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role of norwalk virus in outbreaks of nonbacterial gastroenteritis.twenty-five separate outbreaks of nonbacterial gastrointestinal illnesses were studied serologically for evidence of infection with the norwalk virus and the rotaviruses that affect humans. eight of 25 outbreaks appeared to be related to the norwalk virus. in one of the 25 outbreaks, there was evidence of rotavirus infection. these observations suggest that the norwalk virus or serologically related agents play an important role in epidemic nonbacterial gastroenteritis in adults and older childr ...1979220341
prevalence of antibody to the norwalk virus in various countries.serum samples from children and adults from several countries were tested by radioimmunoassay for antibody to the norwalk virus. antibody was commonly found in adults from all the countries tested. antibody appears to be acquired more rapidly in children from underdeveloped countries than in children from the united states.1979227798
an australia-wide outbreak of gastroenteritis from oysters caused by norwalk virus.at least 2000 persons were involved in an australia-wide outbreak of oyster-associated food poisoning in june and july, 1978. at the time, this episode presented a major health risk to the community as a whole and has subsequently posed a serious economic problem for the oyster farming and distributing industry. although bacteriological investigations indicated some batches of oysters were contaminated by sewage, no bacterial cause could be established. the causative organism was shown to be nor ...1979514174
the diagnosis of srsv infection. 19921284950
detection of norwalk-like virus and specific antibody by immune-electron microscopy with colloidal gold immune complexes.direct electron-microscopy (dem), immune electron microscopy (iem) and four different procedures of immune electron microscopy with colloidal gold immune complexes were evaluated for the detection of norwalk-like virus and specific antibody. a solid-phase immune electron microscopy with colloidal gold immune complexes-triple layer method (spiemgic-tlm) is developed for screening patients' specimens for the detection of norwalk-like virus and its specific antibody. the method demonstrates low non ...19911667789
what did our patients eat? 19911669789
detection of norwalk virus in stool by polymerase chain reaction.a method of reverse transcription (rt) and polymerase chain reaction (pcr) for the detection of norwalk virus in human stools was developed. a cationic detergent, cetyltrimethylammonium bromide, was found to effectively remove from stool extracts factors that inhibit the rt-pcr assay. the specificities of the tests were shown by hybridization of the amplified dna with norwalk virus-specific cdna probes and a consistent correlation between virus detection in stools and infection of volunteers. rt ...19921383265
expression, self-assembly, and antigenicity of the norwalk virus capsid protein.norwalk virus capsid protein was produced by expression of the second and third open reading frames of the norwalk virus genome, using a cell-free translation system and baculovirus recombinants. analysis of the expressed products showed that the second open reading frame encodes a protein with an apparent molecular weight of 58,000 (58k protein) and that this protein self-assembles to form empty viruslike particles similar to native capsids in size and appearance. the antigenicity of these part ...19921328679
pilot study of an extended range of potential etiologic agents of diarrhea in the israel defense forces. 19921310297
virus survival in the environment.viruses pass into the environment from clinically ill or carrier hosts; although they do not replicate outside living animals or people, they are maintained and transported to susceptible hosts. population concentrations and movement, both animal and human, have been steadily increasing in this century, enhancing transmission of respiratory and enteric viruses and compounding the difficulty of preventing environmental transmission. studies on environmental survival factors of viruses have been m ...19911782426
rabbit hemorrhagic disease virus--molecular cloning and nucleotide sequencing of a calicivirus genome.the rna genome of rabbit hemorrhagic disease virus (rhdv) was molecularly cloned. the 5' terminal sequence of the genomic rna was determined after pcr amplification of a g-tailed first strand cdna template. the cloned cdna allowed determination of the first complete caliciviral sequence encompassing 7437 nucleotides without poly(a) tail. the rhdv genome contains one long open reading frame of 2344 codons which in the 5' region encodes the nonstructural proteins. sequence comparison studies revea ...19911840711
antibodies to viral gastroenteritis viruses in crohn's disease.antibody prevalence and titer to rotavirus and norwalk virus were studied in crohn's disease patients and in age-, sex-, and time-matched controls. there were no significant antibody differences between the groups studied.1979215490
implications of recent virological researches.rotaviruses (duoviruses) can be found in more than half the cases of acute diarrhoea in children up to the age of six or seven. about that age almost everyone has antibodies to them. second infections occur and may not be as rare as laboratory findings so far suggest. very young infants sometimes get subclinical disease-the effect of maternal antibody transmitted across the placenta? very similar viruses, all possessing a common antigen detectable by immunofluorescence, are known to infect and/o ...1976186237
