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BMC Infectious Diseases Nov 2017From 31 August to 9 September 2015, a total of 150 military personnel at a military institution in Singapore were infected with acute gastroenteritis (AGE) with an...
BACKGROUND
From 31 August to 9 September 2015, a total of 150 military personnel at a military institution in Singapore were infected with acute gastroenteritis (AGE) with an attack rate of approximately 3%. This study aimed to determine the epidemiology of the outbreak, investigate its origins, and discuss measures to prevent future occurrences.
METHODS
After the AGE outbreak was declared on 31 August 2015, symptom surveys, hygiene inspections, and the testing of water, food, and stool samples were initiated. We collected 86 stool samples from AGE cases and 58 samples from food-handlers during the course of the outbreak and these stool samples were tested for 8 bacterial pathogens and 2 viral pathogens (i.e., norovirus and sapovirus).
RESULTS
We detected Sapovirus (SaV), group I Norovirus (NoV GI) and group II Norovirus (NoV GII) from the stool samples of AGE cases. Further sequence analyses showed that the AGE outbreak in August was caused mainly by three rarely reported calicivirus novel genotypes: NoV GI.7, NoV GII.17 and SaV GII.3. Control measures implemented focused on the escalation of personal and environmental hygiene, which included the separation of affected and unaffected soldiers, enforcement of rigorous hand-washing and hygiene, raising awareness of food and water safety, and disinfection of communal areas with bleach.
CONCLUSIONS
This study identified both NoV and SaV as the causative agents for an AGE outbreak at a Singapore military camp in August 2015. This study is also the first to report SaV as one of the main causative agents, highlighting the importance of caliciviruses as causative agents of AGE outbreaks in the Singapore military. As there are no commercially available vaccines against caliciviruses, strict personal hygiene and proper disinfection of environmental surfaces remain crucial to prevent calicivirus outbreak and transmission.
Topics: Caliciviridae Infections; Disease Outbreaks; Disinfection; Food Handling; Gastroenteritis; Genotype; Hand Disinfection; Humans; Male; Military Personnel; Norovirus; Phylogeny; Sapovirus; Singapore
PubMed: 29137606
DOI: 10.1186/s12879-017-2821-y -
Journal of Virology Dec 2018Sapovirus, an important cause of acute gastroenteritis in humans and animals, travels from the early to the late endosomes and requires late endosomal acidification for...
Sapovirus, an important cause of acute gastroenteritis in humans and animals, travels from the early to the late endosomes and requires late endosomal acidification for viral uncoating. However, the signaling pathways responsible for these viral entry processes remain unknown. Here we demonstrate the receptor-mediated early activation of phosphatidylinositol 3-kinase (PI3K)/Akt and mitogen-activated protein extracellular signal-regulated kinase/extracellular signal-regulated kinase (MEK/ERK) signaling pathways involved in sapovirus entry processes. Both signaling pathways were activated during the early stage of porcine sapovirus (PSaV) infection. However, depletion of the cell surface carbohydrate receptors by pretreatment with sodium periodate or neuraminidase reduced the PSaV-induced early activation of these signaling pathways, indicating that PSaV binding to the cell surface carbohydrate receptors triggered these cascades. Addition of bile acid, known to be essential for PSaV escape from late endosomes, was also found to exert a stiffening effect to stimulate both pathways. Inhibition of these signaling pathways by use of inhibitors specific for PI3K or MEK or small interfering RNAs (siRNAs) against PI3K or MEK resulted in entrapment of PSaV particles in early endosomes and prevented their trafficking to late endosomes. Moreover, phosphorylated PI3K and ERK coimmunoprecipitated subunit E of the V-ATPase proton pump that is important for endosomal acidification. Based on our data, we conclude that receptor binding of PSaV activates both PI3K/Akt and MEK/ERK signaling pathways, which in turn promote PSaV trafficking from early to late endosomes and acidification of late endosomes for PSaV uncoating. These signaling cascades may provide a target for potent therapeutics against infections by PSaV and other caliciviruses. Sapoviruses cause acute gastroenteritis in both humans and animals. However, the host signaling pathway(s) that facilitates host cell entry by sapoviruses remains largely unknown. Here we demonstrate that porcine sapovirus (PSaV) activates both PI3K/Akt and MEK/ERK cascades at an early stage of infection. Removal of cell surface receptors decreased PSaV-induced early activation of both cascades. Moreover, blocking of PI3K/Akt and MEK/ERK cascades entrapped PSaV particles in early endosomes and prevented their trafficking to the late endosomes. PSaV-induced early activation of PI3K and ERK molecules further mediated V-ATPase-dependent late endosomal acidification for PSaV uncoating. This work unravels a new mechanism by which receptor-mediated early activation of both cascades may facilitate PSaV trafficking from early to late endosomes and late endosomal acidification for PSaV uncoating, which in turn can be a new target for treatment of sapovirus infection.
