Genetic polymorphism across regions of the three open reading frames of "Norwalk-like viruses"

Vinjé, Jan; Green, J.; Lewis, David C.; Gallimore, Christopher; Brown, David

doi:10.1007/s007050050020

Cited by 178 publications

(183 citation statements)

References 32 publications

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“…This conserved nucleotide motif is almost identical within each genogroup of NoVs and SaVs, probably facilitating homologous recombination during co-infection of a cell by different genotypes of NoVs or SaVs within the same genogroup. In fact, recombinant NoVs having a recombination site at the RdRp-capsid junction region were identified in humans, calves and pigs [15,48,[59][60][61][62][63]. Two porcine NoVs, QW170 and QW218 strains, which share 99% nt identity at the 3'-end 3kb sequence of the genome, were reported as potential recombinants [15].…”

Section: Recombination Of Porcine Novs and Savsmentioning

confidence: 99%

“…The majority of specific primers have been designed based on the most conserved RdRp region of the genome [29,68]. However, sequence analysis of the polymerase region of a wide range of virus strains indicated that this region is also variable with the nucleotide identity as low as 53% between strains of different genogroups and 60-64% within genogroup [59].…”

Section: Rt-pcrmentioning

confidence: 99%

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Porcine enteric caliciviruses: Genetic and antigenic relatedness to human caliciviruses, diagnosis and epidemiology

Wang

Costantini

Saif

2007

Vaccine

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Porcine enteric caliciviruses include sapoviruses and noroviruses. Porcine sapoviruses infect pigs of all ages and cause diarrhea in young pigs, whereas porcine noroviruses were detected exclusively from adult pigs without clinical signs. Importantly, certain porcine norovirus strains were genetically and antigenically related to human noroviruses. This raises public health concerns that pigs may be reservoirs for emergence of epidemic human norovirus strains. This article reviews the discovery of porcine noroviruses and sapoviruses, their classification, diagnosis, epidemiology and genetic and antigenic relatedness to human caliciviruses.

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Section: Recombination Of Porcine Novs and Savsmentioning

confidence: 99%

Section: Rt-pcrmentioning

confidence: 99%

Porcine enteric caliciviruses: Genetic and antigenic relatedness to human caliciviruses, diagnosis and epidemiology

Wang

Costantini

Saif

2007

Vaccine

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“…Norovirus genotype identities are generally maintained across the open reading frames (ORFs). However, a number of norovirus strains failed to maintain their sequence identities for RNA-dependent RNA polymerase and VP1, and they were shown to be recombinant (16,20,30). Evidence suggested that the recombination site occurred at the conserved polymerase and capsid junction between ORF1 and ORF2.…”

mentioning

confidence: 99%

Norovirus Infections in Symptomatic and Asymptomatic Food Handlers in Japan

Ozawa¹,

et al. 2007

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Noroviruses are the leading cause of outbreaks of gastroenteritis in the world. At present, norovirus genogroup II, genotype 4 (GII/4), strains are the most prevalent in many countries. In this study we investigated 55 outbreaks and 35 sporadic cases of norovirus-associated gastroenteritis in food handlers in foodcatering settings between 10 November 2005 and 9 December 2006 in Japan. Stool specimens were collected from both symptomatic and asymptomatic individuals and were examined for norovirus by real-time reverse transcription-PCR; the results were then confirmed by sequence analysis. Norovirus was detected in 449 of 2,376 (19%) specimens. Four genogroup I (GI) genotypes and 12 GII genotypes, including one new GII genotype, were detected. The GII/4 sequences were predominant, accounting for 19 of 55 (35%) outbreaks and 16 of 35 (46%) sporadic cases. Our results also showed that a large number of asymptomatic food handlers were infected with norovirus GII/4 strains. Norovirus GII had a slightly higher mean viral load (1 log unit higher) than norovirus GI, i.e., 3.81 ؋ 10 8 versus 2.79 ؋ 10 7 copies/g of stool. Among norovirus GI strains, GI/4 had the highest mean viral load, whereas among GII strains, GII/4 had the highest mean viral load (2.02 ؋ 10 8 and 7.96 ؋ 10 9 copies/g of stool, respectively). Importantly, we found that asymptomatic individuals had mean viral loads similar to those of symptomatic individuals, which may account for the increased number of infections and the predominance of an asymptomatic transmission route.The positive-sense polyadenylated single-stranded RNA virus family Caliciviridae contains four genera: Norovirus, Sapovirus, Lagovirus, and Vesivirus (1). The prototype strain of human norovirus is the Norwalk virus (NV/Human/US/1968), which was first discovered in an outbreak of gastroenteritis in an elementary school in Norwalk, OH, in 1968 (15). Noroviruses are the leading cause of outbreaks of gastroenteritis in the world; they cause outbreaks in various settings, including hospitals, cruise ships, schools, and restaurants (2,9,12,15,23,24,29). In addition, noroviruses have been detected in environmental samples (e.g., treated and untreated sewage) as well as in contaminated foods such as oysters, shellfish, sandwiches, salads, raspberries, and even ice (7,18,19,26). Numerous molecular epidemiological studies have revealed a global distribution of these viruses (25,27,31).The most widely used method of detecting noroviruses is reverse transcription-PCR (RT-PCR), which has high sensitivity; also, the products can be used for further genetic analysis. Real-time RT-PCR assays have also been developed; they are sensitive, broadly reactive, and rapid for the detection of human noroviruses in clinical stool specimens and environmental samples (13,14,21).As the detection methods become more and more sensitive, the numbers of genogroups and genotypes are expected to increase. One emerging characteristic is that strains have been found to persist in one geographical region, only to disapp...

