| inactivation of norovirus on dry copper alloy surfaces. | noroviruses (family caliciviridae) are the primary cause of viral gastroenteritis worldwide. the virus is highly infectious and touching contaminated surfaces can contribute to infection spread. although the virus was identified over 40 years ago the lack of methods to assess infectivity has hampered the study of the human pathogen. recently the murine virus, mnv-1, has successfully been used as a close surrogate. copper alloys have previously been shown to be effective antimicrobial surfaces ag ... | 2013 | 24040380 |
| development of a strand specific real-time rt-qpcr assay for the detection and quantitation of murine norovirus rna. | murine norovirus (mnv), currently the only norovirus that efficiently replicates in cell culture, is often used as a model system to understand the molecular mechanisms of norovirus replication. mnv is a single stranded positive sense rna virus of the caliciviridae family. replication of mnv involves the synthesis of both full length genomic and sub-genomic rnas. the replication of these rnas involves the synthesis of negative strand intermediates. to understand the molecular mechanism of rna re ... | 2012 | 22626565 |
| identification of immune and viral correlates of norovirus protective immunity through comparative study of intra-cluster norovirus strains. | whether or not primary norovirus infections induce protective immunity has become a controversial issue, potentially confounded by the comparison of data from genetically distinct norovirus strains. early human volunteer studies performed with a norovirus-positive inoculum initially led to the conclusion that primary infection does not generate long-term, protective immunity. more recently though, the epidemiological pattern of norovirus pandemics has led to the extrapolation that primary norovi ... | 2013 | 24039576 |
| virus transfer proportions between gloved fingertips, soft berries, and lettuce, and associated health risks. | multiple outbreaks of human norovirus (hnov) have been associated with fresh produce, such as soft berries and lettuce. even though food handlers are considered an important source for the introduction of hnov into food chains, their contribution to public health risks associated with hnov remains unknown. to assess to which extent food handlers contribute to the introduction and spread of hnov in fresh produce chains quantitative virus transfer data are needed. we estimated transfer proportions ... | 2013 | 24029026 |
| effect of hypochlorite-based disinfectants on inactivation of murine norovirus and attempt to eliminate or prevent infection in mice by addition to drinking water. | we evaluated the in vitro efficacy of weak acid hypochlorous solution (wahs) against murine norovirus (mnv) by plaque assay and compared the efficacy with diluted naocl (purelox) and 70% ethanol. wahs was as effective as 70% ethanol and diluted purelox for 0.5-min reactions. for 0.5-min reactions in the presence of mouse feces emulsion, the efficacy of whas and 1:600 diluted purelox was decreased, reducing the virus titers by 2.3 and 2.6 log10, respectively, while 70% ethanol reduced the titer b ... | 2013 | 23903059 |
| norovirus and ms2 inactivation kinetics of uv-a and uv-b with and without tio2. | germicidal ultraviolet, such as 254-nm uv-c, is a common method of disinfection of pathogenic enteric viruses. however, the disinfection efficacies of uv-a or -b in terms of inactivating waterborne viruses such as norovirus have not been characterized. we evaluated the inactivation kinetics of ms2 bacteriophage and murine norovirus (mnv), a surrogate of human norovirus (nov), by uv-a and -b. in addition to uv disinfection, we further investigated whether the presence of tio2 could enhance the vi ... | 2013 | 23871257 |
| optimization of an adsorption-elution method with a negatively charged membrane to recover norovirus from lettuce. | viral pathogens, such as norovirus (nov), are frequently associated with foodborne gastroenteritis worldwide, and the detection of nov in food requires appropriate methods and the use of process controls. in this study, an adsorption-elution concentration method using negatively charged membranes was optimized to recover nov from lettuce, using murine norovirus 1 (mnv-1) as a human nov (hunov) surrogate. initially, three elution buffers were evaluated by direct elution using a stomacher® apparat ... | 2013 | 23649411 |
