Publications

introduction: human enteric caliciviruses-an emerging pathogen whose time has come.		2000	10804132
summary of the first international workshop on human caliciviruses.		2000	10804133
the epidemiology of enteric caliciviruses from humans: a reassessment using new diagnostics.	in the united states, acute gastroenteritis is one of the most commonly noted illnesses on hospital discharge records and death certificates, yet few of these cases have an etiologic diagnosis. the application of new molecular diagnostic methods has shown caliciviruses (previously referred to as the norwalk family of viruses or small round structured viruses) to be the most common cause of acute gastroenteritis (age) outbreaks in the united states, and they may emerge as a common cause of sporad ...	2000	10804134
molecular epidemiology of human enteric caliciviruses in the netherlands.	in the netherlands, illness due to norwalk-like viruses (nlvs) of the family caliciviridae is quite common. nlvs cause >80% of the outbreaks of gastroenteritis reported to municipal public health centers and at least 5% of the cases of gastroenteritis for which a general practitioner is consulted. in addition, up to 18% of community cases of gastroenteritis in the 1998/1999 winter season have been attributed to nlvs. patterns of disease activity differ remarkably, with "normal years, when outbre ...	2000	10804135
surveillance of viral gastroenteritis in japan: pediatric cases and outbreak incidents.	surveillance results from pediatric cases and outbreaks of viral gastroenteritis in japan are presented. in winter, both small round structured virus (srsv, or norwalk-like viruses) and rotavirus were detected from infants with gastroenteritis; however, in recent years, the prevailing time of srsv infection has preceded that of rotavirus infection. most nonbacterial gastroenteritis outbreaks were related to srsv infection, and >60% of the outbreaks were caused by contaminated food. in small-size ...	2000	10804136
epidemiology of calicivirus infections in sweden, 1994-1998.	outbreaks of acute gastroenteritis are frequently caused by caliciviruses. electron microscopy was used to search for these viruses in fecal samples from patients with acute gastroenteritis. of 5800 samples collected and analyzed from november 1994 to june 1998, 3700 were associated with outbreaks. a total of 676 outbreaks were analyzed, and viruses were found in 67%. caliciviruses, usually norwalk-like viruses (nlvs), were found in 407 (89%) of 455 outbreaks, while sapporo-like viruses were ide ...	2000	10804137
the impact of foodborne calicivirus disease: the minnesota experience.	the first outbreaks of norwalk virus gastroenteritis in minnesota were confirmed in 1982. since then, norwalk-like caliciviruses have been recognized to be the most common cause of foodborne disease outbreaks, accounting for 41% of all confirmed foodborne outbreaks in minnesota from 1981-1998. although laboratory confirmation of caliciviruses in stool samples was not attempted in most of these outbreaks, all conformed to epidemiologic criteria for defining outbreaks of norwalk virus. since 1996, ...	2000	10804138
cold weather seasonality of gastroenteritis associated with norwalk-like viruses.	norwalk-like viruses (nlvs) are the most common cause of acute nonbacterial gastroenteritis in adults, but little is known about their seasonality. the lack of specific diagnostic tools impeded study of these viruses in the past, and surveys using electron microscopy often grouped nlvs with other unrelated viruses. a search of the scientific literature found eight surveys of gastroenteritis, which were conducted for at least 1 year, that specifically identified nlvs. unpublished data from labora ...	2000	10804139
the discovery of the 27-nm norwalk virus: an historic perspective.	in 1972, a 27-nm virus-like particle was discovered by use of immune electron microscopy (iem) in an infectious stool filtrate derived from an outbreak of gastroenteritis in an elementary school in norwalk, ohio. iem enabled the direct visualization of antigen-antibody interaction, as the particles were aggregated and coated by specific antibodies. this allowed the recognition and identification of a 27-nm virus-like particle that did not have a distinctive morphology, was low-titered, and was a ...	2000	10804141
organization and expression of calicivirus genes.	the application of molecular techniques to the characterization of caliciviruses has resulted in an extensive database of sequence information. this information has led to the identification of 4 distinct genera. the human enteric caliciviruses have been assigned to 2 of these genera. this division is reflected not only in sequence diversity but in a fundamental difference in genome organization. complete genome sequences are now available for 5 enteric caliciviruses and demonstrate that human a ...	2000	10804143
structural studies of recombinant norwalk capsids.	norwalk virus is the major cause of epidemic viral gastroenteritis in humans. attempts to grow this human virus in laboratory cell lines have been unsuccessful; however, the norwalk virus capsid protein, when expressed in insect cells infected with a recombinant baculovirus, spontaneously assembles into virus-like particles. the x-ray crystallographic structure of these recombinant norwalk particles has been determined to 3.4 a, using a 22-a electron cryomicroscopy structure as a phasing model. ...	2000	10804144
