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Other Positive Single-Stranded RNA Viruses
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
According to the current taxonomy (ICTV 2020), the order Stellavirales is one of the two members of the class Stelpaviricetes, together with the Patatavirales order described in the neighboring Chapter 29. The Stelpaviricetes class belongs to the Pisuviricota phylum from the kingdom Orthornavirae, realm Riboviria. The small Stellavirales order currently involves a single family Astroviridae with two genera Avastrovirus and Mamastrovirus and 22 species altogether. Human astrovirus (HAstV) is an important cause of acute gastroenteritis.
Astrovirus
Published in Dongyou Liu, Laboratory Models for Foodborne Infections, 2017
Matthew D. Koci, Stacey L. Schultz-Cherry
Astroviruses are small, round, nonenveloped, positive-sense single-stranded RNA viruses. They were named for their “star-like” appearance when visualized by negative staining electron microscopy in the feces of infants suffering from gastroenteritis.1,2 Since their original discovery, astroviruses have been identified in almost all animal species examined.3 In the vast majority of these species, astrovirus infection is transmitted through the fecal–oral route and causes acute gastroenteritis. In humans, the classical astroviruses are associated with mild to moderate diarrhea and are recognized as one of the leading causes of enteritis in children and the immunocompromised.4,5 More recently, astroviruses have been associated with encephalitis.6,7 In other species, especially poultry, diarrhea can be severe and can involve other organ systems including the liver and kidneys.8,9 Historically, astroviruses have been thought to be species-specific, with only limited evidence of interspecies transmission.10 However, there is increasing evidence that astroviruses can infect multiple species. Convincing evidence for this was first found for avian astroviruses,11–17 but recent reports suggest the same may be true for mammalian astroviruses,18–20 and that there may even be transmission between birds and mammals.21 More recently, astrovirus genotypes associated with human infections were detected in nonhuman primates, strongly supporting the suggestion that astroviruses can cross species barriers.21a
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).
Vaccines against gastroenteritis, current progress and challenges
Published in Gut Microbes, 2020
Hyesuk Seo, Qiangde Duan, Weiping Zhang
Progress has been also made in vaccine development for the other enteric viruses including astroviruses (Astroviridae), adenoviruses (Adenoviridae), and sapoviruses (Caliciviridae). Other Astroviridae members such as VA-Like and MLB-like astroviruses, Picornaviridae (silivirus, cosavirus), and Parvoviridae families (bocaviruses, bufaviruses) are also isolated from patients (usually in infants and children) with gastroenteritis. Several subunit vaccines have been investigated for prevention against astrovirus infections. In particular, a trivalent subunit vaccine for hepatitis E virus, norovirus, and astrovirus was generated by fusing together the dimeric P domains of the three viruses to form a tetramer.93 When intranasally administered to mice, this trivalent product induced significant neutralizing antibody responses to the P domains of all three viruses. Another subunit astrovirus vaccine candidate used the capsid protein (CP) of mink astrovirus elicited high levels of serum anti-CP antib odies and lymphoproliferation responses and also stimulated IFN-γ levels in mice.94 Importantly, it was observed that virus shedding was suppressed and clinical signs including severe diarrhea were reduced in the litters born to the immunized mink mothers when challenged with a heterogeneous astrovirus strain.94 Future human volunteer studies and clinical trials are needed to assess the efficacy of these vaccine candidates against viral gastroenteritis.
Progress on norovirus vaccine research: public health considerations and future directions
Published in Expert Review of Vaccines, 2018
Claire P. Mattison, Cristina V. Cardemil, Aron J. Hall
The Cincinnati Children’s Hospital Medical Center, University of Cincinnati, and Virginia Polytechnic Institute and State University are developing a norovirus vaccine using norovirus P particles, designed to resemble the protruding P domain of the virus [60,61]. Development began on a monovalent GII.4 norovirus vaccine, but as it progressed, hepatitis E and astrovirus antigens were added. A trial of an intranasal GII.4 norovirus P particle vaccine in gnotobiotic pigs showed a higher intestinal T-cell immune response when compared to pigs vaccinated with a GII.4 norovirus VLP vaccine [90]. In mice, an intranasal bivalent vaccine using a fused P protein from the P domains of norovirus and hepatitis E showed increased antibody titers when compared to vaccination with a mixture of P dimers from norovirus and hepatitis E [91]. Most recently, a trivalent intranasal GII.4 norovirus, hepatitis E, and astrovirus vaccine, using a fusion of the three P domains, produced a 1.9-fold higher norovirus IgG titer than immunization with norovirus P particle alone in mice [92]. These trials show the potential for a P particle vaccine to vaccinate against multiple diseases.