One stone two birds:electrochemical and colorimetric dual-mode biosensor based on copper peroxide/covalent organic framework nanocomposite for ultrasensentive norovirus detection

Norovirus(NoV)is regarded as one of the most common causes of foodborne diarrhea in the world.It is urgent to identify the pathogenic microorganism of the diarrhea in short time.In this work,we developed an electrochemical and colorimetric dual-mode detection for NoV based on the excellent dual catalytic properties of copper peroxide/COF-NH_(2)nanocomposite(CuO_(2)@COF-NH_(2)).For the colorimetric detection,NoV can be directly detected by the naked eye based on CuO_(2)@COF-NH_(2)as a laccase-like nonazyme using“peptide-NoV-antibody”recognition mode.The colorimetric assay displayed a wide and quality linear detection range from 1 copy/mL to 5000 copies/mL of NoV with a low limit of detection(LOD)of 0.125 copy/mL.For the electrochemical detection of NoV,CuO_(2)@COF-NH_(2)showed an oxidation peak of copper ion from Cu^(+)to Cu^(2+)using“peptide-NoV-antibody”recognition mode.The electrochemical assay showed a linear detection range was 1-5000 copies/mL with a LOD of 0.152 copy/mL.It's worthy to note that this assay does not need other electrical signal molecule,which provide the stable and sensitive electrochemial detection for NoV.The electrochemical and colorimetric dual-mode detection was used to detect NoV in foods and faceal samples,which has the potential for improving food safety and diagnosing of NoV-infected diarrhea.

Rotavirus, Norovirus and Astrovirus in Children Aged 0 - 5 Years: Evolution of Prevalence over 10 Years (2013-2023) Following the Introduction of Rotavirus Vaccines in Burkina Faso

Rotaviruses, noroviruses, and astroviruses are responsible for gastroenteritis in children under 5 years old. The objective of our study was to estimate the evolution of prevalence of rotavirus, norovirus and astrovirus infections in children aged 0 to 5 years with gastroenteritis, after the introduction of rotavirus vaccines in Burkina Faso. This cross-sectional study was conducted between January and December 2023, collecting 100 stool samples from children with gastroenteritis at Saint Camille Hospital in Ouagadougou and the Charles De Gaulle University Paediatric Hospital. Noroviruses and astroviruses were detected using multiplex real-time PCR with a Sacace biotechnology detection kit. Data analysis was performed with Stata statistical software, version 16.0. The prevalence of norovirus infections was 14% and astrovirus infections were 9%. Rotavirus infections were found at prevalence of 15%. The age group most affected by norovirus and astrovirus infections was 0 - 12 months, with respective prevalence rates of 73.34% and 55.56%. The most frequently observed clinical signs in children infected with astrovirus were fever (77.78%), diarrhea (55.56%), and vomiting (44.44%). The introduction of rotavirus vaccines has reduced rotavirus-related infections. However, this has not significantly impacted the prevalence of norovirus and astrovirus infections in Burkina Faso.

Acute gastroenteritis outbreak caused by a GII.6 norovirus

AIM:To report an acute gastroenteritis outbreak caused by a genogroup 2 genotype 6(GII.6) strain norovirus in Shanghai,China.METHODS:Noroviruses are responsible for approximately half of all reported gastroenteritis outbreaks in many countries.Genogroup 2 genotype 4 strains are the most prevalent.Rare outbreaks caused by GII.6 strains have been reported.An acute gastroenteritis outbreak occurred in an elementary school in Shanghai in December of 2013.Field and molecular epidemiologic investigations were conducted.RESULTS:The outbreak was limited to one class in an elementary school located in southwest Shanghai.The age of the students ranged from 9 to 10 years.The first case emerged on December 10,2013,and the last case emerged on December 14,2013.The cases peaked on December 11,2013,with 21 new cases.Of 45 students in the class,32 were affected.The main symptom was gastroenteritis,and 15.6%(5/32) of the cases exhibited a fever.A field epidemiologic investigation showed the pathogen may have been transmitted to the elementary school from employees in a delicatessen via the first case student,who had eaten food from the delicatessen one day before the gastroenteritis episodes began.A molecular epidemiologic investigation identified the cause of the gastroenteritis as norovirus strain GII.6;the viral sequence of the student cases showed 100% homology with that of the shop employees.Genetic relatedness analyses showed that the new viral strain is closely related to previously reported GII.6 sequences,especially to a strain reported in Japan.CONCLUSION:This is the first report to show that norovirus strain GII.6 can cause a gastroenteritis outbreak.Thus,the prevalence of GII.6 noroviruses requires attention.

