[Detection and genotyping of human bocavirus 2 in children with acute diarrhea]

To investigate the prevalence of HBoV2 in pediatric patients with acute diarrhea in Beijing and the characteristic of the genome of the virus, 553 stool specimens were collected from pediatric outpatients with acute diarrhea in Affiliated Children's Hospital of Capital Institute of Pediatrics during Nov. 2010 to Oct. 2011. TaqMan-based Real-time polymerase chain reaction was performed to detect HBoV2 DNA from these specimens. Two positive specimens with high viral loads were selected for segmented amplification and then the amplified fragments were cloned into the plasmid vector pGEM-T, transformed into Escherichia coli DH5alpha and sequenced. Then genomic sequences assembled from those DNA fragments were compared with other parvovirus genomic sequences in the GenBank. Among these 553 specimens tested, 15 (2.7%) were HBoV2 DNA positive. The highest positive rate was shown in July (7.0%) through the whole year and in 3-6 month age group (4.1%) among different age groups. All these 15 specimens positive for HBoV2 DNA were collected from patients younger than 2 years old, including 4 simultaneously positive for norovirus, 3 positive for rotavirus and 1 positive for adenovirus. By sequence analysis, 2 almost complete HBoV2 genomic sequences assembled from gene fragments amplified from specimens BJQ19 and BJQ390 were typical HBoV2. And they shared high homology with each other (99.2%), while they shared the highest homology with FJ375129 from Shanghai China (99.1% and 99.2%) among other parvoviruses. These data suggest that some of acute diarrhea in pediatric patients in Beijing were associated with HBoV2, and infants and young children aged from 3 months to 2 years, are more likely to be infected by HBoV2.