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Molecular epidemiology and spatiotemporal dynamics of norovirus associated with sporadic acute gastroenteritis during 2013-2017, Zhoushan Islands, China.

ABSTRACT: A total of 1 590 fecal swabs and stool samples from sporadic acute gastroenteritis patients of all ages were collected from January 2013 to March 2018 in the Zhoushan Islands, China, with 99 (6.23%) samples subsequently identified as human norovirus (HuNoV) positive. Phylogenetic analysis of partial RdRp and VP1 gene regions identified 10 genotypes of the GII genogroup and 3 genotypes of the GI genogroup. The predominant genotype was GII.P17-GII.17 (42.86%, 33/77), followed by GII.Pe-GII.4_Sydney 2012 (24.68%, 19/77) and GII.P16-GII.2 (12.96%, 10/77). However, the prevailing genotype in the Zhoushan Islands has shifted on three separate occasions. The GII.Pe-GII.4_Sydney_2012 strain was dominant in 2013-2014, the GII.P17-17 strain was dominant in 2015-2016, and the GII.P16-GII.2 strain was dominant in 2017. Divergence analysis showed that the re-emerging GII.P16-GII.2 strains clustered with the Japanese 2010-2012 GII.P16-GII.2 strains, and the time of the most recent common ancestor was estimated to have occurred in 2012 to 2013. The evolutionary rates of the RdRp gene region of the GII.P16 genotype and the VP1 gene region of the GII.2 genotype were 2.64 × 10(-3) (95% HPD interval, 2.17-3.08 × 10(-3)) and 3.36 × 10(-3) (95% HPD interval, 2.66-4.04 × 10(-3)) substitutions/site/year, respectively. The migration pattern of the HuNoV GII.2 genotype in China demonstrated that the re-emerging GII.P16-GII.2 strains were first introduced into Hong Kong from Japan, and then spread from Hong Kong to other coastal areas. Our results also showed that the GII.P16-GII.2 strains in the Zhoushan Islands were likely introduced from Jiangsu Province, China, in 2016.

SUBMITTER: Chen C

PROVIDER: S-EPMC6051660 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundHuman norovirus is regarded as the leading cause of nonbacterial acute diarrhea in developing and developed countries. Among all genotypes, GII.4 has been the predominant genotype, but in East Asia, it was replaced by the GII.17 in 2014/2015. However, after the prevalence of new GII.17 variant in South China, a sharply increase in the number of norovirus infections associated with sporadic acute diarrhea was detected. In this study, we would investigate the prevalence and genetic diversity of noroviruses in the sporadic acute gastroenteritis cases in the post-GII.17 period in South China.MethodsNorovirus was screened from 217 patients with sporadic acute gastroenteritis from August 2015 to October 2017 by reverse transcription-polymerase chain reaction. Then, two regions including the partial RNA polymerase and the capsid gene of positive samples were amplified and sequenced. Phylogenetic analyses were performed to determine norovirus genotypes. Complete VP1 sequences of GII.4 strains detected in this study were also amplified and subjected into evolutionary tracing analyses.ResultsA total of 43 (19.82%) norovirus samples were confirmed from 217 stool specimens, and it was found that GII.4 resurged as the new predominant variant, accounting for 76.74% (33/43) of positive samples. Only one local strain GZ2015-L550 was clustered with the contemporary GII.P16/GII.4-2012 recombinant variant, and other 32 local strains belonged to the clade with the GII.Pe/GII.4-2012 variant. Other genotypes including GII.17 (n = 4), GII.3 (n = 4), GII.8 (n = 1) and GI. 6 (n = 1) were also detected. Furthermore, all GII.4 strains were phylogenetic analyzed based on their capsid P2 subdomains. Combined with other reported 754 strains, the GII.4-2012 variant could be divided into two clades. Most GII.4 strains collected in 2016 and 2017 in this study (7/8) formed a new cluster A in Clade II with additional 103 contemporaneous strains. In addition, evolutionary tracing of the capsid P2 subdomain of this variant was also analyzed, and one specific amino acid substitutions (N373) was identified for Cluster A.ConclusionIn summary, this study confirmed a norovirus infection peak in the post-GII.17 period in South China, which was caused by the resurgence of the GII.4 variant.