Utility of Droplet Digital PCR Assay for Quantitative Detection of Norovirus in Shellfish, from Production to Consumption in Guangxi, China

Objective Shellfish are recognized as important vehicles of norovirus-associated gastroenteritis. The present study aimed to monitor norovirus contamination in oysters along the farm-to-fork continuum in Guangxi, a major oyster production area in Southwestern China. Methods Oyster samples were collected monthly from farms, markets, and restaurants, from January to December 2016. Norovirus was detected and quantified by one-step reverse transcription-droplet digital polymerase chain reaction（RT-ddPCR）. Results A total of 480 oyster samples were collected and tested for norovirus genogroups I and II. Norovirus was detected in 20.7% of samples, with genogroup II predominating. No significant difference was observed in norovirus prevalence among different sampling sites. The norovirus levels varied widely, with a geometric mean of 19,300 copies/g in digestive glands. Both norovirus prevalence and viral loads showed obvious seasonality, with a strong winter bias. Conclusion This study provides a systematic analysis of norovirus contamination ‘from the farm to the fork＇ in Guangxi. RT-ddPCR can be a useful tool for detection and quantification of low amounts of norovirus in the presence of inhibitors found particularly in foodstuffs. This approach will contribute to the development of strategies for controlling and reducing the risk of human illness resulting from shellfish consumption.

Clinical and epidemiological characteristics of norovirus gastroenteritis among hospitalized children in Lebanon

AIM To assess the burden of norovirus(No V) and to determine the diversity of circulating strains among hospitalized children in Lebanon. METHODS Stool samples were collected from children presenting with acute gastroenteritis to six major hospitals in Lebanon. A total of 739 eligible stool samples, testing negative for diarrhea caused by rotavirus as a possible viral pathogen, were collected between January 2011 and June 2013. A standardized questionnaire including demographic, epidemiological and clinical observations was used at the time of hospitalization of children presenting with diarrhea. Viral RNA was extracted from stool samples followed by reverse transcription polymerase chain reaction and nucleotide sequencing of a fragment of the viral protein 1 capsid gene. Multiple sequence alignments were carried out and phylogenetic trees were constructed using the MEGA 6 software.RESULTS Overall, 11.2% of stool samples collected from children aged < 5 years tested positive for No V genogroups Ⅰ(GⅠ) and Ⅱ(GⅡ). GⅡ accounted for 10.6% of the gastroenteritis cases with only five samples being positive for GⅠ(0.7%). The majority of hospitalized children showed symptoms of diarrhea, dehydration, vomiting and fever. Upon sequencing of positive samples and based on their clustering in the phylogenetic tree, 4/5 of GⅠ gastroenteritis cases were designated GⅠ.3 and one case as GⅠ.4. GⅡ.4 was predominantly detected in stool of our study participants(68%). We report a JB-15/KOR/2008 GⅡ.4 Apeldoorn 2008-like variant strain circulating in 2011; this strain was replaced between 2012 and 2013 by a variant sharing homology with the Sydney/NSW0514/2012/AUS GⅡ.4 Sydney 2012 and Sydney 2012/FRA GⅡ.4 strains. We also report the co-circulation of non-GⅡ.4 genotypes among hospitalized children. Our data show that No V gastroenteritis can occur throughout the year with the highest number of cases detected during the hot months.CONCLUSION The majority of No V-associated viral gastroenteritis cases among our participants are attributable to GⅡ.4, which is compatible with results reported worldwide.

