New Insights into Parvovirus Research

The family Parvoviridae includes an ample and most diverse collection of viruses. Exploring the biological diversity and the inherent complexity in these apparently simple viruses has been a continuous commitment for the scientific community since their first discovery more than fifty years ago. The Special Issue of 'Viruses' dedicated to the 'New Insights into Parvovirus Research' aimed at presenting a 'state of the art' in many aspects of research in the field, at collecting the newest contributions on unresolved issues, and at presenting new approaches exploiting systemic (-omic) methodologies

The clinical use of parvovirus B19 assays: recent advances

Introduction: Parvovirus B19 (B19V), a single-stranded DNA virus in the family Parvoviridae, is a human pathogenic virus, characterized by a selective but not exclusive tropism for erythroid progenitor cells. Widely diffuse, it is responsible for an ample range of clinical manifestations, whose characteristics and outcomes depend on the interplay between the viral properties and the physiological and immune status of the infected individuals. The complexity of virus\u2013host relationship and the diversity of the clinical course of infection pose a diagnostic challenge that may require non-trivial solutions. Areas covered: The review includes an updated description of the course of B19V infection in its complexity and diversity of pathogenetic mechanisms, discusses the consequent requirements for different and appropriated diagnostic approaches, presents the main diagnostic techniques, more recent technical advancements, and their application to the diverse clinical situations. Expert commentary: The complex scenario of the infectious process and the diversity in possible pathogenetic mechanisms make necessary a multi-parametric approach for an accurate and informative laboratory diagnosis of B19V infection, combining as much as possible the molecular detection of viral components, mainly viral DNA, to commonly followed immunological detection of virus-specific antibodies and a critical assessment of laboratory findings

Microfluidic cartridge with integrated array of amorphous silicon photosensors for chemiluminescence detection of viral DNA

Portable and simple analytical devices based on microfluidics with chemiluminescence detection are particularly attractive for point-of-care applications, offering high detectability and specificity in a simple and miniaturized analytical format. Particularly relevant for infectious disease diagnosis is the ability to sensitively and specifically detect target nucleic acid sequences in biological fluids. To reach the goal of real-life applications for such devices, however, several technological challenges related to full device integration are still to be solved, one key aspect regarding on-chip integration of the chemiluminescence signal detection device. Nowadays, the most promising approach is on-chip integration of thin-film photosensors. We recently proposed a portable cartridge with microwells aligned with an array of hydrogenated amorphous silicon (a-Si:H) photosensors, reaching attomole level limits of detection for different chemiluminescence model reactions. Herein, we explore its applicability and performance for multiplex and quantitative detection of viral DNA. In particular, the cartridge was modified to accommodate microfluidic channels and, upon immobilization of three oligonucleotide probes in different positions along each channel, each specific for a genotype of Parvovirus B19, viral nucleic acid sequences were captured and detected. With this system, taking advantage of oligoprobes specificity, chemiluminescence detectability, and photosensor sensitivity, accurate quantification of target analytes down to 70 pmol L-1 was obtained for each B19 DNA genotype, with high specificity and multiplexing ability. Results confirm the good detection capabilities and assay applicability of the proposed system, prompting the development of innovative portable analytical devices with enhanced sensitivity and multiplexed capabilities

Parvovirus B19: Insights and implication for pathogenesis, prevention and therapy

Parvovirus B19 (B19V) is a small ssDNA non-enveloped virus, member of Parvoviridae family. The infection is widely diffused and is responsible for a broad range of clinical manifestations including fifth disease in children, transient aplastic crisis in patients with haematological disorders, non-immune hydrops fetalis in pregnant women, persistent anaemia in immunocompromised patients, arthropathy and inflammation of various other tissues. B19V infects and replicates in erythroid progenitor cells (EPCs) in the bone marrow. The depletion of infected EPCs represents the pathogenetic mechanisms of some haematological B19V-associate diseases. Following a primary infection, the virus can establish lifelong persistence in several tissues. Currently, the pathological potential of persistent virus on the cellular signalling pathways remains unclear. In non-erythroid tissues, the infection is usually, abortive, and the virus seems to exert its pathological role through indirect mechanisms, such as induction of inflammatory and autoimmune processes, or through virus-induced apoptosis mediated by viral proteins. In addition to the diseases for which the etiological role of B19V has been fully demonstrated, there are several clinical conditions, including autoimmune diseases, that are presumably, but not certainly, associated with B19V infection. In this review, we describe recent findings that may give us new insight into the pathogenic role of B19V in systemic sclerosis, an autoimmune disease of unknown multifactorial aetiology. Furthermore, we describe the latest findings on the intrauterine B19V infections. Moreover, since there are some ongoing interesting studies focused on vaccine development and antiviral drug discovery for the prevention and treatment of parvovirus B19 infection we described some advances in this field of research

