[Clinical relevance of human bocavirus with acute respiratory tract infection and diarrhea in children: a prospective case-control study]

To explore the causative role of human bocavirus (HBOV) played in acute respiratory infection and diarrhea in children, a case-control study was prospectively conducted to investigate HBOV detection in symptomatic children with acute respiratory tract infection, diarrhea and asymptomatic children.Between Oct. and Dec. of 2008, 436 nasopharyngeal aspirates (NPA) from hospitalized children with acute respiratory infection and 150 NPA from asymptomatic children undergoing cardiac operations were consecutively collected. During the same time, 220 stool samples were taken from outpatients with acute watery diarrhea and 200 control specimens were obtained from children without diarrhea. HBOV was screened in all samples by real-time PCR method. HBOV-positive respiratory samples were tested for other 9 common respiratory viruses and Mycoplasma pneumoniae. HBOV-positive fecal samples were also tested for common enteric viruses causing diarrhea.HBOV was detected in NPA samples from 45 (10.3%) of 436 symptomatic patients and from 1(0.7%) of 150 asymptomatic control children. There was a statistically significant difference in the detection rates of HBOV between the symptomatic group and the asymptomatic group (P0.001). HBOV co-existence with other respiratory pathogens occurred in 44.7% (20/45) of NPA from symptomatic patients. HBOV was detected in 10.3% (43/417) children with community-acquired respiratory infection and 10.5% (2/19) children with nosocomial respiratory infection. Children with HBOV infection were 1.3 to 72 months of age (mean: 18.3 ± 13.6 months). HBOV was found positive in 6 (2.7%) of 220 stool samples from diarrheal outpatients and in 4 (2%) of 200 control samples. All children with HBOV positive detection in the stool samples were less than 4 years old. No statistical significance was found (P0.05) in HBOV between diarrhea patients and asymptomatic ones. In addition, 5 of 6 HBOV-positive fecal specimens from children with diarrhea were found co-infected with rotavirus.This study supports that HBOV is related to acute respiratory infection in children and HBOV infection usually occurs in infants and young children. However, further study is needed to clarify if HBOV plays a pathogenic role in diarrhea in children.