human, small round structured viruses, caliciviruses and astroviruses.epidemiological studies on srsvs, human calicivirus and astroviruses have been limited by the problems of establishing them in cell culture and the inability to transmit them to animals or to use strains from animals as a source of antigen for diagnostic tests. the use of em and the subsequent development of rias and eias in a few research centres has shown that they are a cause of outbreaks and sporadic cases of diarrhoea and vomiting. srsvs have increasingly been recognized as a major cause of ...19901962728
immune response and prevalence of antibody to norwalk enteritis virus as determined by radioimmunoassay.a solid-phase microtiter radioimmunoassay was established for the detection of norwalk virus and its antibody, with clinical materials from human volunteers previously studied in massachusetts as reagents. a study of 308 massachusetts residents showed that serum antibody to norwalk agent was rarely present during childhood but was detectable in approximately 50% of adults. all volunteers inoculated with norwalk virus who developed illness seroconverted (10/10), whereas only one-third (5/15) of n ...1979118178
norwalk virus in vomitus. 197983510
infection with small round structured viruses: england and wales 1981-1990.infection with small round structured viruses (srsv) usually causes an acute, but short-lived, attack of gastroenteritis in which vomiting is a prominent feature. most documented outbreaks have occurred in institutional and catering establishments and infected food handlers are often implicated. reports of srsv infection have risen substantially during the last decade partly due to an increase in the number of laboratories able to examine samples for this organism. ascertainment is likely to rem ...19911669758
a large nontypical outbreak of norwalk virus. gastroenteritis associated with exposing celery to nonpotable water and with citrobacter freundii.the us air force academy experienced a point-source outbreak of gastroenteritis originally believed to be caused by salmonella. the overall attack rate was 48% among approximately 3000 cadets and staff. food-specific attack rates implicated chicken salad. the odds ratio for chicken salad consumption in ill cadets was 10.7 (95% confidence interval: 8.2; 13.8). the celery component had been exposed to nonpotable water. citrobacter freundii were statistically associated with consumption of the susp ...19911660704
demonstration of low molecular weight polypeptides associated with small, round-structured viruses by western immunoblot analysis.small, round-structured viruses (srsv) were detected in 14 of 300 fecal specimens obtained from patients with acute gastroenteritis by electron microscopy. these srsv strains were morphologically indistinguishable from one another. while 11 of these strains had a single usual major structural protein with molecular weight of 63,000 (63k) daltons (p63), interestingly, three strains possessed a single major structural protein with molecular weight of 33k daltons (p33). treatments of p63-srsv with ...19921282654
pattern of shedding of the norwalk particle in stools during experimentally induced gastroenteritis in volunteers as determined by immune electron microscopy.in 11 of 23 volunteers the norwalk virus-like particle was visualized by immune electron microscopy in at least one stool specimen obtained during the acute phase of experimentally induced nonbacterial gastroenteritis. examination of multiple stool specimens obtained during the course of illness in these 11 volunteers revealed maximal concentration of norwalk virus-like particle at the onset of illness and shortly thereafter; in no case was the norwalk particle visualized in stools obtained befo ...19751151121
gastroenteritis associated with shellfish. 19911669888
[food-borne outbreaks of gastroenteritis caused by small round structured viruses. 1. four outbreaks of gastroenteritis associated with oyster consumption].between december 9, 1988 and january 28, 1989, there were four outbreaks of acute gastroenteritis in saitama prefecture. eighty-two of 123 persons (67%) attending four banquets in restaurants became ill: 44 cases attending three banquets were related to eating raw oysters, and 38 attending one banquet to eating sashimi. the most common symptoms were nausea, diarrhea, abdominal cramps, and vomiting. average incubation periods were 29 to 32 hours long. bacteriologic analysis of stool specimens did ...19911662251
norwalk agent and other small-round structured viruses in the u.k. 19911661318
occurrence of norwalk virus infections among adults in mexico.norwalk virus infection was sought in 48 us, 49 puerto rican, and 27 mexican adults attending medical school in guadalajara (mexico) who were enrolled in a 2-year longitudinal study. serum specimens were collected quarterly and as acute- and convalescent-phase samples around episodes of gastroenteritis. the reciprocal norwalk virus geometric mean titer (gmt) for puerto rican students (567) was significantly higher than that of the us students overall (294; p less than .001) and for four of nine ...19902165112
[outbreaks of acute gastroenteritis caused by small round structured viruses in tokyo].of 34 non-bacterial gastroenteritis outbreaks which occurred at day-care centers, kindergartens, elementary and secondary schools in tokyo during the period from february 1985 to june 1991, 28 outbreaks from which small round structured viruses (srsv) were detected in the patients' stool specimens by electron microscopy were subjected to an epidemiological investigation. the outbreaks tended to occur frequently in the cold season; twenty-two (79%) of these outbreaks from november through april. ...19921331265
