Pathogenesis of respiratory syncytial virus infection in ferret and fetal human tracheas in organ culture.

The pathogenesis of human respiratory syncytial virus infection was studied in ferret and fetal human tracheas in organ culture. Although the patterns of virus growth were similar in these species, the sites and morphologic consequences of virus replication differed markedly. In human trachea, synthesis of respiratory syncytial virus occurred in a population of ciliated epithelial cells, whereas other cells in the epithelial layer were spared. Virus replication was associated with cell injury characterized by ballooning degeneration and syncytium formation. In ferret trachea, virus growth occurred in fibroblasts of the lamina propria and serosa. Ciliated epithelial cells did not contain viral antigen and remained histologically normal. These observations are relevant to understanding the pathogenesis of human disease and the evaluation of animal models of respiratory syncytial virus bronchiolitis.