NV gastroenteritis was independently associated with food-handling hygiene, having more than one household member with gastroenteritis hereafter referred to as household gastroenteritis contact , and having contact with a person with gastroenteritis outside the household hereafter referred to as outside gastroenteritis contact in the week before onset of symptoms Table 1 , Figure 1.
For the risk factor of household gastroenteritis contact, risk was slightly higher if the household member was a child rather than an adult 5. Risks were comparable if the household member had diarrhea or vomiting. Because of the strong correlation of all variables on household contacts, only the number of household gastroenteritis contacts was included in the model.
Cases and controls did not differ significantly. The association of attendance at daycare and primary school with NV gastroenteritis in the univariate analysis was no longer observed after correction for household gastroenteritis contact, especially if the sick household member was a child. Food-handling hygiene and outside gastroenteritis contact were the factors with the highest impact, as measured by PAR Tables 1 and 2. This figure is much lower than the sum of both PARs.
We assumed that all case-patients who had contact with a person with gastroenteritis in the week before onset of symptoms were infected by these contacts. Thirty-four pairs remained for the calculation of OR. For food-handling hygiene, OR was slightly higher for those not having contact with someone with gastroenteritis 1. In total, 48 cases were positive for SLV—21 in both samples, 22 only in the first sample, and 5 only in the second sample.
Of the matched controls, two were positive for SLV but did not have gastroenteritis. Outside gastroenteritis contact was the only independent risk factor for SLV gastroenteritis Table 3.
The location of contacts of case-patients and controls did not differ significantly. In total, 54 cases were positive for rotavirus—11 in both samples, 41 only in the first, and 2 only in the second.
None of the matched controls was positive for rotavirus. Figure 2. Rotavirus gastroenteritis was independently associated with outside gastroenteritis contact and with food-handling hygiene Table 4 and Figure 2. A strong independent negative association was found with presence of a blender in the household.
By univariate analysis, a high education level was a risk factor for rotavirus gastroenteritis, as was a household gastroenteritis contact. The risk was higher if the household gastroenteritis contact was a child OR 5. The association of a household gastroenteritis contact disappeared after correction for outside gastroenteritis contact. The association with educational level disappeared after correction for food-handling hygiene.
Locations of outside gastroenteritis contacts did not differ significantly between cases and controls. The case-patients in 10 pairs had not had any contact with a person with gastroenteritis. In this group, OR for food-handling hygiene was 1.
To our knowledge, this study is the first to describe risk factors for the three main viral pathogens causing gastroenteritis and to estimate the effect of these risk factors in the population.
The main risk factor for NV, SLV, and rotavirus gastroenteritis was contact with persons with gastroenteritis, supporting the hypothesis that these viruses are mainly transmitted from person to person 13 , The high PARs indicate that most of these infections can indeed be prevented by stopping the spread from symptomatic persons to others. Food-handling hygiene in the household was also strongly associated with risk for NV gastroenteritis and with a high PAR.
This association indicates that in a household setting these viruses do not necessarily transmit directly from one person to another but by means of food. Hygienic food-handling procedures can therefore further prevent the infection spreading from one person to another The impact of food-handling hygiene can be partly explained by food contamination that occurs when a sick household member prepares meals.
However, food contaminated at an earlier step in the food chain may also be a source. This figure may be an overestimate, if infection through the shedding of other asymptomatic persons plays a major role, or if the knowledge of respondents about illness in their contacts is limited.
Alternatively, the proportion of NV infections attributable to foodborne transmission might be an underestimate since we assumed that, if contact with symptomatic others had taken place, such contact was always the cause of illness. Clearly, the precise number of community cases of viral foodborne infection cannot be derived by either approach. However, we strongly support the conclusion that a considerable proportion of NV infections may be prevented by improving food hygiene.
In surveillance systems of outbreaks of NV, person-to-person spread and foodborne spread are reported to be the most common transmission routes 1 , 8 , The relative importance of each differs by country and is strongly influenced by the design of the surveillance system Outbreaks covered in a surveillance system do not necessarily represent all outbreaks. Our study shows that in sporadic cases, direct and indirect person-to-person transmission remains the most prominent mode of transmission, followed by food contaminated outside the household.
Nevertheless, extrapolation of our estimate to the population of the Netherlands 16 million suggests that, of the , NV gastroenteritis cases that occur annually, an estimated 80, cases are foodborne, which is more than the estimate for Salmonella 50, foodborne cases each year. No specific food products were associated with NV gastroenteritis. This finding is not remarkable because NV can probably survive on almost all food products that are not cooked before consumption, and a very low infectious dose is required, as has been demonstrated for another naked single-stranded RNA virus, poliovirus Since NV cannot be grown in cell culture, little is known about its heat inactivation profiles.
