[Study of molecular epidemiology and genetic diversity of human bocvirus in children with respiratory tract infection]

To investigate the epidemiological features and clinical features of human bocavirus (HBoV) infection in children with respiratory tract infection in Sichuan, and to analysis the HBoV VP1 gene mutation characteristics of Sichuan clinical strains.Nasopharyngeal secretions were collected from 787 hospitalized children with respiratory tract infection. PCR was used to detect HBoV. The VP1 genetic variations of the nucleotide and amino acid were analysised respectively.Out of 787 specimens from respiratory tract, 8.26% (65/787) were positive for HBoV, 50.77% (33/65) were co-detected with other respiratory viruses. HBoV is usually detected in children under 3 years of age, the positive rate of male children was higher than female children. Most frequently clinical symptoms of HBoV were cough, fever and expectoration. Phylogenetic analyses showed that all the 8 clinical strains were HBoV1 genetype. GA+AG transitions were the most frequent transitions detected, while the nonsynonymous mutations were more than synonymous mutations.HBoV is an important pathogen of respiratory tract infection in children in Sichuan. The main type of nucleotide variation is transitions. Amino acids mutations may relate to immune evasion.