The Role Of Human Bocavirus In Children With Acute Respiratory Tract Infection In Sochow Area

Objective Respiratory tract infections are a leading cause of mobidity and mortality in children worldwide . We sought to determine whether HBoV was circulating in Sochow area and to determine the epidemiology and clinical features associated with HBoV infection .in comparison with the associated with hMPV and RSV infection.Method From February,2009 to january,2006, 1885 samples were collected for bacterial culture,also we tested respiratory specimens for the presence of HBoV and MP by polymerse chian reaction (PCR).These specimens also assayed for respiratory syncytialvirus,influenza A and B,parainfluenze virus 1 to 3, and adenovirus,respiratory syncytial virus by direct fluorescent antibody test,and hMPV by reverse-transcription polymerse chian reaction (RT-PCR). PCR products of HBoV VP1 gene from some patients were randomly selected for sequencing analysis,and the sequences of the nucleotides and deduced amino acids were compared with those in the GenBank.Results Of the 1885 patients screened, 145(7.69%) patients had evidence of HBoV infection and was the second most common viral pathogen. Among them ,single HBoV infection were 120 cases, 25 of 145 HBoV -positive children (17.24%) had coinfection with other respiratory virus (HBoV co).The majority of HBoV-positive individuals were detected in the winter and autumn seasons . The median age age of patients was 22.09 months, and a majority (53.79%) of children who tested positive for HBoV were aged from 6 to 18 months. HBoV was mainly identified in patients with lower respiratory tract infection . The infected children were diagnosed as having upper respiratory tract infection (2.76%),bronchiolitis(1.38%), bronchopneumonia (85.52%),lobar pneumonia(5.52%), severe pneumonia(3.45%) , stomatitis and laryngitis(0.69%). Clinical manifests includeded fever, cough, rhinorrhea, wheezing and abnormal findings on chest radiographs (bronical thicking focal infiltrates , inflation,atelectasis). Clinical symptoms associated with HBoV infection were similar to those associated with RSV and hMPV infection . Sequence analysis of these HBoV VP1 genes showed 98% homolgy to the registered sequence in GenBank.Conculsion (1) HBoV accounted for a small but significant proportion of respiratory–tract disease in children in Sochow area. (2) HBoV prevailed predominantly in the winter and autumn time .(3) HBoV infection was mainly associated with lower respiratory tract infections. (4)Coinfections of HBoV with other respiratory viruses were clinically similar to single infections. (5)The epidemiology of HBoV was similar with pneumonia mycoplasma and was opposite with influenza hemophilus (6) Clinically, HBoV infection can not be discriminated from the infection of other respiratory tract viruses such as RSV and hMPV.