Epidemiological Characteristics and Spatiotemporal Distribution Patterns of Human Norovirus Outbreaks in China, 2012–2018

Objective To clarify the epidemiological characteristics and spatial distribution patterns of human norovirus outbreaks in China, identify high-risk areas, and provide guidance for epidemic prevention and control.Methods This study analyzed 964 human norovirus outbreaks involving 50,548 cases in 26 provinces reported from 2012 to 2018. Epidemiological analysis and spatiotemporal scanning analysis were conducted to analyze the distribution of norovirus outbreaks in China.Results The outbreaks showed typical seasonality, with more outbreaks in winter and fewer in summer, and the total number of infected cases increased over time. Schools, especially middle schools and primary schools, are the most common settings of norovirus outbreaks, with the major transmission route being life contact. More outbreaks occurred in southeast coastal areas in China and showed significant spatial aggregation. The highly clustered areas of norovirus outbreaks have expanded northeast over time.Conclusion By identifying the epidemiological characteristics and high-risk areas of norovirus outbreaks, this study provides important scientific support for the development of preventive and control measures for norovirus outbreaks, which is conducive to the administrative management of high-risk settings and reduction of disease burden in susceptible areas.

An Efficient Method of Noroviruses Recovery from Oysters and Clams

Noroviruses (NoVs) are widespread causes of nonbacterial gastroenteritis. Outbreaks of NoVs caused diseases are commonly ascribed to the consumption of contaminated shellfish. The concentration and RNA extraction of NoVs are crucial steps of detecting NoVs in shellfish. This study aimed to select a simple, rapid and highly efficient recovery method of NoVs detection with real-time RT-PCR. Four methods of recovering GI.3 and GII.4 NoVs from spiked digestive tissues of oysters and clams, respectively, were compared, of them, the method involving proteinase K and PEG 8000 was found the most efficient. With this method, 9.3% and 13.1% of GI.3 and GII.4 NoVs were recovered from oysters and 9.6% and 12.3% of GI.3 and GII.4 NoVs were recovered from clams, respectively. This method was further used to detect NoVs in 84 oysters (Crassostrea gigas) and 86 clams (Ruditapes philippinarum) collected from 10 coastal cities in China from Jan. 2011 to Feb. 2012. The NoVs isolation rates were 10.47% of clams (9/86) and 7.14% of oysters (6/84). All the detected NoVs belonged to genotype GII. The NoVs recovery method selected is efficient for NoVs detection in oysters and clams.

Norovirus Infection and Histo-blood Group Antigens in Children Hospitalized with Diarrhea in Lulong and Chenzhou in China

Norovirus （NOV） is a pathogen that commonly causes viral diarrhea in children. Studies indicate that NoV recognizes human histo-blood group antigens （HBGAs） as cell attachment factors. In order to explore the correlation between of NoV infection and HBGAs, a cross-sectional study was conducted in children less than five years old who were hospitalized with diarrhea in two areas of China between November 2014 and February 2015. Of the paired stool and saliva samples taken from 424 children,

Histo-blood group antigens in Crassostrea gigas and binding profiles with GⅡ.4 Norovirus

