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Norovirus
Published in Firza Alexander Gronthoud, Practical Clinical Microbiology and Infectious Diseases, 2020
Norovirus belongs to the Caliciviridae family, which is a group of non-enveloped, positive-sense, single-stranded RNA (ssRNA) viruses. Another member of this family which causes human infections is sapovirus. The norovirus genus can be subdivided into at least seven genogroups and >40 genotypes. Genogroups II (mostly GII.4), I and infrequently genogroup IV cause human infections. Infections occurring during outbreaks of GII.4 strains are associated with more severe outcomes, including mortality, than infections during outbreaks of non-GII.4 strains.
Sapovirus
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Shoko Okitsu, Pattara Khamrin, Niwat Maneekarn, Hiroshi Ushijima
Sapovirus (SaV) is an important pathogen of gastroenteritis in humans and animals. Human sapovirus was first detected in the stool samples collected from infants with acute gastroenteritis (AGE) by electron microscopy in 1970s.1–3 Being a well-known cause of sporadic AGE in infants and children, SaV also affects other age groups.4–6 Gastroenteritis outbreaks due to foodborne SaV have been reported in numerous settings. Along with norovirus (NoV), SaV remains an important public health problem worldwide, although it demonstrates a lower prevalence than NoV.
Norovirus
Published in Peter M. Lydyard, Michael F. Cole, John Holton, William L. Irving, Nino Porakishvili, Pradhib Venkatesan, Katherine N. Ward, Case Studies in Infectious Disease, 2010
Peter M. Lydyard, Michael F. Cole, John Holton, William L. Irving, Nino Porakishvili, Pradhib Venkatesan, Katherine N. Ward
Noroviruses are unenveloped single stranded RNA viruses with an icosahedral capsid, that were formerly known as Norwalk viruses (because of their first identification in Norwalk, USA) or small round structured viruses (SRSVs) – the latter term arose because of their characteristic feathery, ragged appearance lacking a distinct surface structure as seen by electron microscopy (Figure 2A). The noroviruses belong to the family of caliciviruses – the other group of human caliciviruses are the sapoviruses, which when visualized by electron microscopy have a structure distinct from noroviruses with cup-shaped surface depressions giving a ‘Star of David’ appearance (Figure 2B). Sapovirus infection is endemic in childhood, causing occasional cases of diarrhea.
The incidence of laboratory-confirmed cases of enteric pathogens in Denmark 2018: a national observational study
Published in Infectious Diseases, 2023
Anna Tølbøll Svendsen, Hans Linde Nielsen, Peter Bytzer, John Eugenio Coia, Jørgen Engberg, Hanne Marie Holt, Lars Lemming, Steen Lomborg, Ea Sofie Marmolin, Bente Scharvik Olesen, Leif Percival Andersen, Steen Ethelberg, Anne Line Engsbro
Using a PCR method yielded higher incidences for most enteric pathogens compared to bacterial culture, virus antigen-test, or microscopy for intestinal parasites (Table 2). The diagnostic methods differed between departments of clinical microbiology (Supplementary Tables 4 and 5), particularly for the bacterial pathogens for which seven departments used culture-based methods and only three departments performed PCR on faecal material for the same pathogens. For diagnostics of DEC including STEC, the majority used a culture-based method with subsequent PCR on cultured isolates for differentiation while four departments performed PCR directly on faeces. For the viral pathogens, nine of 10 tested for norovirus, rotavirus and adenovirus, only half tested for sapovirus and three for astrovirus (Supplementary Table S4). The majority of departments of clinical microbiology used PCR for detection of enteric parasites (Supplementary Table S4).
Rotavirus and illness severity in children presenting with acute gastroenteritis at the primary care out-of-hours service
Published in European Journal of General Practice, 2021
Pien Wolters, G. A Holtman, A. A. H Weghorst, M. Knoester, M. Y. Berger
In line with other studies of children with acute gastroenteritis [2,4,23], over half of the children (65.3%) in our study were infected with rotavirus. More than half (57.3%) also had a coinfection, a common phenomenon [24]. The combination of adenovirus and rotavirus (28.0%) occurred most frequently, consistent with research in which 27.4% of children were shown to be infected with this combination [24]. Sapovirus and adenovirus infections were also frequently present in coinfections but the pathogenicity of these viruses was questionable because their viral loads were often lower than those of the coinfections. We also cannot exclude the possibility that adenovirus was shed into the faeces after a recent respiratory tract infection, instead of being a primary gastroenteritis-causing pathogen. A study among hospitalised children also found adenovirus infection to be relatively common (23%), with most cases present as part of a coinfection (73%). Sapovirus has been reported to be present as a coinfection in only one case [4].
Genetic engineering strategies for construction of multivalent chimeric VLPs vaccines
Published in Expert Review of Vaccines, 2020
Xinnuo Lei, Xiong Cai, Yi Yang
Domain switch can be performed among the same viral proteins of different genotypes. For example, the capsid protein (VP1) of sapovirus contains two domains (shell and protruding). Miyazaki et al. switched both shell domain and one subdomain of protruding domain between two genotypes GI.1 and GI.5 to construct two chimeric VP1, which were capable of self-assembling into chi-cVLPs, both of the chi-VLPs had higher levels of cross-relativities to heterogeneous antisera than the parental VLPs [101]. Domain switch can be also achieved between the cognate viral proteins of different virus among the same family. In retroviruses, the major structural polyprotein is encoded by the gag gene, which is necessary and sufficient for the VLP assembly and release. Although Gag proteins vary in size and show almost no sequence identity across genera, they share at least three major domains: matrix, capsid, and nucleocapsid, which are in some cases functionally interchangeable between retroviruses without compromising VLP assembly [102–104]. Chimeric Gag proteins could be successfully constructed via switching the three major domains between two retroviruses, RSV and HIV-1. Chi-cVLPs formed with the chimeric Gag proteins implied that the morphology distinction between RSV and HIV-1 was determined by interactions of capsid domains of each Gag [102,103].