viral agents of gastroenteritis. public health importance and outbreak management.each year, infectious gastroenteritis causes greater than 210,000 children in the united states to be hospitalized and 4-10 million children to die worldwide. since the mid-1970s, knowledge has increased dramatically concerning the viral agents that are responsible for much of this public health burden. rotavirus, the most common cause of diarrhea among children, infects virtually every child in the united states by the age of 4 years and causes potentially lethal dehydration in 0.75% of childre ...19902157945
norwalk agent comes of age. 19902160504
an outbreak of acute gastroenteritis caused by a small round structured virus in a geriatric convalescent facility.an outbreak of acute gastroenteritis (age) occurred in a 201-bed geriatric convalescent facility in los angeles county during december 1988 through january 1989. the attack rate was 55% among residents and 25% among employees. illnesses were characterized by vomiting and diarrhea to a lesser extent, and the absence of fever. bacterial and parasitic tests in a sample of patients were negative. a 27 nm small round structured virus (srsv) was identified in one of 30 stools studied by immune electro ...19902172363
isolation of cytopathic small round viruses with bs-c-1 cells from patients with gastroenteritis.fecal extracts from 12 subjects in outbreaks of oyster-associated nonbacterial gastroenteritis were inoculated with bs-c-1 cells for isolation of the causative viruses. cytopathic agents were isolated from 3 patients. no cross-neutralizing reactions were observed between the isolates and prototypes of human enteroviruses. the isolates were approximately 30 nm in diameter and had a distinct ultrastructure resembling that of astroviruses. four polypeptide bands with molecular sizes of 42, 28, 27, ...19911658159
epidemiology of travelers' diarrhea and relative importance of various pathogens.each year 12 million persons travel from an industrialized country to a developing country in the tropics or subtropics. these travelers experience a high rate of diarrhea caused by a wide variety of enteric pathogens acquired by ingestion of contaminated food or water. one or more pathogens can be found in the stool of a majority of ill individuals. enterotoxigenic escherichia coli generally are the most frequently identified pathogens, having been found in a median of 42% of travelers' diarrhe ...19902406860
a multistate outbreak of norwalk virus gastroenteritis associated with consumption of commercial ice.between 19 and 27 september 1987, a cluster of outbreaks of gastrointestinal illness occurred among persons who had attended a museum fund-raiser in wilmington, delaware and an intercollegiate football game in philadelphia. a survey of four groups attending these events showed that 31% (191/614) became ill. altogether, those who consumed ice were 12 times more likely to experience either vomiting or diarrhea than those who did not (attack rate, 55% vs. 4%, p less than .001). ice consumed at the ...19911658158
an outbreak of acute infectious nonbacterial gastroenteritis in a high school in maryland.an outbreak of acute infectious nonbacterial gastroenteritis (aing) occurred in a high school in maryland in 1984. thirty-six percent of students surveyed met the case definition of gastroenteritis, as did 24 percent of school employees. eating lunch in the cafeteria on january 30 was significantly associated with illness. after controlling for other food items consumed during the january 30 lunch, only the sandwiches were significantly associated with illness, but the source of the contaminatio ...19892539604
viral gastroenteritis. 19911647494
waterborne outbreak of norwalk virus gastroenteritis at a southwest us resort: role of geological formations in contamination of well water.from april 17 to may 1, 1989, gastroenteritis developed in about 900 people during a visit to a new resort in arizona, usa. of 240 guests surveyed, 110 had a gastrointestinal illness that was significantly associated with the drinking of tap water from the resort's well (relative risk = 16.1, 95% confidence interval 14.5 to 17.8) and this risk increased significantly with the number of glasses of water consumed (p less than 0.005). three of seven paired sera tested for antibodies to the norwalk ...19911673747
serum immunoglobulin a response to norwalk virus infection.we describe the serum immunoglobulin a (iga) antibody response to norwalk virus infection in human volunteers and compare it with previously described igm and total antibody responses. whereas specific iga and igm peak within 2 weeks after onset of symptoms, titers of total blocking antibody continue to rise, implying mediation by igg antibody.19892546980
antigenic relatedness among the norwalk-like agents by serum antibody rises.the norwalk, snow mountain (sma), and hawaii agents are etiologically associated with separate outbreaks of acute viral gastroenteritis. previous cross-challenge of volunteers, immune electron microscopy, and/or enzyme-immunoassay analysis suggested that these agents are antigenically distinct. we examined paired sera from human volunteers challenged with these agents for the presence of homologous and heterologous serum antibody titer rises to the agents. two-way cross-reactions occurred betwee ...19901704048
