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Applied and Environmental Microbiology Aug 1995A method for the detection of Norwalk virus and hepatitis A virus from shellfish tissues by PCR was developed. Virus was added to the stomach and hepatopancreatic... (Comparative Study)
Comparative Study
A method for the detection of Norwalk virus and hepatitis A virus from shellfish tissues by PCR was developed. Virus was added to the stomach and hepatopancreatic tissues of oysters or hard-shell clams, and viral nucleic acids were purified by a modification of a previously described method (R.L. Atmar, T.G. Metcalf, F.H. Neill, and M.K. Estes, Appl. Environ. Microbiol. 59:631-635, 1993). The new method had the following advantages compared with the previously described method: (i) more rapid sample processing; (ii) increased test sensitivity; (iii) decreased sample-associated interference with reverse transcription-PCR; and (iv) use of chloroform-butanol in place of the chlorofluorocarbon trichlorotrifluoroethane. In addition, internal standards for both Norwalk virus and hepatitis A virus were made which demonstrated when inhibitors to reverse transcription-PCR were present and allowed quantitation of the viral nucleic acids present in samples. This assay can be used to investigate shellfish-associated gastroenteritis outbreaks and to study factors involved in virus persistence in shellfish.
Topics: Animals; Base Sequence; Bivalvia; Caliciviridae Infections; DNA Primers; DNA, Viral; Disease Outbreaks; Gastroenteritis; Hepatovirus; Humans; Molecular Sequence Data; Norwalk virus; Ostreidae; Polymerase Chain Reaction; RNA; Reference Standards; Sensitivity and Specificity; Shellfish
PubMed: 7487032
DOI: 10.1128/aem.61.8.3014-3018.1995 -
Trends in Microbiology Jun 2004Noroviruses cause the majority of acute viral gastroenteritis cases that occur worldwide. The increased recognition of noroviruses as the cause of outbreaks and sporadic... (Review)
Review
Noroviruses cause the majority of acute viral gastroenteritis cases that occur worldwide. The increased recognition of noroviruses as the cause of outbreaks and sporadic disease is due to the recent availability of improved norovirus-specific diagnostics. Transmission of these viruses is facilitated by their high prevalence in the community, shedding of infectious virus particles from asymptomatic individuals and the high stability of the virus in the environment. Currently, the spectrum of clinical disease and the understanding of host susceptibility factors are changing. Cases of chronic norovirus gastroenteritis have been observed in transplant recipients and unusual clinical presentations have been recognized in otherwise healthy adults that are under physical stress. Recently, noroviruses were found to bind to gut-expressed carbohydrates, leading to a correlation between a person's genetically determined carbohydrate expression and their susceptibility to Norwalk virus infection. Greater community surveillance and further investigation of carbohydrate receptor-binding properties could provide further insights into norovirus transmission, susceptibility and pathogenesis, and should aid in developing vaccines and antiviral therapies for this common viral disease.
Topics: Caliciviridae Infections; Disease Susceptibility; Disease Transmission, Infectious; Gastroenteritis; Humans; Norovirus; Receptors, Virus
PubMed: 15165606
DOI: 10.1016/j.tim.2004.04.005 -
Enteric virus infections and diarrhea in healthy and human immunodeficiency virus-infected children.Journal of Clinical Microbiology Aug 2000Forty-three stool samples from 27 human immunodeficiency virus (HIV)-seropositive children and 38 samples from 38 HIV-negative children, collected during a 15-month...
Forty-three stool samples from 27 human immunodeficiency virus (HIV)-seropositive children and 38 samples from 38 HIV-negative children, collected during a 15-month period, were examined for enteric viruses. Diagnostic assays included enzyme immunoassays for rotavirus, adenovirus, and Norwalk virus; polyacrylamide gel electrophoresis for picobirnavirus and atypical rotavirus; and PCR for astrovirus and enterovirus. Specimens from HIV-positive children were more likely than those of HIV-negative children to have enterovirus (56 versus 21%; P < 0.0002) and astrovirus (12 versus 0%; P < 0.02), but not rotavirus (5 versus 8%; P > 0.5). No adenoviruses, picobirnaviruses, or Norwalk viruses were found. The rates of virus-associated diarrhea were similar among HIV-positive and HIV-negative children. Enteroviruses were excreted for up to 6 months in HIV-positive children; however, no evidence for prolonged excretion of poliovirus vaccine was observed. These results suggest that although infection with enterovirus and astrovirus may be frequent in HIV-infected children, enteric viruses are not associated with the diarrhea frequently suffered by these children.