Noroviruses(NoVs) are the main cause of viral gastroenteritis outbreaks worldwide, and oysters are the most common carriers of NoV contamination and transmission. NoVs bind specifically to oyster tissues through histo-blood group antigens(HBGAs), and this facilitates virus accumulation and increases virus persistence in oysters. To investigate the interaction of HBGAs in Pacific oysters with GⅡ.4 NoV, we examined HBGAs with ELISAs and investigated binding patterns with oligosaccharide-binding assays using P particles as a model of five GⅡ.4 NoV capsids. The HBGAs in the gut and gills exhibited polymorphisms. In the gut, type A was detected(100%), whereas type Leb(91.67%) and type A(61.11%) were both observed in the gills. Moreover, we found that seasonal NoV gastroenteritis outbreaks were not significantly associated with the specific HBGAs detected in the oyster gut and gills. In the gut, we found that strain-2006 b and strain-96/96 US bound to type A and H1 but only weakly bound to type Leb; in contrast, the Camberwell and Hunter strains exhibited weak binding to types H1 and Ley, and strain-Sakai exhibited no binding to any HBGA type. In the gills, strain-96/96 US and strain-2006 b bound to type Leb but only weakly bound to type H1; strains Camberwell, Hunter, and Sakai did not bind to oyster HBGAs. Assays for oligosaccharide binding to GⅡ.4 NoV P particles showed that strain-95/96 US and strain-2006 b strongly bound to type A, B, H1, Leb, and Ley oligosaccharides, while strains Camberwell and Hunter showed weak binding ability to type H1 and Ley oligosaccharides and strain-Sakai showed weak binding ability to type Leb and Ley oligosaccharides. Our study presents new information and enhances understanding about the mechanism for NoV accumulation in oysters. Further studies of multiple NoV-tissue interactions might assist in identifying new or improved strategies for minimizing contamination, including HBGA-based attachment inhibition or depuration.

Molecular study of astrovirus, adenovirus and norovirus in community acquired diarrhea in children: One Egyptian center study

Objective: To determine the prevalence of astrovirus, norovirus, adenovirus in children below five years old with diarrhea by multiplex reverse transcriptase polymerase chain reaction(RT-PCR) along with rotavirus antigen detection by enzyme linked immunosorbant assay.Methods: The study was conducted on children below five years old complaining of acute diarrhea. The study included stool examination by molecular method for detection of norovirus, adenovirus and astrovirus by multiplex RT-PCR. Rotavirus antigen was detected in the stool by enzyme linked immunosorbant assay.Results: The study included 100 children below 5 years old with acute diarrhea.Multiplex RT-PCR was positive in 34% of the children. The most frequently detected virus was rotavirus(44%), followed by norovirus(30%), adenovirus(20%) and astrovirus(14%). The clinical symptoms were more significantly associated with viral diarrhea such as fever(P = 0.03), bloody diarrhea(P = 0.025), vomiting(P = 0.000 1) and watery diarrheas(P = 0.05). The frequency of diarrhea with viral pathogen was significantly presented in winter season(39.7%). There were significant frequencies of norovirus and adenovirus in age ranging 1–2 years old(P = 0.04, P = 0.01 respectively).Conclusions: The present study spotlights on the prevalence of viral pathogens as an important etiology in diarrhea in children below five years old. Astrovirus, norovirus and adenovirus are common along with rotavirus in this group of patients. Multiplex PCR leads to improve the laboratory diagnosis of these viruses along with antigen detection method. Further longitudinal studies are required to evaluate the epidemiological data associated with these viruses and for proper management of such drastic infection.

Stochastic optimal control for norovirus transmission dynamics by contaminated food and water

Norovirus is one of the most common causes of viral gastroenteritis in the world,causing significant morbidity,deaths,and medical costs.In this work,we look at stochastic modelling methodologies for norovirus transmission by water,human to human transmission and food.To begin,the proposed stochastic model is shown to have a single global positive solution.Second,we demonstrate adequate criteria for the existence of a unique ergodic stationary distribution R0 s>1 by developing a Lyapunov function.Thirdly,we find sufficient criteria Rs<1 for disease extinction.Finally,two simulation examples are used to exemplify the analytical results.We employed optimal control theory and examined stochastic control problems to regulate the spread of the disease using some external measures.Additional graphical solutions have been produced to further verify the acquired analytical results.This research could give a solid theoretical foundation for understanding chronic communicable diseases around the world.Our approach also focuses on offering a way of generating Lyapunov functions that can be utilized to investigate the stationary distribution of epidemic models with nonlinear stochastic disturbances.

