The Fluid Dynamics of Respiratory Disease Transmission

致命病毒(如H1N1、SARS)和细菌(如结核病)感染的出现和爆炸性传播是一个全球关注的问题，具有巨大的人类和经济后果。人口和网络疾病模型提供了洞察和指导旨在缓解这些公共卫生威胁传播的政策。在这些模型中，接触的中心概念对疾病流行结果有很大影响，但其定义仍然模糊。这个项目通过发展我们对呼吸道疾病传播的流体动力学的理解，澄清了接触的概念。一系列日益复杂的数学模型与模拟的实验室实验相结合，阐明了几个直接与接触和疾病传播有关的流体动力学问题。具体地说，该项目阐明了影响飞沫传播的病原体在呼吸道内的产生和传播的因素，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。这些模型对通过呼气传播病原体的范围和有效性提供了有价值的见解，从而指导了在医院和飞机等受限环境中管理感染患者的政策。这项研究强调了流体动力学在疾病传播中所起的关键作用，并提出了在疾病传播的经典数学模型中解决开放问题的新方法。一个主要目标是改进作为流行病学模型输入的接触的量化，从而提高其预测准确性。这项研究还将提高空气传播的数学模型的门槛，方法是利用已建立的多相、多尺度界面流动的数学模型，阐明影响通过空气中携带细菌或病毒的微滴感染的可能性的因素。因此，这项研究可以为有限环境中呼吸道疾病的接触建模提供信息，从而指导医院和飞机上的疾病传播政策。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。通过将这些问题介绍给流体力学社区，正如传统上驻留在应用数学、工程和物理系中的那样，它启动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.