Topics: Adenovirus Infections, Human; Adenoviruses, Human; Child, Preschool; Diarrhea; Enterovirus; Enterovirus Infections; Feces; HIV Infections; Humans; Infant; Infant, Newborn; Mamastrovirus; Molecular Sequence Data; RNA Virus Infections; RNA Viruses
PubMed: 10921942
DOI: 10.1128/JCM.38.8.2873-2877.2000 -
The Journal of Clinical Investigation Apr 1991Norwalk virus, an important cause of epidemic, acute, nonbacterial gastroenteritis in adults and children, has eluded adaptation to tissue culture, the development of an...
Norwalk virus, an important cause of epidemic, acute, nonbacterial gastroenteritis in adults and children, has eluded adaptation to tissue culture, the development of an animal model, and molecular cloning. In this study, a portion of the Norwalk viral genome encoding an immunoreactive region was cloned from very small quantities of infected stool using sequence-independent single primer amplification. Six overlapping complementary DNA (cDNA) clones were isolated by immunologic screening. The expressed recombinant protein from a representative clone reacted with six of seven high titer. Norwalk-specific, postinfection sera but not with corresponding preinfection sera. Nucleic acid sequence for all clones defined a single open reading frame contiguous with the lambda gt11-expressed beta-galactosidase protein. Only oligonucleotide probes specific for the positive strand (defined by the open reading frame) hybridized to an RNaseA-sensitive, DNaseI-resistant nucleic acid sequence extracted from Norwalk-infected stool. Furthermore, RNA extracted from serial postinfection, but not preinfection, stools from three of five volunteers hybridized to a Norwalk virus cDNA probe. Clone-specific oligonucleotide probes hybridized with cesium chloride gradient fractions containing purified Norwalk virion. In conclusion, an antigenic, protein-coding region of the Norwalk virus genome has been identified. This epitope has potential utility in future sero- and molecular epidemiologic studies of Norwalk viral gastroenteritis.
Topics: Amino Acid Sequence; Antigens, Viral; Base Sequence; Cloning, Molecular; DNA; DNA Probes; Feces; Gastroenteritis; Molecular Sequence Data; Oligonucleotides; Polymerase Chain Reaction; RNA Viruses; RNA, Viral
PubMed: 2010555
DOI: 10.1172/JCI115152 -
Journal of Virology Oct 1996Norwalk virus (NV) is the prototype strain of a group of noncultivable human caliciviruses responsible for epidemic outbreaks of acute gastroenteritis. While these...
Norwalk virus (NV) is the prototype strain of a group of noncultivable human caliciviruses responsible for epidemic outbreaks of acute gastroenteritis. While these viruses do not grow in tissue culture cells or animal models, expression of the capsid protein in insect cells results in the self-assembly of recombinant Norwalk virus-like particles (rNV VLPs) that are morphologically and antigenically similar to native NV. We have used these rNV VLPs to examine virus-cell interactions. Binding and internalization of VLPs to cultured human and animal cell lines were studied in an attempt to identify potentially susceptible cell lines for virus propagation in vitro and to determine if early events in the replication cycle were responsible for the narrow host range and restriction of virus growth in cell culture. Radiolabeled VLPs specifically bound to a saturable number of binding molecules on the cell surface of 13 cell lines from different origins, including human intestine (differentiated and undifferentiated Caco-2) and insect (Spodoptera frugiperda 9) ovary. Differentiated Caco-2 cells bound significantly more rNV VLPs than the other cell lines. Variations in the amount of bound VLPs among the different cell lines did not correlate with the tissue or species of origin. VLP binding was specific, as determined by competition experiments with unlabeled rNV VLPs; however, only 1.4 to 6.8% of the specifically prebound radiolabeled VLPs became internalized into cells. Blocking experiments using polygonal and monoclonal anti-rNV sera and specific antipeptide sera were performed to map the domains on rNV VLPs involved in binding to cells. One monoclonal antibody (NV8812) blocked binding of rNV VLPs to human and animal cell lines. The binding site of monoclonal antibody NV8812 was localized to the C-terminal 300 to 384 residues of the capsid protein by immunoprecipitation with truncated and cleaved forms of the capsid protein. These data suggest that the C-terminal region of the capsid protein is involved in specific binding of rNV VLPs to cells.
Topics: Animals; Capsid; Cell Line; Humans; Norwalk virus; Recombinant Proteins; Virus Replication
PubMed: 8794293
DOI: 10.1128/JVI.70.10.6589-6597.1996 -
Preventive Medicine Dec 1974Two virus-like particles have been found to be associated with acute viral gastroenteritis. One, a 270-nm parvovirus-like particle (the Norwalk agent), was visualized...
