Human Bocavirus quantitative DNA detection in French children hospitalized for acute bronchiolitis

BACKGROUND: Human Bocavirus (HBoV) is a newly discovered parvovirus whose role as a causative agent of respiratory disease remains unclear. STUDY DESIGN: We investigated the presence of HBoV by quantitative PCR in the nasopharyngeal samples of 192 French children consecutively hospitalized for acute bronchiolitis. Other common respiratory viruses were detected using immunofluorescence assays, cell culture detection, or RT-PCR assays. RESULTS: HBoV was detected in 24 (12.5%) of 192 study children. In 14/192 cases (7%) HBoV was the sole isolate and in 10/192 (5%) it was part of a mixed viral infection. HBoV was the third most common pathogen detected after respiratory syncytial virus (45/192; 23%) and rhinovirus (24/192; 12%). It occurred more often in infants aged 1–12 months (P = 0.002). Median levels of HBoV DNA genome in respiratory samples were significantly higher in patients with single HBoV infection than in patients with mixed respiratory viral infection with HBoV (4 × 10(8) copies/ml vs. 2 × 10(3) copies/ml, P < 0.001). CONCLUSIONS: Our data suggest that HBoV at a high viral load could be an etiologic agent of respiratory tract disease, whereas the exact role of HBoV at a low viral load, as etiological cause or as pathophysiological co-factor of respiratory diseases, remains to be determined.