| multiple effects of dendritic cell depletion on murine norovirus infection. | dendritic cells (dcs) are permissive to murine norovirus (mnv) infection in vitro and in vivo. however, their roles during infection in vivo are not well defined. to determine the role of dcs during infection, conventional dcs were depleted from cd11c-dtr mice and infected with a persistent mnv strain. viral titres in the intestine and secondary lymphoid organs were determined at early time points during infection, and anti-mnv antibody responses were analysed later during infection. depletion o ... | 2013 | 23636823 |
| impact of sodium chloride, sucrose and milk on heat stability of the murine norovirus and the ms2 phage. | until now, little is known about the influence of food additives on heat inactivation of noroviruses. only a few studies have shown a protective or inhibiting effect on virus infectivity caused by the food matrix. therefore, the aim of this study was to examine the influence of sodium chloride, sucrose and milk on heat stability of the surrogates murine norovirus (mnv) and ms2 phage at 60 °c for 1-5 min in pbs for mnv and for 5-120 min in suspension medium buffer for ms2 phage. different concent ... | 2013 | 23625486 |
| persistent enteric murine norovirus infection is associated with functionally suboptimal virus-specific cd8 t cell responses. | norovirus (nv) gastroenteritis is a major contributor to global morbidity and mortality, yet little is known about immune mechanisms leading to nv control. previous studies using the murine norovirus (mnv) model have established a key role for t cells in mnv clearance. despite these advances, important questions remain regarding the magnitude, location, and dynamics of the mnv-specific t cell response. to address these questions, we identified mnv-specific major histocompatibility complex (mhc) ... | 2013 | 23596300 |
| norovirus surrogate survival on spinach during preharvest growth. | produce can become contaminated with human viral pathogens in the field through soil, feces, or water used for irrigation; through application of manure, biosolids, pesticides, and fertilizers; and through dust, insects, and animals. the objective of this study was to assess the survival and stability of human noroviruses and norovirus surrogates (murine norovirus [mnv] and tulane virus [tv]) on foliar surfaces of spinach plants in preharvest growth conditions. spinach plants were housed in a bi ... | 2013 | 23506365 |
| common vole (microtus arvalis) and bank vole (myodes glareolus) derived permanent cell lines differ in their susceptibility and replication kinetics of animal and zoonotic viruses. | pathogenesis and reservoir host adaptation of animal and zoonotic viruses are poorly understood due to missing adequate cell culture and animal models. the bank vole (myodes glareolus) and common vole (microtus arvalis) serve as hosts for a variety of zoonotic pathogens. for a better understanding of virus association to a putative animal host, we generated two novel cell lines from bank voles of different evolutionary lineages and two common vole cell lines and assayed their susceptibility, rep ... | 2019 | 31513859 |
| natural infection of murine norovirus in conventional and specific pathogen-free laboratory mice. | noroviruses cause most cases of acute viral gastroenteritis worldwide. the lack of a cell culture infection model for human norovirus necessitates the use of molecular methods and/or viral surrogate models amenable to cell culture to predict norovirus inactivation. murine norovirus (mnv) may be used to construct a small animal model for studying the biology and pathogenesis of noroviruses because mnv is the only norovirus that replicates in cell culture and a small animal model. however, recent ... | 2013 | 23386847 |
| pressure inactivation of tulane virus, a candidate surrogate for human norovirus and its potential application in food industry. | human norovirus (hunov) is the leading causative agent for foodborne disease. currently, studies of hunov usually rely on surrogates such as murine norovirus (mnv) due to the lack of a suitable cell culture system and a small animal model for hunov. tulane virus (tv), a monkey calicivirus, is a cultivable enteric calicivirus that not only recognizes the same receptors as hunov, but is also genetically closely related to hunov. in this study, we determined the ph stability of tv and mnv-1, as wel ... | 2013 | 23353553 |
| comparison of rna extraction methods for the detection of a norovirus surrogate in ready-to-eat foods. | four nucleic acid extraction methods were evaluated for the purpose of quantifying a norovirus surrogate (murine norovirus [mnv-1]) concentrated from different food samples. simple (strawberries and lettuce) and complex (sliced turkey breast, soft-shell clams, and potato salad) food matrices were inoculated with a viral suspension containing high (4×10(5) pfu) or low (4×10(3) pfu) numbers of viral particles. mnv-1 was eluted using either the pulsifier™ or repetitive pipetting. the four methods w ... | 2013 | 23320423 |
