RESUMO
OBJECTIVES: To document the viral etiology of acute lower respiratory tract infection (ALRIs) in Chinese children. SETTING: Children Hospital, Zhejiang University, China. STUDY DESIGN: Cross-sectional. PARTICIPANTS: 34885 children with ALRI between January 2001 to December 2006. METHODS: Nasopharyngeal aspirates were collected from all subjects. Respiratory syncytial virus (RSV), adenovirus (ADV), type 1 to 3 parainfluenza viruses (PIV), and type A and B influenza virus (Flu) were detected by direct immunofluorescence. RESULTS: Viruses were identified in 32.3% cases, including RSV (23.6%), PIV 3 (4.3%), Flu A (2.0%), ADV (1.7%), PIV I (0.6%), Flu B (0.2%) and PIV 2 (0.1%). RSV and PIV 3 predominated in younger children while Flu A and Flu B predominated in older children (P<0.001, respectively). PIV 1 was more prevalent in children aged 1 to 3 years. The peak frequency of RSV, PIV 3 and Flu A were in early spring, June to August, and August and September, respectively. Flu B had a peak in the winter and spring. Adenovirus infections occurred in all seasons with a relatively constant frequency. CONCLUSIONS: Viruses are an important cause of ALRIs in Chinese children constituting 1/3 of total cases. RSV is the most common pathogen.