广东地区急性呼吸道感染儿童人类博卡病毒的流行状况

The prevalence of human bocavirus among children with acute respiratory tract infection in Guangdong

目的了解广东地区急性呼吸道感染患儿人类博卡病毒（HBoV）的感染情况。方法收集广东地区2007年6月至2008年5月期间呼吸道感染患儿的鼻咽分泌物447份，采用PCR法检测HBoV衣壳蛋白（VP）基因片段，阳性标本作核酸序列测定，并与基因库中的已知序列进行序列比对和系统进化树分析。结果447例呼吸道感染患儿标本中HBoV阳性率为5．1%，其中10例患儿与萁他病毒混合感染，占阳性标本的43．5％。阳性患儿的主要临床诊断为喘息性肺炎、毛细支气管炎和支气管肺炎，年龄分布从42d到6岁，主要集中在1岁以内，HBoV感染的季节分布偏向夏、秋及晚春。经序列比对和进化树分析，阳性株的VP基因片段与瑞典株ST1的核酸及氨基酸序列同源性分别为97．8％～98．8％及99．3％～100．0％。结论HBoV是广东地区儿童下呼吸道感染的重要病原之一，且在1岁以内患儿中高发。该地区HBoV流行株的VP基因片段较为保守，但也存在导致氨基酸改变的突变株。

Objective To investigate the prevalence of human bocavirus （HBoV） among children with acute respiratory tract infection （ARTI） in Guangdong Province. Methods Four hundred and forty-seven nasopharyngeal aspirates or swabs samples from children with ARTI in Guangdong Province were collected from June 2007 to May 2008. HBoV capsid protein VP gene fragments were detected using polymerase chain reaction （PCR）. Positive PCR products were sequenced. The DNA and translated amino acid sequences were aligned with known HBoV sequences in GenBank and phylogenetic analysis was also done. Results The positive rate of HBoV was 5.1% of samples from 447 ARTI cases. Ten samples were positive for both HBoV and other respiratory virus, which was 43.5% of positive samples. The main diagnosis for HBoV positive children included wheezing pneumonia, bronchiolitis and bronchial pneumonia. HBoV positive children ranged from 42 days to 6 years old, and most of them were younger than one year. HBoV infection was more common during summer, early autumn and late spring. Through sequence alignment and phylogenetic analysis, the DNA sequences and amino acid sequences of VP gene fragments of isolated HBoV strains showed 97.8%-98.8% and 99.3% -100.00% identity with ST1, respectively, Conclusions HBoV is one of the important pathogens of lower respiratory tract infection in children in Guangdong Province, which is more prevalent in infants younger than one year. Although VP gene fragment of HBoV is conservative in general, there are still some missense mutations.