| comparing human norovirus surrogates: murine norovirus and tulane virus. | viral surrogates are widely used by researchers to predict human norovirus behavior. murine norovirus (mnv) is currently accepted as the best surrogate and is assumed to mimic the survival and inactivation of human noroviruses. recently, a new calicivirus, the tulane virus (tv), was discovered, and its potential as a human norovirus surrogate is being explored. this study aimed to compare the behavior of the two potential surrogates under varying treatments of ph (2.0 to 10.0), chlorine (0.2 to ... | 2013 | 23317870 |
| reliability of non-culturable virus monitoring by pcr-based detection methods in environmental waters containing various concentrations of target rna. | owing to the lack of practical cell culture system for human noroviruses (hunov), various detection methods based on conventional reverse transcription-pcr (rt-pcr) and the quantitative real-time pcr have been major tools for monitoring environmental water safety. in this study, we showed that the proportion of water sample concentrates used for one-step rt-pcr significantly influences false-negative findings of the non-culturable viruses. in total, 59 archived samples of previously analyzed wat ... | 2012 | 23124739 |
| survival of murine norovirus and f-rna coliphage ms2 on pork during storage and retail display. | the existence of animal strains of norovirus (nv) that are closely related to human strains raises concerns about interspecies recombination and the potential for zoonotic transmission through undercooked meat products. contamination of meat with nv can occur both via meat processing operations and poor food handler hygiene. there is a lack of knowledge on the survival of nv on raw meat because nv cannot be effectively cultivated and its detection is limited to molecular methods. the survival of ... | 2012 | 23107497 |
| a single-amino-acid change in murine norovirus ns1/2 is sufficient for colonic tropism and persistence. | human norovirus (hunov) is the major cause of acute nonbacterial gastroenteritis worldwide but has no clear animal reservoir. hunov can persist after the resolution of symptoms, and this persistence may be essential for viral maintenance within the population. many strains of the related murine norovirus (mnv) also persist, providing a tractable animal model for studying norovirus (nov) persistence. we have used recombinant cdna clones of representative persistent (cr6) and nonpersistent (cw3) s ... | 2013 | 23077309 |
| plaque assay for murine norovirus. | murine norovirus (mnv) is the only member of the norovirus genus that efficiently grows in tissue culture. cell lysis and cytopathic effect (cpe) are observed during mnv-1 infection of murine dendritic cells or macrophages. this property of mnv-1 can be used to quantify the number of infectious particles in a given sample by performing a plaque assay. the plaque assay relies on the ability of mnv-1 to lyse cells and to form holes in a confluent cell monolayer, which are called plaques. multiple ... | 2012 | 22951568 |
| high-resolution functional profiling of the norovirus genome. | human noroviruses (hunov) are a major cause of nonbacterial gastroenteritis worldwide, yet details of the life cycle and replication of hunov are relatively unknown due to the lack of an efficient cell culture system. studies with murine norovirus (mnv), which can be propagated in permissive cells, have begun to probe different aspects of the norovirus life cycle; however, our understanding of the specific functions of the viral proteins lags far behind that of other rna viruses. genome-wide fun ... | 2012 | 22915807 |
| human norovirus transfer to stainless steel and small fruits during handling. | human noroviruses (novs) cause an estimated 58% of foodborne illnesses in the united states annually. the majority of these outbreaks are due to contamination by food handlers. the objective of this study was to quantify the transfer rate and degree of contamination that occurs on small fruits (blueberries, grapes, and raspberries) and food contact surfaces (stainless steel) when manipulated with nov-contaminated hands. human novs (genogroups i and ii [gi and gii]) and murine norovirus (mnv-1) w ... | 2012 | 22856567 |