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
immunity to calicivirus infection.	the evolution of our understanding of immunity to calicivirus infection, using norwalk virus as the prototype, is discussed in three stages: (1) "ancient times (1972-1978), when human volunteer studies prevailed, (2) the "middle ages (1978-1990), which were characterized by the development and implementation of solid-phase immunoassays based on native viral antigens, and (3) "modern times (1990 to present), which began with the cloning of the genome of the noncultivatable 8fiia strain of norwalk ...	2000	10804146
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
diagnosis of human caliciviruses by use of enzyme immunoassays.	the application of molecular technologies, such as the expression of viral proteins in baculovirus, has provided a powerful approach to the diagnosis of human calicivirus (hucv) infections. the baculovirus-expressed hucv capsid protein self-assembles into virus-like particles, providing excellent reagents for immunologic assays, such as enzyme immunoassays (eias). following the expression of the capsid protein of norwalk virus, the capsid proteins of 8 other hucv strains have been expressed in b ...	2000	10804148
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
norwalk virus vaccines: challenges and progress.	human caliciviruses (hucvs) are the major cause of outbreaks of acute nonbacterial gastroenteritis throughout the world. an increasing recognition of the clinical significance of these viruses as human pathogens causing foodborne and waterborne disease indicates that an effective vaccine would be useful. this article reviews the current challenges that exist for the development of a vaccine for the hucvs as well as the status of development of a candidate vaccine. hucvs are viruses that exhibit ...	2000	10804150
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
possible community immunity to small round structured virus gastroenteritis in a rural aboriginal community.	in april 1998 an outbreak of gastroenteritis affected visitors, but none of the aboriginal residents, at a territory health services luncheon in a rural aboriginal community in central australia. the epidemiological features and identification of small round structured virus (srsv) from two participants suggest that this was an outbreak caused by a srsv. the attack rate in the visitors who ate or drank food at the luncheon was 73% (11 of 15). seventeen aboriginal residents were interviewed, none ...	2000	10812750
members of the family caliciviridae (norwalk virus and sapporo virus) are the most prevalent cause of gastroenteritis outbreaks among infants in japan.	norwalk virus (nv) and sapporo virus (sv) were approved as type species of the genus norwalk-like viruses and the genus sapporo-like viruses, respectively, within the family caliciviridae. to clarify the importance of nv and sv as causes of gastroenteritis outbreaks in infants, stool samples obtained from 36 outbreaks of nonbacterial gastroenteritis that occurred during 1976-1995 in an infant home in sapporo, japan, were examined for diarrhea viruses using electron microscopy, enzyme immunoassay ...	2000	10837186
[genetic characterization of norwalk-like viruses (nlvs) detected in japan from 1989 to 1998 and establishment of consensus primers].	by means of reverse transcription-polymerase chain reaction using various pairs of primers, 902 strains of norwalk-like viruses (nlvs) were detected during 10 years from 1989 to 1998 in the nationwide area of japan including hokkaido and okinawa. nucleotide sequencing was done on 177 strains, and we found that 153 strains (86%) of them belonged to geno-group ii (gii). gii could be classified into five subgroups (g2a, g2b, g2c, g2d and g2e) based on the amino acid sequences showing a similarity o ...	2000	10860360
norwalk virus open reading frame 3 encodes a minor structural protein.	norwalk virus (nv) is a causative agent of acute epidemic nonbacterial gastroenteritis in humans. the inability to cultivate nv has required the use of molecular techniques to examine the genome organization and functions of the viral proteins. the function of the nv protein encoded by open reading frame 3 (orf 3) has been unknown. in this paper, we report the characterization of the nv orf 3 protein expressed in a cell-free translation system and in insect cells and show its association with re ...	2000	10864672
simultaneous detection and genotyping of "norwalk-like viruses" by oligonucleotide array in a reverse line blot hybridization format.	"norwalk-like viruses" (nlvs) are the most common cause of outbreaks of nonbacterial gastroenteritis worldwide. to date, the method most widely used for typing of nlv strains is sequencing and subsequent phylogenetic analysis of reverse transcription (rt)-pcr products, which has revealed the existence of stable distinct lineages (genotypes). this typing method is rather costly, not routinely used in clinical laboratories, and not very suitable for the analysis of large numbers of samples. theref ...	2000	10878050