Most published foodborne outbreaks could be traced back to infected food handlers at some point in the production chain, suggesting that this is by far the most common source of foodborne infections 8 , 22 — Our results show that, without applying extraordinary hygienic practices but by just following normal hygiene procedures, a substantial portion of sporadic NV infections could be prevented.
Because of the high transmission rate in households, persons with a household member with gastroenteritis are at greater risk of being infected. Since several foodborne outbreaks have been reported in which the food handler who had most likely contaminated the food was not symptomatic yet , making professional food handlers aware of their higher probability of being infected when living with a household member with gastroenteritis might be useful For children, only part of the transmission from one person to another in the household is through food-handling hygiene.
Possibly, for young children, exposure is very common and better food-handling hygiene in the household only prevents a minority of exposure possibilities. A large study in U. In contrast to rotavirus and SLV gastroenteritis, NV gastroenteritis is not limited to the youngest age groups.
This finding could explain why food-handling hygiene and having a household gastroenteritis contact had a higher impact on NV gastroenteritis than on SLV gastroenteritis. For rotavirus and SLV, undetected asymptomatic infections not included as cases in this study may occur at older age through these routes. Living in a household with a child attending a daycare center or primary school was univariately associated with NV gastroenteritis.
However, when the data were corrected for a household gastroenteritis contact, especially with a child, this association disappeared. This finding suggests that daycare centers and primary schools are the settings in which the primary infection in the household was acquired. We could not confirm the association between rotavirus gastroenteritis and daycare center attendance, as has been reported by others 26 , A study with comparable methods in England also did not find this association The optimized score for food-handling hygiene was fitted in the same NV data for which it was used to estimate the effect of hygiene.
This might have resulted in an overestimate for NV because noise is also modeled in the prediction. Although all the factors included in the food-handling hygiene index are related to food handling, we cannot exclude the possibility that the index might be a proxy for hygiene as a whole and not just related to food handling. Finally, we assumed that the relationship between the hygiene score and the risk for NV gastroenteritis was exponential.
Copy Export. Details: Alternative Title:. Publisher's site:. Personal Author:. Viral pathogens are the most common causes of gastroenteritis in the community. To identify modes of transmission and opportunities for prevention, a case-control study was conducted and risk factors for gastroenteritis attributable to norovirus NV , Sapporo-like virus SLV , and rotavirus were studied. Transmission of these viral pathogens occurs primarily from person to person.
However, for NV gastroenteritis, foodborne transmission seems to play an important role. Emerg Infect Dis. Document Type:. Journal Article ;. Collection s :. Emerging Infectious Diseases. Main Document Checksum:. Although different methods electron microscopy, ELISA, and PCR assays with different primer sets were used in these studies, the sapovirus positive rates ranged from 2. Eight studies also detected other gastroenteritis pathogens, and sapoviruses ranked second to fourth as the major viral pathogens among patients with sporadic gastroenteritis Table 6.
Similar to the case for noroviruses , , , , sapoviruses were detected mainly in the cold season among patients with sporadic gastroenteritis 89 , 99 , — , , , , — , although different seasonal peaks among years have also been reported , Sapovirus illnesses occur more frequently in younger children than in older children and adults , , Sapovirus positive rates in gastroenteritis patients from 13 studies that detected more than 30 strains during the study period.
Although the reported outbreak numbers are less for sapoviruses than for noroviruses , , — , sapovirus gastroenteritis outbreaks occur throughout the year in all ages of people in various settings, such as child day care centers, kindergartens, schools, colleges, hospitals, nursing homes, restaurants, hotels, wedding halls, and ships 3 , — 7 , 9 , 80 , 98 , , , , , , , , , , , , , , , , , — Suspected foodborne sapovirus outbreaks have also been reported 44 , , , , , An epidemiological investigation pointed to contaminated box lunches which were prepared by food handlers who were shedding sapovirus.
Data from four studies suggest that sapovirus caused 1. Coinfections of sapoviruses and multiple enteric viruses e. Coinfections with different sapovirus strains i. Sapoviruses genetically indistinguishable i. These sapoviruses were likely viruses of human fecal origin that were discharged into environmental waters and accumulated in shellfish i.
