Norwalk-like virus (NLV), one of the emerging enteric pathogens in sporadic cases and outbreaks of acute gastroenteritis (AG) worldwide, are 30-35 nm in diameter and have a single stranded RNA genome, size 7.6 kb. As genomic sequence data from several isolates of NLVs are being reported, the genetic relationships among these viruses are now being described. Based on the level of sequence similarity in the RNA polymerase region of NLVs, at least three genogroups can be defined: the Norwalk virus (NV)-, the Snow Mountain agent (SMA)-, and the Sapporo-genogroups. A high prevalence of serum antibody to NV-related viruses but no antigenpositve stools (either observed to contain the NLV by immune electron microscopy or suspected of containing the NLV) has suggested that genomically different NLVs are present among Korean children. The purpose of our work therefore was to detect NLVs from Korean infants and children with AG and to characterize the partial genome (RNA-dependent RNA polymerase region) of currently circulating Korean isolates. The cDNA fragments of 110 to 470 bp corresponding to the RNA polymerase region were generated by reverase transcription-polymerase chain reaction (RT-PCR) using three primer pairs (36/35, 36/51, or 36/101) derived from the prototype NV (8FIIaNV/68/US). Of 279 stool samples tested, 25 (9%) specimens were positive by RT-PCR and the amplified productscontained GLPSG and YGDD amino acid motifs, characteristic of positive-strand RNA-dependent RNA polymerases, at the predicted distance from the primers. In 6% of the infectious episodes with diarrhea, NLVs appeared to be the sole pathogen. Double infections occurred mainly with rotavirus and triple infections occured with both rotavirus and adenovirus or with both rotavirus and astrovirus. This study indicates that NLVs are a common cause of sporadic AG in Korean infants.
Adenoviridae ; Amino Acid Motifs ; Child* ; Diarrhea ; Disease Outbreaks ; DNA, Complementary ; DNA-Directed RNA Polymerases ; Gastroenteritis* ; Genome ; Genotype ; Humans ; Infant ; Microscopy, Electron ; Norovirus* ; Norwalk virus ; Prevalence ; RNA ; Rotavirus ; Snow

The present study was designed to estimate the seroprevalence of NLVs among diarrheagenic children and in healthy adults in Seoul and its vicinity with the use of an EIA and an Western blot (WB) based on recombinant Norwalk virus capsid protein (rNV) and crude virus preparations as antigen. Seroconversion was observed in 34 (83%) of 41 tested using the EIA and in 21 (54%) of 39 using the WB, suggesting that the NLVs with epitopes common to rNV are prevalent in Seoul area. Diarrheal children who were known to have been infected with several other strains of the NLVs showed no significant antibody response to the rNV. Infection with rNV occurred earlier in life: primary infections with rNV were common before the age of 6 months and over 91% of children had evidence of infection by that age by the EIA. Since the amount of the NLV antigens available for seroepidemiologic surveys is limited, we tried to detect NLV antibody by using crude virus preparations as antigen. One crude virus preparation of a child whose stool yielded genetically distinct NLV revealed the presence of the plural number of bands upon SDS-PAGE, but precipitated only one band (62 kDa) after the WB with a serum (collected 10 days after the onset of symptoms) of another diarrheal child. The WB assay we present in this report revealed that the NLVs are prevalent among Korean population and that the sera contained antibody to a single major structural protein, with molecular sizes of 58 to 62 kDa, compatible with the sizes reported for the Norwalk virus and Snow Mountain agent proteins, respectively. When the results of the WB were compared with those obtained by the EIA, the EIA antibody assay was sensitive enough to detect an antibody rise of as much as 4096-fold but not as specific as the WB. The WB assay presented in this paper will provide a powerful tool to elucidate not only antigenic structures of the NLVs but also seroepidemiology of the NLV infection. The availability of an unlimited source of antigen will enable a large scale serologic studies that will greatly increase our understanding of the role of NLVs in human enteric illness.
Adult ; Antibody Formation ; Blotting, Western ; Capsid Proteins ; Capsid* ; Child ; Electrophoresis, Polyacrylamide Gel ; Epitopes ; Humans ; Norovirus* ; Norwalk virus* ; Seoul* ; Seroepidemiologic Studies* ; Snow

