| immunoglobulin class and subclass deficiencies prior to epstein-barr virus infection in males with x-linked lymphoproliferative disease. | patients with x-linked lymphoproliferative (xlp) disease are characterized by extreme vulnerability to epstein-barr virus (ebv). following infection with ebv, affected males develop fatal infectious mononucleosis (im), hypogammaglobulinemia (h), or non-hodgkin's lymphoma (nhl). in addition, hyper igm, red cell aplasia, necrotizing lymphoid vasculitis (nlv), and aplastic anemia occur rarely. the recent use of dna restriction fragment length polymorphism (rflp) probes in linkage with the xlp gene ... | 1991 | 1683154 |
| three serotypes of norwalk-like virus demonstrated by solid-phase immune electron microscopy. | solid phase immune electron microscopy (spiem) was used to investigate the serological differences between norwalk-like virus (nlv) strains from five different outbreaks within the united kingdom. the existence of two previously demonstrated serotypes, lewis et al. (journal of clinical microbiology 26:938-942, 1988), was confirmed by the use of whole convalescent sera and purified igm. a third serotype was found to be the agent of two recent hospital outbreaks and could similarly be typed by use ... | 1990 | 2154547 |
| 3'-terminal sequences of the rna genomes of narcissus latent and maclura mosaic viruses suggest that they represent a new genus of the potyviridae. | the nucleotide sequences of part of the nuclear inclusion body b (nib) gene, the complete coat protein gene and the 3' untranslated regions of narcissus latent virus (nlv) and maclura mosaic virus (macmv) were determined. deduced amino acid sequences for the nib and coat protein genes revealed that nlv and macmv are closely related. gel analysis and western blotting of the coat proteins of nlv and macmv from infected tissue or purified virus indicated that they have molecular masses of 39.5 kda ... | 1997 | 9010311 |
| norwalk-like viral gastroenteritis in u.s. army trainees--texas, 1998. | during august 27-september 1, 1998, 99 (12%) of 835 soldiers in one unit at a u.s. army training center in el paso, texas, were hospitalized for acute gastroenteritis (age). their symptoms included acute onset of vomiting, abdominal pain, diarrhea, and fever. review of medical center admission records for age during the previous year indicated that fewer than five cases occurred each month. this report describes the outbreak investigation initiated on august 30 by a u.s. army epidemiologic consu ... | 1999 | 10220254 |
| molecular characterization and interviral relationships of a flexuous filamentous virus causing mosaic disease of sugarcane (saccharum officinarum l.) in india. | a virus isolate causing mosaic disease of commercial sugarcane was purified to homogeneity. electron microscopy revealed flexuous filamentous virus particles of ca 890 x 15 nm. the virus isolate reacted positively with heterologous antiserum to narcissus latent virus form uk, but failed to react with potyvirus group specific antiserum. n-terminal sequencing of the intact coat protein (cp) and the tryptic peptides indicated that the virus was probably a potyvirus but distinct from several reporte ... | 1999 | 10226614 |
| an outbreak of acute gastroenteritis in a geriatric long-term-care facility: combined application of epidemiological and molecular diagnostic methods. | to assess possible transmission modes of, and risk factors for, gastroenteritis associated with norwalk-like viruses (nlvs) in a geriatric long-term-care facility. | 1999 | 10349945 |
| genomic diversity of "norwalk like viruses" (nlvs): pediatric infections in a brazilian shantytown. | "norwalk-like viruses" (nlvs) are a common cause of epidemic gastroenteritis in adults and children in developed countries. however, little is known about the role of nlvs in endemic pediatric gastroenteritis in developing countries. we sequenced genogroup i and ii nlv reverse transcription-polymerase chain reaction (rt-pcr) products from an 81-nucleotide region of the viral rna polymerase gene to examine the molecular epidemiology of nlv infection in children younger than 5 years of age in fort ... | 1999 | 10421412 |
| immunoglobulin m antibody test to detect genogroup ii norwalk-like virus infection. | sera obtained from adult volunteers inoculated with genogroup ii norwalk-like viruses (nlvs), hawaii virus, and snow mountain virus and from patients involved in outbreaks of gastroenteritis were tested for genogroup ii nlv mexico virus-specific immunoglobulin m (igm) by use of a monoclonal antibody, recombinant mexico virus antigen (rmxv)-based igm capture enzyme-linked immunosorbent assay (elisa). sera from genogroup i norwalk virus (nv)-inoculated volunteers and from patients involved in a ge ... | 1999 | 10449486 |
| outbreak of viral gastroenteritis due to drinking water contaminated by norwalk-like viruses. | heinävesi, a finnish municipality with a population of 4860 inhabitants, had an outbreak of gastroenteritis in march 1998. on the basis of an epidemiologic survey, an estimated 1700-3000 cases of acute gastroenteritis occurred during the outbreak. municipal water consumption was found to be associated with illness (risk ratio [rr]=3.5, 95% confidence interval, 3.11>rr>3.96). norwalk-like virus (nlv) genogroup ii (ggii) was identified in untreated water, treated water, and 4 tap water samples by ... | 1999 | 10558930 |
| molecular detection of norwalk-like caliciviruses in sewage. | in this study, norwalk-like virus (nlv) rna was detected by reverse transcriptase pcr (rt-pcr) in sewage water concentrates. sequence analysis of the rt-pcr products revealed identical sequences in stools of patients and related sewage samples. in 6 of 11 outbreak-unrelated follow-up samples, multiple nlv genotypes were present. levels as high as 10(7) rna-containing particles per liter were found. these data show that high loads of nlvs may be present in sewage and warrant further studies addre ... | 1999 | 10584031 |
| confirmation of norwalk-like virus amplicons after rt-pcr by microplate hybridization and direct sequencing. | a large number of norwalk-like viruses (nlvs) have been identified from stool samples by rt-pcr by amplifying part of the polymerase-coding gene. a set of probes were selected based on sequence analysis of the viruses circulating in finland during the years 1996-97 for confirmation of the findings by hybridization. a microplate hybridization test, which provides a rapid semi-automatic detection for pcr products, was designed and compared with agarose gel electrophoresis. from the material of 210 ... | 1999 | 10598090 |
| development of methods to detect "norwalk-like viruses" (nlvs) and hepatitis a virus in delicatessen foods: application to a food-borne nlv outbreak. | "norwalk-like viruses" (nlvs) and hepatitis a virus (hav) are the most common causes of virus-mediated food-borne illness. epidemiological investigations of outbreaks associated with these viruses have been hindered by the lack of available methods for the detection of nlvs and hav in foodstuffs. although reverse transcription (rt)-pcr methods have been useful in detecting nlvs and hav in bivalve mollusks implicated in outbreaks, to date such methods have not been available for other foods. to a ... | 2000 | 10618226 |
| norwalk-like virus and bacterial pathogens associated with cases of gastroenteritis onboard a us navy ship. | acute gastroenteritis is a potential cause of substantial morbidity in u.s. military personnel during deployment. this study investigated the microbial causes of diarrhea in u.s. troops on exercises in southeast asia aboard the u.s.s. germantown from march through may 1996. a total of 49 (7%) patients with diarrhea reported to sick call during a 3-month deployment involving 721 personnel. diarrheal samples from 49 patients were subjected to bacterial and parasitologic examination, but sufficient ... | 1999 | 10674668 |