As evidence, sapoviruses were detected more frequently with higher viral RNA levels from environmental water samples i. In addition, similar sapovirus strains were detected from gastroenteritis patients, wastewater, and oysters, which were collected from geographically related areas in the same season In contrast, sapoviruses genetically indistinguishable from those detected in human clinical specimens have not been discovered in other animals i.
Based on complete VP1 sequences, GV. These results suggest the existence of interspecies barriers among human and animal sapoviruses, although further epidemiological studies for other animals and experimental infection studies using human sapoviruses in various animals are necessary.
Transmission of sapovirus is through the fecal-oral route. These transmission routes are similar to those for norovirus , and sapovirus may also have a low infectious dose similar to that of norovirus i. No host genetic factors for susceptibility or resistance to human sapovirus infection and disease have been identified.
Susceptibility to human sapoviruses is not associated with histo-blood group antigen HBGA phenotypes In vitro data also support no binding of sapovirus to HBGAs , Sialic acids have recently been reported as binding factors for porcine sapovirus The serological responses to sapovirus infection were demonstrated by immune electron microscopy, ELISA, or radioimmunoassay using paired sera i. These results suggest that sapovirus infection is common during early childhood.
A similar phenomenon was also observed in gastroenteritis outbreaks that occurred in mother and baby units 7. Adults who had serum antibodies to antigenically indistinguishable human sapoviruses did not show any clinical symptoms on reinfection 7.
Recent epidemiological studies with improved diagnostic assays have highlighted the impact of sapovirus-associated gastroenteritis. Genetically highly diverse sapovirus strains were identified through epidemiological surveillance studies.
Continuous surveillance with a broadly reactive detection system s and molecular characterization will permit the identification of changes in major strains as well as the emergence of new strains and an understanding of the evolution of sapoviruses among humans and animals. To date, no vaccines or antiviral drugs are available for the control and prevention of human sapovirus infections. The mechanisms of virus binding and entry into target cells and viral RNA replication and translation are undefined, partially due to the lack of a cell culture system.
Extensive studies of human sapoviruses in clinical cases, the use of the cell culture-adapted porcine sapovirus strain as a model, and establishment of a human sapovirus cell culture system will improve our knowledge of sapoviruses and may lead to more targeted control measures for prevention of sapovirus gastroenteritis in the future.
We thank Yasutaka Yamashita, who kindly provided transmission EM pictures for human sapovirus and norovirus, and Kelly A. Scheuer and Susan Sommer-Wagner for their editing of the manuscript. He received his B. Since then, his research has focused mainly on noroviruses and sapoviruses.
From September to August , he studied at Dr. Linda J. Saif's lab and at Dr. During to , she was a postdoctoral fellow at the Medical College of Wisconsin. Since , her interests have focused on enteric viruses.
Her research focus is on enteric caliciviruses and coronaviruses, including diagnosis of viral infections, molecular epidemiology, molecular characterization of new viruses, propagation of enteric viruses in cell culture, molecular mechanisms of cell culture adaptation and attenuation, interspecies transmission of viruses between humans and animals, the mechanism of enteric virus transmission through leafy greens, and the development of vaccines.
He obtained his Ph. After graduation, he worked as a research scientist in infectious diseases and diagnostics at Bio Medical Laboratories, Inc. His main focus is basic research on noroviruses, sapoviruses, and rotaviruses. From to , he studied a norovirus reverse genetics system in Dr. Mary K.
Estes's lab at Baylor College of Medicine. Recently, he successfully developed a reverse genetics system for murine and human noroviruses. Her research focuses on enteric and respiratory viral infections coronaviruses, rotaviruses, and caliciviruses of food animals and humans, zoonotic infection, mucosal and neonatal immunity, and vaccine development. Her lab identified new enteric viruses group C rotavirus and caliciviruses and characterized their pathogenesis.
Saif has authored or coauthored over journal publications and 57 book chapters pertaining to her research. She is a member of the U. National Academy of Sciences. National Center for Biotechnology Information , U. Journal List Clin Microbiol Rev v. Clin Microbiol Rev. Author information Copyright and License information Disclaimer.
Corresponding author. Address correspondence to Tomoichiro Oka, pj. Comprehensive review of human sapoviruses. Clin Microbiol Rev — All Rights Reserved. This article has been cited by other articles in PMC. HISTORY Sapovirus particles are small about 30 to 38 nm in diameter and icosahedral and have cup-shaped depressions on the surface, which is a typical calicivirus morphology Fig.