Topics: Animals; Caliciviridae Infections; Cell Line; Endosomes; Epithelial Cells; Kidney; MAP Kinase Signaling System; Phosphatidylinositol 3-Kinase; Proto-Oncogene Proteins c-akt; Sapovirus; Sf9 Cells; Swine; Virus Internalization; Virus Uncoating
PubMed: 30282712
DOI: 10.1128/JVI.01674-18 -
Diagnostic Microbiology and Infectious... Oct 2018We estimated the prevalence of astrovirus, sapovirus, and norovirus among patients enrolled in research protocols and receiving medical care at the Clinical Center of...
We estimated the prevalence of astrovirus, sapovirus, and norovirus among patients enrolled in research protocols and receiving medical care at the Clinical Center of the National Institutes of Health, Bethesda, MD, a clinical research hospital with a large immunocompromised patient population. We identified patients whose fecal specimens were submitted to the Clinical Center for testing on the Biofire FilmArray Gastrointestinal Panel from September 15, 2015 through November 30, 2016. Among 442 patients with fecal specimens submitted for multiplex testing, 11% had norovirus identified, 2% had astrovirus, and 2% had sapovirus. Like norovirus, astrovirus was detected in multiple sequential samples from a single patient, consistent with chronic infection or the occurrence of multiple reinfections. Coinfection with non-viral gastrointestinal pathogens was detected in 31% of patients with positive results for norovirus, astrovirus, or sapovirus. Norovirus remains common in this immunocompromised patient population, and both sapovirus and astrovirus are present.
Topics: Adult; Aged; Aged, 80 and over; Astroviridae Infections; Caliciviridae Infections; Child; Child, Preschool; Coinfection; Feces; Hospitals; Humans; Immunocompromised Host; Mamastrovirus; Middle Aged; Norovirus; Prevalence; Sapovirus; Tertiary Healthcare; Young Adult
PubMed: 29934072
DOI: 10.1016/j.diagmicrobio.2018.05.017 -
Frontiers in Microbiology 2021The are a family of viruses with a single-stranded, non-segmented RNA genome of positive polarity. The ongoing discovery of caliciviruses has increased the number of... (Review)
Review
The are a family of viruses with a single-stranded, non-segmented RNA genome of positive polarity. The ongoing discovery of caliciviruses has increased the number of genera in this family to 11 (, , , , , , , , , , and ). Caliciviruses infect a wide range of hosts that include fishes, amphibians, reptiles, birds, and marine and land mammals. All caliciviruses have a genome that encodes a major and a minor capsid protein, a genome-linked viral protein, and several non-structural proteins. Of these non-structural proteins, only the helicase, protease, and RNA-dependent RNA polymerase share clear sequence and structural similarities with proteins from other virus families. In addition, all caliciviruses express two or three non-structural proteins for which functions have not been clearly defined. The sequence diversity of these non-structural proteins and a multitude of processing strategies suggest that at least some have evolved independently, possibly to counteract innate and adaptive immune responses in a host-specific manner. Studying these proteins is often difficult as many caliciviruses cannot be grown in cell culture. Nevertheless, the study of recombinant proteins has revealed many of their properties, such as intracellular localization, capacity to oligomerize, and ability to interact with viral and/or cellular proteins; the release of non-structural proteins from transfected cells has also been investigated. Here, we will summarize these findings and discuss recent studies that identified previously overlooked putative functional domains and structural features, including transmembrane domains that suggest the presence of viroporins.