| expression of recombinant norwalk-like virus capsid proteins using a bacterial system and the development of its immunologic detection. | the capsid protein of norwalk-like virus (nlv) isolates nlv-36 (mexico virus type, genogroup ii [gii]), nlv-21 (lordsdale virus type, gii), nlv-114 (untyped gii virus), and nlv-96-908 (ky89 virus type, gi) have been expressed in an escherichia coli system. the expressed recombinant nlv capsid proteins, fused with maltose binding protein (mbp-rv) and thioredoxin (trx-rv) in e. coli lysate, were analyzed using sodium dodecyl sulfate-polyacrylamide gel eletrophoresis. rabbit igg (r-igg) in hyperimm ... | 2000 | 10686033 |
| evaluation of f-specific rna bacteriophage as a candidate human enteric virus indicator for bivalve molluscan shellfish. | escherichia coli is a widely utilized indicator of the sanitary quality of bivalve molluscan shellfish sold for human consumption. however, it is now well documented that shellfish that meet the e. coli standards for human consumption may contain human enteric viruses that cause gastroenteritis and hepatitis. in this study we investigated using f-specific rna bacteriophage (frna bacteriophage) to indicate the likely presence of such viruses in shellfish sold for consumption. frna bacteriophage a ... | 2000 | 10742200 |
| seroprevalence and seroincidence of norwalk-like virus infection among brazilian infants and children. | to determine the importance of norwalk-like viruses (nlvs) as pediatric pathogens in a developing country, the seroprevalence and seroincidence of this group of viruses in a cohort of children less than 4 years of age in an urban shantytown in northeastern brazil was examined. serum samples were collected approximately every 6 months from 135 children who were surveyed three times each week for diarrhea and vomiting. nlv igg was measured by an enzyme immunosorbent assay (eia) with recombinant no ... | 2000 | 10745243 |
| outbreak of viral gastroenteritis due to sewage-contaminated drinking water. | in august 1998, a large outbreak of gastroenteritis occurred in a swiss village of 3500 inhabitants whereof more than 50% were affected. a high contamination of drinking water with faecal coliforms revealed a defect in the waste water system. the objective of the present study was to investigate the outbreak in respect of the presence of human pathogenic viruses. drinking water and clinical samples from patients were examined for the presence of 'norwalk-like viruses' (nlvs) and enteroviruses. n ... | 2000 | 10746582 |
| taxonomy of the caliciviruses. | the international committee on taxonomy of viruses (ictv) has recently approved several proposals submitted by the present caliciviridae study group. these proposals include the division of the family into 4 new genera designated lagovirus, vesivirus, "norwalk-like viruses (nlvs), and "sapporo-like viruses (slvs); the latter 2 genera were assigned temporary names until acceptable names can be determined by the scientific community. the genera have been further divided into the following species: ... | 2000 | 10804145 |
| genetic classification of "norwalk-like viruses.. | reverse transcription-polymerase chain reaction has been used worldwide for the diagnosis of norwalk-like virus (nlv) infection, yet a commonly accepted genetic classification scheme has not been established. amino acid sequences from four regions of open-reading frame 2 (orf2) were used to analyze 101 nlv strains, including 2 bovine strains. on the basis of this analysis, a genetic classification scheme is proposed that differentiates 99 human strains into 2 major genetic groups consisting of 5 ... | 2000 | 10804147 |
| detection of norwalk-like virus in shellfish implicated in illness. | in the 1990s, norwalk-like viruses (nlvs) were identified in patient specimens as the primary pathogen associated with shellfish-borne gastroenteritis in the united states. identification of these viruses from implicated shellfish has been difficult due to inefficient recovery of viruses, natural polymerase chain reaction (pcr) inhibitors in shellfish, and low virus contamination. recent improvements to the method of detecting nlvs in shellfish include enhanced processing of virus and shellfish ... | 2000 | 10804149 |
| multi-state outbreaks of acute gastroenteritis traced to fecal-contaminated oysters harvested in louisiana. | norwalk-like viruses (nlvs), or small round structured viruses, are known to cause acute gastroenteritis associated with eating contaminated shellfish. between 1993 and 1996, three oyster-related gastroenteritis outbreaks attributed to nlv occurred in louisiana. intensive trace-back and environmental investigations revealed that the overboard disposal of sewage by oyster harvesters into oyster-bed waters was the most likely source of contamination in at least two of the outbreaks. the small infe ... | 2000 | 10804152 |
| norwalk-like virus infection in military forces: epidemic potential, sporadic disease, and the future direction of prevention and control efforts. | the impact of norwalk-like virus (nlv) infection on military forces is evaluated in this report. nlvs were a major cause of both outbreaks and sporadic disease among crowded us ground troops in the 1991 war with iraq. nlvs also have been found to be a cause of acute gastroenteritis in other ground and shipboard deployments. four large outbreaks of acute gastroenteritis were investigated aboard us navy aircraft carriers between 1992 and 1997. in these outbreaks, nlvs were identified as the probab ... | 2000 | 10804153 |
| the heteroduplex mobility assay (hma) as a pre-sequencing screen for norwalk-like viruses. | molecular epidemiological studies of norwalk-like viruses (nlvs), previously known as small round structured viruses (srsvs), are dependant currently on dna sequencing of pcr amplicons, which is expensive and time consuming. the heteroduplex mobility assay (hma) was evaluated as a method for identification of pcr amplicons from the commonly circulating nlv strains without dna sequencing. the procedure was developed for use with two reference strains, a mexico virus-like strain (mxv-like; hu¿nlv¿ ... | 2000 | 10856763 |
| major change in the predominant type of "norwalk-like viruses" in outbreaks of acute nonbacterial gastroenteritis in osaka city, japan, between april 1996 and march 1999. | in osaka city, japan, between april 1996 and march 1999, a total of 350 fecal specimens from 64 outbreaks of acute nonbacterial gastroenteritis were examined to investigate infection by "norwalk-like viruses" (nlvs). by reverse transcription (rt)-pcr, 182 samples (52.0%) from 47 outbreaks (73.4%) were nlv positive. during those three years, the incidence of nlv-associated outbreaks showed seasonality, being higher during january to march (winter to early spring). the ingestion of contaminated oy ... | 2000 | 10878058 |
| combined infection of norwalk-like virus and verotoxin-producing bacteria associated with a gastroenteritis outbreak. | detection of multiple pathogens, particularly a combination of viruses and bacteria, is infrequently documented in outbreaks of gastroenteritis. this paper reports the presence of norwalk-like virus (nlv) and enterohaemorrhagic verotoxin-producing escherichia coli in one individual, and nlv and verotoxin-producing aeromonas sobria in another individual, both part of a large gastroenteritis outbreak. the causes of gastroenteritis in such outbreaks may be more complex than previously thought. | 1999 | 10892495 |
