[Epidemiological study on respiratory syncytial virus and its bronchopneumonia among children in Suzhou].
OBJECTIVE
To probe the epidemiological trend of respiratory syncytial virus (RSV) and cellular immunological change of RSV bronchopneumonia among children in Suzhou in the past five years.


METHODS
10,205 children with acute respiratory tract infection from January 2001 to December 2005 were enrolled into the study. Nasopharyngeal aspirates were obtained from the respiratory tract by aseptic vacuum aspiration. Direct immuno-fluorescence assay was employed to detect seven kinds of virus antigens including RSV antigen. CD3, CD4, CD8, CD19, CD16 and CD56 in peripheral blood mononuclear cells of 30 patients with RSV bronchopneumonia (1.5-24.0 months old group) were analyzed by flow cytometry analysis, and 15 normal infants (1.5-24.0 months old group) were enrolled as control group.


RESULTS
The annual positive rate of RSV was 24.94%, 25.83%, 24.05%, 25.39% and 27.30% respectively from 2001 to 2005. It also found that the peak season for RSV infection was spring or winter (January to March or November to December). The positive rate of RSV was significantly higher in 1-12 months old group than that in > 12 months old group (chi2 = 97.320, P < 0.01), as well as the groups between 1-12 months old (chi2 = 7.804, P < 0.05, the highest positive rate was occurred at 3-6 months old group). The positive rate of RSV was significantly higher in boys than that in girls (chi2 = 9.693, P < 0.01). The percentages of CD3+, CD4+, CD8+ and NK (CD16 + 56)+ cells were significantly lower in RSV bronchopneumonia than those in control group (t = 3.199, P < 0.01; t = 2.215, P < 0.05; t = 2.619, P < 0.05 and t = 5.240, P < 0.01, respectively). While the percentage of CD19+ cells was significantly elevated in RSV bronchopneumonia than that in control group (t = 2.875, P < 0.01).


CONCLUSIONS
RSV infection is of obvious seasonal changes. The younger the patient, the higher positive rates of RSV infection is, while and the cellular immunity function is lower. The effective measures for preventing RSV infection are important, especially for the infants. Further investigation is necessary to understand the causes of the variations for RSV infections between boys and girls.
Zhang
Xue-lan
XL
Clinical Laboratory Children's Hospital Affiliated to Soochow University, Suzhou, China.
Ji
Wei
W
Ji
Zheng-hua
ZH
Ding
Yun-fang
YF
Zhu
Hong
H
Yan
Yong-dong
YD
Huang
Yi-ping
YP
He
Ya-xiang
YX
Ye
Jian-xin
JX
Ji
Xue-qiang
XQ
D000293:Adolescent; D001996:Bronchopneumonia / Q000453:epidemiology* / Q000276:immunology / Q000821:virology*; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology* / Q000276:immunology; D012136:Respiratory Syncytial Viruses