Human Bocavirus Infection in Children With Respiratory Tract Disease

Background: Human bocavirus (HBoV) is a ubiquitous, newly described member of the Parvoviridae family frequently detected in the respiratory tract of children, but only few reports provide data proving the link between HBoV and respiratory tract disease (RTD). Objectives: To evaluate the incidence of HBoV infection in children with RTD; to analyze the clinical features of HBoV infection; and to clinically compare HBoV, respiratory syncytial virus (RSV), and human metapneumovirus (HMPV) infections. Study Design: A prospective 1-year study was conducted in children < 5 years of age hospitalized with RTD and in asymptomatic control children. Results: Human bocavirus was detected in 55 (10.8%) of the 507 children tested and in none of the 68 asymptomatic control children (P = 0.01). About 80% of these infections Occurred between November and March. Coinfection with another virus was observed in 22 (40%) of the HBoV-positive children. HBoV viral load was significantly higher in samples from children with HBoV monoinfection than in those with coinfection. Subsequent detection of HBoV more than 2 months after the initial detection could be documented in 3 children. Clinical features associated with HBoV infection were similar to those observed with either RSV or HMPV infections, but HBoV infections were less severe than RSV infections. Conclusions: The difference observed in HBoV prevalence between children with RTD and controls provides Support for a role of this virus in RTD. The frequent associations of HBoV with other respiratory viruses might be explained by the persistence of HBoV in the respiratory tract. The significance of HBoV viral load in nasopharyngeal secretions as a marker of pathogenicity merits further investigation.