一起诺如病毒引起的急性胃肠炎暴发的分子流行病学分析

Molecular epidemiological analysis of acute gastroenteritis outbreak caused by norovirus

目的了解青岛市某小学暴发的一起急性胃肠炎中诺如病毒感染的分子流行特征。方法将收集到的患者的粪便标本27份,采用RT-PCR方法进行诺如病毒检测,阳性标本进行核苷酸序列测定和遗传进化树分析,确定基因型。结果青岛市2012年12月份暴发的病毒性胃肠炎,27份粪便标本中检测出9株阳性毒株,阳性率为33.33%,其中7株测序成功,2株由于病毒浓度较低而测序失败。检测出的7株阳性毒株进行同源性分析,结果显示所测序列与诺如病毒参考株JX459908_GⅡ-4/Sydney\NSW0514\2012\AU的同源性均为100%,证实为诺如病毒GⅡ型,利用基因进化树分析得出是由GⅡ.4亚型的诺如病毒引起。结论诺如病毒是引起此次急性胃肠炎暴发流行的主要病原体,且引起暴发的流行病毒株属于GⅡ.4型。

Objective To investigate the molecular epidemiological features of norovirus infection in an outbreak of norovirus gastroenteritis occurring in a school in Qingdao. Methods All the fecal specimens were examined with RT- PCR to detect the norovirus. The positive specimens were selected and subjected to sequencing and phylogenetic analysis to identify their genotypes. Results Viral gastroenteritis outbreaks in Qingdao in December 2012,9 strains of positive strains were detected in27 stool specimens,the positive rate was 33. 33%,among them 7 strains were sequenced successfully,2 strains of virus failed to sequence due to the low concentration. The detected 7 positive strains were conducted for homology analysis,the results showed the sequence was 100% homology with norovirus reference strains JX459908_GⅡ- 4 / Sydney ／ NSW0514 ／ 2012 ／ AU,and confirmed norovirus GⅡ. By using gene phylogenetic tree it was caused by GⅡ. 4 subtype of norovirus. Conclusion The findings suggest that norovirus are a major etiologicagent of gastroenteritis outbreak in Qingdao. The GⅡ. 4 is the predominant genotype.