| antigenic diversity of norwalk-like viruses: expression of the capsid protein of a genogroup i virus, distantly related to norwalk virus. | the gene encoding the capsid protein of a genogroup i norwalk-like virus (nlv) (hu/nlv/stav/95/nor) was cloned and expressed in insect cells using a baculovirus vector. the his-tagged recombinant capsid protein (rstav) was antigenic and immunogenic, showed an apparent molecular weight of approximately 68 kd in protein gels, and was only soluble under denaturing conditions. the amino acid sequence of the rstav protein showed 65-88% similarity to capsid protein sequences from other genogroup i nlv ... | 2000 | 10893150 |
| three-year study to assess human enteric viruses in shellfish. | the main pathogenic enteric viruses able to persist in the environment, such as hepatitis a virus (hav), norwalk-like virus (nlv), enterovirus (ev), rotavirus (rv), and astrovirus (av), were detected by reverse transcription-pcr and hybridization in shellfish during a 3-year study. oyster samples (n = 108), occasionally containing bacteria, were less frequently contaminated, showing positivity for av (17%), nlv (23%), ev (19%), and rv (27%), whereas mussel samples, collected in areas routinely i ... | 2000 | 10919776 |
| distinct epidemiological patterns of norwalk-like virus infection. | norwalk-like viruses (nlv) are important economically as a cause of both sporadic gastroenteritis in the community and large outbreaks in hospitals and other institutional settings. despite the description of several antigenic types relatively little is known about the epidemiology of these individual types. nlvs were detected by electron microscopy in faecal specimens from 706 outbreaks of gastroenteritis that represented 68% of all outbreaks of non-bacterial gastroenteritis. these outbreaks to ... | 2000 | 10935995 |
| detection of sporadic cases of norwalk-like virus (nlv) and astrovirus infection in a single irish hospital from 1996 to 1998. | 'norwalk-like viruses' (nlv) and astroviruses are recognised as the most important etiologic agents of viral gastroenteritis, excluding rotaviruses. however, neither of these two groups of viruses is routinely screened for in irish hospital laboratories. | 2000 | 10942091 |
| evidence for airborne transmission of norwalk-like virus (nlv) in a hotel restaurant. | an outbreak of gastroenteritis followed a meal in a large hotel during which one of the diners vomited. the clinical features of the illness suggested norwalk-like virus (nlv, small round structured virus) infection, and this was confirmed by electron microscopy and reverse transcriptase polymerase chain reaction (rt-pcr) of stool samples. further characterization of the virus by nucleotide sequence analysis of the pcr amplicons revealed identical strains in all the affected individuals. the foo ... | 2000 | 10982072 |
| serotype-specific antigen elisa for detection of chiba virus in stools. | chiba virus (cv), a norwalk-like virus (nlv), was first identified as a cause of oyster-associated outbreak of gastroenteritis that occurred in chiba prefecture, japan, in 1987. an enzyme-linked immunosorbent assay (elisa), based on hyperimmune antisera to recombinant baculovirus-expressed capsid proteins of cv (rcv), was developed to detect cv antigen in stools. no cross-reactions were observed with other enteric viruses including enteroviruses, rotaviruses, astroviruses, or enteric adenoviruse ... | 2000 | 11002253 |
| three nursing home outbreaks of norwalk-like virus in brisbane in 1999. | we report on three nursing home outbreaks of gastroenteritis in brisbane in 1999. the presence of norwalk-like virus (nlv) genogroup 2 was demonstrated by reverse transcription polymerase chain reaction (rt-pcr) in all three outbreaks. common findings of these investigations were rapid spread of the illness within the institutions and difficulties in identifying a common source. nursing home populations are vulnerable and it is important for each institution to have infection control policies in ... | 2000 | 11022388 |
| widespread environmental contamination with norwalk-like viruses (nlv) detected in a prolonged hotel outbreak of gastroenteritis. | a protracted outbreak of norwalk-like virus (nlv)-associated gastroenteritis occurred in a large hotel in north-west england between january and may 1996. we investigated the pattern of environmental contamination with nlv in the hotel during and after the outbreak. in the ninth week, 144 environmental swabs taken from around the hotel were tested for nlv by nested rt-pcr. the sites were categorized according to the likelihood of direct contamination with vomit/faeces. the highest proportion of ... | 2000 | 11057964 |
| norwalk-like virus sequences detected by reverse transcription-polymerase chain reaction in mineral waters imported into or bottled in switzerland. | norwalk-like viruses (nlvs) is a genus belonging to the caliciviridae. nlvs are transmitted by the fecal-oral and the aerosol route and are the most common cause of outbreaks of nonbacterial gastroenteritis. nlvs are responsible for an estimated 67% of all illnesses caused by known foodborne pathogens and for 96% of nonbacterial gastroenteritis in the united states. many outbreaks could be associated with the consumption of primarily or secondarily contaminated foods. to our knowledge, no epidem ... | 2000 | 11079703 |
| pcr detection of human enteric viruses in bathing areas, waste waters and human stools in southwestern france. | detection of human pathogenic viruses by molecular techniques might be suitable for identifying viral pollution in environmental waters and for improving diagnosis in patients. environmental samples were taken from bathing areas and sewage treatment plants in southwestern france. small volume samples (50 microl) were tested. five groups of enteric pathogenic viruses were studied: enteroviruses, norwalk-like viruses (nlvs), hepatitis a virus, rotaviruses and adenoviruses. moreover, human samples ... | 2000 | 11081583 |
| complete nucleotide sequence of the chiba virus genome and functional expression of the 3c-like protease in escherichia coli. | we cloned the genome rna of the chiba virus (chv; hu/nlv/chiba 407/1987/jp) and determined its complete nucleotide sequence. the genome is predicted to be a positive-sense, single-stranded rna of 7697 bases, excluding a poly(a) tract. comparison of the nucleotide and amino acid sequences with those of other members of the species norwalk virus (nv) revealed that chv belongs to genogroup i nv. the chv genome contains three open reading frames (orfs). a large 5'-terminal orf (orf1) encodes a polyp ... | 2000 | 11118371 |
| immunomagnetic separation of a norwalk-like virus (genogroup i) in artificially contaminated environmental water samples. | rabbit polyclonal antibodies were raised against a recombinant capsid protein from a genogroup i norwalk-like virus (nlv). magnetic beads coated with these antibodies were used in immunomagnetic separation (ims) of the nlv. after capture of the nlv and washing of the beads, viral rna was heat released and detected by rt-pcr. this ims procedure was shown to have high sensitivity for detection of homologous nlv, while capture of a genogroup ii nlv was less efficient. antigen capture was not influe ... | 2000 | 11139018 |
| development of a reverse transcription-pcr-dna enzyme immunoassay for detection of "norwalk-like" viruses and hepatitis a virus in stool and shellfish. | outbreaks of food- and waterborne gastroenteritis are being increasingly reported throughout the world. the analysis of environmental samples by newer diagnostic techniques such as reverse transcription-pcr (rt-pcr) amplification of nucleic acid has begun to identify human enteric viruses (predominantly "norwalk-like" viruses [nlvs]) as the cause of many of these outbreaks. to streamline nlv detection from environmental samples such as shellfish, we have developed an rt-pcr-oligoprobe amplificat ... | 2001 | 11157239 |
