河南省汝阳县婴幼儿流行性喘憋性肺炎暴发流行的病原学研究

Etiological study on an outbreak of epidemic asthma like pneumonia of infants and children in Ruyang county, Henan province, China

目的 了解 1999年 11月～ 2 0 0 0年 1月我国河南省汝阳县婴幼儿流行性喘憋性肺炎(简称流喘肺炎 )暴发流行的病原。方法 分别采集 12例流喘肺炎患儿的咽拭子和鼻咽分泌物标本进行病毒分离、间接免疫荧光检测常见的呼吸道病毒抗原以进行快速诊断 ;用RT PCR对分离到的呼吸道合胞病毒 (RSV)株进行分型 ;16例用免疫荧光法检测双份血清中RSV抗体滴度 ;用核苷酸序列测定对分离到的病毒株进行基因分析。结果 12例患儿咽拭子标本中 (除 1例污染外 ) 4例分离到RSV ,阳性率为 36 % ,3例为A亚型 ,1例为B亚型 ;12例鼻咽分泌物脱落细胞经免疫荧光法检测 9例为RSV阳性 ,阳性率为 75 % ,未检测到其它呼吸道病毒 ;16例患儿双份血清中 ,有 10例 (6 3 % )恢复期血清RSV特异性IgG抗体比急性期有 4倍以上升高 ,分离株F蛋白基因的部分序列测定显示与RSV的A亚型标准株有较高的同源性。

Objective To identify and characterize the etiological agent of an outbreak of epidemic asthma like pneumonia among infants and young children 2 months to 2 years old in Ruyang county, Henan province, China from November 1999 to January 2000. More than 5 000 patients with the asthma like wheezing and stress in breathing and pneumonia were sent to the county hospital and 9 died during that outbreak. Methods Nasopharyngeal aspirates and throat swabs collected from sick children were inoculated to Hep 2 cells as soon as the specimens were collected. Respiratory viral antigens, such as respiratory syncytial virus (RSV), influenza virus, parainfluenza virus, and adenovirus were detected from the pellets of the specimens by using indirect immunofluorescence technique. With RT PCR and cDNA sequencing the authors typed RSV strains isolated from the specimens. Paired sera were collected from sick children and RSV specific antibody was detected by using indirect immunofluorescence technique. Results Out of 12 throat swab specimens, RSV was isolated from 4 specimens (positive rate was 36%) and RSV antigen was detected from 9 specimens (positive rate was 75%). No other respiratory viral antigen was detected. Out of 4 RSV strains isolated, 3 were RSV subtype A and 1 subtype B, which was determined by RT PCR. RSV specific antibody titer increased ≥ 4 folds in 10 out of 16 paired sera (63%) collected during the outbreak. Sequence analysis of the cDNA from amplified the F gene segment of the RSV isolates showed high homology with RSV prototype subtype A. Conclusion Data presented here indicated that RSV subtype A was the etiological agent of the outbreak.