prospects for development of a rotavirus vaccine against rotavirus diarrhea in infants and young children.major advances have been made in elucidating the etiologic agents of severe infantile diarrhea, and it is clear that rotaviruses are the single most important etiologic agents. progress in the development of rotavirus vaccine candidates has also moved swiftly with the "jennerian" approach, in which a related live, attenuated rotavirus strain from a nonhuman host is used as the immunizing antigen. if this strategy is not effective against all rotavirus serotypes, reassortant rotaviruses hold grea ...19892548276
viral gastrointestinal infections.numerous disease-causing viruses of the gastrointestinal tract have been described. the diseases that they induce range from subclinical to fatal gastrointestinal or systemic organ infection. recent advances in molecular biology and virus culture techniques, as well as improvements in animal models of these infections, have increased our understanding of pathologic processes associated with these viruses. although our overall understanding of these viruses has improved to the extent that many mo ...19921324891
norwalk virus in norway: an outbreak of gastroenteritis studied by electron microscopy and radioimmunoassay.an outbreak of acute gastroenteritis affected approximately half of 40 children staying at a holiday centre in southern norway. by direct electron microscopy norwalk-like viruses were demonstrated in 4/8 available stool specimens. no other pathogens were detected. antibody against these viruses was demonstrated by immune electron microscopy in all of 7 convalescent phase sera but in none of 11 acute phase sera collected. radioimmunoassay examination showed a rise in titre of norwalk virus antibo ...19892555911
small round structured viruses and their spread. 19892563823
viral gastroenteritis aboard a cruise ship.a 32-nm small round structured virus (srsv), possibly related to the snow mountain agent (sma), was implicated as the cause of recurrent outbreaks of gastroenteritis on a cruise ship. there was no identifiable relation to food or water consumption, but the risk of gastroenteritis among passengers who had shared toilet facilities was twice that of those who had a private bathroom and the rate of illness was related to the number of passengers sharing a communal restroom (ie, with one or more toil ...19892571872
enteric infections associated with exposure to animals or animal products.the epidemiology and clinical presentation of enteric infections are discussed in this article. these include bacterial, viral, and parasitic illnesses, and are associated with the increasing popularity of drinking unpasteurized milk; eating raw fish and shellfish; consuming undercooked pork, poultry, and eggs; and having contact with pets. salmonella, campylobacter jejuni, vibrio, yersinia, aeromonas, edwardsiella, hepatitis a virus, norwalk virus, anisakis, eustrongylides, diphyllobothrium, na ...19911955706
antigenic relationships between human caliciviruses and norwalk virus.we investigated antigenic relationships between human calicivirus (hcv) strains and norwalk virus by using immune electron microscopy (iem) and radioimmunoassay (ria). three serologically distinct hcv strains, uk1, uk2, and japan, were demonstrated by iem, as was evidence for two additional strains, uk3 and uk4. although hcv strains and norwalk virus were distinct by iem, 12 of 20 patients with gastroenteritis due to hcv uk4 and two of eight with gastroenteritis due to uk2 showed seroconversions ...19872821127
small round structured viruses: an important infection control problem? 19902172362
risk factors for secondary transmission in households after a common-source outbreak of norwalk gastroenteritis.in november 1984, a foodborne outbreak of norwalk gastroenteritis occurred in a k-12 public school in northern vermont. the outbreak offered an opportunity to systematically study in detail secondary transmission rates in households. eating salad at tuesday's school-sponsored thanksgiving banquet was associated with illness among students and staff members (p less than 0.025). seven of 11 serum pairs from ill persons showed a fourfold or greater rise in antibody titer to norwalk virus compared w ...19872825520
leads from the mmwr. viral gastroenteritis--south dakota and new mexico. 19882828698
detection of norwalk virus in stool specimens by reverse transcriptase-polymerase chain reaction and nonradioactive oligoprobes.a reverse transcriptase (rt)-polymerase chain reaction (pcr)-oligoprobe (op), or rt-pcr-op, method was developed for the detection of the norwalk virus, which causes acute, epidemic gastroenteritis, in stool specimens. the norwalk virus genome regions encoding the following two proteins were amplified by rt-pcr: the rna polymerase (260-bp product) and a putative immunogenic protein (224-bp product). the resulting dna fragments (amplicons) were hybridized to a digoxigenin-labeled internal op spec ...19921280649
an electron microscopical investigation of faecal small round viruses.a retrospective study of small round featureless viruses (srvs) initially identified by negative-staining electron microscopy of stool samples was performed. a variety of technique, including immunoelectron microscopy and caesium chloride gradient centrifugation, was applied in an attempt to classify further these viruses. over a four-year period, 64 srv-positive samples were reported (1.8% of the stool samples sent for electron microscopy and 6.2% of the total number of positive samples), of wh ...19882832539