Two virus-like particles have been found to be associated with acute viral gastroenteritis. One, a 270-nm parvovirus-like particle (the Norwalk agent), was visualized and recognized by immune electron microscopy in an infectious stool filtrate derived from a community outbreak of nonbacterial gastroenteritis. It appears to be one of the etiologic agents of a usually self-limited form of gastroenteritis which commonly occurs in community outbreaks. The other, a 70-nm reovirus-like particle, has been observed by electron microscopy in specimens from infants and children with severe diarrhea in many parts of the world. The reovirus-like particle may emerge as a major etiologic agent of diarrhea of infants and young children.
Topics: Acute Disease; Antibodies, Viral; Feces; Gastroenteritis; Humans; Inclusion Bodies, Viral; Infant; Microscopy, Electron; Parvoviridae; Reoviridae; Reoviridae Infections
PubMed: 4373705
DOI: 10.1016/0091-7435(74)90019-x -
Uirusu Dec 2000
Review
Topics: Adjuvants, Immunologic; Animals; Gastritis; Humans; Norwalk virus; Recombination, Genetic; Rotavirus Infections; Rotavirus Vaccines; Vaccines, Attenuated; Vaccines, DNA; Vaccines, Synthetic; Viral Vaccines
PubMed: 11276808
DOI: No ID Found -
Methods (San Diego, Calif.) Sep 2006Viruses-like particles (VLPs), assembled from capsid structural subunits of several different viruses, have found a number of biomedical applications such as vaccines... (Review)
Review
Viruses-like particles (VLPs), assembled from capsid structural subunits of several different viruses, have found a number of biomedical applications such as vaccines and novel delivery systems for nucleic acids and small molecules. Production of recombinant proteins in different plant systems has been intensely investigated and improved upon in the last two decades. Plant-derived antibodies, vaccines, and microbicides have received great attention and shown immense promise. In the case of mucosal vaccines, orally delivered plant-produced VLPs require minimal processing of the plant tissue, thus offering an inexpensive and safe alternative to more conventional live attenuated and killed virus vaccines. For other applications which require higher level of purification, recent progress in expression levels using plant viral vectors have shown that plants can compete with traditional fermentation systems. In this review, the different methods used in the production of VLPs in green plants are described. Specific examples of expression, assembly, and immunogenicity of several plant-derived VLPs are presented.
Topics: Biotechnology; Chemistry, Pharmaceutical; Hepatitis B Antigens; Norwalk virus; Plants, Genetically Modified; Virosomes
PubMed: 16997715
DOI: 10.1016/j.ymeth.2006.05.020 -
Bailliere's Clinical Gastroenterology Sep 1990In summary, the pathogenesis of many gut virus infections remains uncertain. However, human and animal studies indicate that the majority of gut viruses infect villous... (Comparative Study)
Comparative Study Review
In summary, the pathogenesis of many gut virus infections remains uncertain. However, human and animal studies indicate that the majority of gut viruses infect villous enterocytes. Viruses appear to have different affinities for enterocytes at different sites on the villus. Infection of enterocytes leads to cell death, extrusion into the lumen, and villous atrophy when the rate of cell production in the crypts cannot keep pace with the rate of enterocyte loss. This results in a reduced surface area as well as impairment of digestive and absorptive functions. This may also result in a net secretory state. All these changes, along with others such as reduced enzymatic activity and reduced epithelial integrity, may contribute to the induction of an acute but transient malabsorptive diarrhoea which may persist until the digestive/absorptive functions of the enterocyte are restored. However, if colonic compensation is sufficient to handle the increased fluid load, diarrhoea may not be evident. The roles of villous ischaemia, altered countercurrent exchanger of altered immune responses still remain uncertain and require further investigation.
Topics: Adenoviridae Infections; Adult; Animals; Caliciviridae; Cattle; Child; Diarrhea; Dogs; Gastroenteritis; Humans; Infant; Intestinal Diseases; Mamastrovirus; Mice; Norwalk virus; Picornaviridae Infections; Rats; Rotavirus Infections; Swine; Virus Diseases
PubMed: 1962725
DOI: 10.1016/0950-3528(90)90051-h -
Microbiological Reviews Jun 1984
Review
Topics: Adenoviruses, Human; Caliciviridae; Coronaviridae; Coronaviridae Infections; Gastroenteritis; Genes, Viral; Humans; Mamastrovirus; Morphogenesis; Norwalk virus; Picornaviridae Infections; Rotavirus; Rotavirus Infections; Viral Proteins; Virus Diseases
PubMed: 6330511
DOI: 10.1128/mr.48.2.157-179.1984