Clinical and microbiological impact of human bocavirus on children with acute otitis media.

Human Bocavirus (HBoV) as a newly discovered parvovirus has been commonly detected in respiratory tract infections. However, its role in acute otitis media (AOM) has not been well studied. We examined HBoV in Japanese children with AOM and evaluated the virus prevalence together with clinical manifestations and bacterial findings. Overall, 222 nasopharyngeal swabs and 176 middle ear fluids (MEF) samples were collected from 222 children with AOM (median age, 19 months) between May 2006 and April 2007. HBoV detection was performed by PCR and bacterial isolation by standard culture methods. HBoV was found in the nasopharyngeal aspirates of 14 children (6.3%) and in the MEF of six children (2.7%). When HBoV detection results were evaluated with clinical characteristics of children, resolution time of AOM was significantly longer (p=0.04), and rate of fever symptom was also higher in HBoV-positive group (p=0.04). Furthermore, we found positive correlation between detection of HBoV and Streptococcus pneumoniae in the MEF (p=0.004). Nevertheless, nasopharyngeal proportion of S. pneumoniae was similar between virus positive and negative groups. Furthermore, S. pneumoniae was detected as a single pathogen in all MEF of HBoV-positive cases but one, while it presents mixed with other pathogenic bacteria in nasopharynx. In conclusion, HBoV may worsen the clinical symptoms and prolong the clinical outcome of AOM in pediatric population. Finally, HBoV may prime the secondary bacterial infection in the middle ear in favor of S. pneumoniae.