Viral diversity in asthma.

Asthma exacerbations are precipitated primarily by respiratory virus infection and frequently require immediate medical intervention. Studies of childhood and adult asthma have implicated a wide variety of respiratory viruses in exacerbations. By focusing on both RNA and DNA respiratory viruses and some newly identified viruses, this review illustrates the diversity and highlights some of the uncertainties that exist in our understanding of virus-related asthma exacerbations.