pathogenesis of gut virus infection.in summary, the pathogenesis of many gut virus infections remains uncertain. however, human and animal studies indicate that the majority of gut viruses infect villous enterocytes. viruses appear to have different affinities for enterocytes at different sites on the villus. infection of enterocytes leads to cell death, extrusion into the lumen, and villous atrophy when the rate of cell production in the crypts cannot keep pace with the rate of enterocyte loss. this results in a reduced surface a ...19901962725
production of a monoclonal antibody against the snow mountain agent of gastroenteritis by in vitro immunization of murine spleen cells.the snow mountain agent (sma) is a 27- to 32-nm noncultivatable virus that causes acute gastroenteritis in humans. sma is morphologically similar to but immunologically distinct from the norwalk agent. sma has been partially purified from the stool of experimentally infected volunteers and contains a single structural protein of mr 62,000 as well as one or more non-virion-associated soluble proteins. further characterization of this important human pathogen and other norwalk-like viruses has bee ...19882835775
the isolation and characterization of a norwalk virus-specific cdna.norwalk virus, an important cause of epidemic, acute, nonbacterial gastroenteritis in adults and children, has eluded adaptation to tissue culture, the development of an animal model, and molecular cloning. in this study, a portion of the norwalk viral genome encoding an immunoreactive region was cloned from very small quantities of infected stool using sequence-independent single primer amplification. six overlapping complementary dna (cdna) clones were isolated by immunologic screening. the ex ...19912010555
foodborne gastroenteritis due to norwalk virus in a winnipeg hotel. 19902154305
[food-borne outbreak of gastroenteritis caused by small round structured virus. 2. an outbreak associated with bakery product consumption].in december 1989, an outbreak of gastroenteritis associated with cake consumption occurred in a day-care center with 60 children and 12 staff in saitama prefecture. children were served cakes at the christmas party held in the day-care center and ate them with their families. thirty-three of the 59 children (56%), 16 of the 74 families (22%) and 1 of the 10 staff (10%) eating the cakes became ill. illness consisted primarily of nausea, vomiting, diarrhea and fever; the median incubation period w ...19911664441
[food poisoning outbreak probably of viral etiology caused by norwalk virus].in may 1989, a foodborne outbreak of acute gastroenteritis was identified in a state school in adzaneta, castellón. a dtudy was undertaken to describe it, investigate its causes, and recommend adequate control measures. sixteen children and 2 teachers were affected (attack rate: 28.57%). kaplan and cols clinical and epidemiological criteria for norwalk-like virus as the responsible agent were present. the probable origin of the outbreak was a foodhandler who was already ill beforehand. the exami ...19911664422
foodborne gastroenteritis due to norwalk virus in a winnipeg hotel. 19902161705
norwalk-like gastroenteritis epidemic in a teaching hospital--quebec. 19902170034
polymicrobial aetiology of travellers' diarrhoea.of 35 us peace corps volunteers in thailand, 20 (57%) had a total of 30 episodes of diarrhoea during their first 6 weeks in the country. enteric pathogens were associated with 90% of the episodes. a single pathogen was identified in 17 (57%) episodes, 2-4 pathogens were identified in 10 (33%) episodes, and there were 15 symptomless infections. enterotoxigenic escherichia coli (etec) was identified in 37% of these episodes, and various salmonella serotypes were isolated in 33%. infections with 9 ...19852857430
diarrheal disease during operation desert shield.under combat conditions infectious disease can become a major threat to military forces. during operation desert shield, there were numerous outbreaks of diarrhea among the u.s. forces. to evaluate the causes of and risk factors for diarrheal disease, we collected clinical and epidemiologic data from u.s. troops stationed in northeastern saudi arabia.19911656260
large outbreak of foodborne norwalk-type viral gastroenteritis in a district general hospital--united kingdom. 19902170035
[viral diarrheas].it is now well known that several viruses are responsible for acute diarrhoea or gastroenteritis in both children and adults. these viruses are difficult to identify since most of them cannot be isolated by stool cultures on cells. the reality of proven reinfection by some of these organisms is not always clearly understood, even though the existence of several serotypes in the same group (notably rotavirus) can be blamed, and this explains why vaccines are difficult to develop.19921313558
evidence of immunity induced by naturally acquired rotavirus and norwalk virus infection on two remote panamanian islands.for better understanding of the role of humoral immunity in ameliorating infections with rotavirus (rv) and norwalk virus (nw), 305 cuna indians living on two isolated islands located off panama's carribean coast were surveyed daily for diarrhea over a seven-month period. nine (8%) of 108 persons with a baseline rv antibody titer of greater than 1:4 developed rv infection compared with 70 (46%) of 151 persons with a baseline rv antibody titer of less than 1:4 (p less than .001). thirty-eight (25 ...19852981278