| comparison of elisa attachment and infectivity assays for murine norovirus. | human noroviruses cause approximately 58% of foodborne illnesses in the usa. recent studies have shown norovirus attachment to the carbohydrates moieties of host cellular receptors. using murine norovirus (mnv) as a surrogate, an elisa method was utilized to assess attachment through binding to host cell receptors; mnv attachment was correlated to infectivity determined by plaque assay. elisa plates were coated with porcine gastric mucin and untreated, heat-, high pressure-, ozone- and uv-treate ... | 2012 | 22820074 |
| favipiravir (t-705) inhibits in vitro norovirus replication. | human noroviruses are the primary cause of foodborne gastroenteritis. potent and safe inhibitors are needed for the treatment/prophylaxis of norovirus infections. we demonstrate that favipiravir [t-705, a drug in advanced clinical development for the treatment of infections with the influenza virus] inhibits in vitro murine norovirus replication. time-of-drug addition studies reveal that t-705 exerts its activity at a time-point that coincides with onset of viral rna synthesis, which is in line ... | 2012 | 22809499 |
| norovirus rna synthesis is modulated by an interaction between the viral rna-dependent rna polymerase and the major capsid protein, vp1. | using a cell-based assay for rna synthesis by the rna-dependent rna polymerase (rdrp) of noroviruses, we previously observed that vp1, the major structural protein of the human gii.4 norovirus, enhanced the gii.4 rdrp activity but not that of the related murine norovirus (mnv) or other unrelated rna viruses (c. v. subba-reddy, i. goodfellow, and c. c. kao, j. virol. 85:13027-13037, 2011). here, we examine the mechanism of vp1 enhancement of rdrp activity and the mechanism of mouse norovirus repl ... | 2012 | 22787222 |
| reverse genetics mediated recovery of infectious murine norovirus. | human noroviruses are responsible for most cases of human gastroenteritis (ge) worldwide and are recurrent problem in environments where close person-to-person contact cannot be avoided (1, 2). during the last few years an increase in the incidence of outbreaks in hospitals has been reported, causing significant disruptions to their operational capacity as well as large economic losses. the identification of new antiviral approaches has been limited due to the inability of human noroviruses to c ... | 2012 | 22760450 |
| structure of a murine norovirus ns6 protease-product complex revealed by adventitious crystallisation. | murine noroviruses have emerged as a valuable tool for investigating the molecular basis of infection and pathogenesis of the closely related human noroviruses, which are the major cause of non-bacterial gastroenteritis. the replication of noroviruses relies on the proteolytic processing of a large polyprotein precursor into six non-structural proteins (ns1-2, ns3, ns4, ns5, ns6(pro), ns7(pol)) by the virally-encoded ns6 protease. we report here the crystal structure of mnv ns6(pro), which has b ... | 2012 | 22685603 |
| development of a reverse-genetics system for murine norovirus 3: long-term persistence occurs in the caecum and colon. | human noroviruses (hunov) are a major cause of viral gastroenteritis worldwide, yet, due to the inability to propagate hunov in cell culture, murine norovirus (mnv) is typically used as a surrogate to study norovirus biology. mnv-3 represents an attractive strain to study norovirus infections in vivo because it establishes persistence in wild-type mice, yet causes symptoms resembling gastroenteritis in immune-compromised stat1(-/-) mice. the lack of reverse-genetics approaches to recover genetic ... | 2012 | 22495235 |
| structure-based inhibition of norovirus rna-dependent rna polymerases. | caliciviridae are rna viruses with a single-stranded, positively oriented polyadenylated genome, responsible for a broad spectrum of diseases such as acute gastroenteritis in humans. recently, analyses on the structures and functionalities of the rna-dependent rna polymerase (rdrp) from several caliciviruses have been reported. the rdrp is predicted to play a key role in genome replication, as well as in synthesis and amplification of additional subgenomic rna. starting from the crystal structur ... | 2012 | 22446684 |
| effect of temperature, ph, and nacl on the inactivation kinetics of murine norovirus. | we investigated the resistance of murine norovirus (mnv) and coliphage ms2, a culturable human norovirus surrogate, to temperature, salt, and ph. virus inactivation was measured by plaque, real-time taqman reverse transcription (rt) pcr, and long-template rt-pcr assays. both mnv and ms2 were rapidly inactivated at temperatures above 60°c. similarly, mnv tolerated low salt concentrations (0.3% nacl) to a greater degree than high salt concentrations (3.3 to 6.3% nacl). mnv was relatively resistant ... | 2012 | 22410228 |