Open in a separate window. FIG 1. FIG 2. FIG 3. FIG 4. Evolution and Emergence of Predominant Sapovirus Strains Genogroup and genotype analysis is important to characterize the currently circulating sapoviruses in the population. FIG 5.
Antigen Detection Methods Enzyme-linked immunosorbent assays ELISAs have been developed for the detection of human sapovirus antigens 91 , 93 , , and have been used for the detection of sapoviruses from clinical samples 43 , 91 , , — , Full-Genome Sequencing Approaches Full genomic sequence analysis is still not practical for routine diagnosis. TABLE 5 Reported clinical severity scores for sapovirus-, norovirus-, and rotavirus-associated gastroenteritis.
Shedding Levels and Patterns in Feces Sapovirus shedding in feces may continue after symptoms disappear 1 to 4 weeks after onset of illness 6 , 22 , , Sporadic Cases Sapoviruses are detected worldwide i. TABLE 6 Sapovirus positive rates in gastroenteritis patients from 13 studies that detected more than 30 strains during the study period.
Outbreaks Although the reported outbreak numbers are less for sapoviruses than for noroviruses , , — , sapovirus gastroenteritis outbreaks occur throughout the year in all ages of people in various settings, such as child day care centers, kindergartens, schools, colleges, hospitals, nursing homes, restaurants, hotels, wedding halls, and ships 3 , — 7 , 9 , 80 , 98 , , , , , , , , , , , , , , , , , — Sapoviruses in Seafood, Environmental Water, and Animals Sapoviruses genetically indistinguishable i.
Transmission Route and Host Susceptibility Transmission of sapovirus is through the fecal-oral route. Immunity The serological responses to sapovirus infection were demonstrated by immune electron microscopy, ELISA, or radioimmunoassay using paired sera i. Madeley CR. Comparison of the features of astroviruses and caliciviruses seen in samples of feces by electron microscopy. J Infect Dis — Caliciviruses in man. Lancet i — Calicivirus associated with winter vomiting disease. Lancet i An outbreak of gastroenteritis associated with calicivirus in an infant home.
J Med Virol 4 — Winter vomiting disease caused by calicivirus. J Clin Pathol 32 — Fecal shedding of virus in relation to the days of illness in infantile gastroenteritis due to calicivirus. An outbreak of calicivirus infection in a mother and baby unit. J Clin Pathol 33 — An outbreak of calicivirus associated gastroenteritis in an elderly persons home. A possible zoonosis? J Hyg Lond 93 — A new serotype of calicivirus associated with an outbreak of gastroenteritis in a residential home for the elderly.
J Clin Pathol 34 — Members of the family caliciviridae Norwalk virus and Sapporo virus are the most prevalent cause of gastroenteritis outbreaks among infants in Japan. Sapporo virus: history and recent findings. Molecular characterization of morphologically typical human calicivirus Sapporo. Arch Virol — Molecular characterization of a human calicivirus with sequence relationships closer to animal caliciviruses than other known human caliciviruses.
J Med Virol 45 — Full sequence analysis of the original Sapporo virus. Microbiol Immunol 55 — Mayo MA. A summary of taxonomic changes recently approved by ICTV. J Virol 86 — Discovery and genetic characterization of novel caliciviruses in German and Dutch poultry. Characterization of a rhesus monkey calicivirus representing a new genus of Caliciviridae.
J Virol 82 — Genomic characterization of swine caliciviruses representing a new genus of Caliciviridae. Virus Genes 39 — Genetic characterization of a novel calicivirus from a chicken.
Nosocomial infantile gastroenteritis associated with minirotavirus and calicivirus. J Pediatr 93 — The occurrence of calicivirus in infants with acute gastroenteritis.
Kjeldsberg E. Small spherical viruses in faeces from gastroenteritis patients. Propagation of human candidate calicivirus in cell culture. J Gen Virol 65 — Bile acids are essential for porcine enteric calicivirus replication in association with down-regulation of signal transducer and activator of transcription 1. Serial propagation of porcine enteric calicivirus-like virus in primary porcine kidney cell cultures. J Clin Microbiol 26 — Serial propagation of porcine enteric calicivirus in a continuous cell line.
Effect of medium supplementation with intestinal contents or enzymes. Reverse genetics system for porcine enteric calicivirus, a prototype sapovirus in the Caliciviridae. J Virol 79 — The crucial role of bile acids in the entry of porcine enteric calicivirus. Virology — Cell-culture propagation of porcine enteric calicivirus mediated by intestinal contents is dependent on the cyclic AMP signaling pathway. Pathogenesis of porcine enteric calicivirus-like virus in four-day-old gnotobiotic pigs.