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“…Human NVs can be divided into two genogroups, genogroups GI and GII, by genetic analysis of the RNA polymerase and capsid regions (1, 15), with several genotype classifications having been reported independently (1,16,33). Recently, based on the genotype classification of Katayama et al (16), Kageyama et al (15) reported on a detailed scheme for the genotyping of NVs based on distribution analysis by using the pairwise distance of the capsid N-terminal/shell domain.…”

mentioning

confidence: 99%

Genetic Analysis of Noroviruses in Chiba Prefecture, Japan, between 1999 and 2004

et al. 2005

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Noroviruses (NVs) are common pathogens that consist of genetically divergent viruses that induce gastroenteritis in humans and animals. Between September 1999 and June 2004, 1,898 samples obtained from patients showing sporadic or outbreak gastroenteritis in Chiba Prefecture, Japan, were tested for NVs by reverse transcription-PCR. NVs were detected in 603 samples. Approximately 80% were positive for genogroup GII, 13% were positive for genogroup GI, and the remaining 7% were positive for both genogroups. Phylogenetic analysis showed that the GI and GII genogroups could be further divided into 13 and 16 genotypes (including new genotypes), respectively. The GII-4 genotype, which included five small genetic clusters (subtypes), was the most common in this study and was detected in approximately 40% of positive samples. The P2 regions of 10 strains belonging to each of the five GII-4 subtypes showed 5 to 18% amino acid diversity. The amino acid substitutions accumulated in the protruding (P) region during the 5-year study period. Our data suggest that highly variable NV strains are circulating in Chiba Prefecture, with a high rate of genetic change observed during the 5-year study period.The genus Norovirus is a member of the family Caliciviridae. Caliciviruses contain a positive-sense single-stranded RNA genome and include a further three genera, Vesivirus, Lagovirus, and Sapovirus (2,3,8). Noroviruses (NVs) have three major open reading frames (ORFs) that encode nonstructural, capsid, and minor structural proteins, respectively (8). They are one of the most common causes of gastroenteritis and have been detected in fecal samples from both humans (12,15,28) and animals (20,30,37). Human-associated NV outbreaks resulting from ingestion of contaminated water or food, such as oysters (4,5,18,23), and outbreaks in public places, particularly hospitals, schools, and cruise ships (9,11,22,36), pose an important public health problem.Reverse transcription-PCR (RT-PCR) and sequencing of the partial viral genome are the most popular and useful procedures for obtaining epidemiological and genetic information on NVs. Human NVs can be divided into two genogroups, genogroups GI and GII, by genetic analysis of the RNA polymerase and capsid regions (1, 15), with several genotype classifications having been reported independently (1,16,33). Recently, based on the genotype classification of Katayama et al. (16), Kageyama et al. (15) reported on a detailed scheme for the genotyping of NVs based on distribution analysis by using the pairwise distance of the capsid N-terminal/shell domain. They classified the GI and GII genogroups into 14 and 17 genotypes, respectively.During the winter of 2002-2003, an increase in NV outbreaks was reported in Europe and the United States (6, 21). Moreover, worldwide, the GII-4 genotype (Bristol virus-like genotype) has been shown to be the predominant strain of NV associated with gastroenteritis (13,21,(34)(35)(36). Changes in the phylogenetic and genetic characteristics of GII-4 genotype strains...

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Genetic polymorphism across regions of the three open reading frames of "Norwalk-like viruses"

Cited by 178 publications

References 32 publications

Porcine enteric caliciviruses: Genetic and antigenic relatedness to human caliciviruses, diagnosis and epidemiology

Porcine enteric caliciviruses: Genetic and antigenic relatedness to human caliciviruses, diagnosis and epidemiology

Norovirus Infections in Symptomatic and Asymptomatic Food Handlers in Japan

Genetic Analysis of Noroviruses in Chiba Prefecture, Japan, between 1999 and 2004

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