PubMed: 34335548
DOI: 10.3389/fmicb.2021.712710 -
Frontiers in Pediatrics 2022To investigate the epidemiology of human adenovirus (HAdV), human astrovirus (HAstV), and sapovirus (SaV), children with acute diarrhea in Chongqing, China from 2017 to...
OBJECTIVE
To investigate the epidemiology of human adenovirus (HAdV), human astrovirus (HAstV), and sapovirus (SaV), children with acute diarrhea in Chongqing, China from 2017 to 2019 were enrolled. Improved surveillance could provide better guidance for diarrhea prevention.
METHODS
Between 2017 and 2019, fecal specimens were collected from children <14 years of age presenting with acute diarrhea for treatment at the outpatient department of the Children's Hospital, Chongqing Medical University. Human HAdV in the fecal specimens was detected by PCR, while RT-PCR was adopted for the detection of HAstV and SaV.
RESULTS
A total of 1,352 fecal specimens were screened in this study. The detection rate of HAdV was 4.44% (60/1352), HAstV was 2.81% (38/1352), and SaV was 1.04% (14/1352). The prevalence of enteric viruses in males was not significantly different to females ( > 0.05). We found 96.67% (58/60) of the HAdV-positive cases, 92.11% (35/38) of the HAstV-positive cases, and 100% (14/14) of the SaV-positive cases among the children under 4 years old. HAdV cases were identified throughout the year, while the infection of HAstV peaked from March to May every year. By contrast, SaV was detected in May, July, and from September to December. In total, 41 strains of HAdV-F were identified, including F41 (39/60) and F40 (2/60). Furthermore, A31, B3, B7, C1, C2, C5, and C6 were also detected in the study. In addition, we detected two genotypes of HAstV, HAstV-1 (34/38) and HAstV-5 (4/38), and two genotypes of SaV, GI0.1 (13/14), GI0.2 (1/14).
CONCLUSION
The enteric viruses HAdV, HAstV, and SaV contribute to the overall burden of diarrhea in Chongqing, especially in children <4 years of age. Two genotypes were identified for HAstV (HAstV-1 and HAstV-5) and SaV (GI.1 and GI.2) with an additional nine genotypes detected in HAdV cases. While the F41 HAdV strain was predominant, HAdV-A31 was also detected in 10% of cases. The study results along with continuous surveillance of enteric viruses will aid in the design and implementation of future enteric vaccines and diarrhea mitigation strategies.
PubMed: 35311045
DOI: 10.3389/fped.2022.826600 -
Applied and Environmental Microbiology Aug 2011To evaluate membrane bioreactor wastewater treatment virus removal, a study was conducted in southwest France. Samples collected from plant influent, an aeration basin,...
To evaluate membrane bioreactor wastewater treatment virus removal, a study was conducted in southwest France. Samples collected from plant influent, an aeration basin, membrane effluent, solid sludge, and effluent biweekly from October 2009 to June 2010 were analyzed for calicivirus (norovirus and sapovirus) by real-time reverse transcription-PCR (RT-PCR) using extraction controls to perform quantification. Adenovirus and Escherichia coli also were analyzed to compare removal efficiencies. In the influent, sapovirus was always present, while the norovirus concentration varied temporally, with the highest concentration being detected from February to May. All three human norovirus genogroups (GI, GII, and GIV) were detected in effluent, but GIV was never detected in effluent; GI and GII were detected in 50% of the samples but at low concentrations. In the effluent, sapovirus was identified only once. An adenovirus titer showing temporal variation in influent samples was identified only twice in effluent. E. coli was always below the limit of detection in the effluent. Overall, the removal of calicivirus varied from 3.3 to greater than 6.8 log units, with no difference between the two main genogroups. Our results also demonstrated that the viruses are blocked by the membrane in the treatment plant and are removed from the plant as solid sludge.