Am J Vet Res 49 — Comparative pathogenesis of tissue culture-adapted and wild-type Cowden porcine enteric calicivirus PEC in gnotobiotic pigs and induction of diarrhea by intravenous inoculation of wild-type PEC.
J Virol 75 — Rotavirus-like, calicivirus-like, and nm virus-like particles associated with diarrhea in young pigs. J Clin Microbiol 12 — The polypeptide of a human calicivirus. Arch Virol 78 :1—7. Biochemical characterization of porcine enteric calicivirus: analysis of structural and nonstructural viral proteins. Stability of and attachment to lettuce by a culturable porcine sapovirus surrogate for human caliciviruses.
Appl Environ Microbiol 78 — Green KY. Caliciviridae: the noroviruses: specific virus families , p — Characterization of an enteropathogenic bovine calicivirus representing a potentially new calicivirus genus. J Virol 76 — Rabbit hemorrhagic disease virus—molecular cloning and nucleotide sequencing of a calicivirus genome. Organization and expression of calicivirus genes.
Human enteric caliciviruses have a unique genome structure and are distinct from the Norwalk-like viruses. Virus Genes 15 — Sapporo-like human caliciviruses are genetically and antigenically diverse. Parkville virus: a novel genetic variant of human calicivirus in the Sapporo virus clade, associated with an outbreak of gastroenteritis in adults. J Med Virol 52 — Genetic diversity among sapoviruses. Genetic variability in the sapovirus capsid protein. Virus Genes 33 — Discovery and genomic characterization of a novel bat sapovirus with unusual genomic features and phylogenetic position.
PLoS One 7 :e Proteolytic processing of sapovirus ORF1 polyprotein. Identification of the cleavage sites of sapovirus open reading frame 1 polyprotein. J Gen Virol 87 — Structural and biological constraints on diversity of regions immediately upstream of cleavage sites in calicivirus precursor proteins.
Highly conserved configuration of catalytic amino acid residues among calicivirus-encoded proteases. J Virol 81 — Comparative site-directed mutagenesis in the catalytic amino acid triad in calicivirus proteases.
Structural basis for specific recognition of substrates by sapovirus protease. Front Microbiol 3 Cleavage activity of the sapovirus 3C-like protease in Escherichia coli. Functional characterization of the cleavage specificity of the sapovirus chymotrypsin-like protease.
Virus Genes 42 — Isolation of enzymatically active replication complexes from feline calicivirus-infected cells. Processing map and essential cleavage sites of the nonstructural polyprotein encoded by ORF1 of the feline calicivirus genome. Identification of a calicivirus isolate of unknown origin. J Gen Virol 84 — Detection of viral proteins after infection of cultured hepatocytes with rabbit hemorrhagic disease virus.
J Virol 72 — In vitro proteolytic processing of the MD norovirus ORF1 nonstructural polyprotein yields stable precursors and products similar to those detected in calicivirus-infected cells. J Virol 77 — Stable expression of a Norwalk virus RNA replicon in a human hepatoma cell line. Cleavage map and proteolytic processing of the murine norovirus nonstructural polyprotein in infected cells.
J Virol 80 — Investigation of norovirus replication in a human cell line. Rabbit hemorrhagic disease virus: genome organization and polyprotein processing of a calicivirus studied after transient expression of cDNA constructs. Pfister T, Wimmer E. Polypeptide p41 of a Norwalk-like virus is a nucleic acid-independent nucleoside triphosphatase. J Virol 74 — Structures of the compact helical core domains of feline calicivirus and murine norovirus VPg proteins. J Virol 87 — Self-assembly of sapovirus recombinant virus-like particles from polyprotein in mammalian cells.
Microbiol Immunol 53 — Sapovirus-like particles derived from polyprotein. Virus Res — Norwalk virus minor capsid protein VP2 associates within the VP1 shell domain. Expression and characterization of Sapporo-like human calicivirus capsid proteins in baculovirus.
J Virol Methods 78 — Expression and self-assembly in baculovirus of porcine enteric calicivirus capsids into virus-like particles and their use in an enzyme-linked immunosorbent assay for antibody detection in swine. J Clin Microbiol 39 — Inter- and intragenus structural variations in caliciviruses and their functional implications. J Virol 78 — Cross-reactivity among sapovirus recombinant capsid proteins. Enhancement of sapovirus recombinant capsid protein expression in insect cells.
0コメント