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
a novel "small round virus" inducing poult enteritis and mortality syndrome and associated immune alterations.	the role of a novel "small round virus" (srv) isolated from poult enteritis and mortality syndrome (pems) cases in inducing pems and associated immune alterations was examined in this study. specific-pathogen-free and conventional poults were orally challenged with srv and/or turkey coronavirus and monitored for clinical signs. intestines, thymus, bursa, and spleens were examined for srv antigen at various days postinoculation (dpi). peripheral blood lymphocytes (pbls), thymocytes, and splenic l ...	2000	10879906
viral agents associated with poult enteritis and mortality syndrome: the role of a small round virus and a turkey coronavirus.	intestinal samples from turkey poults affected with poult enteritis and mortality syndrome (pems) were examined for viruses by immune electron microscopy and double-stranded rna virus genome electropherotyping. turkey coronavirus (tcv), avian rotaviruses, reovirus, and a yet undefined small round virus (srv) were detected. the srv and tcv were isolated and propagated in turkey embryos. challenge of specific-pathogen-free turkey poults with srv, tcv, or both resulted in mortality and clinical res ...	2000	10879909
human immune responses to a novel norwalk virus vaccine delivered in transgenic potatoes.	a new approach for delivering vaccine antigens is the use of inexpensive, plentiful, plant-based oral vaccines. norwalk virus capsid protein (nvcp), assembled into virus-like particles, was used as a test antigen, to determine whether immune responses could be generated in volunteers who ingested transgenic potatoes. twenty-four healthy adult volunteers received 2 or 3 doses of transgenic potato (n=20) or 3 doses of wild-type potato (n=4). each dose consisted of 150 g of raw, peeled, diced potat ...	2000	10882612
[development of molecular tests for rapid detection of enteropathogens].	amplification of specific dna sequences by polymerase chain reaction (pcr), enables rapid, sensitive and direct, specific identification of pathogens at very low concentrations in clinical samples. studies in recent years have reported identification of several enteropathogens directly from stool samples by pcr. the amplification process includes the use of primers complementary to the dna sequences specific to the pathogen, thus relying on the pathogen's genotype, rather than its phenotype on w ...	2000	10883231
evaluation of nine sets of pcr primers in the rna dependent rna polymerase region for detection and differentiation of members of the family caliciviridae, norwalk virus and sapporo virus.	norwalk virus and sapporo virus were approved as type species of the genus "norwalk-like viruses" and the genus "sapporo-like viruses," respectively, in the family caliciviridae. a total of 116 stool specimens containing norwalk virus (nv) or sapporo virus (sv) were tested by rt-pcr and southern hybridization to evaluate nine sets of pcr primers and seven internal oligonucleotide probes in the rna dependent rna polymerase region of nv and sv for detection and differentiation of viruses in the nv ...	2000	10888362
infantile convulsions with mild gastroenteritis.	the development of sensitive new molecular genetic techniques has led to the detection of rotavirus in cerebrospinal fluid, stools and throat swabs from patients with gastroenteritis with accompanying clinical symptoms similar to infantile benign convulsions. small round structured virus (srsv) has also been found in stools of patients with similar clinical symptoms by a new procedure. however, the mechanism by which these viral infections induce benign convulsions remains to be elucidated. the ...	2000	10891637
seroprevalence against norwalk-like human caliciviruses in beijing, china.	serum specimens from 1,109 individuals at different ages in beijing, china, were collected between april 1996 and march 1997 and tested for igg antibodies against human caliciviruses using enzyme immune assays (eias). baculovirus-expressed recombinant norwalk virus (rnv) and mexican virus (rmxv) capsid proteins were used as antigens. the seroprevalence was 89% for rnv and 91% for rmxv. similar seroprevalence between the two antigens was observed in individual age groups and both genders. infants ...	2000	10568770
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
diagnosis of noncultivatable gastroenteritis viruses, the human caliciviruses.	gastroenteritis is one of the most common illnesses of humans, and many different viruses have been causally associated with this disease. of those enteric viruses that have been established as etiologic agents of gastroenteritis, only the human caliciviruses cannot be cultivated in vitro. the cloning of norwalk virus and subsequently of other human caliciviruses has led to the development of several new diagnostic assays. antigen detection enzyme immunoassays (eias) using polyclonal hyperimmune ...	2001	11148001
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
