Caliciviridae Infections ; epidemiology ; virology ; Gastroenteritis ; virology ; Genetic Variation ; Genotype ; Humans ; Norovirus ; classification ; genetics

A new viral sampling concentration device was designed which was equipped with a new cationic filter membrane-Nanoceram suitable for field sampling. Norovirus Genegroup II was detected from environmental water with the aid of this device. The effects on virus recovery of prefiltration, various second-concentration methods, and different eluants were investigated through pre-experiment. The concentration optimized process, and the optimal concentration process were then determined. The results showed that the prefiltration had a profound effect on virus recovery, and two second-concentration method: PEG-NaC1 precipitation and celite adsorption, had almost the same concentration effects. The Na2 HPO4 solution of 0.15 mol/L was selected as the final eluant to elute the adsorbed Nuorovirus from the celite. The virus recovery of Nanoceram was determined to be 3.02%. Finally, successful detection of Norovirus GII in sewage from Yangqiao River, Fengtai District, Beijing was acheived. All these data had shown that the Naneceram filter concentration method could concentrate Norovirus from environmental water with a steady effects.
Filtration ; instrumentation ; methods ; Fractional Precipitation ; instrumentation ; methods ; Genotype ; Norovirus ; classification ; genetics ; isolation & purification ; Rivers ; virology ; Water Microbiology

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

Sequence analysis of a new norovirus (NV) isolated from Lanzou city of China was performed based on partial sequence of RNA dependent RNA polymerase (RdRp) and complete capsid protein (VP1) gene. The isolated strain CHN02/LZ35666 shared high sequence homology with GII-4 NVs. Nucleotide homologies of RdRp region and encoded capsid protein region were 90.4% -- 98.6% and 89.8% -- 95.7% , respectively, while amino acid homology of capsid protein region was 94.4% -- 97.4%. The analysis of GDD motif in RdRp region indicated this GDD motif of Lanzhou strain differed from those of the GII-4 predominant epidemic strains. Lanzhou strain formed an independent branch in GII-4 cluster in the phylogenetic tree based on nucleotide sequence of RdRp region and amino acid sequence of capsid protein. Sequence alignment revealed a mutation at the fourth key site of the receptor-binding interface in the strains isolated after 2002 compared with those of previous strains suggesting a possible change of binding pattern to HBGAs receptors.
Amino Acid Sequence ; Base Sequence ; Capsid Proteins ; genetics ; China ; Gastroenteritis ; virology ; Humans ; Molecular Sequence Data ; Norovirus ; classification ; genetics ; Phylogeny ; RNA Replicase ; genetics ; Sequence Alignment ; Sequence Analysis, DNA

To study the genotype of Norovirus associated with acute gastroenteritis in Guizhou Province 2011, the patients' fecal specimens were collected from the Guizhou Province People's Hospital in the period of May to December 2011. Noroviruses in specimens were detected by a real-time reverse transcription polymerase chain reaction (Real-time RT-PCR). VP1 genes of norovirus-positive strains were then cloned and sequenced. Out of 70 clinical samples, the positive rates for norovirus G I (1 strain) and G II (34 strains) were 1.43% and 48.57, respectively. The VP1 sequencing results of seven norovirus G II showed thatthree strains were genotype G II . 4 and four strains were genotype G II . 3 Those genotype GIL . 4 strains were new variants (GII . 4 2011),closest to GII . 4 2006b variant. One amino acid appeared back mutation. Those genotype G II . 3 strains were divided into 2 gene clusters. One cluster was closest to Korean strain (HM635118) and Shanghai strain(GU991355). One cluster was closest to Japaness strain (AB629943) and 2007 Indian strain (EU921389), Four amino acids appeared back mutations.
Acute Disease ; Amino Acid Sequence ; China ; Gastroenteritis ; virology ; Genotype ; Molecular Sequence Data ; Norovirus ; classification ; genetics ; Phylogeny ; Sentinel Surveillance ; Time Factors ; Viral Structural Proteins ; genetics