a serosurvey of pathogens associated with shellfish: prevalence of antibodies to vibrio species and norwalk virus in the chesapeake bay region.recent concerns regarding the safety of shellfish consumption have focused on the risk posed by naturally occurring marine bacteria such as vibrio species and by viruses such as norwalk and related agents. despite the widespread environmental presence of vibrio species in the chesapeake bay, the rate of reported infections remains low; there have also been no reports of major norwalk outbreaks associated with shellfish in this area. as infections with these agents may not always be recognized be ...19921312771
norwalk virus antigen and antibody response in an adult volunteer study.to better define the optimum timing of specimen collection and identify alternate ways to diagnose norwalk virus outbreaks, we looked at the timing of the antibody response and virus excretion in a human volunteer study. the norwalk virus antibody titers and antigen in stool specimens were examined by biotin-avidin immunoassay. our data suggest that in epidemic situations, convalescent-phase sera could be collected as soon as 13 days after the onset of illness and acute-phase sera could be colle ...19872822766
[gastroenteritis caused by norwalk-group viruses]. 19902158706
travelers' diarrhea. nih consensus development conference.diarrhea is the major health problem in travelers to developing countries. travel to high-risk areas in latin america, africa, the middle east, and asia is associated with diarrhea rates of 20% to 50%. the syndrome is caused by an infection acquired by ingesting fecally contaminated food or beverages. escherichia coli, a common species of enteric bacteria, is the leading pathogen, although a host of other bacteria, viruses, and protozoa have been implicated in some cases. prudent dietary and hyg ...19852985834
[viral diarrheas].in the developing countries diarrhoea ranks among the most frequent diseases: 5-18 million children are estimated to die annually from gastro-intestinal infections. but also in europe and the usa diarrhoea is of utmost medical importance, especially among children and infants. it was only twelve years ago that 2 viral groups, the norwalk and the rotavirus group, were discovered to be etiological agents responsible for a large proportion of gastro-intestinal infections. whilst viruses of the norw ...19852986379
diagnosis of astrovirus gastroenteritis by antigen detection with monoclonal antibodies.an enzyme-linked immunosorbent assay (elisa), based on monoclonal antibodies to the astrovirus group antigen, was designed for the detection of astroviruses in stools of patients with gastroenteritis. compared to immune electron microscopy used as the standard test, the sensitivity of the astrovirus elisa was 91% (31/34) and the specificity was 96% (54/56). all five of the known astrovirus serotypes could be detected in 16 samples on which serotyping was done. in tests on 155 stools containing o ...19902105359
multiple-challenge study of host susceptibility to norwalk gastroenteritis in us adults.in a multiple-challenge study of us adult volunteers with low or high levels of serum antibody to norwalk virus, norwalk inoculum 8fiia was administered to 42 subjects, 22 were challenged 6 months later, and 19 received a third challenge after 6 more months. all 12 with high (greater than or equal to 1:200) but only 19 of 30 with low (less than 1:100) prechallenge titers experienced illness or a fourfold increase in titer after the first challenge (p less than .025). only 4 of those challenged t ...19902153184
norwalk virus gastroenteritis. an outbreak associated with a cafeteria at a college.an explosive outbreak of gastrointestinal illness occurred among students and employees at a small college in florida in november 1980. common symptoms were diarrhea, nausea, weakness, abdominal cramps, chills, vomiting, and low-grade fever. cases of illness were identified in 40% of 628 students and 15% of 162 employees who responded to a survey. among students, there was a sevenfold excess risk associated with eating one or more meals at the campus cafeteria november 3-5 (p much less than 0.00 ...19852990197
viral hepatitis and gastroenteritis transmitted by shellfish and water.the epidemiology and clinical presentation of water-borne viral diseases, including shellfish-associated viral illnesses, are discussed in this article. hepatitis a virus, non a-non b hepatitis and the agents of viral gastroenteritis, norwalk agent, snow mountain agent, rotavirus, the small round viruses, caliciviruses, and astroviruses are included. the technical problems associated with evaluating the viral contamination of water or shellfish are noted.19872848882
two outbreaks of foodborne gastroenteritis caused by a small round structured virus: evidence of prolonged infectivity in a food handler.in two outbreaks of diarrhoea and vomiting that were caused by a small round structured virus (srsv) that affected over 275 people, epidemiological and laboratory evidence showed that certain foods were the vehicles of infection and suggest that one of the chefs who prepared them may have been excreting this virus for a long time.19872887841
role of norwalk virus in two foodborne outbreaks of gastroenteritis: definitive virus association.two separate food-associated outbreaks of gastroenteritis occurred among erie county, new york residents in june 1986. in one outbreak, cases of illness were estimated to have occurred in 50% of the approximately 700 persons in 13 groups who ate at an out-of-county restaurant during a seven-day period, and, in the second outbreak, illness occurred in 26 (30%) of 87 persons who attended a graduation party held in a private home. laboratory investigation included serology (blocking radioimmunoassa ...19892535916
