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 ...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.展开更多
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 N...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.展开更多
BACKGROUND In France,nitazoxanide is available through compassionate use authorization,as there is no summary of product characteristics for this medication.However,it has been marketed in the United States for severa...BACKGROUND In France,nitazoxanide is available through compassionate use authorization,as there is no summary of product characteristics for this medication.However,it has been marketed in the United States for several years,with evidence supporting its use in the treatment of chronic norovirus infections in immunocompromised individuals.Due to its limited use,data on the efficacy and safety of this drug remain sparse.CASE SUMMARY We report the case of a 79-year-old immunocompromised patient,a renal transplant recipient undergoing treatment with mycophenolate mofetil and tacrolimus,who developed toxic agranulocytosis,as absolute neutrophil count dropped from 2.93 G/L to 0.09 G/L within 17 days following the introduction of nitazoxanide for the treatment of chronic diarrhea caused by norovirus infection.Clinical and laboratory findings suggest a toxic mechanism,most likely attributable to nitazoxanide.CONCLUSION This case highlights the potential of nitazoxanide to induce dose-dependent toxic agranulocytosis.While this adverse effect does not necessarily contraindicate reintroduction of the drug,it underscores the necessity for close hematological monitoring in such cases.展开更多
The current recommendation to avoid non-steroidal anti-inflammatory drugs(NSAIDs)in the management of dengue virus disease(DVD)is scientifically considered of very low to low certainty,despite being widely adopted wor...The current recommendation to avoid non-steroidal anti-inflammatory drugs(NSAIDs)in the management of dengue virus disease(DVD)is scientifically considered of very low to low certainty,despite being widely adopted worldwide.The same recommendation,initially made during the coronavirus disease 2019(COVID-19)pandemic,was subsequently proven incorrect.In this clinical report,we present evidence,for the first time globally,from a real-life practice that NSAIDs may actually be lifesaving in the early management of DVD as they have proved to be in COVID-19.Moreover,we propose that the personalized immunemodulatory Kelleni’s protocol,which includes nitazoxanide as a key component,can be safely and effectively used to manage various separate or concomitant viral infections and co-infections,including DVD.Importantly,this article contributes to the current medical knowledge in the global pursuit of a safe and effective broad-spectrum antiviral protocol that can be used to early manage multiple highly infectious viruses.However,it’s crucial that sufficiently powered controlled randomized clinical trials be conducted to thoroughly assess and evaluate the safety of NSAIDs in the early management of DVD as well as the efficacy of nitazoxanide with or without NSAIDs in its management.展开更多
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 electroche...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.展开更多
Norovirus(NoV)infection is a major cause of gastroenteritis worldwide.The virus poses great challenges in developing vaccines with broad immune protection due to its genetic and antigenic diversity.To date,there are n...Norovirus(NoV)infection is a major cause of gastroenteritis worldwide.The virus poses great challenges in developing vaccines with broad immune protection due to its genetic and antigenic diversity.To date,there are no approved NoV vaccines for clinical use.Here,we aimed to develop a broad-acting quadrivalent NoV vaccine based on a chimpanzee adenovirus vector,AdC68,carrying the major capsid protein(VP1)of noroviral GI and GII genotypes.Compared to intramuscular(i.m.),intranasal(i.n.),or other prime-boost immunization regimens(i.m.t i.m.,i.m.t i.n.,i.n.t i.m.),AdC68-GI.1-GII.3(E1)-GII.4-GII.17(E3),administered via i.n.t i.n.induced higher titers of serum IgG antibodies and higher IgA antibodies in bronchoalveolar lavage fluid(BALF)and saliva against the four homologous VP1s in mice.It also significantly stimulated the production of blocking antibodies against the four genotypes.In response to re-stimulation with virus-like particles(VLP)-GI.1,VLP-GII.3,VLP-GII.4,and VLP-GII.17,the quadrivalent vaccine administered according to the i.n.t i.n.regimen effectively triggered specific cell-mediated immune responses,primarily characterized by IFN-γsecretion.Furthermore,the preparation of this novel quadrivalent NoV vaccine requires only a single recombinant adenovirus to provide broad preventive immunity against the major GI/GII epidemic strains,making it a promising vaccine candidate for further development.展开更多
