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.

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.

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.

NoV GⅡ.2亚型RT-RPA-CRISPR/Cas12a检测方法的建立

近年来,一种新的诺如病毒GⅡ.2亚型(norovirus GⅡ.2,NoV GⅡ.2)通过牡蛎等生食海鲜感染人群,引发急性胃肠炎,并在全球广泛传播。为实现NoV感染的现场诊断和快速疫情响应,亟需建立快速便捷的NoV GⅡ.2亚型核酸检测方法。本研究通过设计引物、crRNA,经优化反应条件后,建立了NoV GⅡ.2亚型RTRPA-CRISPR/Cas12a检测方法。结果显示:利用引物NoV-GⅡ.2-F1B和NoV-GⅡ.2-R1对NoV GⅡ.2标准RNA进行RT-RPA扩增,结合crRNA1介导的CRISPR/Cas12a报告体系,能在40 min内完成NoV GⅡ.2核酸检测;该方法检测灵敏度为10 copies/μL,且与轮状病毒、腺病毒、星形病毒、人副肠孤病毒、博卡病毒和札如病毒无交叉反应;应用该方法和qRT-PCR法,分别对30份临床模拟样本进行检测,发现总符合率达96.67%。结果表明,本研究建立的NoV GⅡ.2亚型RT-RPA-CRISPR/Cas12a检测方法无需依赖昂贵设备,具有灵敏度高、特异性强、操作便捷快速等特点,为NoV GⅡ.2感染的现场检测和防控提供了新方法。

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.

A quadrivalent norovirus vaccine based on a chimpanzee adenovirus vector induces potent immunity in mice

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.

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.

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.

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.

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.

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.

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.

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,

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.

臭常山内生真菌Diaporthe orixae sp.nov.化学成分研究

目的:研究臭常山内生真菌Diaporthe orixae sp.nov.的化学成分。方法:综合运用硅胶、Sephadex LH-20葡聚糖凝胶、半制备高效液相等色谱技术对臭常山内生真菌Diaporthe orixae sp.nov.提取物的乙酸乙酯部分进行分离纯化,结合理化性质和波谱数据进行结构鉴定。结果:从臭常山内生真菌Diaporthe orixae sp.nov.中分离得到11个化合物,分别鉴定为:mannitol(1)、邻苯二甲酸二甲酯(2)、(R)-6-hydroxymellein(3)、ethyl acetylorsellinate(4)、8-甲氧基补骨脂素(5)、norpestaphthalide A(6)、norpestaphthalide B(7)、tyrosol(8)、de-O-methyldiaporthin(9)、(R,R)-5,7-dihydroxy-3-(1-hydroxyethyl)phthalide(10)、腺苷(11)。结论:以上化合物均为首次从臭常山内生真菌中分离得到,其中,化合物1~7、9~11为首次从该真菌中分离得到。

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.

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.

渝东北片区聚集性诺如病毒感染毒株的遗传多样性

目的分析2021-2022年渝东北片区聚集性诺如病毒感染毒株遗传多样性,促进重点人群和场所诺如病毒感染防控。方法采集聚集性诺如病毒感染事件中患者肛拭子及环境拭子,实时荧光定量PCR(qRT-PCR)检测诺如病毒核酸,逆转录PCR扩增病毒RNA聚合酶/衣壳蛋白片段并测序分析,诺如病毒分型工具网站(http://www.rivm.nl/mpf/norovirus/typingtool)确定基因型,运用MEGA-X软件按最大似然法构建种系发生树。结果共调查渝东北片区4个区县11起聚集性诺如病毒感染事件,qRT-PCR检测55份样品,均为GII基因群诺如病毒,经测序存在6种基因型。GII.17[P17]基因型导致4起疫情,GII.17[P17]和GII.1[P16]基因型混合感染导致1起疫情,GII.6[P7]及GII.8[P8]基因型各引起2起疫情,GII.2[P16]及GII.3[P12]基因型分别导致1起疫情。种系发生分析显示55株GII基因群毒株分布在5个基因簇。不同事件相同基因型的诺如病毒都位于同一个基因簇。不同事件不同基因型的诺如病毒各自聚集成簇,分属于不同的基因簇。结论2021-2022年渝东北片区11起聚集性诺如病毒感染毒株涉及多种基因型,GII.17[17]是引起聚集性感染事件的常见基因型,绝大多数事件由单一传染源引起,不同事件相同基因型的诺如病毒存在遗传相关性。