Project description:ObjectivesTo study the molecular epidemiological characteristics of norovirus in children with acute gastroenteritis from 2017 to 2019.MethodsA retrospective analysis was performed on the medical data of children with acute gastroenteritis who were admitted to Children's Hospital of Chongqing Medical University from January 2017 to December 2019. A total of 1 458 stool samples were collected from the children, and viral RNA was extracted. Reverse transcription polymerase chain reaction was used for gene amplification, sequencing, and genotype identification of the VP1 region of capsid protein in norovirus.ResultsAmong the 1 458 stool samples, 158 (10.8%) were positive for norovirus. There was no significant difference in the positive detection rate of norovirus between different years (P>0.05). Boys had a norovirus detection rate of 12.2% (105/860), which was significantly higher than that in girls (8.9%, 53/598) (P=0.043). The children aged 12 to <18 months had the highest norovirus detection rate (16.9%, 51/301). August, September, and October were the epidemic peak season. A total of 23 norovirus-positive samples were also positive for rotavirus. The norovirus detected were mainly GII type (97.5%, 154/158), and only 4 cases were GI type (2.5%, 4/158). The sequencing of the VP1 region of capsid protein in the positive samples showed that GII.4 (69.6%, 110/158) was the dominant genotype, among which 99 (62.7%, 99/158) were GII.4 Sydney 2012, followed by GII.3 (15.2%, 24/158), GII.2 (10.1%, 16/158), GII.6 (1.9%, 3/158), and GII.17 (0.6%, 1/158). GI.3 (1.3%, 2/158), GI.2 (0.6%, 1/158), and GI.5 (0.6%, 1/158) were rarely detected.ConclusionsNorovirus GII.4 Sydney 2012 was the major epidemic strain in the children with norovirus gastroenteritis from 2017 to 2019. Although norovirus infection can exist throughout the year, August to October is the peak period. During this period, norovirus surveillance and key population protection are strengthened to help prevent and control norovirus diarrhea.

Project description:BackgroundIn late 2016, an uncommon recombinant NoV genotype called GII.P16-GII.2 caused a sharp increase in outbreaks of acute gastroenteritis in different countries of Asia and Europe, including China. However, we did not observe a drastic increase in sporadic norovirus cases in the winter of 2016 in Huzhou. Therefore, we investigate the prevalence and genetic diversity of NoVs in the sporadic acute gastroenteritis (AGE) cases from January 2016 to December 2017 in Huzhou City, Zhejiang, China.MethodsFrom January 2016 to December 2017, a total of 1001 specimens collected from patients with AGE were screened for NoV by real-time RT-PCR. Partial sequences of the RNA-dependent RNA polymerase (RdRp) and capsid gene of the positive samples were amplified by RT-PCR and sequenced. Genotypes of NoV were confirmed by online NoV typing tool and phylogenetic analysis. Complete VP1 sequences of GII.P16-GII.2 strains detected in this study were further obtained and subjected into sequence analysis.ResultsIn total, 204 (20.4%) specimens were identified as NoV-positive. GII genogroup accounted for most of the NoV-infected cases (98.0%, 200/204). NoV infection was found in all age groups tested (< 5, 5-15, 16-20, 21-30, 31-40, 41-50, 51-60, and >60 years), with the 5-15 year age group having the highest detection rate (17/49, 34.7%). Higher activity of NoV infection could be seen in winter-spring season. The predominant NoV genotypes have changed from GII.Pe-GII.4 Sydney2012 and GII.P17-GII.17 in 2016 to GII.P16-GII.2, GII.Pe-GII.4 Sydney2012 and GII.P17-GII.17 in 2017. Phylogenetic analyses revealed that 2016-2017 GII.P16-GII.2 strains were most closely related to Japan 2010-2012 cluster in VP1 region and no common mutations were found in the amino acids of the HBGA-binding sites and the predicted epitopes.ConclusionsWe report the emergence of GII.P16-GII.2 strains and characterize the molecular epidemiological patterns NoV infection between January 2016 and December 2017 in Huzhou. The predominant genotypes of NoV during our study period are diverse. VP1 amino acid sequences of 2016-2017 GII.P16-GII.2 strains remain static after one year of circulation.

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Molecular epidemiology and spatiotemporal dynamics of norovirus associated with sporadic acute gastroenteritis during 2013-2017, Zhoushan Islands, China.

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