Redesigned Duplex RT-qPCR for the Detection of GI and GII Human Noroviruses

Human noroviruses(HuNoVs)are major foodborne pathogens that cause nonbacterial acute gastroenteritis worldwide.As the tissue-culture system for HuNoVs is not mature enough for routine detection of the virus,detection is mainly dependent on molecular approaches such as reverse transcription polymerase chain reaction(RT-PCR)and reverse transcription quantitative real-time polymerase chain reaction(RTqPCR).The widely used primers and probes for RT-qPCR were established in the early 2000s.As HuNoVs are highly variant viruses,viral genome mutations result in previously designed primers and/or probes that were perfectly matched working less efficiently over time.In this study,a new duplex RT-qPCR(ND-RT-qPCR)was designed for the detection of genogroup Ⅰ(GⅠ)and genogroup Ⅱ(GⅡ)HuNoVs based on an analysis of viral sequences added in the database after 2010.Using long transcribed viral RNAs,the results demonstrate that the sensitivity of ND-RT-qPCR is as low as one genomic copy for both GⅠ and GⅡ HuNoVs.The performance of ND-RT-qPCR was further evaluated by a comparison with the commonly used Kageyama primer/probe sets for RT-qPCR(Kageyama RT-qPCR)for 23 HuNoV-positive clinical samples.All five GⅠ samples were registered as positive by ND-RT-qPCR,whereas only two samples were registered as positive by Kageyama RT-qPCR.All 18 GⅡ samples were registered as positive by ND-RT-qPCR,while 17 samples were registered as positive by Kageyama RT-qPCR.The sensitivity reflected by the quantification cycle(Cq)value was lower in ND-RT-qPCR than in Kageyama RT-qPCR.Our data suggest that ND-RT-qPCR could be a good fit for the detection of current strains of HuNoVs.

Levels of Norovirus and <i>E. coli</i>in Untreated, Biologically Treated and UV-Disinfected Sewage Effluent Discharged to a Shellfish Water

The efficacy of an activated sludge (modified Ludzack-Ettinger (MLE)) UV disinfection processes in removing human noroviruses and E. coli from sewage were compared with the prevalence of these microorganisms in a settled storm discharge from the same sewage treatment works. Both discharges impacted a designated oyster production area. The treatment process delivered average NoV and E. coli reductions of 2.9log10 and 5.2log10, respectively. Most E. coli reductions occurred during the UV disinfection process whereas the MLE process was comparatively more important in reducing NoV levels. A positive relationship was found between NoV removal and measured applied UV dose. The average levels of total NoV in the settled storm tank were of the same order of magnitude of those in screened raw influent at the works. These results highlight the importance of measures to reduce the impact of stormwater discharges to minimise the risk of NoV gastroenteritis associated with the consumption of oysters.

Selected Plant Extracts Show Antiviral Effects against Murine Norovirus Surrogate

Noroviruses are the most common cause of acute gastroenteritis. Annually, 21 million Americans are infected with norovirus. Recent advances in molecular diagnostics have helped to establish norovirus as the most common cause of outbreaks of acute gastroenteritis across all ages. However, there is no effective or efficient treatment/control against norovirus infection. Conventional intervention techniques used to inactivate norovirus have shown lack of efficacy against human norovirus. Currently, effective treatment or control measures against human norovirus have not been identified. In this study, murine norovirus acts as a model to human norovirus to evaluate the inhibitory effects of crude extracts of Zanthoxylum armatum and Hibiscus sabdariffa. The study also separated, identified and quantified the selected compounds using the ultra-liquid chromatography (UPLC). To study the antiviral activities of crude extracts and its fractionated portions of Z. armatum and H. sabdariffa against norovirus surrogate, RAW 264.7 cells were infected with Murine norovirus surrogate virus of human norovirus and incubated at 37?C. Phytochemicals were extracted from the seeds and calyces of the plants using methanolic extraction. Fractionated portions of the crude extracts were subsequently used in both chromatographic and microbiological studies. Our data indicated that there was reduction of viruses, when treated with the 60% aqueous methanol extracts. Amongst the four selected phenolic compounds (myricetin, quercetin, kaempferol and luteolin), quercetin showed the most significant logarithmic viral reductions. These compounds were identified, purified and quantified using UPLC. Extracts of Zanthoxylum armatum and Hibiscus sabdariffa showed antiviral effects. Phenolic compounds are virucidal. Extracts of Hibiscus sabdariffa also exhibits anti-norovirus activities. The results are anticipated to control/prevent the human norovirus infections.