evaluation of the japanese school health surveillance system for influenza.	in order to evaluate the japanese nationwide school absenteeism surveillance system for pediatric influenza in comparison with the national sentinel surveillance for influenza, we used surveillance guidelines (centers for disease control and prevention, 1998) to determine the efficacy of the school health surveillance system (shss). data regarding school absenteeism (age 4-15 years old) was compared with data regarding influenza-like illness (ili) per sentinel sites during the second to the 11th ...	2001	11326126
pathogen filtration, heterogeneity, and the potable reuse of wastewater.	filtration is commonly employed in water and wastewater treatment to remove particles and reduce the concentration of microbial pathogens. all physical models of packed-bed filtration are based on a proportional relationship between particle removal per unit depth of bed and the local particle concentration, dc/dz = -c/l, where l is the filtration length scale. although l is known to vary with time and filter depth for heterogeneous suspensions or "dirty" beds, this paper demonstrates that the f ...	2001	11355195
[studies of acute gastroenteritis among infant and young children in a pediatric clinic].	from october 1998 to april 1999, 72 stool specimens from patients of acute gastroenteritis were collected in a pediatric clinic in urawa city, japan and were examined for the detection of srsv by electron microscopy and reverse transcription-polymerase chain reaction (rt-pcr). forty-eight (67%) out of 72 were srsv positives by both tests. in this season, a prevalence of srsv peaked in december 1998. among reported clinical symptoms, vomiting was reported more frequently than the other symptoms, ...	2001	11357324
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
simultaneous isolation of verotoxin-producing strains of escherichia coli o128:h2 and viruses in gastroenteritis outbreaks.	three outbreaks of gastroenteritis from which the verotoxin producing escherichia coli serotype o128:h2 was isolated are reported. in addition norwalk-like viruses were detected in patients from two of the outbreaks and astrovirus in the third outbreak. while it cannot be specifically determined which of these agents played the major role in these outbreaks, the findings suggest that the viral agents need to be considered in investigations of gastroenteritis outbreaks, regardless of whether bact ...	2001	11247046
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
characterization of "norwalk-like viruses" and astroviruses by liquid hybridization assay.	"norwalk-like viruses" (nlvs) and human astroviruses are causative agents of gastroenteritis in all age-groups. the typing of these agents is generally done by nucleotide sequencing, blot hybridization, or enzyme immunoassay. these techniques are expensive, time-consuming, and sometimes require scarce reagents, which limits the typing of nlvs and astroviruses to a few reference laboratories. this report describes a liquid hybridization assay that uses broadly reactive probes whose sequences are ...	2001	11164493
molecular detection of human calicivirus in young children hospitalized with acute gastroenteritis in melbourne, australia, during 1999.	reverse transcription-pcr and sequence analysis identified calciviruses in 32 of 60 stool specimens (negative for other enteric pathogens) obtained from children admitted to our hospital with acute gastroenteritis. the overall annual incidence rate for calcivirus was 9% (32 of 354 children). molecular analysis identified 30 "norwalk-like virus" genogroup ii (predominantly lordsdale cluster) and 2 "sapporo-like virus" strains.	2001	11427606
an outbreak of viral gastroenteritis in a mother-and-child health clinic.	an outbreak of diarrhoeal disease in a modern mother-and-child health clinic prompted the health authorities to initiate a retrospective cohort study in order to assess the scope of the outbreak and to identify possible risk factors. the management of the clinic had been rather concerned because four similar outbreaks had occurred during the last two years. a total of 151 guests, i.e. mothers with their children, who had arrived some days before the peak of the outbreak for a three-week-stay and ...	2001	11434217
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
structural studies on gastroenteritis viruses.	there are many recent advances in our understanding of the structure-function relationships in rotavirus, a major pathogen of infantile gastroenteritis, and norwalk virus, a causative agent of epidemic gastroenteritis in humans. rotavirus is a large (1000 a) and complex icosahedral assembly formed by three concentric capsid layers that enclose the viral genome of 11 dsrna segments. because of its medical relevance, intriguing structural complexity, and several unique strategies in the morphogene ...	2001	11444031
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
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
