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目的了解河北地区1例儿童手足口病病原学特征。方法采集1例手足口病患儿支气管病理组织切片并做免疫组化分析。培养病变组织标本并分离EV71。经RT-PCR扩增EV71毒株基因及其VP1区基因,经基因测序并构建进化树,分析毒株病原特征。结果患儿支气管黏膜脱落,甚至发生坏死并伴有淋巴细胞浸润,局部小血管内形成小血栓。免疫组化分析,在支气管组织细胞中检测到阳性抗原信号,且主要集中在上皮细胞的胞浆内。RT-PCR扩增,EV71基因目的片段长度约为226bp。确定EV71阳性的标本采用RT-PCR扩增EV71毒株的VP1区基因序列,目的片段大小约为839bp。基因测序及核苷酸序列比对显示,所测序列未发生突变。构建EV71-VP1区核苷酸序列进化树,本研究中的EV71毒株属于C4亚型,其与FJ606448株的同源性达99%,未发生基因突变。结论本研究分离的EV71毒株未发生变异,与北京流行毒株同属于C4亚型,同源性较高,揭示人口流动对EV71病毒株传播影响的重要性,为河北地区儿童手足口病的临床防治提供指导。
Objective To understand the etiological characteristics of 1 case of hand-foot-mouth disease in children in Hebei province. Methods One case of hand-foot-mouth disease in children with bronchial pathological tissue sections and immunohistochemical analysis. The diseased tissue specimens were cultured and EV71 was isolated. The gene of EV71 and its VP1 region were amplified by RT-PCR. The gene sequences were sequenced and the phylogenetic tree was constructed to analyze the pathogenicity of the strain. Results Children with bronchial mucosal shedding, and even necrosis accompanied by lymphocytic infiltration, local small blood vessels formed small thrombus. Immunohistochemical analysis detected positive antigen signals in bronchial cells, and mainly concentrated in the cytoplasm of epithelial cells. RT-PCR amplification, EV71 gene fragment length of about 226bp. EV71-positive specimens were confirmed by RT-PCR amplification of EV71 strains VP1 gene sequence, the size of the fragment of about 839bp. Gene sequencing and nucleotide sequence alignment showed no mutation in the tested sequences. The EV71-VP1 region nucleotide sequence evolutionary tree was constructed. The EV71 strain in this study belongs to the C4 subtype, which has 99% identity with FJ606448 and no gene mutation occurs. Conclusion The EV71 strains isolated in this study did not mutate. They belong to the same subtype as the C4 subtype in Beijing and have high homology. This study reveals the importance of population mobility on the spread of EV71 virus strains, Clinical prevention and treatment to provide guidance.