Electron Micrographic Representations of Mechanisms of Action of Murine Norovirus on ATCC TIB-71 Cells and Level of Gene Expression

Human noroviruses (HuNoV) are the number one cause of viral gastroenteritis worldwide resulting in a significant cause of morbidity and mortality in all age groups. However, despite the medical relevance of HuNoV, effective treatment against norovirus infection is yet to be developed. In this study, we investigated the anti-Noroviral activity of Hibiscus sabdariffa (HS) calyces and Zanthoxylum armatum (ZA) seeds using murine norovirus, a surrogate of human norovirus. The antiviral mechanisms of action were also examined using a gene expression studies and transmission electron microscopy. Our results showed that virus-infected cells were left potentially void of all the cell machineries whereas uninfected cells represent healthy normal and dividing cells. The infected treated cells with extracts showed restoration of the dense cytoplasm, cytoplasmic membrane, and the nucleus. These cells were also associated with the expression of ORF genes. This study demonstrates the antiviral properties of Hibiscus sabdariffa (HS) calyces and Zanthoxylum armatum (ZA) and thus indicates their potential as natural remedies to treat noroviruses.

Treatment Effect of Various Concentration of Plant Extracts on Murine Norovirus

Noroviruses are positive-sense, single-stranded, non-enveloped RNA virus that measures approximately 27 - 35 nm in diameter. It affects humans of all ages and races causing most cases of viral gastroenteritis worldwide. Infection results from ingestion of contaminated food or water as well as causing diarrhea and vomiting in humans. Extracts from plants are known to have antioxidant, anti-inflammatory, and adhesive properties which are associated with barrier functions. The aim of this study was to elucidate whether plaque reduction was due to an effect of methanolic plant extract directly on the virus, whether the extract affects viral replication, and lastly, whether the extract disrupts the cell surface binding with the virus. The plant extracts of interest were the calyces of Hibiscus sabdariffa (HS) and the seeds of Zanthoxylum armatum (ZA). Antiviral activities of these extracts were determined against murine norovirus. The logarithmic viral reduction per plaque-forming unit was (22 log10) PFU/ml (control), (15 log10) PFU/ml (treated HS), and (12 log10) PFU/ml (treated ZA) with a significant reduction (68% and 55% respectively) when compared with the control for the direct effect on the virus. The role of extracts on virus replication showed (25 log10) PFU/ml (control) as against the HS treated-virus-infected cells (9 log10) PFU/ml and ZA treated-virus-infected cells (5 log10) PFU/ml (36% and 20% respectively). Finally, effect of the extract on the viral attachment showed (31 log10) PFU/ml (control), (12 log10) (HS-treated) and (9 log10) PFU/ml (ZA-treated), (39% and 29% respectively. Extract treatment with HS and ZA has shown evidence of a reduced number of plaques formation with the latter having fewer plaques. Both extracts have proven potential to reduce the viral multiplication process by interfering with the replication process. This study shows that Hibiscus sabdariffa (calyces) and Zanthoxylum armatum (seed) extracts disrupt murine norovirus from consistent viral replication.

Norovirus分子生物学特征及其亚基疫苗研究进展

Norovirus(NVs,诺如病毒)是导致人类非细菌性急性胃、肠炎的主要病原,该病毒可以感染各年龄段人群,全年均可爆发,特别是婴幼儿、老年人和免疫系统缺陷病人属于易感人群。目前临床防治或控制norovirus疫情爆发的重要手段之一是使用疫苗。基于此,对norovirus发现、流行病学特征、分子生物学特征和norovirus疫苗的研究进展加以综述。同时,在比较norovirus的病毒类似颗粒(virus-like particles,VLPs)和P粒子(P particles)与人组织血型抗原亲合能力的基础上,对利用植物系统特别是番茄果实生产适于口服norovirus的P粒子作为亚基疫苗优势和存在难点以及本实验室的研究进展进行了讨论,以期为利用植物系统表达口服疫苗研究提供一些借鉴。