| polypeptide p41 of a norwalk-like virus is a nucleic acid-independent nucleoside triphosphatase. | southampton virus (shv) is a member of the norwalk-like viruses (nlvs), one of four genera of the family caliciviridae. the genome of shv contains three open reading frames (orfs). orf 1 encodes a polyprotein that is autocatalytically processed into six proteins, one of which is p41. p41 shares sequence motifs with protein 2c of picornaviruses and superfamily 3 helicases. we have expressed p41 of shv in bacteria. purified p41 exhibited nucleoside triphosphate (ntp)-binding and ntp hydrolysis act ... | 2001 | 11160659 |
| multiple outbreaks of norwalk-like virus gastro-enteritis associated with a mediterranean-style restaurant. | the role of diverse infectious agents, particularly norwalk-like viruses (nlv), in three successive gastro-enteritis outbreaks in one setting (a restaurant) was evaluated. methods included standard bacteriological tests, specific tests for escherichia coli, tests for verocytotoxins, electron microscopy (em) for viruses and reverse transcription-pcr (rt-pcr) methodology for nlv. no pathogenic bacteria were detected. verocytotoxin genes, although detected by pcr in the first outbreak, could not be ... | 2001 | 11211221 |
| prevalence and genomic variation of norwalk-like viruses in central australia in 1995-1997. | norwalk-like viruses (nlvs) have now been found to be important causes of gastroenteritis amongst infants and young children as well as older children and adults. although detected, such viruses appeared not to be a major cause amongst infants and young children hospitalized with gastroenteritis in alice springs, central australia over the period january 1995-december 1997. nine nlv-positive cases were identified amongst stools from 360 different patients. from the nine cases however, eight diff ... | 2000 | 11252671 |
| high level excretion of norwalk-like virus following resolution of clinical illness. | we report the case of an elderly woman excreting high levels (about 5 x 10(5) virions per gram of faeces) of norwalk-like virus (nlv) in the absence of any clinical symptoms of gastroenteritis. analysis by reverse transcription, polymerase chain reaction and dna sequencing was carried out on a 342-nucleotide region of open reading frame 1. this indicated that the nlv belonged to genogroup 2 and was more closely related to the camberwell subgroup, the most common circulating in southeast australi ... | 2001 | 11280609 |
| molecular epidemiology of 'norwalk-like viruses' associated with gastroenteritis outbreaks in new zealand. | outbreaks of gastroenteritis are a major public health problem in new zealand. the introduction of molecular detection methods has now shown that the 'norwalk-like viruses' (nlvs) are the major cause of food and waterborne nonbacterial gastroenteritis. reverse transcription and polymerase chain reaction (rt-pcr) were used to determine the presence of nlvs in faecal specimens from 83 nonbacterial gastroenteritis outbreaks occurring in new zealand between august 1995 and july 1999. further charact ... | 2001 | 11285570 |
| molecular epidemiology of viral pathogens and tracing of transmission routes: hepatitis-, calici- and hantaviruses. | background: the need to rapidly identify new therapeutic drugs and vaccines for clinically important viral infections has resulted in intensive study of the molecular properties of viruses. modern molecular techniques have provided tools for tracing infections and studying the evolution of viruses. objective study and design: two examples illustrating how modern molecular techniques can be used in clinical virology and molecular epidemiology (hepatitis and caliciviruses), and one example documen ... | 2001 | 11397654 |
| heminested multiplex reverse transcription-pcr for detection and differentiation of norwalk-like virus genogroups 1 and 2 in fecal samples. | the present study describes a heminested multiplex reverse transcription (rt)-pcr assay which enables simultaneous detection and differentiation of norwalk-like virus (nlv) genogroups from clinical fecal samples without the need to perform sequencing or hybridization. the assay developed was able to detect concentrations of fewer than 100 viral particles per 5 microl of clarified fecal extract and could differentiate the two genogroups with a specificity of 100%. although the multiplex rt-pcr as ... | 2001 | 11427598 |
| university outbreak of calicivirus infection mistakenly attributed to shiga toxin-producing escherichia coli o157:h7--virginia, 2000. | on february 21-22, 2000, the virginia department of health (vdh) was notified by a university student health center of two suspected cases of escherichia coli o157:h7. at a local hospital laboratory, stool specimens from the two ill students tested positive for shiga toxin-producing e. coli (stec) using a commercially available enzyme immunoassay (eia) kit. further investigation revealed that the outbreak of gastrointestinal illness was caused by a norwalk-like virus (nlv), a member of the calic ... | 2001 | 11428728 |
| etiology of gastroenteritis in sentinel general practices in the netherlands. | data from a general practice-based, case-control study on gastroenteritis and the pathogens related to this disease were used to study the association between specific pathogens and the infected patients' ages and symptoms. for comparison, the occurrence of these pathogens in control patients, stratified by age, also is presented. in children with gastroenteritis who were <5 years of age, rotavirus (in 21% of patients) and norwalk-like virus (nlv; in 15%) were the most common pathogens. among pa ... | 2001 | 11438890 |
| the molecular biology of human caliciviruses. | within the last decade molecular analyses of the genome of norwalk-like viruses (nlvs) have confirmed that this important group of infectious agents belongs to the caliciviridae family. nlvs have a positive-sense, single-stranded rna genome of approximately 7700 nucleotides excluding the polyadenylated tail. the genome encodes three open reading frames: orf 1 is the largest (approximately 1700 amino acids) and is expressed as a polyprotein precursor that is cleaved by the viral 3c-like protease; ... | 2001 | 11444026 |
| molecular epidemiology of human enteric caliciviruses in the netherlands. | caliciviruses are among the most common causes of gastroenteritis in people of all age groups. these antigenetically and genetically diverse viruses have been grouped into two genera within the family caliciviridae, designated norwalk-like viruses (nlv) and sapporo-like viruses (slv). to gain more insight in their epidemiology, we have developed a tentative genotyping scheme, which was used to differentiate the viruses detected in a set of epidemiological studies. nlvs and slvs were detected by ... | 2001 | 11444027 |
| outbreak of norwalk virus in a caribbean island resort: application of molecular diagnostics to ascertain the vehicle of infection. | in 1998, an outbreak of gastroenteritis affected at least 448 persons including 122 staff at a resort hotel in bermuda. a survey among staff indicated that gastroenteritis was associated with eating or drinking at the hotel (or = 60, 95% ci = 2.4-15.1). multiple specimens of drinking water had elevated faecal coliform levels and escherichia coli present, suggestive of faecal contamination. stools from 18 of the 19 persons with gastroenteritis that were tested were positive for genogroup-ii norwa ... | 2001 | 11467799 |
