四川地区儿童呼吸道感染人博卡病毒的流行特征与基因变异分析

Study of Molecular Epidemiology and Genetic Diversity of Human Bocvirus in Children with Respiratory Tract Infection in Sichuan

目的分析四川地区儿童呼吸道感染人博卡病毒(HBoV)的流行概况和临床特征,探讨HBoV四川分离株衣壳蛋白基因(VP1)变异特征。方法收集787例呼吸道感染儿童鼻咽分泌物标本,PCR方法检测HBoV,扩增VP1基因序列全长并测序,分析核苷酸和氨基酸变异特征。结果 HBoV的检出率为8.26%(65/787),50.77%(33/65)混合感染其它呼吸道病毒。全年均有检出,主要感染<3岁的儿童,其中男童检出率高于女童。引起的呼吸道症状主要有咳嗽、发热及咳痰。系统进化树分析表明8株四川分离株均为HBoV1基因型。碱基变异以GA+AG转换为主,非同义突变大于同义突变。结论 HBoV是四川地区儿童呼吸道感染的重要病原之一;VP1基因核苷酸序列变异以碱基转换为主;氨基酸突变位点可能与免疫逃避有关。

Objective 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. Methods 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. Results 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. Conclution 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.