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Order Piccovirales
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
Figure 9.1 presents some pictures of the numerous Parvoviridae x-ray and electron microscopy structures available at the PDB and VPERdb collections. As reviewed extensively by Cotmore et al. (2019), the T = 1 virions are 23–28 nm in diameter and exceptionally rugged, often remaining infectious in the environment for months or years. The capsids are assembled from a nested set of 60 viral protein (VP) proteins, typically encoded on the single structural VP gene that includes the entire coding sequence for VP1 (generally 75–100 kDa), while one or more smaller forms (VP2–5) share a common C-terminal sequence but have N-terminal truncations of different length. Thus, the capsids of the important Erythroparvovirus and Protoparvovirus genera are composed of 60 copies of the major capsid protein VP2 and 6 to 10 copies of the minor capsid protein VP1, where VP1 is identical to VP2 but contains an additional N-terminal stretch of 227 aa. A portion of that region of VP1 is external to the capsid, but the VP1 itself is not required for capsid formation. The VP monomers interdigitate extensively to create 60 asymmetric units per particle, which coordinate at 12 5-fold, 20 3-fold and 20 2-fold axes. Each VP chain forms a core β-barrel structure of at least 8 strands, while individual β-strands are linked by loops of variable length, sequence, and conformation, most of which project toward the outer surface of the capsid and give individual viruses their unique surface topology.
Diagnostic Approach to Fulminant Hepatitis in the Critical Care Unit
Published in Cheston B. Cunha, Burke A. Cunha, Infectious Diseases and Antimicrobial Stewardship in Critical Care Medicine, 2020
Parvovirus B19 is a DNA virus belonging to the Parvoviridae family. Parvovirus B19 occurs commonly in children and manifests as erythema infectiosum or aplastic anemia. In adults, arthropathy or hydrop fetalis during pregnancy can occur [45]. Parvovirus B19 has been associated with ALF in solid-organ transplantation and hematopoietic stem cell transplantation. Clinical manifestation is atypical and can include fever, rash, arthralgia, anemia and organ-invasive disease such as hepatitis and myocarditis. Liver function abnormalities resemble that of other viral hepatitides [46]. Diagnosis can be made via serology (IgM and IgG) and serum PCR for parvovirus B19, although serology is unreliable in the context of immunosuppression, as patients may mount a delayed immune response. Direct viral detection in blood or, in the case of hepatitis, liver biopsy specimen should be performed if both serology and PCR are negative but suspicion remains high. Treatment of parvovirus B19 is with intravenous immunoglobulins [45,46].
Human Bocavirus
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
José Luiz Proença-Módena, Guilherme Paier Milanez, Eurico Arruda
Although members of the family Parvoviridae are known to cause several significant diseases in animals, until the end of the twentieth century, only one autonomous parvovirus was linked to human disease. The virus, named B19 virus (B19V), was described in 1975 and has been associated with erythema infectiosum and other clinical diseases in humans [1,2].
Liver-directed gene-based therapies for inborn errors of metabolism
Published in Expert Opinion on Biological Therapy, 2021
Pasquale Piccolo, Alessandro Rossi, Nicola Brunetti-Pierri
AAV is a small non-enveloped, nonpathogenic virus of the Parvoviridae family. Its single stranded DNA genome contains sequences encoding for viral replication machinery (rep) and capsid (cap) proteins flanked by palindromic inverted terminal repeats (ITR) containing the origin of replication and packaging signals. Naturally occurring AAV are replication defective and they establish latent asymptomatic infections when co-infection with a helper virus (typically adenovirus or herpes simplex virus) occurs. As a result of the infection, anti-AAV antibodies can be found in most subjects, with AAV2 showing the highest prevalence [12]. The complete lack of pathogenicity of AAV has been recently challenged by the finding of clonal integration of AAV genomes into human HCC tissues [13,14].
Gut non-bacterial microbiota contributing to alcohol-associated liver disease
Published in Gut Microbes, 2021
Wenkang Gao, Yixin Zhu, Jin Ye, Huikuan Chu
The exact role of gut virome in the etiology of ALD is still unclear, as not only the complex pathogenesis of ALD but also our fragmented understanding of the gut viruses and limited relevant studies. In 2020, scientists systematically described an intestinal virome signature in AH patients for the first time. They observed an increased viral diversity in the stools of patients with ALD. In AH patients, Escherichia-, Enterobacteria-, and Enterococcus phages were over-represented and mammalian viruses such as Parvoviridae and Herpesviridae significantly increased. Staphylococcus phages and Herpesviridae were associated with severity and mortality of ALD.127128 Above findings were consistent with previous research. In fecal samples, most detected Herpesviridae such as herpesvirus‐6128,129 and herpesvirus‐8130,131 are associated with the severity of ALD, and they could be classified into Epstein-Barr virus (EBV). EBV infection often causes liver inflammation, but the pathogenesis remains unknown.129 A retrospective study of patients with liver cirrhosis found that EBV-positive patients had higher Child-Pugh scores, more severe liver injury and a higher rate of chronic acute liver failure,132 which suggested the reactivation of EBV might contribute to the development of alcoholic hepatitis.
The clinical use of parvovirus B19 assays: recent advances
Published in Expert Review of Molecular Diagnostics, 2018
The family Parvoviridae includes viruses with a single-stranded DNA genome, encapsidated in a icosahedral protein capsid, about 22–26 nm in diameter. Replication occurs in the nucleus of infected cells and is highly dependent on cellular environment, so that a productive cycle is usually achieved only in actively dividing cells, or in some cases when supported by complementation from helper viruses. The subfamily Parvovirinae includes viruses infecting vertebrate hosts, within it the most recent taxonomical revision distinguishes eight viral genera, and within each genus individual virus species that collect the viral isolates normally recognized in clinical or laboratory settings. In the genus Erythroparvovirus, the species Primate erythroparvovirus 1 includes the human parvovirus B19 (B19V), and a further subdivision is introduced in three distinct B19V genotypes, that differ in their genome sequence by about 10%, while constituting a single serotype and showing similar biological properties [1].