Objective: To understand the epidemiological and etiological characteristics of outbreaks on acute gastroenteritis caused by sapovirus (SaV) worldwide. Methods: Literature about the outbreaks on acute gastroenteritis caused by SaV were retrieved from the databases including WanFang, CNKI, PubMed and Web of Science after evaluation. Time, geography, setting and population distributions of outbreaks, transmission mode, SaV genotype and clinical characteristics of the patients were analyzed. Results: A total of 34 papers about SaV were included, involving 146 outbreaks occurred between October 1976 and April 2016. In these papers, 138 outbreaks were reported on the related months. All these outbreaks occurred in northern hemisphere. SaV outbreaks occurred all year around, but mainly in cold season, the incidence was highest in December (25 outbreaks) and lowest in in August (2 outbreaks). Most outbreaks were reported by Japan, followed by Canada, the United States of America and the Netherlands. There were 141 outbreaks for which the occurring settings were reported, child-care settings were most commonly reported setting (48/141, 34.04%), followed by long-term care facility (41/141, 29.08%) and hospital (16/141, 11.35%). Clinical symptoms of 1 704 cases in 31 outbreaks were reported, with the most common symptom was diarrhea (1 331/1 704, 78.12%), followed by nausea (829/1 198, 69.20%), abdominal pain (840/1 328, 63.25%), vomiting (824/1 704, 48.36%) and fever (529/1 531, 34.53%). Genotypes of SaV were determined for 119 outbreaks. GⅠ(51/119, 42.86%) and GⅣ (45/119, 37.82%) were predominant. The outbreaks of GⅣ SaV increased suddenly in 2007, and the outbreaks of GⅠ SaV mainly occurred in 2008 and during 2011-2013. Conclusions: SaV outbreaks were reported mainly by developed countries, with most outbreaks occurred in cold season, in child-care settings and long term care facility. GⅠ and GⅣ were the most common genotypes of SaV. Prevention and control of SaV outbreak in China seemed relatively weak, and it is necessary to conduct related training and to strengthen the SaV outbreak surveillance in areas where service is in need.
Caliciviridae Infections/virology* ; Child ; China/epidemiology* ; Disease Outbreaks ; Feces/virology* ; Gastroenteritis/virology* ; Genotype ; Humans ; Phylogeny ; RNA, Viral/genetics* ; Sapovirus/isolation & purification* ; Sequence Analysis, DNA

Objective: To understand the epidemiological and molecular characteristics of a norovirus- borne outbreak caused by GⅡ.4 Sydney 2012 in a university of Guangzhou to provide evidence for the prevention and control strategy on norovirus-caused epidemics. Methods: A self-designed questionnaire was used to collect clinical information from the patients as well as other data related to the epidemic. Pathogen detections were performed through anal swab specimens from the patients, kitchen workers and samples from the environment. Positive samples were further sequenced for phylogenetic analysis. A case-control study was employed to identify the risk factors related to this outbreak. Results: A total of 226 cases of norovirus-borne infection were identified between September 17 and 21, 2017, including 223 students, with an attack rate of 0.73% (223/30 711), and 3 kitchen workers. Students staying in the A dormitory area had the highest attack rate (1.73%, 164/9 459). No clustering was found in different colleges or classes. Results from the case-control study revealed that people who ate at the canteen in A dormitory area during September 18 to 20 was at risk for the onset of illness (OR=10.75, 95%CI: 5.56-20.79). The highest risk was related to the dinner on September 18. Another significant risk factor (OR=3.65, 95%CI: 1.92-6.94) was close personal contact in the same room of the dorm. The 3 norovirus infected kitchen workers were all from the canteen in A dormitory area where the positive rate of norovirus identified in kitchen workers was 26.67% (12/45). Positive samples were sequenced and sub-typed with results showing that the GⅡ.4 Sydney 2012 variant and the nucleotide sequences of cases and kitchen workers were 100% identical. Conclusions: The outbreak was caused by norovirus GⅡ.4 Sydney 2012 variant at campus. Similar outbreaks had been seen since 2013, with the routes of transmission most likely due to food-borne or personal contact.
Adolescent ; Adult ; Caliciviridae Infections/epidemiology* ; Case-Control Studies ; China/epidemiology* ; Disease Outbreaks ; Female ; Foodborne Diseases/virology* ; Gastroenteritis/virology* ; Humans ; Male ; Norovirus/isolation & purification* ; Phylogeny ; Surveys and Questionnaires