| nucleotide sequence analysis and development of consensus primers of rt-pcr for detection of norwalk-like viruses prevailing in japan. | a total of 177 different nucleotide sequences of the rna polymerase region of norwalk-like viruses (nlvs) genomes, collected via a nation-wide survey project in japan between 1989 and 1998, were examined by reverse transcription-polymerase chain reaction (rt-pcr) employing various primer pairs. the nucleotide sequences of different strains showed great diversity, with a range of 57 to 100% identities among strains. the strains could be classified into five clusters: norwalk (nv), snow mountain a ... | 2001 | 11468745 |
| clinical spectrum and transmission characteristics of infection with norwalk-like virus: findings from a large community outbreak in sweden. | a large foodborne outbreak caused by norwalk-like virus (nlv) among children and staff at 30 day care centers provided an opportunity to study symptomatology and attack rates among patients in different age groups, as well as secondary transmission rates in centers and households. a retrospective cohort study of 775 subjects from 13 randomly chosen centers was performed. diarrhea was more common in adults than in children (p=.001), whereas the reverse was noted with regard to vomiting (p=.003). ... | 2001 | 11477530 |
| "norwalk-like viruses" as a cause of foodborne disease outbreaks. | while outbreaks of foodborne disease remain an important public health concern, their aetiology is not identified in a majority of instances. in targeted studies, the application of newly developed molecular assays has demonstrated that a large proportion of these outbreaks may be caused by the "norwalk-like viruses" (nlv), a genus of genetically related viruses belonging to the family caliciviridae. nlv outbreaks associated with consumption of faecally contaminated oysters are frequently report ... | 2001 | 11479930 |
| raw oyster consumption and outbreaks of viral gastroenteritis in new zealand: evidence for risk to the public's health. | to investigate the relationship between consumption of raw pacific half shell oysters and outbreaks of norwalk-like virus (nlv) gastroenteritis in auckland in the last third of 1999. | 2001 | 11494991 |
| gastroenteritis outbreaks associated with norwalk-like viruses and their investigation by nested rt-pcr. | norwalk-like viruses are the most common cause of gastroenteritis outbreaks and sporadic cases of vomiting and diarrhoea. in healthy individuals infection is often mild and short-lived but in debilitated patients infection can be severe. it is essential that the virus laboratory can offer a sensitive and specific test, delivered in a timely manner. | 2001 | 11511325 |
| molecular detection and sequencing of "norwalk-like viruses" in outbreaks and sporadic cases of gastroenteritis in ireland. | norwalk-like viruses (nlvs) are now established as the most important causative agents of epidemic gastroenteritis worldwide. the overall objective of this study was to determine the molecular epidemiology of irish nlv isolates for the first time by obtaining sequence data from specimens originating from outbreaks and sporadic cases of gastroenteritis. eight samples from sporadic cases of gastroenteritis and nine isolates from separate nlv outbreaks were examined. of the sporadic isolates, six w ... | 2001 | 11536249 |
| the genome of hawaii virus and its relationship with other members of the caliciviridae. | hawaii virus (hu/nlv/gii/hawaii virus/1971/us), a member of the genus 'norwalk-like viruses' (nlvs) in the family caliciviridae, has served as one of the reference strains for the fastidious caliciviruses associated with epidemic gastroenteritis in humans. the consensus sequence of the rna genome of hawaii virus was determined in order to establish its relatedness with other members of the family. the rna genome is 7,513 nucleotides (nts) in length, excluding the 3'-end poly (a) tract, and is or ... | 2001 | 11556401 |
| sensor, a population-based cohort study on gastroenteritis in the netherlands: incidence and etiology. | a prospective population-based cohort study with a nested case-control study was conducted to estimate the incidence of gastroenteritis and the associated pathogens in the general dutch population. follow-up of two consecutive cohorts was performed by weekly reporting cards from december 1998 to december 1999. cases and controls in the case-control study supplied a questionnaire and stool samples. the standardized gastroenteritis incidence was 283 per 1,000 person-years. the incidence rose with ... | 2001 | 11581101 |
| improved detection of human enteric viruses in foods by rt-pcr. | human enteric viruses (including hepatitis a virus (hav) and norwalk-like viruses (nlvs)) are now recognized as common causes of foodborne disease. while methods to detect these agents in clinical specimens have improved significantly over the last 10 years, applications to food samples have progressed more slowly. in an effort to improve the sensitivity and speed of virus detection from non-shellfish food commodities by reverse transcription-polymerase chain reaction (rt-pcr), we (i) evaluated ... | 2002 | 11742653 |
| prevalence of "norwalk-like virus" infections in outbreaks of acute nonbacterial gastroenteritis observed during the 1999-2000 season in osaka city, japan. | we have investigated the incidence of norwalk-like viruses (nlvs) associated with outbreaks of acute nonbacterial gastroenteritis in osaka city, japan, since april 1996 using reverse transcription (rt)-pcr and electron microscopy methods. from the results of the first 3 years, between april 1996 and march 1999, we previously reported that multiple genetic types of nlvs were detected in 71.9% of outbreaks using rt-pcr with ando's primers except for one outbreak [iritani et al., 2000]. however, du ... | 2002 | 11748669 |
| systemic, mucosal, and heterotypic immune induction in mice inoculated with venezuelan equine encephalitis replicons expressing norwalk virus-like particles. | norwalk-like viruses (nlvs) are a diverse group of single-stranded, nonenveloped, positive-polarity rna viruses and are the leading cause of epidemic acute gastroenteritis in the united states. in this study, the major capsid gene of norwalk virus, the prototype nlv, has been cloned and expressed in mammalian cells using a venezuelan equine encephalitis (vee) replicon expression system. upon infection of baby hamster kidney (bhk) cells with vee replicon particles (vrps), the norwalk virus capsid ... | 2002 | 11752163 |
| an outbreak of norwalk-like viral gastroenteritis in a frequently penalized food service operation: a case for mandatory training of food handlers in safety and hygiene. | in 1999, in toledo, ohio, an outbreak of gastroenteritis occurred among people who had attended a christmas dinner banquet and had eaten food prepared by a local caterer. overall, 93 of the 137 attendees (67.9 percent) reported illness. eight sought medical care, and one was hospitalized. case-control studies revealed that the illness was associated with eating tossed salad (odds ratio [or] = 2.5, 95 percent confidence interval [ci] = 1.02-6.26). eleven of 12 stool specimens that were taken from ... | 2001 | 11764683 |
| norwalk-like virus outbreaks at two summer camps--wisconsin, june 2001. | on june 27 and 28, 2001, the wisconsin division of public health was notified by two local health departments of outbreaks of gastroenteritis at two summer recreational camps (camps a and b) in northern wisconsin. this report summarizes the investigation of these outbreaks, which documents person-to-person transmission of "norwalk-like virus" (nlv) and underscores the importance of cleaning environmental surfaces and the availability and use of hand-washing facilities at recreational camps. | 2001 | 11787574 |