rapid and efficient extraction method for reverse transcription-pcr detection of hepatitis a and norwalk-like viruses in shellfish.	as part of an effort to develop a broadly applicable test for norwalk-like viruses and hepatitis a virus (hav) in shellfish, a rapid extraction method that is suitable for use with one-step reverse transcription (rt)-pcr-based detection methods was developed. the method involves virus extraction using a ph 9.5 glycine buffer, polyethylene glycol (peg) precipitation, tri-reagent, and purification of viral poly(a) rna by using magnetic poly(dt) beads. this glycine-peg-tri-reagent-poly(dt) method c ...	2001	11526018
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
sensitive detection and differentiation of sapporo virus, a member of the family caliciviridae, by standard and booster nested polymerase chain reaction.	norwalk virus and sapporo virus (sv) were approved as type species of the genus norwalk-like viruses and the genus sapporo-like viruses, respectively, in the family caliciviridae. nested polymerase chain reaction (pcr), using newly designed primers in the rna-dependent rna polymerase region, was developed to detect and differentiate viruses in the three genetic groups of sv based on the relative size of the pcr products obtained. in addition, a booster nested pcr that performs nested pcr in a si ...	2001	11536253
recombinant norwalk virus-like particles administered intranasally to mice induce systemic and mucosal (fecal and vaginal) immune responses.	recombinant norwalk virus-like particles (rnv vlps) were administered to balb/c mice by the intranasal (i.n.) route to evaluate the induction of mucosal antibody responses. the results were compared to systemic and mucosal responses observed in new and previous studies (j. m. ball, m. e. hardy, r. l. atmar, m. e. connor, and m. k. estes, j. virol. 72:1345-1353, 1998) after oral administration of rnv vlps. immunizations were given in the presence or absence of a mucosal adjuvant, mutant escherich ...	2001	11559804
diffusion of macromolecules and virus-like particles in human cervical mucus.	to determine whether or not large macromolecules and viruses can diffuse through mucus, we observed the motion of proteins, microspheres, and viruses in fresh samples of human cervical mucus using fluorescent recovery after photobleaching and multiple image photography. two capsid virus-like particles, human papilloma virus (55 nm, approximately 20,000 kda) and norwalk virus (38 nm, approximately 10,000 kda), as well as most of the globular proteins tested (15-650 kda) diffused as rapidly in muc ...	2001	11566767
from the centers for disease control and prevention. norwalk-like virus outbreaks at two summer camps--wisconsin, june 2001.		2001	11575312
outbreaks of acute gastroenteritis associated with norwalk-like viruses in campus settings.	norwalk-like viruses (nlvs) are transmitted by fecally contaminated food, water, fomites, and person-to-person contact. they are a leading cause of acute gastroenteritis epidemics in industrialized countries. nlv outbreaks are characterized by a 12- to 48-hour incubation period; nausea, vomiting, and diarrhea for 24 to 72 hours; and high secondary attack rates. nlv infections spread rapidly on college and university campuses because of close living quarters, shared bathrooms and common rooms, ma ...	2001	11590984
enteric virus contamination of foods through industrial practices: a primer on intervention strategies.	hepatitis a and e viruses, rotaviruses, norwalk-like caliciviruses, and astroviruses are among the enteric viruses known to cause food- and waterborne illness. these viruses are spread by the fecal-oral route and are a major cause of morbidity and mortality worldwide. foods may be contaminated at any time pre- or post-harvest; however, many outbreaks are associated with foods handled by infected restaurant workers. produce may be contaminated by improper irrigation or fertilization practices, by ...	2001	11641770
prevalence of norwalk viruses in southern and northern parts of hiroshima prefecture, japan in 2000/2001 season.		2001	11684786
characterization of norwalk virus gi specific monoclonal antibodies generated against escherichia coli expressed capsid protein and the reactivity of two broadly reactive monoclonal antibodies generated against gii capsid towards gi recombinant fragments.	norwalk virus causes outbreaks of acute non-bacterial gastroenteritis in humans. the virus capsid is composed of a single 60 kda protein. in a previous study, the capsid protein of recombinant norwalk virus genogroup ii was expressed in an e. coli system and monoclonal antibodies were generated against it. the analysis of the reactivity of those monoclonal antibodies suggested that the n-terminal domain might contain more antigenic epitopes than the c-terminal domain. in the same study, two broa ...	2001	11710959
multistate outbreak of norwalk-like virus gastroenteritis associated with a common caterer.	in february 2000, an outbreak of gastroenteritis occurred among employees of a car dealership in new york. the same meal was also supplied to 52 dealerships nationwide, and 13 states reported illness at dealerships where the banquet was served. a retrospective cohort study was conducted to identify risk factors associated with the illness. stool samples were collected to detect norwalk-like virus, and sera were drawn and tested for immunoglobulin a antibodies to the outbreak strain. by univariat ...	2001	11724717
