湖南省甲型H1N1流行性感冒大流行后乙型流行性感冒病毒的特征  

Characterization of influenza B viruses isolated in Hunan Province after pandemic influenza A （H1 N1）

作　　者：黄一伟 高立冬 李芳彩 张恒娇 李文超 刘运芝 胡世雄 张红 陈长 李俊华 

机构地区：[1]湖南省疾病预防控制中,长沙410005

出　　处：《中华传染病杂志》2012年第6期334-338,共5页Chinese Journal of Infectious Diseases

基　　金：国家“十一五”科技重大专项资助项目（2008ZX10004-018）;湖南省卫生厅科研基金课题资助项目（A2007008）;湖南省科技厅科研基金课题资助项目（2010ZK3034）

摘　　要：目的分析湖南省甲型H1N1流行性感冒（流感）大流行后乙型流感的流行情况和病毒基因特征，并探究可能造成其流行的原因。方法对湖南省2010年23家哨点医院门诊流感样病例中采集的咽拭子标本使用犬肾传代细胞进行病毒分离，阳性毒株使用血凝抑制实验进行型别鉴定，对选取的10株乙型流感病毒进行全基因组测序，对序列进行进化树和分子特征分析。结果随着甲型H1N1流感分离毒株的减少，乙型流感病毒在2010年上半年成为优势毒株，以B／Victoria系（BV系）为主，两种型别共存。2010年11起已知型别的聚集性疫情中，7起为乙型流感。在除核蛋白（NP）外的其他聚合酶（PB2、PB1、PA）、血凝素（HA）、神经氨酸酶（NA）、NB蛋白、膜蛋白（M1）、乙型流感病毒M2蛋白（BM2）、非结构蛋白（NS1、NS2）10个蛋白的基因进化树中，10株病毒均按照其系的分类分在BV和B／Florida系（BY系）两个分支中，而NP进化树10株病毒均在BY分支中。与世界卫生组织疫苗株比较，10株病毒11个蛋白的氨基酸同源性均较高，为97．2％-100．0％，但仍发现有一些碱基位点的改变。未发现对NA抑制剂类药物耐药位点的突变。相对于日常监测病毒，2株聚集性疫情毒株编码NA、NB、PB1、PB2和NS2的碱基有一些突变。结论乙型流感病毒有一些基因位点发生插入和重配，显示病毒持续进化，这可能是湖南省甲型H1N1流感大流行后B型流感病毒成为优势毒株的原因。Objective To analyze the prevalence status and the genetic characterizations of influenza B viruses isolated in Hunan Province after pandemic influenza A （HIN1） 2009, and to explore possible reasons for the prevalence. Methods Throat swabs were collected from outpatients with influenza-like illness in 23 sentinel hospitals of Hunan Province in 2010. Influenza viruses were isolated with Madin-Darby canine kidney （MDCK） cells and identified by haemagglutination inhibition test. The genomes of 10 selected influenza B viruses were sequenced and analyzed for phylogenetic and molecular characterization. Results With the reduction of isolation of pandemic influenza A （H1N1） 2009 viruses, influenza B virus became the predominant isolated strain in the first half of 2010. Epidemic viruses mainly belonged to the B/Victoria lineage, and both two lineages co-circulated. Sevenout of 11 influenza outbreaks caused by type B. Ten strains were filled into 2 branches of BV and BY which were classified by their lineage typeS in polymerase （PB2, PB1, PA）, hemagglutinin （HA）, neuraminidase （NA）, NB, membrane protein （M1）, influenza B virus membrane protein M2 （BM2）, and non-structural protein （NS1, NS2） phylogenetic trees except the NP phyiogenetic tree in which 10 strains were all in the BY branch. Compared with World Health Organization （WHO） vaccine strains, the amino acid identity of 11 proteins of the 10 strains was high （97.2%-100.0%）. However, some amino acid point mutations were found. No mutation was found in drug resistance mutation sites. Some mutations in NA, NB, PB1, PB2 and NS2 molecules were found in 2 strains isolated from outbreaks compared with strains from sentinel surveillance. Conclusions The point mutations, insertions and genetic reassortment indicate viruses sustaining evolution, which is probably the reason for predominant influenza B viruses after pandemic influenza A （H1N1） 2009 in Hunan Province.

关 键 词：流感病毒B型 流感病毒A型 H1N1亚型 流感 人 哨点监测 序列分析 抗原 变异 

分 类 号：R51[医药卫生—内科学] R1[医药卫生—临床医学]