Background:The present comprehensive protocol is focused on the detection of pathogenic enteric RNA viruses,explicitly focusing on norovirus genogroup II(GII),astrovirus,rotavirus,Aichi virus,sapovirus,hepatitis A and...Background:The present comprehensive protocol is focused on the detection of pathogenic enteric RNA viruses,explicitly focusing on norovirus genogroup II(GII),astrovirus,rotavirus,Aichi virus,sapovirus,hepatitis A and E viruses in wastewater treatment plants through droplet digital PCR(ddPCR).Enteric viruses are of significant public health concern,as they are the leading cause of diseases like gastroenteritis.Regular monitoring of environmental samples,particularly from wastewater treatment plants,is crucial for early detection and control of these viruses.This research aims to improve the understanding of the prevalence and dynamics of enteric viruses in urban India and will serve as a model for similar studies in other regions.Our protocol's objective is to establish a novel ddPCRbased methodology for the detection and molecular characterization of enteric viruses present in wastewater samples sourced from Bhopal,India.Our assay is capable of accurately quantifying virus concentrations without standard curves,minimizing extensive optimization,and enhancing sensitivity and precision,especially for low-abundance targets.Methods:The study involves fortnightly collecting and analyzing samples from nine wastewater treatment plants over two years,ensuring comprehensive coverage and consistent data.Our study innovatively applies ddPCR to simultaneously detect and quantify enteric viruses in wastewater,a more advanced technique.Additionally,we will employ next-generation sequencing for detailed viral genome identification in samples tested positive for pathogenic viruses.Conclusion:This study will aid in understanding these viruses’genetic diversity and mutation rates,which is crucial for developing tailored intervention strategies.The findings will be instrumental in shaping public health responses and improving epidemiological surveillance,especially in localities heaving sewage networks.展开更多
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...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.展开更多
Norovirus is an infectious disease that can cause non-bacterial gastroenteritis,which has a low infectious dose,rapid onset,and strong transmission ability;therefore,rapid and sensitive detection is essential to reduc...Norovirus is an infectious disease that can cause non-bacterial gastroenteritis,which has a low infectious dose,rapid onset,and strong transmission ability;therefore,rapid and sensitive detection is essential to reduce the transmission of gastroenteritis.In the study,a norovirus GII loop-mediated isothermal amplification assay was developed and prepared into freeze-drying microspheres,and a closed-cassette-based,integrated,reagent-ambient storage,on-site instant detection platform for norovirus GII was constructed using a commercial,fully automated nucleic acid analyzer with integrated magnetic bearing based nuclear acid extraction and nucleic acid detection,with a sensitivity of 10 copies/μL,with no cross-reactivity with other 5 viruses.For 28 simulated samples,the integrated assay platform was consistent with the experimental results of reverse transcription-quantitative polymerase chain reaction(RT-qPCR)assays after conventional laboratory nucleic acid extraction.The entire process can be finished in about 1 h,which is ideal for immediate rapid detection.展开更多
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 astrovir...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.展开更多
Human norovirus(HuNoV)is the leading cause of acute gastroenteritis.The varying severity of chronic infection in patients with underlying immune deficiencies poses additional burdens on public health.However,the poten...Human norovirus(HuNoV)is the leading cause of acute gastroenteritis.The varying severity of chronic infection in patients with underlying immune deficiencies poses additional burdens on public health.However,the potential effects of HuNoV infection during pregnancy,a specific immune perturbed state,have been rarely reported.Recently,four cases of HuNoV-infected patients in the late stages of pregnancy were admitted to the Guangzhou Women and Children's Medical Center,and premature rupture of membranes as primary adverse outcome was observed in these cases.Samples of fetal accessory tissue were collected from two of these cases at delivery to explore the potential pathogenesis.Pathological analysis showed placental malperfusion in both maternal and fetal vascular,while a decrease in vessels was not observed in villi of placenta.There was obvious pathological change in the chorion of fetal membrane,accompanied by a tendency of Th-1 immune bias.Notably,aggregation of M2 macrophages was observed in the chorion of the fetal membrane,potentially recruited for tissue repair.Next-generation sequencing showed minimal changes in immune pathways within placenta tissue.A gene panel associated with immunosuppression was identified in the fetal membrane of HuNoV-infected women compared to those of normal parturient.Taken together,this study provides clues for the association between the HuNoV and premature delivery,which requires the attention of the clinicians.展开更多