Topics: Adenoviridae; Bioreactors; Escherichia coli; Micropore Filters; Norovirus; RNA, Viral; Reverse Transcriptase Polymerase Chain Reaction; Sapovirus; Sewage; Water Purification
PubMed: 21666029
DOI: 10.1128/AEM.00583-11 -
Microbiology Spectrum Feb 2023Seasonal variation of viral gastroenteritis is related to weather conditions, but the relationship with the incidence of viral gastroenteritis (GE) is not fully...
Seasonal variation of viral gastroenteritis is related to weather conditions, but the relationship with the incidence of viral gastroenteritis (GE) is not fully understood. This study examined the impact of outdoor climate factors on seasonal variation in detection rates of gastroenteritis viruses, with emphasis on norovirus. Weekly detection rates of norovirus genogroup I (GI) and II (GII), rotavirus, adenovirus, astrovirus, and sapovirus were analyzed in relation to average weekly means of meteorological parameters. Associations between rates of PCR detection of the viral GE pathogens and climate factors were investigated with generalized linear models. Low absolute humidity was correlated with increased detection of adenovirus (0.007), astrovirus (0.005), rotavirus (0.004), norovirus GI (0.001), and sapovirus (0.002). In each investigated season, a drop in absolute humidity preceded the increase in norovirus GII detections. We found a correlation between declining absolute humidity and increasing norovirus GII detection rate. Absolute humidity was a better predictor of gastrointestinal virus seasonality compared to relative humidity. Viral gastroenteritis causes considerable morbidity, especially in vulnerable groups such as the elderly and chronically ill. Predicting the beginning of seasonal epidemics is important for the health care system to withstand increasing demands. In this paper we studied the association of outdoor climate factors on the detection rates of gastrointestinal viruses and the association between these factors and the onset of annual norovirus epidemics. Declining absolute humidity preceded the increase in diagnosed norovirus GII cases by approximately 1 week. These findings contribute to the understanding of norovirus epidemiology and allow health care services to install timely preventive measures and can help the public avoid transmission.
PubMed: 36786608
DOI: 10.1128/spectrum.02433-22 -
PloS One 2018Noroviruses (NoVs) and Sapoviruses (SaVs) are enteric caliciviruses that have been detected in multiple mammalian species, including humans. Currently, efficient cell...
Noroviruses (NoVs) and Sapoviruses (SaVs) are enteric caliciviruses that have been detected in multiple mammalian species, including humans. Currently, efficient cell culture systems have been established only for murine NoVs and porcine SaV Cowden strain. Establishment of an efficient in vitro cell culture system for other NoVs and SaVs remains challenging; however, human NoV (HuNoV) replication in 3D cultured Caco-2 cells and a clone of Caco-2 cells, C2BBe1, human enteroids and in human B cells has been reported. In this study, we tested various cells and culture conditions to grow HuNoVs and a human SaV (HuSaV) to test the possibility of the propagation in different cells and culture conditions. We also attempted to grow a bovine NoV (BoNoV) in ex vivo organ cultures. We did not observe significant RNA level increases for HuSaV and BoNoV under our test conditions. HuNoV RNA levels increased to a maximum of ~600-fold in long-term Caco-2 cells that were cultured for 1-2 months in multi-well plates and inoculated with HuNoV-positive and bacteria-free human stool suspensions using serum-free medium supplemented with the bile acid, GCDCA. However, this positive result was inconsistent. Our results demonstrated that HuNoVs, BoNoV and HuSaV largely failed to grow in vitro under our test conditions. Our purpose is to share our findings with other researchers with the goal to develop efficient, reproducible simplified and cost-effective culture systems for human and animal NoVs and SaVs in the future.