foodborne gastroenteritis due to norwalk virus in a winnipeg hotel.within 1 week four separate incidents of gastroenteritis presumed to be foodborne were reported by guests of a winnipeg hotel. investigation revealed poor food-handling practices and illness among the kitchen staff. elevated bacterial counts and escherichia coli were found in 15 of 24 samples of food tested, and staphylococcus aureus was isolated from 2 pastry samples. culture of 14 stool samples for bacteria yielded clostridium perfringens in 1 sample from a staff member and coagulase-positive ...19892541881
[epidemiology, etiology and laboratory diagnosis of infectious diarrhea diseases in the tropics].diarrhoeal diseases belong to the leading causes of morbidity and mortality in tropical countries, especially in infants and small children. about one billion episodes are estimated for this group of age with 4.6 million fatalities. many causes are discussed to explain the high incidence: bottle feeding of infants, protein malnutrition, unsafe drinking water and unsafe disposal of excrements and sewage, unsufficient consciousness of personal and domestic hygiene, lack of knowledge on the origin ...19853000920
other viruses with etiologic roles in childhood gastroenteritis.rotaviruses and norwalk-like viruses are the two groups of viruses most frequently associated with gastroenteritis, but as outlined in this review several other viral agents have also been associated with acute gastroenteritis. the gastroenteritis viruses are generally fastidious, and thus traditional cell culture isolation and detection procedures are not applicable; therefore electron microscopy and immunoelectron microscopy remain among the most powerful techniques for studying these viruses. ...19863003721
small round structured viruses and persistence of infectivity in food handlers. 19872889072
solid-phase immune electron microscopy with human immunoglobulin m for serotyping of norwalk-like viruses.a solid-phase immune electron microscopy method that uses protein a, goat anti-human immunoglobulin m (igm), and human serum is described. evaluation of the method with different immunoglobulin fractions showed that human igm constituted the major virus capture antibody. the method appeared to distinguish between two norwalk-like virus serotypes and demonstrated specific igm responses to these serotypes in infected individuals. further work is being carried out to define the relationship of thes ...19882838506
outbreak of gastroenteritis in a home for the aged--ontario. 19882854008
inactivation of norwalk virus in drinking water by chlorine.norwalk virus in water was found to be more resistant to chlorine inactivation than poliovirus type 1 (lsc2ab), human rotavirus (wa), simian rotavirus (sa11), or f2 bacteriophage. a 3.75 mg/liter dose of chlorine was found to be effective against other viruses but failed to inactivate norwalk virus. the norwalk virus inoculum remained infectious for five of eight volunteers, despite the initial presence of free residual chlorine. infectivity in volunteers was demonstrated by seroconversion to no ...19852996421
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 ...19902154547
characterization of the snow mountain agent of viral gastroenteritis.snow mountain agent (sma) is a 27- to 32-nm virus which is the etiologic agent of outbreaks of acute gastroenteritis in colorado and vermont. sma is morphologically similar to but antigenically distinct from the norwalk and hawaii agents of viral gastroenteritis but, like those agents, has not been cultivated in vitro. we purified and characterized sma directly from human stool specimens containing the virus. the density of the sma virion was 1.29 g/cm3 and 1.21 to 1.22 g/cm3 on potassium tartra ...19863009862
detection of norwalk virus in stools by enzyme immunoassay.the development of a solid-phase microtiter enzyme immunoassay (eia) for detection of norwalk virus antigen in stool samples is described. the eia was compared with a previously developed radioimmunoassay (ria) for detection of norwalk virus antigen in stools obtained from 30 volunteers who received norwalk virus. the eia detected viral antigen in stools from 17 of the volunteers and the ria detected viral antigen in 15. seroconversion was a more sensitive indicator of infection in some patients ...19852997382
gastroenteritis outbreaks on two caribbean cruise ships. 19863012310
viral enteritis in the 1980s: perspective, diagnosis and outlook for prevention. 19892549497
a statewide assessment of the role of norwalk virus in outbreaks of food-borne gastroenteritis. 19852982970
pathogens that cause travelers' diarrhea in latin america and africa.with the advent of rapid and convenient means of transportation, millions of persons travel each year from industrialized to developing countries in the tropics and subtropics. these travelers are at risk for a variety of infectious diseases that are endemic in these areas; the most frequently occurring of these is diarrhea. studies of groups of travelers to latin america and africa have found that approximately one-half develop diarrhea during their stay abroad. etiologic investigations of thes ...19863014633
update of viral gastroenteritis. 19882834120
norwalk virus genome cloning and characterization.major epidemic outbreaks of acute gastroenteritis result from infections with norwalk or norwalk-like viruses. virus purified from stool specimens of volunteers experimentally infected with norwalk virus was used to construct recombinant complementary dna (cdna) and derive clones representing most of the viral genome. the specificity of the clones was shown by their hybridization with post- (but not pre-) infection stool samples from volunteers infected with norwalk virus and with purified norwa ...19902177224