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 o...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.展开更多
Noroviruses(NoVs)are the primary cause of acute gastroenteritis worldwide.Histo-blood group antigens(HBGAs)are receptors or attachment factors that affect the prevalence and host susceptibility of NoVs.GII.6 NoV is on...Noroviruses(NoVs)are the primary cause of acute gastroenteritis worldwide.Histo-blood group antigens(HBGAs)are receptors or attachment factors that affect the prevalence and host susceptibility of NoVs.GII.6 NoV is one of the predominant genotypes in humans,which recognizes the type ABO secretor of HBGAs.However,the structural basis of GII.6 NoV's interaction with HBGAs receptors remains elusive.In this study,we investigated the binding features of the GII.6 strain to HBGAs using saliva-and glycan-ELISA assays and characterized the molecular basis of the GII.6 virus that recognizes H disaccharide.We showed that the GII.6 P domain recognized some A and O secretor's saliva samples,most B secretor's saliva samples,and H disaccharide antigen,but did not bind non-secretors’saliva.Further,we determined the crystal structures of GII.6 and its complex with H disaccharides at 1.7Å,revealing that the P domain of GII.6 shares the conventional binding interface and mode of GII HBGAs.Single residue mutations at the GII.6-H binding sites could inhibit the binding of GII.6 to HBGAs,demonstrating that the interaction residues were crucial in maintaining NoV-glycan integrity.Finally,structural and sequence analyses showed that the major residues of the GII.6-H interaction were conserved among NoVs in the GII genogroup.Taken together,our study characterized the functional and structural features of GII.6 that allow it to interact with HBGAs,and shed light on NoV evolution,epidemiology,and anti-viral drug development.展开更多
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 commo...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.展开更多
Noroviruses are the leading cause of acute gastroenteritis in humans. Real-time reverse transcription-polymerase chain reaction(real-time RT-PCR) is a promising molecular method for the detection of noroviruses. In th...Noroviruses are the leading cause of acute gastroenteritis in humans. Real-time reverse transcription-polymerase chain reaction(real-time RT-PCR) is a promising molecular method for the detection of noroviruses. In this study, the performance of three Taq Man real-time RT-PCR assays was assessed, which were one commercially available real-time RT-PCR kit(assay A:Norovirus Real Time RT-PCR kit) and two in-house real-time RT-PCR assays(assay B: Light Cycler RNA Master Hybprobe and assay C: Real Time ready RNA Virus Master). Assays A and B showed higher sensitivity than assay C for norovirus GI, while they all had the same sensitivity(103 DNA copies/m L) for GII DNA standard controls. Assay B had the highest efficiency for both genogroups.No cross-reactivity was observed among GI and GII noroviruses, rotavirus, hepatitis A virus, and poliovirus. The detection rates of these assays in GI and GII norovirus-positive fecal samples were not significantly different. However, the mean quantification cycle(Cq) value of assay B for GII was lower than assays A and C with statistical significance(P-value, 0.000). All three real-time RT-PCR assays could detect a variety of noroviruses including GI.2, GII.2, GII.3, GII.4, GII.6, GII.12, GII.17,and GII.21. This study suggests assay B as a suitable assay for the detection and quantification of noroviruses GI and GII due to good analytical sensitivity and higher performance to amplify norovirus on DNA standard controls and clinical samples.展开更多
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 gastro...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.展开更多
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 ma...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.展开更多
基金supported by the Ministry of Science and Technology of China(2017YFC1601200)the National Natural Science Foundation of China(31772078)the Agri-X Interdisciplinary Fund of Shanghai Jiao Tong University(2017).
文摘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.
基金supported by the China-Australia Bilateral Research Program (No. 2010DFA31720)the National Key Technology R&D Program (2012BAD28B05)
文摘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.