This study investigated the recovery and absorption rates of murine norovirus, a surrogate for human norovirus, by using NanoCeram(R) filters which served as a tool for recovering viruses. In the study, two types of NanoCeram(R) filters were employed: one was a cartridge type and the other was a disc type (phi 47 mm) whose surface area is 75 times smaller than the cartridge type. The analytical method was the real-time reverse transcription-polymerase chain reaction (RT-PCR). The study found that the average recovery rates of the cartridge type and the disc type were 30.9% and 29.5% respectively. Since these two rates were very close to each other, the adsorption rate of the cartridge type could be predicted with the disc type. Analyzing recovery and absorption rates of the disc type based on different filtered volumes showed that when the volume increased from 0.5 L to 20 L, the average recovery rate rose from 14.78% to 30.41 %, while the average absorption rate dropped from 56.33% to 10.48%. The increase in turbidity from less than 1 NTU to less than 3 NTU raised the average recovery rate from 47.23% to 82.84%.
Absorption ; Adsorption ; Humans ; Norovirus

No abstract available.
Liver ; Norovirus ; Transaminases

No abstract available.
Gangwon-do* ; Humans ; Norovirus* ; Sequence Analysis*

Noroviruses (NoVs) are one major etiologic agent in acute gastroenteritis (AGE) in all ages and are the primary cause of food-borne gastroenteritis worldwide. GII-4 NoVs has predominated since 1990s, and novel recombinant strains have been reported worldwide. Researchers face difficulties in making vaccines and therapeutic agents against NoVs due to the lack of cell culture and animal-model systems and the rapid emergence of novel variant strains. Recently, a randomized clinical trial for intranasal NoVs vaccine has been reported, which casts a light in the way of vaccine production. This review discusses the recent findings on the structure, immunity, and vaccination of NoVs.
Cell Culture Techniques ; Child ; Gastroenteritis ; Humans ; Light ; Norovirus ; Vaccination ; Vaccines

PURPOSE: Our aim was to describe the clinical features of noroviral gastroenteritis in children. METHODS: This study included 22 children with noroviral gastroenteritis, as confirmed by stool RT-PCR, who were admitted to Bundang CHA Hospital between July 2006 and June 2008. Their medical records were reviewed and compared with those of 45 children with rotaviral gastroenteritis. RESULTS: In the norovirus group, 19 (86.4%) children showed vomiting and 21 (95.5%) children showed diarrhea, while all children in the rotaviral group showed both vomiting and diarrhea. The duration of vomiting was not different in the two groups, but mean episodes of vomiting/24 h were higher in the norovirus group than in the rotavirus group. The duration of diarrhea was longer and mean episodes of diarrhea/24 h were higher in the rotavirus group. The Vesikari Scale was not different in the two groups. Frequency and duration of fever did not show a significant difference. Most children in both groups were below 2 years of age. CONCLUSION: Clinical features of noroviral gastroenteritis were largely similar to those of rotaviral gastroenteritis, but vomiting was more severe in noroviral infection, and diarrhea was more severe and prolonged in rotaviral infection. With regard to noroviral infection, further epidemiologic investigations and preventive efforts are essential.
Child ; Diarrhea ; Fever ; Gastroenteritis ; Humans ; Medical Records ; Norovirus ; Rotavirus ; Vomiting

OBJECTIVETo reveal the genetic characteristics of GII.12 Norovirus strains isolating from stool samples of adults with diarrhea in Beijing during 2008-2009.

METHODSRdRp, ORF2, ORF3 and ORF1/ORF2 overlap region were respectively amplified by primers using RT-PCR. The products were purified, cloned, sequenced and then aligned, phylogenetic and recombinant analyzed by softwares of DNAStar, MEGA and SimPlot.

RESULTSAccording to the phylogenetic analysis, 11 strains belonged to G II.g in the RdRp region,while GII.12 in the ORF2 and ORF3. SimPlot analysis further confirmed the 11 strains were recombinant strains ( G II.g [RdRp]/G II.12 [capsid]).

CONCLUSIONG II.12 Norovirus prevailing in Beijing and other regions of the world belonged to the same strain, and we identified the genetic characteristics of G II.12 Norovirus in Beijing.

China ; epidemiology ; Diarrhea ; epidemiology ; virology ; Disease Outbreaks ; Humans ; Norovirus

Norovirus ; chemistry ; genetics ; physiology ; ultrastructure ; Open Reading Frames ; Virus Replication