Review
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Oct 21, 2016; 22(39): 8684-8697
Published online Oct 21, 2016. doi: 10.3748/wjg.v22.i39.8684
Human bocavirus: Current knowledge and future challenges
Marcello Guido, Maria Rosaria Tumolo, Tiziano Verri, Alessandro Romano, Francesca Serio, Mattia De Giorgi, Antonella De Donno, Francesco Bagordo, Antonella Zizza
Marcello Guido, Francesca Serio, Mattia De Giorgi, Antonella De Donno, Francesco Bagordo, Laboratory of Hygiene, Department of Biological and Environmental Sciences and Technologies, Faculty of Sciences, University of Salento, 73100 Lecce, Italy
Maria Rosaria Tumolo, Antonella Zizza, Institute of Clinical Physiology, National Research Council, 73100 Lecce, Italy
Tiziano Verri, Laboratory of Physiology, Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
Alessandro Romano, Neuropathology Unit, Institute of Experimental Neurology and Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
Author contributions: Guido M and Tumolo MR are co-first authors and equally contributed to this article; all authors contributed to the conception and design of the study, literature review and analysis, drafting, critical revision and editing of the manuscript, and approval of the final version to be published.
Conflict-of-interest statement: The authors declare no conflicts of interests for this article.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Marcello Guido, Professor, Laboratory of Hygiene, Department of Biological and Environmental Sciences and Technologies, Faculty of Sciences, University of Salento, Via Provinciale Lecce-Monteroni, 73100 Lecce, Italy. marcello.guido@unisalento.it
Telephone: +39-832-298686 Fax: +39-832-298626
Received: March 28, 2016
Peer-review started: April 1, 2016
First decision: May 12, 2016
Revised: August 30, 2016
Accepted: September 14, 2016
Article in press: September 14, 2016
Published online: October 21, 2016
Processing time: 205 Days and 22.2 Hours
Abstract

Human bocavirus (HBoV) is a parvovirus isolated about a decade ago and found worldwide in both respiratory samples, mainly from early life and children of 6-24 mo of age with acute respiratory infection, and in stool samples, from patients with gastroenteritis. Since then, other viruses related to the first HBoV isolate (HBoV1), namely HBoV2, HBoV3 and HBoV4, have been detected principally in human faeces. HBoVs are small non-enveloped single-stranded DNA viruses of about 5300 nucleotides, consisting of three open reading frames encoding the first two the non-structural protein 1 (NS1) and nuclear phosphoprotein (NP1) and the third the viral capsid proteins 1 and 2 (VP1 and VP2). HBoV pathogenicity remains to be fully clarified mainly due to the lack of animal models for the difficulties in replicating the virus in in vitro cell cultures, and the fact that HBoV infection is frequently accompanied by at least another viral and/or bacterial respiratory and/or gastroenteric pathogen infection. Current diagnostic methods to support HBoV detection include polymerase chain reaction, real-time PCR, enzyme-linked immunosorbent assay and enzyme immunoassay using recombinant VP2 or virus-like particle capsid proteins, although sequence-independent amplification techniques combined with next-generation sequencing platforms promise rapid and simultaneous detection of the pathogens in the future. This review presents the current knowledge on HBoV genotypes with emphasis on taxonomy, phylogenetic relationship and genomic analysis, biology, epidemiology, pathogenesis and diagnostic methods. The emerging discussion on HBoVs as true pathogen or innocent bystander is also emphasized.

Keywords: Human bocavirus; Respiratory virus; Molecular tests; Gastrointestinal virus; Pathogenesis; Epidemiology; Immunoassay methods

Core tip: Four genotypes compose the genus Bocavirus: Human bocavirus (HBoV) 1, predominantly found in the respiratory tract; and, HBoV2, 3 and 4, mainly detected in stool and associated with gastroenteritis. Despite worldwide occurrence, human bocavirus infection remains poorly understood, and the comprehension of many aspects of these viruses’ biology (i.e., taxonomy, phylogenetic relationships with other viruses, epidemiology, molecular mechanisms of interaction with human cells, association with other pathogens, etc.) is necessary to clarify whether they are harmless passengers or true pathogens. Development of new diagnostic tools for detection of human bocaviruses will support this type of research.