文摘BACKGROUND In France,nitazoxanide is available through compassionate use authorization,as there is no summary of product characteristics for this medication.However,it has been marketed in the United States for several years,with evidence supporting its use in the treatment of chronic norovirus infections in immunocompromised individuals.Due to its limited use,data on the efficacy and safety of this drug remain sparse.CASE SUMMARY We report the case of a 79-year-old immunocompromised patient,a renal transplant recipient undergoing treatment with mycophenolate mofetil and tacrolimus,who developed toxic agranulocytosis,as absolute neutrophil count dropped from 2.93 G/L to 0.09 G/L within 17 days following the introduction of nitazoxanide for the treatment of chronic diarrhea caused by norovirus infection.Clinical and laboratory findings suggest a toxic mechanism,most likely attributable to nitazoxanide.CONCLUSION This case highlights the potential of nitazoxanide to induce dose-dependent toxic agranulocytosis.While this adverse effect does not necessarily contraindicate reintroduction of the drug,it underscores the necessity for close hematological monitoring in such cases.
文摘The current recommendation to avoid non-steroidal anti-inflammatory drugs(NSAIDs)in the management of dengue virus disease(DVD)is scientifically considered of very low to low certainty,despite being widely adopted worldwide.The same recommendation,initially made during the coronavirus disease 2019(COVID-19)pandemic,was subsequently proven incorrect.In this clinical report,we present evidence,for the first time globally,from a real-life practice that NSAIDs may actually be lifesaving in the early management of DVD as they have proved to be in COVID-19.Moreover,we propose that the personalized immunemodulatory Kelleni’s protocol,which includes nitazoxanide as a key component,can be safely and effectively used to manage various separate or concomitant viral infections and co-infections,including DVD.Importantly,this article contributes to the current medical knowledge in the global pursuit of a safe and effective broad-spectrum antiviral protocol that can be used to early manage multiple highly infectious viruses.However,it’s crucial that sufficiently powered controlled randomized clinical trials be conducted to thoroughly assess and evaluate the safety of NSAIDs in the early management of DVD as well as the efficacy of nitazoxanide with or without NSAIDs in its management.
基金financially supported by National Key Research and Development Program of China(2022YFC2601604)Major science and technology project of Yunnan Province(202202AE090085)+9 种基金the National Natural Science Foundation of China(3216059732160236)Science and technology talent and platform plan of YunnanKey Scientific and Technology Project of Yunnan(202203AC100010)Spring City Plan:the High-level Talent Promotion and Training Project of Kunming(2022SCP001)the second phase of“Double-First Class”program construction of Yunnan Universitygrants from State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan,Yunnan University(2021KF005)Key Scientific and Technology Project of Yunnan(202002AE320005)Program for Excellent Young Talents of Yunnan Universitythe Program for Donglu Scholars of Yunnan University。
文摘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.
基金supported by the National Natural Science Foundation of China(82241065,32070926)to D.Z.the Sichuan Science and Technology Program(2023JDRC0090)to H.L.
文摘Norovirus(NoV)infection is a major cause of gastroenteritis worldwide.The virus poses great challenges in developing vaccines with broad immune protection due to its genetic and antigenic diversity.To date,there are no approved NoV vaccines for clinical use.Here,we aimed to develop a broad-acting quadrivalent NoV vaccine based on a chimpanzee adenovirus vector,AdC68,carrying the major capsid protein(VP1)of noroviral GI and GII genotypes.Compared to intramuscular(i.m.),intranasal(i.n.),or other prime-boost immunization regimens(i.m.t i.m.,i.m.t i.n.,i.n.t i.m.),AdC68-GI.1-GII.3(E1)-GII.4-GII.17(E3),administered via i.n.t i.n.induced higher titers of serum IgG antibodies and higher IgA antibodies in bronchoalveolar lavage fluid(BALF)and saliva against the four homologous VP1s in mice.It also significantly stimulated the production of blocking antibodies against the four genotypes.In response to re-stimulation with virus-like particles(VLP)-GI.1,VLP-GII.3,VLP-GII.4,and VLP-GII.17,the quadrivalent vaccine administered according to the i.n.t i.n.regimen effectively triggered specific cell-mediated immune responses,primarily characterized by IFN-γsecretion.Furthermore,the preparation of this novel quadrivalent NoV vaccine requires only a single recombinant adenovirus to provide broad preventive immunity against the major GI/GII epidemic strains,making it a promising vaccine candidate for further development.