antigen detection in the diagnosis of norwalk virus gastroenteritis. 19863016117
radioimmunoassay for detection of the snow mountain agent of viral gastroenteritis.the snow mountain agent (sma) is a norwalk-like viral agent of acute gastroenteritis that has been detected only by immune electron microscopy (iem). we established a solid phase microtiter radioimmunoassay (ria) for sma antigen employing pre-and post-challenge sera from volunteer studies as capture antibodies. sma was detected in 12 of 67 stool samples from volunteers who were ill after oral challenge with sma. all samples in which virus particles were detected by iem were positive by ria, but ...19863009701
enzyme-linked immunosorbent assays for snow mountain and norwalk agents of viral gastroenteritis.enzyme-linked immunosorbent assays (elisas) for antigen detection and blocking elisas for serum antibody rises were developed for the snow mountain and norwalk agents of viral gastroenteritis. the elisas were as sensitive as the existing radioimmunoassays and were specific for the snow mountain or norwalk agent. the blocking elisas detected the same number of significant rises in antibodies to these agents as did the existing blocking radioimmunoassays.19863020085
two institutional outbreaks of norwalk-like gastroenteritis--ontario. 19892544302
development and evaluation of an igm capture enzyme immunoassay for diagnosis of recent norwalk virus infection.a capture enzyme immunoassay specific for norwalk igm class antibody was developed. the assay was moderately sensitive, identifying 33/53 (62%) of patients with naturally acquired norwalk virus infection and 17/18 (94%) of experimentally infected volunteers. the assay was also specific for igm class antibody and acute norwalk virus infection and results were generally reproducible. a specific igm response correlated with seroconversion by total antibody blocking assay and occurred independently ...19892547819
foodborne snow mountain agent gastroenteritis in a school cafeteria.in 1984, an outbreak of gastroenteritis occurred at a school with 1,860 students in brooklyn, ny. in a single-stage cluster sample of 375 students, 129 (34%) had illnesses that met our case definition of vomiting or diarrhea. the mean incubation period was 26 hours, and the mean illness duration was 24 hours. all case students had eaten in the cafeteria on at least one day between nov 13 and 16, compared with 174/214 (81%) noncase students (p = 10(-8), fisher exact test). foods implicated were f ...19873029660
serologic survey of rotavirus, norwalk agent and prototheca wickerhamii in wastewater workers.analysis of paired sera from 48 wastewater workers and controls who reported gastrointestinal illness did not reveal any excess of seroconversions to norwalk agent or to rotavirus. inexperienced wastewater-exposed workers had higher levels of antibody to norwalk agent than did experienced and control workers and those with high and medium aerosol exposure had higher titres than those in the low aerosol category. analysis for prototheca antibody titres was essentially negative.19852981485
25- to 30-nm virus particle associated with a hospital outbreak of acute gastroenteritis with evidence for airborne transmission.between november 1 and 22, 1985, an outbreak of acute, nonbacterial gastroenteritis occurred in a 600-bed hospital in toronto, ontario, canada. illness in 635 of 2,379 (27%) staff was characterized by fatigue, nausea, diarrhea, and vomiting and had a median duration of 24-48 hours. the finding of virus-like particles measuring 25-30 nm in six stool specimens and low rates of seroresponse to norwalk virus (3/39) and snow mountain agent (1/6) suggest that a norwalk-like virus was responsible for t ...19882835899
clinical associations of norwalk-like virus in the stools of children.from among 1,360 stool specimens examined during the 19-month period from march 1982 to september 1983, small round-structured viruses, morphologically indistinguishable from the norwalk agent, were detected by electron microscopy in 42 specimens from 28 children. diarrhoea was mild, and vomiting, although frequently observed, was not an invariable feature. mild pyrexia occurred in three patients. many cases occurred some time after admission to the ward; this and other features suggested a hosp ...19863016227
novel agents of viral enteritis in humans.considerable information has recently emerged regarding certain "groups" of novel viruses associated with gastroenteritis in humans. the viruses reviewed here are 20-35 nm in diameter and can be detected in the stools of acutely ill individuals with gastroenteritis. these viruses can be conveniently divided into four "groups": norwalk-like agents, caliciviruses, astroviruses, and other small round viruses. the evidence for the etiologic association of these agents with gastroenteritis varies fro ...19873027199
norwalk-like gastroenteritis epidemic in a toronto hospital.an epidemic of gastroenteritis in a teaching hospital affected 57 patients and 69 staff over a 26-day period. the index case was a patient admitted with acute abdominal pain and diarrhea two days prior to the outbreak. the epidemic curve indicated person-to-person transmission. the incubation period, duration and types of symptoms were typical of norwalk gastroenteritis, and norwalk-like virus particles, serologically different from the prototype norwalk virus strain, were observed in 17 of 20 f ...19873028187
leads from the mmwr. gastroenteritis on two caribbean cruise ships. 19863014174
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