Norovirus (NoV) is a pathogen that commonly causes viral diarrhea in children. Studies indicate that NoV recognizes human histo-blood group antigens (HBGAs) as cell attachment factors. In order to explore the correlation between of NoV infection and HBGAs, a cross-sectional study was conducted in children less than five years old who were hospitalized with diarrhea in two areas of China between November 2014 and February 2015. Of the paired stool and saliva samples taken from 424 children, NoV was detected in 24 (6%) children, with viral genotypes GII.3 (n=5), GII.4 (n=14), GII.12 (n=1), and GII.17 (n=4). All of the individuals having NoV infection were either secretors (Lea-b+/Lex-y+) or partial secretors (Lea+b+/Lex+y+) except one GII.3 infection of a non-secretor (Lea+b-/Lex+y-). These results suggest that secretor positive is associated with NoV infection, although non-secretors are not absolutely protected from NoV infection.
Blood Group Antigens ; genetics ; Caliciviridae Infections ; blood ; complications ; virology ; Child, Preschool ; China ; Cross-Sectional Studies ; Diarrhea ; blood ; etiology ; virology ; Feces ; virology ; Gastroenteritis ; blood ; virology ; Genotype ; Humans ; Infant ; Norovirus ; physiology

Interactions between noroviruses (NoVs) and the receptors of histo-blood group antigens (HB-GAs) affect the infectivity and host susceptibility of NoVs. We elucidated the binding profile of a GII. 12 NoV to HBGAs. First, we synthesized the P domain sequence of the GII. 12 NoV strain Pune (GenBank accession number EU921353). Protein of the P domain was expressed in a prokaryotic system. Formation of the P particle was monitored by gel-filtration chromatography. Antiserum was prepared by immunization of mice with GII. 12 P particles. The binding profile of the GII. 12 NoV Pune strain was determined by binding of the P particle with a panel of saliva samples with various known HBGAs phenotypes. The GII. 12 NoV was bound strongly to saliva samples of subjects with B and AB types and weakly to A, O secretor, and non-secretor saliva samples, suggesting higher affinity with B antigen by GII. 12 NoV. These results were consistent with those determined by a previous crystallography study of GII. 12 NoV. These data suggested that individuals with B and AB blood types may be more susceptible to infection by GII. 12 NoV compared with those with other blood types. Our findings may provide a basis for the prevention and control of an epidemic of GII. 12 NoV.
Animals ; Blood Group Antigens ; metabolism ; Caliciviridae Infections ; metabolism ; virology ; Female ; Gastroenteritis ; metabolism ; virology ; Genotype ; Humans ; Mice ; Mice, Inbred BALB C ; Norovirus ; genetics ; metabolism ; Protein Binding ; Receptors, Virus ; metabolism ; Viral Proteins ; genetics ; metabolism

Feline calicivirus (FCV) is an important and highly prevalent pathogen of cats that causes feline respiratory disease. The reverse genetic systems for FCV have been established in national and international laboratories since 1995. This technique has been used widely in FCV basic research and good progress has consequently been made to determine the relationship between viral genome structures and the function of their proteins, the expression of foreign proteins, virus-host interactions, and viral pathogenic mechanisms. In this article,we review the state of progress with regards to the establishment and application of the FCV reverse genetic operating system,which will provide a useful reference tool for future related research.
Animals ; Caliciviridae Infections ; veterinary ; virology ; Calicivirus, Feline ; genetics ; metabolism ; Cat Diseases ; virology ; Cats ; Reverse Genetics ; methods ; trends ; Viral Proteins ; genetics ; metabolism

Because of limited viral replication and lack of cytopathic effect in cell culture, a new PCR-based rapid seroneutralization assay for detection of GII.4 norovirus neutralized antibodies was developed with serum samples from acute-phase patients, convalescent-phase patients and healthy controls. According to this study, neutralizing antibodies were detected in 100% of convalescent-phase sera, and in 2.5% of healthy controls sera. However, all of the acute-phase serum samples could not neutralize virus efficiently. Compared to the results from ELISA (96.2% at sensitivity and 80% at specificity), the present in vitro neutralization assay is more specific and more sensitive.
Antibodies, Neutralizing ; immunology ; Base Sequence ; Caliciviridae Infections ; diagnosis ; virology ; Case-Control Studies ; Cell Line ; DNA Primers ; Enzyme-Linked Immunosorbent Assay ; Gastroenteritis ; diagnosis ; virology ; Humans ; Norovirus ; immunology ; isolation & purification ; Polymerase Chain Reaction ; methods ; Sensitivity and Specificity

