Viral etiology and epidemiology of acute lower respiratory tract infections in Korean children.

Viral etiologic agents of acute lower respiratory tract infections were studied from November, 1990, through April, 1994, in Korean children. From 712 children who visited or were admitted to Seoul National University Children's Hospital because of acute lower respiratory tract infections, 804 nasal aspirates were collected; viral agents were detected by virus isolation and virus antigen was detected by indirect immunofluorescent staining. One or more viral agents were identified in 369 (45.9%) cases; of which 3.3% were mixed infections. The pathogens identified were respiratory syncytial virus (27.2%), parainfluenza virus type 3 (7.8%), influenza A virus (3.9%), adenovirus (3.9%), parainfluenza virus type 1 (1.7%), influenza B virus (1.4%), parainfluenza virus type 2 (0.5%), measles virus (0.1%) and others (0.9%). The clinical patterns of viral lower respiratory tract included pneumonia (56.6%), bronchiolitis (35.2%), croup (6.5%) and tracheo-bronchitis (1.6%). Infections with respiratory syncytial virus, parainfluenza virus types 1 and 3 and influenza A and B virus occurred in epidemics, whereas adenovirus was isolated sporadically throughout the study period. The data expand our understanding of the epidemiology of acute viral lower respiratory tract infections in Korean children and may be helpful to the clinicians and researchers interested in the control of viral respiratory tract infections.