Human bocavirus: a new respiratory pathogen?

[Human bocavirus (HBoV)]

The human bocavirus (HBoV) has been recently identified by means of molecular screening techniques in respiratory tract secretions from children with acute respiratory tract disease. This virus, which belongs to the Parvoviridae family, has been detected worldwide with a 5 to 10% prevalence among children with upper or lower respiratory tract infections, essentially during the winter period. A seroepidemiological study has shown that almost all the children have antibodies to HBoV by the age of five years, and HBoV infection seems to be rare in adults. HBoV is often detected in association with other respiratory viruses. This virus has also been detected in stools, but its role in gastroenteritis has not been yet established. Virological diagnostic of HBoV infection is based on the detection of viral DNA by PCR. Viral load determination by viral DNA quantitation in respiratory tract secretions could be a tool to differentiate between symptomatic HBoV infection and virus carriage.

Infections respiratoires virales émergentes

Viral respiratory infections are very frequent diseases with variable degrees of severity. During the past few years, new respiratory viruses have been discovered by means of molecular biology techniques. In fact, these so far unidentified viruses have been present in humans for a long time but remained unidentified. These viruses are mainly represented by the human metapneumovirus (HMPV), the coronaviruses HCoV-NL63, HCoV-NH and HCoVHKU1, the human bocavirus (HBoV), and the newly described human polyomaviruses WU and KI. Beside these newly identified viruses, new respiratory viruses have emerged in humans within the last years. These viruses have been introduced from animal reservoirs and they generally present a high degree of pathogenicity with high level of mortality in humans. These emerging respiratory viruses are represented by the henipaviruses (Hendra and Nipah viruses), the New World hantaviruses associated with the Hantavirus Pulmonary Syndrome, the coronavirus responsible for the Severe Acute Respiratory Syndrome (SARS-CoV), and the avian influenza virus H5N1. This latter constitutes a major threat, with the risk of a murderous pandemic offering some parallels with the 1918-1919 Spanish flu which caused 20-50 millions deaths worldwide.