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Abstract：
Norovirus (NoV) is the major cause of acute gastroenteritis across all age groups. In particular, variants of genogroup II, genotype 4 (GII.4) have been associated with epidemics globally, occurring approximately every three years. The pandemic GII.4 variant, Sydney 2012, was first reported in early 2012 and soon became the predominant circulating NoV strain globally. Despite its broad impact, both clinically and economically, our understanding of the fundamental diversity and mechanisms by which new NoV strains emerge remains limited. In this study, we describe the molecular epidemiological trends of NoV-associated acute gastroenteritis in Australia and New Zealand between January 2013 and June 2014.
Overall, 647 NoV-positive clinical faecal samples from 409 outbreaks and 238 unlinked cases of acute gastroenteritis were examined by RT-PCR and sequencing. Phylogenetic analysis was then performed to identify NoV capsid genotypes and to establish the temporal dominance of circulating pandemic GII.4 variants. Recombinant viruses were also identified based on analysis of the ORF1/2 overlapping region.
Peaks in NoV activity were observed, however the timing of these epidemics varied between different regions. Overall, GII.4 NoVs were the dominant cause of both outbreaks and cases of NoV-associated acute gastroenteritis (63.1%, n = 408/647), with Sydney 2012 being the most common GII.4 variant identified (98.8%, n = 403/408). Of the 409 reported NoV outbreaks, aged-care facilities were the most common setting in both Western Australia (87%, n = 20/23) and New Zealand (58.1%, n = 200/344) while most of the NoV outbreaks were reported from hospitals (38%, n = 16/42) in New South Wales, Australia. An analysis of a subset of non-GII.4 viruses from all locations (125/239) showed the majority (56.8%, n = 71/125) were inter-genotype recombinants. These recombinants were surprisingly diverse and could be classified into 18 distinct recombinant types, with GII.P16/GII.13 (24% of recombinants) the most common.
This study revealed that following its emergence in 2012, GII.4 Sydney 2012 variant continued to be the predominant cause of NoV-associated acute gastroenteritis in Australia and New Zealand between 2013 and 2014.
Overall, 647 NoV-positive clinical faecal samples from 409 outbreaks and 238 unlinked cases of acute gastroenteritis were examined by RT-PCR and sequencing. Phylogenetic analysis was then performed to identify NoV capsid genotypes and to establish the temporal dominance of circulating pandemic GII.4 variants. Recombinant viruses were also identified based on analysis of the ORF1/2 overlapping region.
Peaks in NoV activity were observed, however the timing of these epidemics varied between different regions. Overall, GII.4 NoVs were the dominant cause of both outbreaks and cases of NoV-associated acute gastroenteritis (63.1%, n = 408/647), with Sydney 2012 being the most common GII.4 variant identified (98.8%, n = 403/408). Of the 409 reported NoV outbreaks, aged-care facilities were the most common setting in both Western Australia (87%, n = 20/23) and New Zealand (58.1%, n = 200/344) while most of the NoV outbreaks were reported from hospitals (38%, n = 16/42) in New South Wales, Australia. An analysis of a subset of non-GII.4 viruses from all locations (125/239) showed the majority (56.8%, n = 71/125) were inter-genotype recombinants. These recombinants were surprisingly diverse and could be classified into 18 distinct recombinant types, with GII.P16/GII.13 (24% of recombinants) the most common.
This study revealed that following its emergence in 2012, GII.4 Sydney 2012 variant continued to be the predominant cause of NoV-associated acute gastroenteritis in Australia and New Zealand between 2013 and 2014.
摘要：
诺如病毒（NoV）是所有年龄组急性胃肠炎的主要原因。特别是,基因组II的变体，基因型4（GII.4）与全球流行病有关，大约每三年发生一次。大流行GII.4变种，悉尼2012年，于2012年初首次报道，并很快成为全球主要的NoV病毒株。尽管影响广泛,在临床和经济上，我们对新NoV菌株出现的基本多样性和机制的理解仍然有限。在这项研究中,我们描述了2013年1月至2014年6月澳大利亚和新西兰NoV相关性急性胃肠炎的分子流行病学趋势.
总的来说，通过RT-PCR和测序检查了409例暴发和238例急性胃肠炎的647例NoV阳性临床粪便样本。然后进行系统发育分析以鉴定NoV衣壳基因型并建立循环大流行GII.4变体的时间优势。还基于ORF1/2重叠区的分析鉴定了重组病毒。
观察到NoV活性的峰值，然而，这些流行病的时间在不同地区之间有所不同。总的来说,GII.4NoVs是NoV相关急性胃肠炎暴发和病例的主要原因(63.1%,n=408/647),悉尼2012年是最常见的GII.4变种(98.8%，n=403/408）。在报告的409起NoV疫情中，老年护理设施是两个西澳大利亚州最常见的环境(87%，n=20/23)和新西兰(58.1%，n=200/344)，而大多数NoV疫情是由医院报告的(38%，n=16/42）在新南威尔士州，澳大利亚。对来自所有地点的非GII.4病毒子集（125/239）的分析表明，大多数（56.8％，n=71/125)是基因型间重组体。这些重组体令人惊讶地多样化，可以分为18种不同的重组类型，GII。P16/GII.13(24%的重组体)最常见。
这项研究表明，在2012年出现之后，GII.4悉尼2012变种在2013年至2014年期间仍然是澳大利亚和新西兰NoV相关急性肠胃炎的主要原因。
总的来说，通过RT-PCR和测序检查了409例暴发和238例急性胃肠炎的647例NoV阳性临床粪便样本。然后进行系统发育分析以鉴定NoV衣壳基因型并建立循环大流行GII.4变体的时间优势。还基于ORF1/2重叠区的分析鉴定了重组病毒。
观察到NoV活性的峰值，然而，这些流行病的时间在不同地区之间有所不同。总的来说,GII.4NoVs是NoV相关急性胃肠炎暴发和病例的主要原因(63.1%,n=408/647),悉尼2012年是最常见的GII.4变种(98.8%，n=403/408）。在报告的409起NoV疫情中，老年护理设施是两个西澳大利亚州最常见的环境(87%，n=20/23)和新西兰(58.1%，n=200/344)，而大多数NoV疫情是由医院报告的(38%，n=16/42）在新南威尔士州，澳大利亚。对来自所有地点的非GII.4病毒子集（125/239）的分析表明，大多数（56.8％，n=71/125)是基因型间重组体。这些重组体令人惊讶地多样化，可以分为18种不同的重组类型，GII。P16/GII.13(24%的重组体)最常见。
这项研究表明，在2012年出现之后，GII.4悉尼2012变种在2013年至2014年期间仍然是澳大利亚和新西兰NoV相关急性肠胃炎的主要原因。
