ABSTRACT
Cough is a defensive and clearing mechanism that functions to remove mechanical and chemical irritants and debris from the airways. Cough may occur as a single event or as a cough “epoch”that includes several or many expiratory efforts in a single episode. This chapter discusses the epidemiology and burden of cough, the physiology of cough as it relates to viral infection and the viruses commonly associated with cough in children. It also discusses the gaps in clinical and public health knowledge that need to be addressed by high-quality studies. To appreciate the physiology of cough related to viral infections, one needs a basic understanding of the physiology of the three phases of cough. These are inspiratory phase, compressive phase, and expiratory phase. Cough can be voluntarily initiated or suppressed except when it is part of the laryngeal expiratory reflex when the larynx is mechanically stimulated by foreign materials.
