1起学校诺如病毒急性胃肠炎暴发的病原学检测

目的 对1起学校急性胃肠炎暴发疫情进行病原学检测分析。方法 对该学校暴发疫情的急性胃肠炎病例、厨房工作人员及病例对照采集肛拭子标本,提取核酸RNA,应用实时荧光RT-PCR试剂盒进行诺如病毒、札如病毒、轮状病毒、腺病毒、星状病毒检测,对阳性标本进行核衣壳编码区RT-PCR扩增、序列测定和系统进化分析。结果 21份患者肛拭样本中有16份GII型诺如病毒实时荧光RT-PCR阳性;所有标本的札如病毒、轮状病毒、腺病毒、星状病毒检测阴性。14份诺如病毒核酸阳性标本获得321bp目标片段序列,彼此间核苷酸相似性100%,提示同一来源;GenBank的BLAST结果显示,本次诺如病毒疫情毒株与GⅡ.2的参考株AY134748(Snowmoutain/1976/US)、X81879 (Melksham/1989)同源性最高,进化树上处于同一进化分支,属于GⅡ.2群。结论 该起学校急性胃肠炎暴发疫情是由诺如病毒GⅡ.2感染所致。

Pathogen detection of an acute gastroenteritis outbreak caused by Norovirus in a school

Objective To understand the pathogen of an acute gastroenteritis outbreak in a school. Methods Anal swab specimens were collected from the acute gastroenteritis cases, kitchen staff and case-controls in the school. Nucleic acid RNA extractions were conducted and detected by using real-time fluorescent RT-PCR kit targeted for Norovirus, sapovirus, rotavirus,, adenovirus, and astrovirus. The positive samples were subjected to RT-PCR amplification, sequencing and phylogenetic analysis targeted of the nucleocapsid coding area. Results There were positive results for GII type of Norovirus in 16 of 21 acute gastroenteritis cases, and negative for the other four gastroenteritis viruses to all samples. The 321bp targeted fragment sequences were obtained from 14 Norovirus nucleic acid positive samples, and the similarity was 100% between each other, suggesting from the same source. The BLAST results in GenBank showed that, the homology was high between the epidemic virus strains and the reference strain of Norovirus genotype GII.2, AY134748 (Snowmoutain/1976/US) and X81879 (Melksham/1989), evolving in the same evolutionary branch. Conclusion This outbreak of acute gastroenteritis in the school is caused by the Norovirus genotype GII.2.