The object of this study is to develop a duplex fluorescent quantitative one-step RT-PCR assay for detection and quantitation of GI and GII norovirus. The specific primers, Taqman probes, optimized reaction solution and condition were used to develop the duplex fluorescent quantitative one-step RT-PCR assay. The sensitivity, specificity and reproducibility of the assay were evaluated. The assay was evaluated by testing the 100 specimen samples and compared with the reference assay conventional RT-PCR. The assay possessed high specificity for norovirus detection without any evident cross-reaction with enteric adenovirus, rotavirus or astrovirus. The detection limit of the real-time RT-PCR assay, for GI and GII norovirus was up to 10(3) copy/microL respectively. Compared with the conventional RT-PCR assay, the assay in this study had higher sensitivity with higher detection rate of norovirus in stool specimens. The duplex fluorescent quantitative one-step RT-PCR assay provides rapid, sensitive and reliable detection of GI and GII norovirus, and could be used as a laboratory diagnosis of norovirus in acute gastroenteritis patients.
DNA Primers ; genetics ; Feces ; virology ; Gastroenteritis ; diagnosis ; virology ; Genotype ; Humans ; Norovirus ; classification ; genetics ; isolation & purification ; Reverse Transcriptase Polymerase Chain Reaction ; instrumentation ; methods

OBJECTIVETo investigate the molecular epidemiological characteristics of norovirus in Guangzhou from 2009 to 2011.

METHODSA total of 183 water samples, 1162 seafood samples and 1066 diarrhea stool specimens were collected from January 2010 to May 2011, June 2009 to June 2011 and July 2009 to December 2010 respectively in Guangzhou. Norovirus was detected by real time reverse transcript-PCR (qRT-PCR). The partial polymerase gene was amplified from norovirus positive samples, then sequenced and compared with the sequences of norovirus in GenBank. The phylogenetic tree was created.

RESULTSThe positive rate was 19.67% (36/183), 8.26% (96/1162) and 37.05% (395/1066) in water samples, seafood and diarrhea patients respectively. Noroviruses from positive samples could be divided into 10 representative strains, in which 7 representative strains of genotype of 208 samples was type G2-4. The sequences from water, seafood and stool specimens were highly homologous with the similarity of 94% - 100%.

CONCLUSIONIn Guangzhou, the predominant Norovirus genotype was G2-4 and the positive rate of samples was high.

Base Sequence ; Caliciviridae Infections ; epidemiology ; virology ; China ; epidemiology ; Diarrhea ; virology ; Genotype ; Humans ; Molecular Epidemiology ; Norovirus ; classification ; genetics ; isolation & purification ; Phylogeny ; RNA, Viral ; genetics ; Seafood ; virology ; Water Microbiology

OBJECTIVETo study the clinical manifestations for norovirus gastroenteritis in infants and young children.

METHODSStool specimens were collected from infants and children with acute diarrhea who visited the affiliated Children's Hospital to Capital Institute of Pediatrics from January 2002 to December 2006. Enzyme-linked immunosorbent assay (ELISA) was used to detect human norovirus antigen in stool specimens and polyacrylamide gel electrophoresis (PAGE) was performed to detect rotavirus genome.

RESULTSOut of the 318 specimens under testing, 79 showed positive for norovirus antigen, with a positive rate of 24.8% (79/318). Among those positive specimens, 48(48/79, 60.8%) were detected in October to December, suggesting the seasonal preference of the virus. Most of the positive specimens (91.2%) were from those under 2 years of age. Rotavirus genome were detected from 16 out of 79 norovirus positive specimens (16/79, 20.3%), indicating those patients were co-infected by these two viruses. There was significant difference found in the severity of fever but not in the frequencies of diarrhea between rotavirus and norovirus co-infection group and noroviral infection group. Fourteen out of 79 norovirus positive patients were admitted to hospitals under the diagnosis other than gastroenteritis but started to develop symptoms of diarrhea between 1 to 11 days after hospitalization.