文摘Background:The present comprehensive protocol is focused on the detection of pathogenic enteric RNA viruses,explicitly focusing on norovirus genogroup II(GII),astrovirus,rotavirus,Aichi virus,sapovirus,hepatitis A and E viruses in wastewater treatment plants through droplet digital PCR(ddPCR).Enteric viruses are of significant public health concern,as they are the leading cause of diseases like gastroenteritis.Regular monitoring of environmental samples,particularly from wastewater treatment plants,is crucial for early detection and control of these viruses.This research aims to improve the understanding of the prevalence and dynamics of enteric viruses in urban India and will serve as a model for similar studies in other regions.Our protocol's objective is to establish a novel ddPCRbased methodology for the detection and molecular characterization of enteric viruses present in wastewater samples sourced from Bhopal,India.Our assay is capable of accurately quantifying virus concentrations without standard curves,minimizing extensive optimization,and enhancing sensitivity and precision,especially for low-abundance targets.Methods:The study involves fortnightly collecting and analyzing samples from nine wastewater treatment plants over two years,ensuring comprehensive coverage and consistent data.Our study innovatively applies ddPCR to simultaneously detect and quantify enteric viruses in wastewater,a more advanced technique.Additionally,we will employ next-generation sequencing for detailed viral genome identification in samples tested positive for pathogenic viruses.Conclusion:This study will aid in understanding these viruses’genetic diversity and mutation rates,which is crucial for developing tailored intervention strategies.The findings will be instrumental in shaping public health responses and improving epidemiological surveillance,especially in localities heaving sewage networks.
基金supported by a grant from Chiang Mai University(Center of Excellence in Emerging and Re-emerging Diarrheal Viruses,RG37/2566)Chiang Mai,Thailand and the Thailand Science Research and Innovation(FF66/006).
文摘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.
基金funded by the Science and Technology Development Fund,Macao SAR(Nos.0065/2020/A2,SKLQRCM(MUST)-2020-2022)Shenzhen-Hong Kong-Macao Science and Technology Project(Grade c)(No.SGDX20210823104201010).
文摘Norovirus is an infectious disease that can cause non-bacterial gastroenteritis,which has a low infectious dose,rapid onset,and strong transmission ability;therefore,rapid and sensitive detection is essential to reduce the transmission of gastroenteritis.In the study,a norovirus GII loop-mediated isothermal amplification assay was developed and prepared into freeze-drying microspheres,and a closed-cassette-based,integrated,reagent-ambient storage,on-site instant detection platform for norovirus GII was constructed using a commercial,fully automated nucleic acid analyzer with integrated magnetic bearing based nuclear acid extraction and nucleic acid detection,with a sensitivity of 10 copies/μL,with no cross-reactivity with other 5 viruses.For 28 simulated samples,the integrated assay platform was consistent with the experimental results of reverse transcription-quantitative polymerase chain reaction(RT-qPCR)assays after conventional laboratory nucleic acid extraction.The entire process can be finished in about 1 h,which is ideal for immediate rapid detection.
文摘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.
基金supported by the National Natural Science Foundation of China(No.82241071,32370163&32400134)National Key Research and Development program(2019YFC0121905).
文摘Human norovirus(HuNoV)is the leading cause of acute gastroenteritis.The varying severity of chronic infection in patients with underlying immune deficiencies poses additional burdens on public health.However,the potential effects of HuNoV infection during pregnancy,a specific immune perturbed state,have been rarely reported.Recently,four cases of HuNoV-infected patients in the late stages of pregnancy were admitted to the Guangzhou Women and Children's Medical Center,and premature rupture of membranes as primary adverse outcome was observed in these cases.Samples of fetal accessory tissue were collected from two of these cases at delivery to explore the potential pathogenesis.Pathological analysis showed placental malperfusion in both maternal and fetal vascular,while a decrease in vessels was not observed in villi of placenta.There was obvious pathological change in the chorion of fetal membrane,accompanied by a tendency of Th-1 immune bias.Notably,aggregation of M2 macrophages was observed in the chorion of the fetal membrane,potentially recruited for tissue repair.Next-generation sequencing showed minimal changes in immune pathways within placenta tissue.A gene panel associated with immunosuppression was identified in the fetal membrane of HuNoV-infected women compared to those of normal parturient.Taken together,this study provides clues for the association between the HuNoV and premature delivery,which requires the attention of the clinicians.