Next Generation Sequencing for the Analysis of Parvovirus B19 Genomic Diversity

Parvovirus B19 (B19V) is a ssDNA human virus, responsible for an ample range of clinical manifestations. Sequencing of B19V DNA from clinical samples is frequently reported in the literature to assign genotype (genotypes 1-3) and for finer molecular epidemiological tracing. The increasing availability of Next Generation Sequencing (NGS) with its depth of coverage potentially yields information on intrinsic sequence heterogeneity; however, integration of this information in analysis of sequence variation is not routinely obtained. The present work investigated genomic sequence heterogeneity within and between B19V isolates by application of NGS techniques, and by the development of a novel dedicated bioinformatic tool and analysis pipeline, yielding information on two newly defined parameters. The first, alpha-diversity, is a measure of the amount and distribution of position-specific, normalised Shannon Entropy, as a measure of intra-sample sequence heterogeneity. The second, sigma-diversity, is a measure of the amount of inter-sample sequence heterogeneity, also incorporating information on alpha-diversity. Based on these indexes, further cluster analysis can be performed. A set of 24 high-titre viraemic samples was investigated. Of these, 23 samples were genotype 1 and one sample was genotype 2. Genotype 1 isolates showed low alpha-diversity values, with only a few samples showing distinct position-specific polymorphisms; a few genetically related clusters emerged when analysing inter-sample distances, correlated to the year of isolation; the single genotype 2 isolate showed the highest alpha-diversity, even if not presenting polymorphisms, and was an evident outlier when analysing inter-sample distance. In conclusion, NGS analysis and the bioinformatic tool and pipeline developed and used in the present work can be considered effective tools for investigating sequence diversity, an observable parameter that can be incorporated into the quasispecies theory framework to yield a better insight into viral evolution dynamics

Co-localization of two different viral genomes in the same sample by double-chemiluminescence in situ hybridization

A double-chemiluminescence in situ hybridization has been developed that combines the advantages of chemiluminescence with the detection of two different viral DNAs, i.e., herpes simplex virus (HSV..

Pre-Existing Intrarenal Parvovirus B19 Infection May Relate to Antibody-Mediated Rejection in Pediatric Kidney Transplant Patients

Viral infections can lead to transplant dysfunction, and their possible role in rejection is described. In total, 218 protocol biopsies performed in 106 children at 6, 12 and 24 months after transplantation were analyzed according to Banff ’15. RT-PCR for cytomegalovirus, Epstein-Barr virus, BK virus and Parvovirus B19 was performed on blood and bioptic samples at the time of transplant and each protocol biopsy. The prevalence of intrarenal viral infection increases between 6 and 12 months after transplantation (24% vs. 44%, p = 0.007). Intrarenal Parvovirus B19 infection is also associated with antibody-mediated rejection (ABMR) (50% ABMR vs. 19% T-cell-mediated rejection, p = 0.04). Moreover, Parvovirus infection is higher at 12 months of follow-up and it decreases at 48 months (40.4% vs. 14%, p = 0.02), while in 24% of grafts, Parvovirus is already detectable at the moment of transplantation. Intrarenal Parvovirus B19 infection seems to be related to ABMR in pediatric kidney recipients. The graft itself may be the way of transmission for Parvovirus, so performance of a PCR test for Parvovirus B19 should be considered to identify high-risk patients. Intrarenal Parvovirus infection presents mainly during the first-year post-transplantation; thus, we recommend an active surveillance of donor-specific antibodies (DSA) in patients with intrarenal Parvovirus B19 infection during this period. Indeed, it should be considered a treatment with intravenous immunoglobulins in patients with intrarenal Parvovirus B19 infection and DSA positivity, even in the absence of ABMR criteria for kidney biopsy