与模拟实验室实验相结合，阐明了与接触和疾病传播直接相关的几个流体动力学问题。具体而言，本项目阐明了影响呼吸道内飞沫传播病原体的产生和运输的因素，以及它们随后通过咳嗽、打喷嚏或正常呼吸在空气中传播的因素。这些模型对病原体通过呼吸传播的范围和功效产生了有价值的见解，从而指导了在医院和飞机等密闭环境中管理受感染患者的政策。本研究强调了流体动力学在疾病传播中的关键作用，并提出了解决经典疾病传播数学模型中开放性问题的新方法。一个主要目标是完善作为流行病学模型输入的接触量化，从而提高其预测准确性。该研究还将提高空气传播的数学模型的标准，利用已建立的多相、多尺度界面流动的数学模型来阐明通过携带细菌或病毒的空气飞沫感染可能性的影响因素。因此，该研究可以为密闭环境中呼吸道疾病接触的建模提供信息，从而指导医院和飞机上疾病传播的政策。最后，该项目具有变革性，将现代流体动力学的数学框架引入了一类新的重要生物医学问题。通过将这些问题引入传统上存在于应用数学、工程和物理系的流体力学界，它开创了一个令人兴奋的跨学科科学分支。

The emergence and explosive spread of virulent viral (e.g. H1N1, SARS) and bacterial (e.g. Tuberculosis) infections is a problem of global interest with enormous human and economic consequences. Population and network disease models yield insight into, and guide policy aimed at mitigating, the spread of these public health threats. In such models, the central notion of contact greatly influences the disease epidemic outcomes, but its definition remains nebulous. This project clarifies the notion of contact through developing our understanding of the fluid dynamics of respiratory disease transmission. A hierarchy of mathematical models of increasing complexity are combined with analogue laboratory experiments to elucidate several fluid dynamics problems bearing directly on contact and disease spread. Specifically, this project elucidates the factors influencing the generation and transport of droplet-borne pathogens inside the respiratory tract, and their subsequent dispersal through the air via coughing, sneezing or normal breathing. Such models yield valuable insight into the range and efficacy of pathogen transport via exhalation and so guide policy on the management of infected patients in confined environments such as hospitals and airplanes.This research highlights the key role played by fluid dynamics in disease transmission, and suggests novel approaches to open questions in the classical mathematical modeling of disease spread. One principal goal is to refine the quantification of contact as input for epidemiological models, thus improving their predictive accuracy. The research will also raise the bar on the mathematical modeling of airborne transmission, by drawing on established mathematical models of multiphase, multiscale interfacial flows to elucidate the factors influencing the likelihood of infection via bacteria- or virus-laden airborne droplets. The research can thus inform the modeling of contact in respiratory diseases in confined environments, and so guide policy for disease transmission in hospitals and airplanes. Finally, the project is transformative, bringing the mathematical framework of modern fluid dynamics to a new class of important biomedical problems. Through introducing these problems to the fluid dynamics community, as resides traditionally in applied mathematics, engineering and physics departments, it initiates an exciting branch of interdisciplinary science.