文摘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.
基金supported by grants from the National Natural Science Foundation of China(no.32100111,21934005)Guangdong Basic and Applied Basic Reuter Foundation(no.2019A1515110220)+1 种基金China Postdoctoral Science Foundation(no.2020M682900)Shenzhen High-level Hospital Construction Fund.
文摘Noroviruses(NoVs)are the primary cause of acute gastroenteritis worldwide.Histo-blood group antigens(HBGAs)are receptors or attachment factors that affect the prevalence and host susceptibility of NoVs.GII.6 NoV is one of the predominant genotypes in humans,which recognizes the type ABO secretor of HBGAs.However,the structural basis of GII.6 NoV's interaction with HBGAs receptors remains elusive.In this study,we investigated the binding features of the GII.6 strain to HBGAs using saliva-and glycan-ELISA assays and characterized the molecular basis of the GII.6 virus that recognizes H disaccharide.We showed that the GII.6 P domain recognized some A and O secretor's saliva samples,most B secretor's saliva samples,and H disaccharide antigen,but did not bind non-secretors’saliva.Further,we determined the crystal structures of GII.6 and its complex with H disaccharides at 1.7Å,revealing that the P domain of GII.6 shares the conventional binding interface and mode of GII HBGAs.Single residue mutations at the GII.6-H binding sites could inhibit the binding of GII.6 to HBGAs,demonstrating that the interaction residues were crucial in maintaining NoV-glycan integrity.Finally,structural and sequence analyses showed that the major residues of the GII.6-H interaction were conserved among NoVs in the GII genogroup.Taken together,our study characterized the functional and structural features of GII.6 that allow it to interact with HBGAs,and shed light on NoV evolution,epidemiology,and anti-viral drug development.
文摘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.
基金supported by research grant from the Thailand Research Fund (TRF) through the Royal Golden Jubilee Ph.D. program (Grant No. PHD/0085/2554)the Thai Government Budget through Mahidol University, fiscal year 2015-2017
文摘Noroviruses are the leading cause of acute gastroenteritis in humans. Real-time reverse transcription-polymerase chain reaction(real-time RT-PCR) is a promising molecular method for the detection of noroviruses. In this study, the performance of three Taq Man real-time RT-PCR assays was assessed, which were one commercially available real-time RT-PCR kit(assay A:Norovirus Real Time RT-PCR kit) and two in-house real-time RT-PCR assays(assay B: Light Cycler RNA Master Hybprobe and assay C: Real Time ready RNA Virus Master). Assays A and B showed higher sensitivity than assay C for norovirus GI, while they all had the same sensitivity(103 DNA copies/m L) for GII DNA standard controls. Assay B had the highest efficiency for both genogroups.No cross-reactivity was observed among GI and GII noroviruses, rotavirus, hepatitis A virus, and poliovirus. The detection rates of these assays in GI and GII norovirus-positive fecal samples were not significantly different. However, the mean quantification cycle(Cq) value of assay B for GII was lower than assays A and C with statistical significance(P-value, 0.000). All three real-time RT-PCR assays could detect a variety of noroviruses including GI.2, GII.2, GII.3, GII.4, GII.6, GII.12, GII.17,and GII.21. This study suggests assay B as a suitable assay for the detection and quantification of noroviruses GI and GII due to good analytical sensitivity and higher performance to amplify norovirus on DNA standard controls and clinical samples.
基金Supported by an investigator-initiated research grant from Merck Sharpe and Dohme(MSD)University Review Board Grant,American University of Beirut
文摘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.
文摘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.