Noroviruses (NoVs) are one of the most important foodborne viral pathogens worldwide. Shellfish are the most common carriers of NoVs as they can concentrate and accumulate large amounts of the virus through filter feeding from seawater. Shellfish may selectively accumulate NoVs with different genotypes, and this bioaccumulation may depend on the season and location. Our previous studies found various histo-blood group antigens (HBGAs) in shellfish tissues. While HBGAs might be the main reason that NoVs are accumulated in shellfish, the detailed mechanism behind NoV concentration and bioaccumulation in shellfish is not clear. Here we review current research into NoV bioaccumulation, tissue distribution, seasonal variation, and binding mechanism in shellfish. This paper may provide insight into controlling NoV transmission and decreasing the risks associated with shellfish consumption.
Animals ; Caliciviridae Infections ; transmission ; virology ; Food Contamination ; analysis ; Foodborne Diseases ; virology ; Humans ; Norovirus ; classification ; genetics ; isolation & purification ; physiology ; Shellfish ; virology

Human noroviruses (huNoVs) recognize histo-blood group antigens (HBGAs) as attachment factors, in which genogroup (G) I and GII huNoVs use distinct binding interfaces. The genetic and evolutionary relationships of GII huNoVs under selection by the host HBGAs have been well elucidated via a number of structural studies; however, such relationships among GI NoVs remain less clear due to the fact that the structures of HBGA-binding interfaces of only three GI NoVs with similar binding profiles are known. In this study the crystal structures of the P dimers of a Lewis-binding strain, the GI.8 Boxer virus (BV) that does not bind the A and H antigens, in complex with the Lewis b (Le(b)) and Le(y) antigens, respectively, were determined and compared with those of the three previously known GI huNoVs, i.e. GI.1 Norwalk virus (NV), GI.2 FUV258 (FUV) and GI.7 TCH060 (TCH) that bind the A/H/Le antigens. The HBGA binding interface of BV is composed of a conserved central binding pocket (CBP) that interacts with the β-galactose of the precursor, and a well-developed Le epitope-binding site formed by five amino acids, including three consecutive residues from the long P-loop and one from the S-loop of the P1 subdomain, a feature that was not seen in the other GI NoVs. On the other hand, the H epitope/acetamido binding site observed in the other GI NoVs is greatly degenerated in BV. These data explain the evolutionary path of GI NoVs selected by the polymorphic human HBGAs. While the CBP is conserved, the regions surrounding the CBP are flexible, providing freedom for changes. The loss or degeneration of the H epitope/acetamido binding site and the reinforcement of the Le binding site of the GI.8 BV is a typical example of such change selected by the host Lewis epitope.
Binding Sites ; Blood Group Antigens ; chemistry ; immunology ; Caliciviridae Infections ; immunology ; virology ; Crystallography, X-Ray ; Epitopes ; chemistry ; immunology ; Evolution, Molecular ; Humans ; Lewis Blood-Group System ; chemistry ; immunology ; Norovirus ; chemistry ; immunology ; pathogenicity ; Protein Binding ; Viral Proteins ; chemistry ; immunology

Murine norovirus (MNV) was first discovered in mice in 2003. MNV is a member of the genus Norovirus in the family Caliciviridae. It is one of the most important and prevalent pathogens of laboratory mice, and almost all mouse strains are susceptible to MNV infection. In this study, a MNV strain was isolated from the cecal contents of infected mice and identified by the cytopathic effect (CPE) assay, virus plaque assay, 50% tissue culture infectious dose (TCID50) assay, electron microscopy, indirect immunofluorescence assay (IFA) and nucleotide sequencing. On infection, the RAW264.7 cell line showed obvious cytopathic effects within 24 to 48 hours post-inoculation, as infected cells became rounded, bright and shrunken, with ultimate disintegration of the cell sheet. After the isolation of the MNV virus, the virus was plaque-purified in RAW264.7 cells. The TCID50 of the virus was 10(5.25/0.1 mL. Electron microscopic observations of the purified virus showed the presence of spherical and non-enveloped viral particles that were 30 to 35 nm in diameter. According to the identification results, the isolate was named as MNV Guangzhou/K162/09/CHN. Thereafter, five overlapping gene fragments that covered the entire open reading frame (ORF) were amplified by RT-PCR, and the 3'-untranslated region (UTR) and 5'-UTR were amplified using the 3'-rapid amplification of cDNA ends (RACE) and the 5'-RACE method, respectively. Each of the gene fragments were cloned and sequenced, and whole genome sequences of the strain were obtained by assembling the cDNA fragment sequences. The results showed that the length of the complete genome was 7 380 nucleotides (GenBank accession number: HQ317203). The comparison of nucleotide and deduced amino acid sequences of the isolate was performed against other MNV strains in the GenBank database. A phylogenetic tree based on VP1 nucleotide sequences was constructed using MEGA5.0 software. The homology of nucleotides between the MNV Guangzhou/K162/09/CHN strain and other MNV isolates ranged from 87.4% to 89.7%. Phylogenetic analysis showed that there was a close genetic relationship between the Guangzhou/K162/09/CHN strain and MNV strains isolated from Japan (S7-P2 and S7-PP3 isolates), Korea (K4 isolate), and Germany (Berlin/04/06/DE and Berlin/05/06/DE isolates). This is the first report of the isolation and identification of MNV in China, and the first report of the genetic analysis of its complete genome.
Animals ; Caliciviridae Infections ; veterinary ; virology ; Mice ; Molecular Sequence Data ; Norovirus ; classification ; genetics ; isolation & purification ; physiology ; Open Reading Frames ; Phylogeny ; Rodent Diseases ; virology ; Sequence Homology, Amino Acid ; Viral Proteins ; chemistry ; genetics