Molecular epidemiological characteristics of norovirus gastroenteritis outbreaks in Guangdong province

The purpose of this work is to study the molecular epiderniological characteristics of norovirus gastroenteritis outbreaks in Guangdong. During October 2003 and December 2004, fecal and anal swabs specimens collected from 13 outbreaks of non-bacterial gastroenteritis were tested for nomvirus. Specimens were detected by RT-PCR and sequenced. The descriptive data were also collected. Eight in 13 outbreaks of gastroenteritis were positive for nomvirus. All of 8 virus strains were identified as genogroup Ⅱ but belonged to 3 genotypes. Six strains were G Ⅱ -4 genotype. Nomvirus is a major cause of outbreaks of nonbacterial gastroenteritis in Guangdong province and has a wide distribution. The illness happended from late autumn to winter. The prevalent strains were genogroup Ⅱ virus.

The complete genomic sequence analysis of human norovirus NVgz01 strain in Guangzhou

The aim of this study is to explore the genomic molecular organization and genogroup of human nomvirus from infected infants in Guangzhou of China. Primers were designed according to the genomic sequence of norovims in the GenBank, and the nomvirus genome was amplified by RT-PCR. The PCR- products were cloned into T vector and sequenced, and the genomic nucleotide sequences were analyzed with the programs CLUSTAL W/X, DNASTAR and RAT （Recombination Analysis Tool）. The NVgz01 strain genome is 7558 bp in length and encodes three open reading frames （GenBank accession No. is DQ369797）. The genomic sequences of NVgz01 were compared with those of nomvirus in GenBank, which revealed that the homology with genogroup Ⅱ ranges between 76%-90%, and genogroup Ⅰ between 43%-44%. The ORF1 region shared 94% and 88% identity with Mc37 and Famiington strains, respectively; the capsid region （ORF2） shared 65% and 94% identity with Mc37 and Farmington strains, respectively. Phylogenetic trees were reconstructed by the neighbor-joining method. Comparative complete sequence analysis of the NVgz01 with reported human norovirus genomic sequences revealed that this isolate belongs to genogroup Ⅱ . The ORF1 and ORF2 regions shared different identity with Mc37 and Fannington strains, suggesting NVgz01 could be a recombinant virus.

Diverse genotypes of norovirus genogroup Ⅰ and Ⅱ contamination in environmental water in Thailand during the COVID-19 outbreak from 2020 to 2022

Noroviruses(NoVs)are the most significant viral pathogens associated with waterborne and foodborne outbreaks of nonbacterial acute gastroenteritis in humans worldwide.This study aimed to investigate the prevalence and diversity of NoVs contaminated in the environmental water in Chiang Mai,Thailand.A total of 600 environmental water samples were collected from ten sampling sites in Chiang Mai from July 2020 to December 2022.The presence of NoV genogroups I(GI),GII,and GIV were examined using real-time RT-PCR assay.The genotype of the virus was determined by nucleotide sequencing and phylogenetic analysis.The results showed that NoV GI and GII were detected at 8.5%(51/600)and 11.7%(70/600)of the samples tested,respectively.However,NoV GIV was not detected in this study.NoV circulated throughout the year,with a higher detection rate during the winter season.Six NoV GI genotypes(GI.1-GI.6)and eight NoV GII genotypes(GII.2,GII.3,GII.7,GII.8,GII.10,GII.13,GII.17,and GII.21)were identified.Among 121 NoV strains detected,GII.17 was the most predominant genotype(24.8%,30 strains),followed by GII.2(21.5%,26 strains),GI.3(17.4%,21 strains),and GI.4(16.5%,20 strains).Notably,NoV GII.3,GII.7,GII.8,and GII.10 were detected for the first time in water samples in this area.This study provides insight into the occurrence and seasonal pattern of NoV along with novel findings of NoV strains in environmental water in Thailand during the COVID-19 outbreak.Our findings emphasize the importance of further surveillance studies to monitor viral contamination in environmental water.