| crystal structures of murine norovirus-1 rna-dependent rna polymerase in complex with 2-thiouridine or ribavirin. | murine norovirus-1 (mnv-1) shares many features with human norovirus (hunov) and both are classified within the norovirus genus of caliciviridae family. mnv-1 is used as the surrogate for hunov research since it is the only form that can be grown in cell culture. hunov and mnv-1 rna dependent rna polymerase (rdrp) proteins with the sequence identity of 59% show essentially identical conformations. here we report the first structural evidence of 2-thiouridine (2tu) or ribavirin binding to mnv-1 r ... | 2012 | 22341781 |
| mouse norovirus 1 utilizes the cytoskeleton network to establish localization of the replication complex proximal to the microtubule organizing center. | human noroviruses (family caliciviridae) are the leading cause of nonbacterial gastroenteritis worldwide. although human noroviruses are significant enteric pathogens, there exists no reliable vaccine or therapy to treat infected individuals. to date, attempts to cultivate human noroviruses within the laboratory have met with little success; however, the related murine norovirus mouse norovirus 1 (mnv-1) has provided an ideal model system to study norovirus replication due to the ease with which ... | 2012 | 22301146 |
| evaluation of four antiseptics using a novel murine norovirus. | we isolated a novel murine norovirus (mnv), mt30-2 strain, from feces of conventional mice in japan to evaluate the virucidal activity of four antiseptics. the mnv mt30-2 strain was inactivated by as little as 0.2% (w/v) povidone-iodine (pvp-i) and 0.1% (w/v) sodium hypochlorite (naocl) treatment as determined by a novel plaque assay. importantly, pvp-i reduced the mnv titer by 4 log(10) within 15 s of exposure. the other two antiseptics, benzethonium chloride (bec) and chlorhexidine gluconate ( ... | 2012 | 22293670 |
| effect of high hydrostatic pressure on murine norovirus in manila clams. | eating raw or insufficiently cooked bivalve molluscs contaminated with human noroviruses (nvs) can result in acute cases of gastroenteritis in humans. manila clams (ruditapes philippinarum) are particularly prone to exposure to nvs due to the brackish environment in which they are farmed which is known to be susceptible to human faecal contamination. high hydrostatic pressure processing (hhp) is a food treatment technique that has been shown to inactivate nv. | 2012 | 22268557 |
| evaluation of methods measuring the capsid integrity and/or functions of noroviruses by heat inactivation. | attempts were made to evaluate methods measuring the capsid integrity and/or functions of noroviruses (novs) following heat treatment. intact viruses (murine norovirus-1 [mnv-1] and human nov gii.4), virus like particles (vlps) and p particles (expressed in vitro from the protruding domain of the viral capsid) of novs were used in this study. following heat treatment, no significant difference of viral titer of mnv-1 versus nov gii.4 was observed by rnase one rt-pcr or cell-binding rt-pcr, altho ... | 2012 | 22266875 |
| protruding domain of capsid protein is necessary and sufficient to determine murine norovirus replication and pathogenesis in vivo. | human noroviruses (hunovs) are the major cause of epidemic, nonbacterial gastroenteritis worldwide. due to the lack of a tractable model system and the inability to grow hunovs in cell culture, factors required for the norovirus (nov) life cycle and pathogenesis in the host remain largely unknown. the discovery of murine norovirus (mnv) and the development of reverse-genetics systems for this virus provide an opportunity to study these aspects of nov infection in vitro and in vivo. previous stud ... | 2012 | 22258242 |
| comparative transcriptomic response of primary and immortalized macrophages to murine norovirus infection. | murine norovirus (nov) is genetically similar to human nov and offers both an efficient in vitro cell culture system and an animal model by which to investigate the molecular basis of replication. in this study, we present a detailed global view of host alterations to cellular pathways that occur during the progression of a nov infection. this was accomplished for both mus musculus balb/c-derived raw264.7 (raw) cells, an immortalized cell line widely used in in vitro replication studies, and pri ... | 2018 | 29735480 |