OBJECTIVETo monitor the epidemiology of norovirus infection in diarrheal children in Shanghai between 2009 and 2011 and characterize the genotypes of norovirus strains.

METHODThe stool samples were collected from children visiting outpatient clinic for acute non-dysenteric diarrhea between 2009 and 2011.One step real-time RT-PCR was used for screening norovirus genogroups GI and GII. The genotypes of norovirus genogroup GII were classified based on the nucleotide sequences of both partial capsid and polymerase fragments.

RESULTA total of 2 288 outpatient children with acute diarrhea were included in this study, out of whom, 531 (23.1%) were positive for norovirus in the fecal specimens based on real-time RT-PCR test.Norovirus was prevalent throughout the year and an increased activity of norovirus infection was usually observed between July and October. Children <4 years of age accounted for 95.2% of norovirus-infected cases, and the detection rate of norovirus was significantly higher in diarrheal children <4 years than in those ≥ 4 years (24.4% vs. 10.7%,χ(2) = 10.66, P < 0.05).Of 531 norovirus-positive specimens, 4 (1.7%) were positive for genogroup GI and 527 (98.3%) positive for genogroup GII. Seven distinct capsid genotypes were identified in 234 norovirus strains, including 153 (64.4%) GII.4 (9 belonging to 2010 variants and 145 belonging to 2006b variants), 66 (27.6%) GII.3, 7 (2.9%) GII.2, 6 (2.5%) GII.6, 4 (1.7%) GII.12, 1 (0.4%) GII.7 and GII.14 in each. Seven polymerase genotypes were identified in 244 norovirus strains, including 189 (77.5%) GII.4 (14 belonging to 2010 variants and 175 belonging to 2006b variants), 47 (19.3%) GII.12, 2 (0.8%) GII.16, GII.b and GII.g in each, 1 (0.4%) GII.2 and GII.6 in each. A new GII.4-2010 (New Orleans) variant was first detected in June 2010 and sporadically circulated afterwards.Of 198 norovirus strains in which both polymerase and capsid genotypes were determined, 56 showed discordant results, indicating potential norovirus recombinants. The common discordant combinations of the polymerase and capsid genotypes were GII.12/GII.3 (69.6%) and GII.4/GII.3 (8.9%).

CONCLUSIONNorovirus is a common causative agent responsible for diarrhea in Shanghai children over the three years and norovirus-associated diarrhea was epidemic year round with high activity in late summer and autumn in Shanghai.Infants and young children are susceptible to norovirus infection. The circulating norovirus showed genetic diversity. The GII.4-2006b variant continued to predominate in Shanghai during the period of 2009-2011 despite the emergence of the novel GII.4-2010 (New Orleans) variant.

Adolescent ; Caliciviridae Infections ; epidemiology ; virology ; Capsid Proteins ; genetics ; Child ; Child, Preschool ; China ; epidemiology ; Diarrhea ; epidemiology ; virology ; Feces ; virology ; Female ; Gastroenteritis ; epidemiology ; virology ; Genetic Variation ; Genotype ; Humans ; Infant ; Male ; Molecular Epidemiology ; Norovirus ; classification ; genetics ; isolation & purification ; Prevalence ; RNA, Viral ; genetics ; isolation & purification ; Reverse Transcriptase Polymerase Chain Reaction ; Sequence Analysis, DNA