ABSTRACT
This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book describes respiratory viruses are important human pathogens due to their propensity to cause disease and their fast transmission rate among humans via aerosols. They are the most common cause of infection and frequently lead to a large burden of illness and increased mortality, as well as high socioeconomic cost. The consequence of respiratory viral infections is clearly dependent upon complex interactions between the host and pathogen. The importance of any shift in these interactions is illustrated by the enhanced susceptibility of those with chronic respiratory disease to infection. Viral respiratory tract infections remain an important medical and social problem, ranging from trivial infections to life-threatening episodes. As knowledge in regard to the innate immune response in the airways has increased, it is becoming increasingly recognized that this early response is crucial in determining the outcome of virus infection.