| experimental infection of macaca nemestrina with a toronto norwalk-like virus of epidemic viral gastroenteritis. | norwalk virus (nv) and norwalk-like viruses (nlvs) are common etiologic agents of viral gastroenteritis. viral gastroenteritis is a common disease that is highly transmissible, spreading rapidly through families, institutions, and communities. because methods for in vitro cultivation of norwalk etiologic agents are not available, information regarding this syndrome has come largely from studies in human volunteers. sequential passaging of an nlv through an immunoincompetent newborn pigtail macaq ... | 2002 | 11793394 |
| a predominant role for norwalk-like viruses as agents of epidemic gastroenteritis in maryland nursing homes for the elderly. | stool specimens from 156 maryland nursing home residents, who became ill during 20 outbreaks of gastroenteritis from november 1987 through february 1988, were analyzed. all tested negative for astroviruses, enteroviruses, group a rotaviruses, sapporo-like caliciviruses, and enteric bacteria (i.e., salmonella, clostridium, and shigella species). eighty-two (52%) were positive for norwalk-like viruses (nlvs), members of the family caliciviridae. six distinct genetic clusters within genogroups i an ... | 2002 | 11807686 |
| food-borne outbreak of gastroenteritis associated with genogroup i calicivirus. | an outbreak of gastroenteritis affecting 158 of 219 (72%) guests and employees at a hotel is described. food served at the hotel restaurant is believed to have been the source of the outbreak and to have been contaminated by sick employees working in the restaurant. a secondary attack rate of 22% was seen involving 43 persons in all. in stool specimens from seven of eight patients, norwalk-like viruses (nlvs) were detected by electron microscopy. while nlv-specific pcr using primers jv12 and jv1 ... | 2002 | 11880395 |
| norwalk-like virus sequences in mineral waters: one-year monitoring of three brands. | in a recent study, rna with nucleotide sequeces specific for "norwalk-like viruses" (nlv) was detected in 11 different brands of european mineral waters. to clarify this finding, a 1-year monitoring study was conducted. samples of three european brands of mineral water without gas were monitored weekly by reverse transcriptase pcr using generic and genogroup-specific oligonucleotides. additional analyses were performed to investigate a possible correlation between nlv sequence contamination and ... | 2002 | 11916714 |
| characterization of norwalk-like virus associated with gastroenteritis in indonesia. | norwalk virus and norwalk-like viruses (nlvs) are reportedly responsible for 2.5-4.0% of nonbacterial acute gastroenteritis (nbag) worldwide. to help clarify the impact of nlvs on nbag in indonesia, stool specimens from 102 patients, 74 with nbag and 28 with bag, were screened for the presence of nlvs, using a reverse transcription-polymerase chain reaction (rt-pcr) assay. the specimens were subtyped using prototype-specific oligonucleotide probes and were sequenced and compared with published n ... | 2002 | 11992587 |
| waterborne outbreak of norwalk-like virus gastroenteritis at a tourist resort, italy. | in july 2000, an outbreak of gastroenteritis occurred at a tourist resort in the gulf of taranto in southern italy. illness in 344 people, 69 of whom were staff members, met the case definition. norwalk-like virus (nlv) was found in 22 of 28 stool specimens tested. the source of illness was likely contaminated drinking water, as environmental inspection identified a breakdown in the resort water system and tap water samples were contaminated with fecal bacteria. attack rates were increased (51.4 ... | 2002 | 12023910 |
| foodborne viruses. | foodborne and waterborne viral infections are increasingly recognized as causes of illness in humans. this increase is partly explained by changes in food processing and consumption patterns that lead to the worldwide availability of high-risk food. as a result, vast outbreaks may occur due to contamination of food by a single foodhandler or at a single source. although there are numerous fecal-orally transmitted viruses, most reports of foodborne transmission describe infections with norwalk-li ... | 2002 | 12069883 |
| practical lessons from the management of an outbreak of small round structured virus (norwalk-like virus) gastroenteritis. | an outbreak of viral gastroenteritis caused illness in 92 people during october 2000. all the cases had an association with one hotel and 80% of cases identified had attended one of two buffet meals on 18th october 2000. cohort analysis did not implicate any particular foodstuff in this outbreak. all bacteriological tests on food samples were negative. small round structured virus (srsv)/norwalk-like virus (nlv) particles were seen by electron microscopy in 6 out of 27 stool samples submitted fo ... | 2002 | 12070977 |
| [phylogenetic analysis of 14 strains of norwalk-like viruses: identification of the region in the genome for genotyping]. | 'norwalk-like viruses(nlv)', a member of the family caliciviridae, are the major causative agent of acute gastroenteritis and genetically divided into two groups, geno-group i(gi) and genogroup ii(gii). we have determined complete nucleotide sequences, of 9 new nlv strains. using this information together with 5 known nlv sequences, we investigated the criteria to further classify genotypes of nlv. validation of the topological error based on the bootstrap value and the branch length(distance) i ... | 2002 | 12078090 |
| cross-reactivity among several recombinant calicivirus virus-like particles (vlps) with monoclonal antibodies obtained from mice immunized orally with one type of vlp. | human caliciviruses (hucvs) are classified into the norwalk-like viruses (nlv) and sapporo-like viruses (slv) as genera within the family caliciviridae: the nlv genus is further classified into genogroups i and ii, based on sequence similarities. to study the antigenic determinants on the hucv capsid protein and develop new diagnostic tools for field samples, we established and characterized monoclonal antibodies (mabs) against baculovirus-expressed recombinant hucv virus-like particles (vlps). ... | 2002 | 12089262 |
| outbreak of norwalk-like virus infection associated with salad provided in a restaurant. | preliminary enquiries following the reporting of some cases of suspected food poisoning by members of the public revealed that they had all eaten at the same restaurant during the preceding weekend. subsequent investigation, including a merged cohort study, identified 49 people with gastrointestinal symptoms, six of whom showed evidence of infection with norwalk-like virus (nlv). over a four day period all had eaten at the restaurant. eating salad was strongly associated with infection. one of t ... | 2001 | 12109400 |
| molecular detection and sequence analysis of human caliciviruses from acute gastroenteritis outbreaks in hungary. | three viral gastroenteritis (vge) outbreaks that occurred in 1998-1999, in hungary were investigated for the presence of human caliciviruses (hucvs). hucvs in stool specimens were detected by reverse transcription-polymerase chain reaction (rt-pcr) using primer pair 289/290, which was designed based on the rna-dependent rna polymerase (rdrp) sequence. rt-pcr results were confirmed by sequencing showing that all three outbreak strains belonged to genogroup ii of "norwalk-like viruses" (nlvs). two ... | 2002 | 12116006 |
