诺如病毒新型GII.4流行株Sydney_2012在上海地区的检出和鉴定

The Emergence of Novel GII.4Norovirus Variant,Sydney_2012,in Shanghai,China

为了解上海地区诺如病毒相关急性胃肠炎疫情的流行病学特点及流行株基因型的演化情况，2012年3月至2013年2月，收集上海市两处哨点医院成人急性胃肠炎粪便样本进行诺如病毒的分子检测并对其基因特征进行系统分析。在502份样本中，GI群共检出19例，检出率3．78％，呈现低位流行、全年散发的状态，无明显的季节分布；GII群检出86例，检出率17．13％，在10～12月出现高位流行，并发现中老年人群GII群诺如病毒检出率显著高于青年个体（Pd0．05）。同时首次于2012年9月在上海地区检出新型GII．4变异株Sydney-2012，证实是该变异株引发了2012年秋冬季诺如病毒急性胃肠炎的高位流行。序列分析表明该变异株为GII．e型开放阅读框（Openreadingframe，ORF）1与GII．4型ORF2的重组体，目前已成为本地区的优势流行株。研究发现，2012年上海地区出现GII．4新型变异株Sydney_2012，并引发秋冬季诺如病毒急性胃肠炎的高位流行。

To describe the epidemiological characteristics of norovirus （NOV） associated acute gastroenteri- tis in Shanghai and characterize the evolution pattern of circulating strains. From March 2012 to February 2013, 502 stool specimens were collected from adult （≥16 years） outpatients who visited either of the two sentinel hospitals in Shanghai for acute gastroenteritis. Molecular detection and genotyping of NoV were performed and the phylogenetic relationship of the circulating strains has also been comprehensively ana- lyzed. The epidemics level of GI NoV was low throughout the surveillance period, with the positive rate of 3.78% （19 cases）, and no seasonality of GI NoV infection could be distinguished. For GII genogroup, higher epidemics in adults in Shanghai, with the detection rate of 17.13% （86 cases）, were observed. And relatively high epidemics of GII NoV infection were spotted between October and December in 2012. The frequency of NoV associated acute gastroenteritis in older people is significantly higher than that in young individuals （P〈0.05）. Sequencing and genotyping analysis revealed that the high epidemics of GII NoV infection between October and December in 2012 is associated with the emergence of a novel OIL 4 norovir us strain, termed Sydney_2012. Sequence analysis also demonstrated that this was a recombinant virus be tween a GII. e polymerase and GII. 4 capsid, which has also been the dominant circulating strain in Shang- hai. In 2012, a new GII. 4 variant, of acute gastroenteritis during late termed Sydney_2012, emerged in Shanghai and caused high epidemics autumn and winter.