Respiratory virus are the most frequent cause of asthma attacks, and are responsible for more than 80% of episodes of wheezing in children. Atopic subjects have a higher risk of respiratory virus infections, benign or severe, than healthy persons. In children older than 8 years, most respiratory infections are caused by rhinovirus (RV). RV colonizes the respiratory epithelium and provokes a symptomatic rhinitis by non-inflammatory routes (with non involvement of leucocytes). In the nose the most importance of these routes are nerves. In the lower respiratory airways, infection with RV causes an inflammatory reaction with persistence of eosinophils. IL-8 and the other cytokines produced by the infected epithelium extend the action of eosinophils and the inflammatory reaction. The viral/inflammatory pathway is an important new target for development of strategies for the prevention of asthma.