Coexistence of Multiple Genotypes, Including Newly Identified Genotypes, in Outbreaks of Gastroenteritis Due to
            <i>Norovirus</i>
            in Japan

Kageyama, Tsutomu; Shinohara, Michiyo; Uchida, Kenzo; Fukushi, Shuetsu; Hoshino, Fuminori B.; Kojima, Saburo; Takai, Reiko; Oka, Takahiro; Takeda, Naokazu; Katayama, Kazuhiko

doi:10.1128/jcm.42.7.2988-2995.2004

Cited by 353 publications

(365 citation statements)

References 32 publications

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“…10 Other reports showed a high molecular diversity and multiple mutations during outbreaks in the United Kingdom or Japan. 11,12 Obviously, as all test results were obtained with the same lot, we cannot exclude kit-specific false positive results.…”

Section: Discussionmentioning

confidence: 99%

Apparently non-specific results found using a norovirus antigen immunoassay for fecal specimens from neonates

et al. 2007

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Norovirus is increasingly recognized as a frequent cause of non-bacterial gastroenteritis. Despite a 10-fold increase in the number of cases reported following the availability of enzyme immunoassays, there are no reports yet from preterm neonates. We report on a sudden clustering of antigen-positive enzyme immuno assays results in a level III neonatal intensive care unit, involving 22 of 43 infants screened. Although antigen-positive samples were significantly associated with bloody stools (P<0.001) and gastric residues (P<0.02), norovirus infection could not be confirmed by reversetranscriptase polymerase chain reaction or electron microscopy. We question the validity of the so called norovirus-specific antigen assays and warn against overreacting to positive enzyme immunoassays results without reverse-transcriptase polymerase chain reaction confirmation especially in the neonatal setting.

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Section: Discussionmentioning

confidence: 99%

Apparently non-specific results found using a norovirus antigen immunoassay for fecal specimens from neonates

et al. 2007

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“…SybrGreen and TaqMan, have been used for detection of human NoVs from fecal and shellfish samples [69,70,[82][83][84][85][86][87]. These may be used for detection of porcine NoVs and SaVs in the near future.…”

Section: Real-time Rt-pcr-in the Past 2-3 Years Various Real-time Rtmentioning

confidence: 99%

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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“…Nucleotide sequences were aligned with Clustal X, and the distances were calculated by Kimura's two-parameter method. Phylogenetic trees with bootstrap analysis from 1,000 replicas were generated by the neighborjoining method as described previously (14).…”

Section: Methodsmentioning

confidence: 99%

“…Recently, noroviruses have been divided into five genetically distinct genogroups, but the majority of human noroviruses can be divided into two genetically distinct genogroups, genogroup I (GI) and GII, which can be subdivided into at least 14 GI and 17 GII genotypes (14). Norovirus genotype identities are generally maintained across the open reading frames (ORFs).…”

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confidence: 99%

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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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Coexistence of Multiple Genotypes, Including Newly Identified Genotypes, in Outbreaks of Gastroenteritis Due to Norovirus in Japan

Cited by 353 publications

References 32 publications

Apparently non-specific results found using a norovirus antigen immunoassay for fecal specimens from neonates

Apparently non-specific results found using a norovirus antigen immunoassay for fecal specimens from neonates

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

Norovirus Infections in Symptomatic and Asymptomatic Food Handlers in Japan

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