Topics: Caco-2 Cells; Humans; In Vitro Techniques; Norovirus; Polymerase Chain Reaction; Sapovirus; Virus Replication
PubMed: 29438433
DOI: 10.1371/journal.pone.0178157 -
Emerging Infectious Diseases Nov 2022Knowledge of the epidemiology of sporadic acute gastroenteritis (AGE) in the United States is limited. During September 2016-September 2017, we surveyed Kaiser...
Knowledge of the epidemiology of sporadic acute gastroenteritis (AGE) in the United States is limited. During September 2016-September 2017, we surveyed Kaiser Permanente Northwest members in Oregon and Washington, USA, to collect data on the 30-day prevalence of dually defined AGE and diarrhea disease and related health-seeking behavior; from a subset of participants, we obtained a stool specimen. Using the iterative proportional fitting algorithm with raked weights, we generated AGE prevalence and annualized rate estimates. We detected norovirus, rotavirus, astrovirus, and sapovirus from submitted stool specimens through real-time quantitative reverse transcription PCR (qRT-PCR). We estimated a 30-day prevalence of 10.4% for AGE and 7.6% for diarrhea only; annual rates were 1.27 cases/person/year for AGE and 0.92 cases/person/year for diarrhea only. Of those with AGE, 19% sought medical care. Almost one quarter (22.4%) of stool specimens from those reporting AGE tested positive for ≥1 viral pathogen, compared with 8.2% from those without AGE.
Topics: Humans; United States; Infant; Child; Incidence; Feces; Gastroenteritis; Rotavirus; Diarrhea; Patient Acceptance of Health Care; Caliciviridae Infections
PubMed: 36285882
DOI: 10.3201/eid2811.220247 -
Journal of Clinical Microbiology Sep 2021Sapovirus is increasingly recognized as an important cause of acute gastroenteritis (AGE) worldwide; however, studies of sapovirus prevalence, genetic diversity, and...
Sapovirus is increasingly recognized as an important cause of acute gastroenteritis (AGE) worldwide; however, studies of sapovirus prevalence, genetic diversity, and strain-specific clinical implications have been scarce. To fill this knowledge gap, we used reverse transcription-real-time PCR and sequencing of the partial major capsid protein VP1 gene to analyze stool specimens and rectal swabs obtained from 3,347 children with AGE and 1,355 asymptomatic controls (all <18 years old) collected between December 2014 and August 2018 in Alberta, Canada. Sapovirus was identified in 9.5% (317/3347) of the children with AGE and 2.9% of controls. GI.1 (36%) was the predominant genotype identified, followed by GI.2 (18%), GII.5 (8%), and GII.3 (6%). Rare genotypes GII.1, GII.2, GV.1, GII.4, GIV.1, GI.3, and GI.7 were also seen. Sapovirus was detected year-round, peaking during the winter months of November to January. The exception was the 2016-2017 season, when GI.2 overtook GI.1 as the predominant strain, with a high detection rate persisting into April. We did not observe significant difference in the severity of gastroenteritis by genogroup or genotype. Repeated infection by sapovirus of different genogroups occurred in three controls who developed AGE later. Our data suggest that sapovirus is a common cause of AGE in children with high genetic diversity.
Topics: Adolescent; Alberta; Caliciviridae Infections; Child; Child, Preschool; Feces; Gastroenteritis; Genetic Variation; Genotype; Humans; Molecular Epidemiology; Phylogeny; Sapovirus
PubMed: 34288727
DOI: 10.1128/JCM.00986-21