VIRAL RESPIRATORY-INFECTIONS

Viral infections constitute more than 60% of acute lower respiratory i llnesses. Respiratory syncytial virus (RSV) and parainfluenza viruses are the most frequent etiologic agents. After transmission by large dr oplet aerosol or direct contact, the viruses gain entry into host cell s through specific viral surface proteins; subsequently, pathogenetic mechanisms cause tissue injury and result in clinical disease. In the intensive care unit the mainstay of treatment is primarily supportive. Nonspecific treatment may include nebulized P-agonists, aminophylline , and steroids. Ribavarin is the only specific antiviral agent approve d for respiratory syncytial virus infection but its efficacy remains c ontroversial. New therapies and vaccines offer hope for improved outco me from viral respiratory infections such as RSV.