新冠流行前后江苏省诺如病毒食源性感染特征

目的了解江苏省诺如病毒监测情况,并对新冠流行前和流行期间检出特征进行比较。方法通过江苏省食源性疾病监测网络收集2015—2021年诺如病毒病例标本检测和分型结果,采用描述性流行病学方法,对诺如病毒检测结果进行分析,并比较2015—2019年(新冠流行前)与2020—2021年(新冠流行期间)诺如病毒检出情况。结果2015—2021年江苏省共检测73190份样本,诺如病毒阳性率5.68%;7年检出率在4.35%~10.59%,差异有统计学意义(χ^(2)=586.24,P<0.01)。诺如病毒阳性检出率以14~34岁组(7.03%)、冬季(10.81%)、有呕吐症状(9.26%)、进食场所为集体食堂(9.82%)、可疑食品为肉与肉制品(6.72%)较高,不同年龄组、季节、症状、进食场所、可疑食品类型的检出率差异均有统计学意义(χ^(2)值为12.75~827.56,P值均<0.05)。流行前阳性检出率(6.26%)高于流行期间(4.46%);与流行前阳性检出率相比,春、夏、秋季降低为22.25%~50.96%,冬季提高了42.81%,以上差异均有统计学意义(χ^(2)值为16.14~86.45,P值均<0.05)。7年共成功分型诺如病毒2657份,基因型以GII型为主(占71.70%),其次依次为GI型(占23.71%)和GI/GII型(占4.59%);流行前和流行期间的基因型构成比顺位相同,但分布差异有统计学意义(χ^(2)=1840.71,P<0.05)。结论针对COVID-19流行的防控措施可降低诺如病毒食源性感染的流行水平。

牛诺如病毒感染相关腹泻犊牛粪便菌群的特征分析

[目的]比较哺乳期健康犊牛和感染牛诺如病毒(Bovine norovirus,BNoV)的腹泻犊牛粪便菌群多样性和物种组成,初步揭示BNoV感染的腹泻犊牛粪便菌群特征。[方法]首先应用PCR和RT-PCR法对健康和腹泻犊牛粪便中的腹泻相关病原进行检测,然后采用16S rRNA扩增子测序技术对病原检测阴性的健康犊牛粪便(H组)和仅BNoV检测阳性的腹泻犊牛粪便(BNoV组)的微生物多样性、菌群组成和功能进行比较分析。[结果]与H组相比,BNoV组粪便菌群操作分类单元(OTUs)数量和Chao1指数显著升高(P<0.05),Shannon和Simpson指数极显著降低(P<0.01)。与H组相比,BNoV组粪便变形菌门、埃希-志贺属、丁酸球菌属丰度极显著升高(P<0.01),放线菌门、柯林斯菌属、巨球型菌属、厄氏菌属、双歧杆菌属、粪杆菌属等丰度极显著或显著降低(P<0.01;P<0.05)。双歧杆菌属、柯林斯菌属、巨球型菌属、厄氏菌属、粪杆菌属等在H组显著富集,而丁酸球菌属、埃希-志贺属、脆弱拟杆菌、梭菌属等在BNoV组显著富集。与H组相比,BNoV组粪便菌群胞内过程和信号传导、脂质代谢、新陈代谢、异生物质生物降解与代谢、萜类和聚酮类化合物代谢等显著或极显著上调(P<0.05;P<0.01),而膜转运、复制与修复、翻译、核苷酸代谢、遗传信息处理等显著或极显著下调(P<0.05;P<0.01)。[结论]感染BNoV的腹泻犊牛粪便菌群丰富度、多样性、物种组成和功能与健康犊牛显著不同,提示BNoV感染犊牛处于肠道菌群紊乱状态。