clinical severity of norwalk virus and sapporo virus gastroenteritis in children in hokkaido, japan.	to clarify the clinical significance and etiologic impact of norwalk virus (nv) and sapporo virus (sv) in viral gastroenteritis in japanese children.	2001	11734762
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
[hospital outbreak of viral gastroenteritis attributed to norwalk-like viruses in japan].	norwalk-like viruses (nlvs), rna viruses in the family of caliciviridae, are known as a pathogen of nonbacterial food-borne gastroenteritis associated with eating raw oysters. nlv can spread from person to person with strong infectivity and can cause large epidemics in communities, schools, nursing homes, and hospitals. here, we describe an outbreak of gastroenteritis associated with nlvs, possibly introduced from outside the hospital, in four different wards on four different occasions between ...	2002	11852472
baculovirus expression and antigenic characterization of the capsid proteins of three norwalk-like viruses.	human caliciviruses (hucvs) are antigenically diverse. the antigenic relationships among different hucvs have been difficult to study because hucvs cannot be passaged in the laboratory. in this study, we describe cloning, sequencing and expression of the viral capsid proteins of three hucvs that were identified in outbreaks of acute gastroenteritis in virginia in 1997-1998. yields of the capsid proteins similar to previously expressed recombinant norwalk virus were obtained using the baculovirus ...	2002	11855626
expression and self-assembly of norwalk virus capsid protein from venezuelan equine encephalitis virus replicons.	the norwalk virus (nv) capsid protein was expressed using venezuelan equine encephalitis virus replicon particles (vrp-nv1). vrp-nv1 infection resulted in large numbers of recombinant nv-like particles that were primarily cell associated and were indistinguishable from nv particles produced from baculoviruses. mutations located in the n-terminal and p1 domains of the nv capsid protein ablated capsid self-assembly in mammalian cells.	2002	11861868
development of a virus concentration method and its application to detection of enterovirus and norwalk virus from coastal seawater.	we developed a new procedure for concentration of enteric viruses from water using a negatively charged membrane. rinsing the membrane with 0.5 mm h(2)so(4) (ph 3.0) in order to elute cations prior to viral elution with 1 mm naoh (ph 10.5) promoted poliovirus recovery yields from 33 to 95% when applied to pure water and 38 to 89% when applied to natural seawater from tokyo bay, japan, respectively. this method showed average recovery yields of spiked poliovirus of 62% (n = 8) from 1 liter of art ...	2002	11872447
vectorborne infectious diseases.		2002	11876508
norwalk virus gastroenteritis among israeli soldiers: lack of evidence for flyborne transmission.	paired sera collected from subjects before and after a fly-control intervention trial conducted in the israel defense force (idf) were tested for seroconversion to norwalk virus (nv) to examine the role of nv as a cause of diarrhea in this population and to ascertain whether flies might also be implicated in transmission.	2002	11876512
structural requirements for the assembly of norwalk virus-like particles.	norwalk virus (nv) is the prototype strain of a group of 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 nv virus-like particles (rnv vlps) that are morphologically and antigenically similar to native nv. the x-ray structure of the rnv vlps has revealed that the capsid protein folds into two princip ...	2002	11907243
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
norwalk virus infection and disease is associated with abo histo-blood group type.	some people are resistant to norwalk virus (nv) infection; however, the factor(s) responsible for resistance or susceptibility to nv infection has not been identified. this study investigated the relationship between a person's abo histo-blood group type and the risk of nv infection and symptomatic disease after clinical challenge. abo phenotypes were identified by using serum samples from volunteers who participated in an nv challenge study (n=51). individuals with an o phenotype were more like ...	2002	12001052
a norwalk-like virus outbreak on the appalachian trail.	in may and june 1999, an outbreak of acute gastrointestinal illness occurred among long-distance hikers on the appalachian trail between catawba and troutville, virginia. an investigation found that 45 out of 70 hikers had become ill within two days of arriving in catawba, virginia. water samples were collected from a general store frequented by the hikers and from several nearby buildings and a popular all-you-can-eat restaurant. symptoms were consistent with those caused by norwalk-like viruse ...	2002	12004584
virus-like particles of a fish nodavirus display a capsid subunit domain organization different from that of insect nodaviruses.	the structure of recombinant virus-like particles of malabaricus grouper nervous necrosis virus (mgnnv), a fish nodavirus isolated from the grouper epinephelus malabaricus, was determined by electron cryomicroscopy (cryoem) and three-dimensional reconstruction at 23-a resolution. the cryoem structure, sequence comparison, and protein fold recognition analysis indicate that the coat protein of mgnnv has two domains resembling those of tomato bushy stunt virus and norwalk virus, rather than the ex ...	2002	12021370