CONCLUSIONNorovirus seemed one of the most important pathogens for acute diarrhea among infants and young children and could cause nosocomial infectious gastroenteritis.

Caliciviridae Infections ; diagnosis ; virology ; Child ; Child, Preschool ; Electrophoresis, Polyacrylamide Gel ; Enzyme-Linked Immunosorbent Assay ; Female ; Gastroenteritis ; diagnosis ; virology ; Genome, Viral ; genetics ; Humans ; Infant ; Male ; Norovirus ; classification ; genetics ; pathogenicity

OBJECTIVETo study molecular epidemiology of norovirus (NV) infections, stool specimens collected from children with acute diarrhea were tested by TaqMan real-time reverse transcription polymerase chain reaction (RT-PCR) for the viral specific nucleic acid segments.

METHODSFecal samples from a total of 1260 children who had watery diarrhea seen from December 2006 to December 2007 in Guangzhou were analyzed by real-time RT-PCR. The primers and probes used for rapid detection and typing of NV strain target NV sequences were at the ORF1-ORF2 junction, a highly conserved region of the NoV genome. The positive specimens were determined by nested PCR and sequenced.

RESULTSTotally 257 specimens were positive for NV with a positive rate of 20.40%. Shedding of NV type GI was detected in 6.90%, type GII in 16.98% respectively, while the positive number of mixed infection with GI and GII was 44. Of the NV strains that were cloned and sequenced, GI was GI-3, GI-2 and GI-4 detected in positive specimens respectively; meanwhile, GII-4 was most commonly seen in genome II, followed by GII-3 and GII-7. In addition, the average age of children infected with NV was less than 2 years. An epidemic occurred during the winter and early spring (December through the next March).

CONCLUSIONNV was one of the important pathogens for acute diarrhea among children in Guangzhou, which suggested GII-4 was the prevalent strain.

Caliciviridae Infections ; epidemiology ; Child, Preschool ; China ; epidemiology ; Diarrhea ; epidemiology ; etiology ; virology ; Feces ; virology ; Humans ; Infant ; Molecular Epidemiology ; Norovirus ; classification ; genetics ; RNA, Viral ; genetics ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo analyze the epidemiological characteristics of an acute gastroenteritis outbreak in a nursing home caused by norovirus (NoV) and the genotype of the pathogen.

METHODSOn January 29th 2013, a total of 26 acute gastroenteritis patients infected by norovirus were reported in the nursing home of Jinshan, Shanghai. A questionnaire was used to acquire information of patients involved in the outbreak, 9 stool or anal swab samples were collected from 9 patients without treatment by simple random sampling method, and 4 environmental samples from the surface of doorknobs or toilets were collected. The samples were detected by Real-time PCR for NoV, and positive samples were then amplified by routine RT-PCR. The PCR products were purified, sequenced, and aligned by comparing sequences in GenBank. Phylogenetic trees were constructed by using Clustal X, employing MEGA 5.1 program package.

RESULTSFor the 26 patients, 7 were men and 19 were women.8 samples were found NoV positive among the 13 samples when detected by real-time PCR. The sequence alignment showed that the nucleotide sequence homology between Jinshan08 and Jinshan12 strain which obtained sequencing signal was 100%. The phylogenetic analysis revealed that Jinshan08, Jinshan12 and GII.e/NV2634/BCN/Spain/2008 strains in the RdRp region were on the the same branch of evolutionary tree, the confidence level was 99%, and in the N/S region of the Capsid, 2 other strains and Lordsdal strain were in the same branch, the confidence level was 97%.

CONCLUSIONIt was confirmed that the acute gastroenteritis outbreak was caused by the new GII.4 NoV recombinant.

Aged ; Aged, 80 and over ; China ; epidemiology ; Disease Outbreaks ; Female ; Gastroenteritis ; epidemiology ; genetics ; virology ; Genetic Variation ; Humans ; Male ; Middle Aged ; Molecular Epidemiology ; Norovirus ; classification ; genetics ; isolation & purification ; Phylogeny