OBJECTIVETo evaluate the viral pathogen of pneumonia in children.

METHODSA total of 13 642 cases of children pneumonia in 3 years were enrolled in this study. Antigens of viral pathogen in respiratory excretion, including respiratory syncytial virus (RSV), type 1, 2 and 3 parainfluenza virus, type A and B influenza virus, and adenovirus were detected by direct immunofluorescence method.

RESULTSViral pneumonia accounted for 34.3% of all cases, including 25.8% cases of RSV, 4.7% of parainfluenza virus, 2.4% of type A influenza virus, 0.2% of type B influenza virus and 1.3% of adenovirus. Coinfection was found in 20 cases, in which 17 cases (85%) were infected with RSV and another virus. Positive rates of RSV in children < or = 1 year, 1 to 3 years, and >3 years were 33.1%, 19.7% and 5.1% with a significant difference (chi(2)(trend)=763.4, P < 0.001). The positive rate of adenovirus in children < or =1 year (0.7%) was significantly lower than that in children aged 1 to 3 years and in children >3 years (2.3% and 2.5%) (all P<0.01). The positive rate of type A influenza virus in children aged 1 to 3 years was higher than that in children < or =1 year (chi(2)=18.2, P<0.01). Type 1 parainfluenza virus was found in 1.2% children aged 1 to 3 years with most prevalence (P<0.05). Infection rates of type 3 parainfluenza in children < or =1 year, 1 to 3 years, and >3 years were 4.7%, 3.2% and 1.4% respectively with a significant difference (chi(2)(trend)=52.4, P<0.01). Although there were some differences of infection rate of RSV in different years, it tended to increase from November to next April with a highest rate of 62.8%. Type 3 parainfluenza virus and Type A influenza virus were almost sporadic while type A influenza virus was epidemic in August 2003 with an infection rate of 15.7%.

CONCLUSIONThe highest infection rate of viral pathogen of pneumonia in children is RSV and the follows are parainfluenza, influenza and adenovirus in turn.