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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, Handbook of Foodborne Diseases, 2018
Victoria A. Meliopoulos, Virginia Hargest, Valerie Cortez
After the virus was first sequenced in 1993, it was proposed that these unique enteric pathogens be classified under a new family: Astroviridae.11 The International Committee on Taxonomy of Viruses divides Astroviridae into two genera according to species specificity12: Avastrovirus infects avian species and Mamastrovirus infects mammalian species (Figure 3.1). Both genera are subdivided into two genogroups on the basis of their genetic relatedness within the ORF2 gene, which encodes the highly variable capsid protein. These genogroups are further classified into individual genotypes according to their mean amino acid distance.
Astrovirus
Published in Dongyou Liu, Laboratory Models for Foodborne Infections, 2017
Matthew D. Koci, Stacey L. Schultz-Cherry
Since the Astroviridae family was established by the ICTV in 1995, there have been considerable changes in our understanding of the diversity, molecular evolution, and host range of the family. In just the last decade, the numbers of host species detected with astroviruses have increased more than fourfold.22 Additionally our appreciation of the diversity of astrovirus genotypes capable of infecting a given host has led to a reevaluation of their classification system. Currently, Astroviridae is divided into two genera (Table 3.1), Mamastrovirus (MAstV) and Avastrovirus (AAstV), representing viruses that affect mammals and avian species, respectively. Within each of these two genera, viruses are classified by distinct genotypic differences within their polymerase and/or capsid genomic sequences.23
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.