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目的查明杭州某县市一家幼儿园无菌性脑炎疫情的流行病学特征及病原。方法通过查阅幼儿园晨检、因病缺课记录;某医院发热门诊就诊记录和现场个案调查展开流行病学调查。采集患儿粪便、血清标本先通过荧光RTPCR和ELISA方法初筛,然后选肠道病毒通用阳性标本进行病毒分离、培养;通过逆转录-聚合酶链反应(RT-PCR)鉴定上述培养物,并扩增埃可病毒9型(简称ECHO-9)VP1区全长基因和序列测定,利用生物信息学软件对序列进行分析,构建基因进化树。结果该幼儿园共累计报告病例18例,发热、头痛、呕吐为主要症状。从采集的7份样本中分离到ECHO阳性毒株2株,VP1基因全序列测定结果显示其与ECHO-9代表株核苷酸和氨基酸的相似性最高,分别为73.5%~93.6%、85.4%~97.0%。结论引起此次疫情的病原为ECHO-9。进化树分析表明与近年来已报道的ECHO-9相比有一定的亲缘关系。
Objective To identify the epidemiological characteristics and pathogens of aseptic encephalitis in a kindergarten in a county in Hangzhou. Methods The epidemiological investigation was conducted by referring to the morning kindergarten examination, the record of absence due to illness, the visiting records of fever clinic in a hospital and the case investigation on site. The stool samples of children were collected and the serum samples were initially screened by fluorescent RTPCR and ELISA. Then, the virus was isolated and cultured with universal positive samples of enterovirus. The above cultures were identified by reverse transcription-polymerase chain reaction (RT-PCR) The full length gene and sequence of VP1 gene of Echovirus 9 (ECHO-9) were amplified and bioinformatics software was used to analyze the sequence to construct the phylogenetic tree. Results The kindergarten accumulated a total of 18 reported cases, fever, headache, vomiting as the main symptoms. Two strains of ECHO positive isolates were isolated from 7 samples collected. The results of VP1 gene sequence analysis showed that the nucleotide and amino acid identities of ECHO-9 were 73.5% -93.6%, 85.4% ~ 97.0%. Conclusion The cause of the outbreak is ECHO-9. Phylogenetic tree analysis showed that there was a certain genetic relationship with ECHO-9 which has been reported in recent years.