norwalk virus binds to histo-blood group antigens present on gastroduodenal epithelial cells of secretor individuals.	norwalk virus (nv) is a member of the caliciviridae family, which causes acute epidemic gastroenteritis in humans of all ages and its cellular receptors have not yet been characterized. another calicivirus, rabbit hemorrhagic disease virus, attaches to h type 2 histo-blood group oligosaccharide present on rabbit epithelial cells. our aim was to test if, by analogy, recombinant nv-like particles (rnv vlps) use carbohydrates present on human gastroduodenal epithelial cells as ligands.	2002	12055602
[norwalk virus: recent findings].	acute gastroenteritis due to norwalk virus(nv), a member of the family caliciviridae, is a common illness worldwide. nv is a human pathogen causing food-borne and water-borne diseases that occur in various epidemiological settings. the disease is mild and self-limiting and the symptomatic phase lasts 24 to 72 hours. genetic analyses of the polymerase and the capsid protein indicate that nv is grouped into two clusters, genogroup i and genogroup ii. the development of recombinant virus-like parti ...	2002	12078086
[molecular epidemiology of norwalk virus].	norwalk virus is one of the most important diarrheal viruses. although the virus was discovered in 1970, the genetic analysis has started from 1990. the virus appears in sporadic cases but also in outbreaks in children and adults. the symptoms are vomiting and diarrhea, but rarely are convulsion and others. the molecular epidemiological method is useful to detect the pathogen in environments and hosts. as the results of molecular epidemiology, it was found that the common virus with the identica ...	2002	12078087
[epidemiology on norwalk virus-related gastroenteritis outbreaks among elderly persons living in nursing homes].	person-to-person transmission of norwalk virus(nv) is important factor for outbreaks in nursing homes in addition to foodborne and waterbone transmission. nv spread easily among residents and staffs through the care process and highly infectious contamination generated by vomitus and feces remains on the environmental surface. as a result, the outbreak continues for long period(a few weeks) compared with foodborne gastroenteritis outbreak in restaurant. for prevention and control of nv outbreak ...	2002	12078088
[identification and genotyping of norwalk virus by stringent microplate hybridization of pcr products].	there are many genotypes of norwalk virus(nv), and the microplate hybridization method for identification and genotyping of nv requires preparation of many probes. however, the method is simple and the detection sensitivity is high at 10 ng/ml dna, and many samples can be simultaneously examined in an identification test and genotyping of nv. increasing the hybridization temperature increases precision and the homology rate between a probe and dna fragment can be estimated. mixed genotypes of nv ...	2002	12078091
[rapid and efficient detection method of norwalk virus].	a rapid and efficient rt-pcr with fluorogenic probe(taqman-pcr) was developed for detection of norwalk virus(nv) genomes in clinical specimens. we designed nv genogroup specific primers and fluorogenic probes in the junction of open reading frame (orf)1 and orf2. eighty specimens from patients of gastroenteritis, in which nv-like particles were detected by electron microscopy, were examined by taqman-pcr and rt-pcr using primer sets previously reported; two sets in rdrp region of nv and one set ...	2002	12078092
[characteristic of norwalk gastroenteritis and its prevention].	the application of recently developed molecular technique revealed the important role of the norwalk virus(nv). the major role of the nv as agents of food and water-related outbreaks of gastroenteritis has now been recognized in the world. moreover, a part of nv is also documented as important agents of gastroenteritis in childhood and infancy. a high rate of food-related viral gastroenteritis outbreaks was observed following ingestion of shellfish in japan. specific methods are not available fo ...	2002	12078095
[the relationship between epidemic gastroenteritis caused by norwalk viruses (nvs) and acute gastroenteritis in children--based on the history of nvs in japan].	norwalk viruses(nvs) are well known pathogens that can cause acute nonbacterial epidemic gastroenteritis in adults as well as acute gastroenteritis in children. in food poisoning cases due to raw oysters, nvs is considered as an important pathogen and the molecular epidemiological studies of nvs are the most suitable method to trace these routes of infections in conjunction with oyster supply mechanism. furthermore, the prevalence of genotypes of nvs which are detected from cases of acute gastro ...	2002	12078096