| detection of both hepatitis a virus and norwalk-like virus in imported clams associated with food-borne illness. | hepatitis a virus (hav) and norwalk-like virus (nlv) were detected by reverse transcription-pcr in clams imported into the united states from china. an epidemiological investigation showed that these clams were associated with five cases of norwalk-like gastroenteritis in new york state in august 2000 (food and drug administration import alert 16-50). they were labeled "cooked" but appeared raw. viral rna extraction was performed by using dissected digestive tissues rather than whole shellfish m ... | 2002 | 12147490 |
| general outbreaks of infectious intestinal disease linked with salad vegetables and fruit, england and wales, 1992-2000. | between 1992 and 2000, 1,518 foodborne general outbreaks of infectious intestinal disease (iid) were reported to the public health laboratory service (phls) communicable disease surveillance centre (cdsc), of which 83 (5.5%) were associated with the consumption of salad vegetables or fruit (svf). the pathogens most frequently reported were salmonellas (41.0%) and norwalk-like virus (nlv) (15.7%). in total 3,438 people were affected; 69 were admitted to hospital and one person died. most outbreak ... | 2002 | 12166293 |
| phylogenetic analysis of the complete genome of 18 norwalk-like viruses. | "norwalk-like viruses" (nlv), a member of the family caliciviridae, are the major causative agents of acute gastroenteritis and are genetically divided into two groups, genogroup i (gi) and genogroup ii (gii). we have determined the complete nucleotide sequences of 10 new nlv strains. using this information together with eight known nlv sequences, the criteria to further classify genotypes of nlv were investigated. validation of the topological error based on the bootstrap value and the branch l ... | 2002 | 12202225 |
| norwalk-like virus 95/96-us strain is a major cause of gastroenteritis outbreaks in australia. | norwalk-like viruses (nlvs) were detected using a nested reverse transcriptase-polymerase chain reaction (rt-pcr) with primers directed to the rna polymerase region. samples were examined from 11 separate outbreaks of gastroenteritis and five sporadic cases of childhood gastroenteritis between 1997 and 2000. phylogenetic analysis of the 298 bp sequences showed that all strains belong to nlv genogroup ii and the majority of the sequenced isolates (30/36) were members of the 95/96-us subset of str ... | 2002 | 12210438 |
| an application of microplate hybridization assay for the confirmation and probe typing of "norwalk-like viruses". | "norwalk-like virus" (nlv) genomes are generally detected by using reverse transcription-pcr and confirmed by blot hybridization and nucleotide sequencing because of their fastidious nature. in the present study, the confirmation and typing of nlv genomes were carried out using a streptavidin-biotin binding technique and microplate hybridization assay with digoxigenin labeled probes. eight probe typing sets (g1a, g1b, g2a, g2b, g2c, g2d, g2e, and g2f) formatted from 6 newly designed probes and 8 ... | 2002 | 12222937 |
| characterization of an enteropathogenic bovine calicivirus representing a potentially new calicivirus genus. | bovine enteric caliciviruses (bec) are associated with diarrhea in young calves. the bec strains detected in europe form a third genogroup within the genus "norwalk-like viruses" (nlv) of the family caliciviridae. in this report, we present sequence, clinical, and histological data characterizing a novel enteropathogenic bec strain, nb, detected in fecal specimens from calves in the united states. the complete rna genome of the nb virus is 7,453 bases long and is organized into two open reading ... | 2002 | 12239283 |
| detection of norwalk-like virus infection aboard two u.s. navy ships. | two u.s. navy ships experienced outbreaks of gastroenteritis following port visits to southeast asia during august to september 1999. the uss peleliu (lha 5) had 162 (6% attack rate) medical visits and the uss constellation (cv 64) had 425 medical visits (9% attack rate). navy environmental and preventive medicine unit no. 5 personnel conducted on-board molecular diagnostic assays to presumptively detect the presence of genogroup i norwalk-like viruses (nlv) in both outbreaks. nlv rna were detec ... | 2002 | 12392249 |
| an outbreak of viral gastroenteritis following environmental contamination at a concert hall. | in january 1999, an outbreak of viral gastroenteritis affected more than 300 people who attended a metropolitan concert hall over a 5-day period. norwalk-like virus (nlv) was confirmed in faecal samples by reverse transcription polymerase chain reaction assay. the index case was a concert attendee who vomited in the auditorium and adjacent male toilet. gastrointestinal illness occurred among members of 8/15 school parties who attended the following day. children who sat on the same level of the ... | 2002 | 12403111 |
| ultraviolet inactivation of feline calicivirus, human enteric viruses and coliphages. | norwalk and norwalk-like viruses (nlv) are major causes of food- and water-related disease in the united states. there is no host cell line in which the nlv can be tested for infectivity. feline calicivirus (fcv) and nlv both belong to the family caliciviridae. fcv can be assayed for infectivity in the crandell reese feline kidney cell line, so fcv serves as a surrogate for nlv. this study is the first report of uv inactivation of fcv and also of using the plaque technique, in contrast to the 50 ... | 2002 | 12405148 |
| binding of norwalk virus-like particles to abh histo-blood group antigens is blocked by antisera from infected human volunteers or experimentally vaccinated mice. | attachment of norwalk (nv), snow mountain (smv), and hawaii (hv) virus-like particles (vlps) to specific abh histo-blood group antigens was investigated by using human saliva and synthetic biotinylated carbohydrates. the three distinct norwalk-like viruses (nlvs) have various capacities for binding abh histo-blood group antigens, suggesting that different mechanisms for nlv attachment likely exist. importantly, antisera from nv-infected human volunteers, as well as from mice inoculated with pack ... | 2002 | 12414974 |
| rapid response and strict control measures can contain a hospital outbreak of norwalk-like virus. | norwalk-like viruses (nlvs) are a major cause of sporadic gastroenteritis in the community and of large outbreaks of gastroenteritis in hospitals and other institutions. in january 2001, 38 staff and 20 patients on an acute elderly care ward became ill in an outbreak of gastrointestinal infection. using reverse transcription polymerase chain reaction (rt-pcr) the causative agent was identified as nlv. no link was found between particular foods eaten and illness. at various times in the course of ... | 2002 | 12434696 |
| selection of more appropriate pcr primer pairs for improved efficiency in detecting norwalk-like virus (nlv) rna. | a pair of primers, nv35 and nv36, and another pair of primers, nv81 and nv82/sm82, are commonly used for polymerase chain reaction (pcr) detection of norwalk-like virus (nlv) genome rna sequences in authorized test laboratories in japan. however, the efficiency of nlv genome rna detection with these primer pairs has been less than satisfactory. in the present study, we attempted to establish more appropriately matched primer pairs for improved detection of nlv genome rna sequences using a combin ... | 2001 | 12483611 |
