Although recently it was found that HBoV could be cultured in differentiated human airway epithelial cells [6] , routine viral culturing of HBoV remains difficult. Real-time PCR has been used to estimate viral load and its usefulness has been proved as an indicator of the degree of active viral infection, interactions between the virus and the host, and the role of viral reactivation or persistence in the progression of disease [7] . In this study, we investigated the epidemiology of HBoV and the clinical features of respiratory infection associated with HBoV, especially in terms of HBoV load. KJLM from 1,815 patients were randomly selected among the 5,891 samples collected from patients referred to the Korea University Guro Hospital for screening for respiratory viruses. Among the patients, 59.0% were men, and the ages of the patients ranged from 1 day to 86.0 yr (mean = 6.1 yr, median = 26 months); children aged 5 yr or less constituted 75.3% of the study population. The nasopharyngeal aspirates (NPAs) obtained from all patients were stored in a viral transport medium and quickly delivered to the laboratory by using wet ice. R-Mix culture system (Diagnostic HY-BRIDS, Athens, OH, USA) was used to screen the samples for presence of 5 respiratory viruses (influenza A and B viruses, parainfluenza viruses, respiratory syncytial virus, and adenovirus).