[contamination of oyster sea farm with the norwalk virus: mechanisms and control].	the norwalk virus(nv) is widely known as a cause of nonbacterial food poisoning, infant diarrhea, and acute gastroenteritis in the winter months between november and march. while it is strongly suspected that nv that is excreted by humans flows into coastal seawaters via rivers and wastewater treatment facilities to contaminate oysters that are grown in farms in the area, light has yet to be shed on the behavior of this virus in the natural environment. we therefore conducted a polymerase chain ...	2002	12078097
[vaccine development for norwalk virus].	the rationale for developing a vaccine generally is made on the basis of the clinical and socioeconomical significance of a specific viral disease. the disease burden for rotavirus gastroenteritis in infants is well evaluated and several candidate vaccines for rotavirus has now been developing. an increasing recognition of the clinical significance of norwalk virus causing acute gastroenteritis in humans of all ages, foodborne outbreaks in adults, and relatively severe gastroenteritis in childre ...	2002	12078098
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
concentration and detection of caliciviruses from food contact surfaces.	outbreaks of human norwalk virus (nv) and norwalk-like viruses often originate in food service establishments. no reliable method is available for the detection of these human caliciviruses on food contact surfaces. we describe a simple method for the detection of nv from stainless steel work surfaces using cultivable feline calicivirus (fcv) as a model. stainless steel surfaces were artificially contaminated with known amounts of fcv, followed by its elution in a buffer solution. three methods ...	2002	12092735
viral causes of diarrhea.		2002	12093939
viruses detected in the caecum contents of healthy pigs representing a new genetic cluster in genogroup ii of the genus "norwalk-like viruses".	viruses of the genus 'norwalk-like viruses' (nlvs) detected in humans have been genetically classified into two major genetic groups, genogroups i and ii (gi and gii), which together are made up of at least 14 genetic subgroups. however, a comparable classification of nlvs in other species remains to be carried out. we sequenced a 2-kb region from within the rna polymerase gene to the 3' end of open reading frame 2 (orf2) of two nlv strains previously detected in the caecum contents of healthy p ...	2002	12191780
detection and differentiation of norwalk virus by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay.	we have developed a reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay (rt-pcr-elisa), using genetic cluster-specific probes in a microtiter plate format, for the detection and differentiation of norwalk virus (nv) in stool samples. the specificity of the rt-pcr-elisa was confirmed by testing 76 stool specimens and 15 tissue culture fluids derived from growths of unrelated viruses. the sensitivity of the rt-pcr-elisa was compared with conventional pcr and south ...	2002	12210421
substrate specificity of the norwalk virus 3c-like proteinase.	the norwalk virus (nv) is the prototype strain of human caliciviruses that cause epidemic outbreaks of foodborne and waterborne gastroenteritis. these viruses do not grow in cell culture and the mechanisms of virus replication are obscure. the nv genome is a 7.7 kb ssrna molecule that encodes three open reading frames (orfs). the first orf is a 1789 amino acid polyprotein that is processed into nonstructural proteins by a viral protease similar to the picornavirus 3c protease. primary cleavage s ...	2002	12367748
inactivation of hepatitis a virus and a calicivirus by high hydrostatic pressure.	potential application of high hydrostatic pressure processing (hpp) as a method for virus inactivation was evaluated. a 7-log10 pfu/ml hepatitis a virus (hav) stock, in tissue culture medium, was reduced to nondetectable levels after exposure to more than 450 mpa of pressure for 5 min. titers of hav were reduced in a time- and pressure-dependent manner between 300 and 450 mpa. in contrast, poliovirus titer was unaffected by a 5-min treatment at 600 mpa. dilution of hav in seawater increased the ...	2002	12380746
zirconium hydroxide effectively immobilizes and concentrates human enteric viruses.	detection of human enteric viruses in foods and environmental samples requires concentration of viruses from complex matrices before application of molecular or cultural methods. previous studies have described the use of zirconium hydroxide to concentrate bacteria from clinical, environmental, and food samples.	2002	12390492
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
distribution of human virus contamination in shellfish from different growing areas in greece, spain, sweden, and the united kingdom.	viral pollution in shellfish has been analyzed simultaneously across a wide range of geographical regions, with emphasis on the concomitant variations in physicochemical characteristics and social features. the methods for sample treatment and for the detection of human enteric viruses were optimized by the participating laboratories. the second part of this study involves the selection of a protocol for virus detection, which was validated by analyzing the distribution and concentration of huma ...	2002	12450820
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