| modified concentration method for the detection of enteric viruses on fruits and vegetables by reverse transcriptase-polymerase chain reaction or cell culture. | fruits and vegetables may act as a vehicle of human enteric virus if they are irrigated with sewage-contaminated water or prepared by infected food handlers. an elution-concentration method was modified to efficiently detect, by reverse transcriptase-polymerase chain reaction (rt-pcr) or by cell culture, contamination by poliovirus, hepatitis a virus (hav), and norwalk-like virus (nlv) of various fresh and frozen berries and fresh vegetables. the protocol included washing the fruit or vegetable ... | 2002 | 12495017 |
| general outbreaks of infectious intestinal disease (iid) in hospitals, england and wales, 1992-2000. | between 1992 and 2000, 26.6% (1,396/5,257) of all general outbreaks of infectious intestinal disease (iid) reported to the public health laboratory service (phls) communicable disease surveillance centre (cdsc) occurred in hospitals. over 29,000 patients and staff were affected and the mortality risk was higher than for outbreaks in other settings [relative risk 2.00 (95% ci: 1.52-2.63) p<0.001]. person-to-person spread was the predominant mode of transmission. the mortality risk was highest in ... | 2003 | 12495678 |
| a feline kidney cell line-based plaque assay for feline calicivirus, a surrogate for norwalk virus. | feline calicivirus (fcv) has been used by researchers as a surrogate for norwalk virus (nv), since they share a similar genomic organization, physicochemical characteristics, and are grouped in the same family, caliciviridae. unlike nv, however, fcv can grow in established cell lines and produce a syncytial form of cytopathic effect. in this report, we describe the development and standardization of a plaque assay for fcv using monolayers of an established line of feline kidney (crfk) cells in 1 ... | 2003 | 12505630 |
| [a gastroenteritis epidemic caused by a norwalk-like virus after 2 weddings in a restaurant; a plea for integral microbiological investigation]. | to elucidate the cause of an epidemic of gastroenteritis amongst the guests and waiting staff of two weddings celebrated on the same day in the same restaurant. | 2002 | 12518521 |
| [an outbreak of vomiting and diarrhea in a nursing home caused by the norwalk-like virus: implications of the dutch law on infectious diseases and new diagnostic options]. | several residents on a psychogeriatric ward developed vomiting and diarrhoea within a short time of each other. the causal factor was the highly contagious norwalk-like virus (nlv) with a high rate of infection amongst both residents and staff (84%). this virus is the most frequent cause of gastroenteritis in institutions. the illness is self-limiting and can be transmitted from person to person. in weakened individuals the course can be serious. the virus can be detected in faeces with modern m ... | 2002 | 12518523 |
| a waterborne outbreak of norwalk-like virus among snowmobilers-wyoming, 2001. | in february 2001, episodes of acute gastroenteritis were reported to the wyoming department of health from persons who had recently vacationed at a snowmobile lodge in wyoming. a retrospective cohort study found a significant association between water consumption and illness, and testing identified norwalk-like virus (nlv) in 8 of 13 stool samples and 1 well. nucleotide sequences from the positive well-water specimen and 6 of the positive stool samples were identical. this multistrain nlv outbre ... | 2003 | 12552455 |
| epidemiology of norwalk-like virus infections in cattle in the netherlands. | "norwalk-like viruses" (nlvs) are the most common cause of acute non-bacterial gastroenteritis in humans. cattle may be a reservoir of nlvs although never bovine nlvs have been found in humans. to gain more insight into the epidemiology of nlv, infections in cattle in the netherlands were studied. individual faecal samples from a large dairy herd and 243 pooled samples from veal calf farms were analysed for nlv by rt-pcr. calves under 3 months of age in the dairy herd were sampled three to five ... | 2003 | 12554100 |
| evaluation of the nuclisens basic kit assay for detection of norwalk virus rna in stool specimens. | norwalk-like viruses (nlvs) are a genetically diverse group of human caliciviruses that are the most common cause of epidemic gastroenteritis and are detected typically in stool by reverse transcription (rt)-pcr or electron microscopy (em). the application of a rapid nucleic acid sequence-based amplification (nasba) assay for the detection of nlv rna in stool is described using the nuclisens basic kit. primers and probes for the nlv basic kit assay were based on the rna polymerase region of the ... | 2003 | 12565163 |
| incidence of enteric viruses in groundwater from household wells in wisconsin. | recent studies on the contamination of groundwater with human enteric viruses have focused on public water systems, whereas little is known about the occurrence of viruses in private household wells. the objective of the present study was to estimate the incidence of viruses in wisconsin household wells located near septage land application sites or in rural subdivisions served by septic systems. fifty wells in seven hydrogeologic districts were sampled four times over a year, once each season. ... | 2003 | 12571044 |
| evaluation of a commercial elisa for detecting norwalk-like virus antigen in faeces. | a commercially available enzyme immunoassay, the ideia norwalk-like virus (nlv) enzyme linked immunosorbent assay (elisa; dako cytomation, ely, uk) for detecting nlv antigen in faecal samples and determining the nlv genogroup was evaluated. the performance of the elisa was compared with that of electron microscopy and the reverse transcription polymerase chain reaction by testing a panel of faecal samples collected from patients involved in outbreaks of gastroenteritis. when compared with revers ... | 2003 | 12589841 |
| incidence and characteristics of endemic norwalk-like virus-associated gastroenteritis. | endemic gastroenteritis associated with the norwalk-like viruses (nlvs) is little understood. this study tested for nlv in gastroenteritis cases in 257 households in melbourne, australia, for the period september 1997 to february 1999 by a reverse transcription hemi-nested polymerase chain reaction. positive samples were studied by nucleotide sequencing and phylogenetic analysis. nlv was detected in 73 (11.4%) of 638 faecal specimens tested. twelve (1.9%) were nlv genogroup 1 (g1) and 61 (9.6%) ... | 2003 | 12601766 |
| laboratory capability in europe for foodborne viruses. | this report describes a survey of national laboratory capabilities of diagnostics and surveillance databases for foodborne viruses among the "foodborne viruses in europe" consortium. all the countries have laboratories that can test for hav antibody in human serum. eight of the ten surveyed european countries maintain a national database of hav cases. food can be tested for the presence of hav in finland, italy, spain, france and denmark. all surveyed countries have at least one laboratory that ... | 2002 | 12631939 |
| comparative reduction of norwalk virus, poliovirus type 1, f+ rna coliphage ms2 and escherichia coli in miniature soil columns. | norwalk-like viruses (nlvs) are important agents of waterborne illness and have been linked to several groundwater-related outbreaks. the presence of human enteric viruses, in particular the presence of nlvs, is difficult to detect in the environment. consequently, surrogate organisms are typically used as indicators of viruses from faecal contamination. whether traditional bacterial indicators are reliable indicators for viral pathogens remains uncertain. few studies have directly compared mobi ... | 2003 | 12639010 |