江苏省2011年乙型流感病毒血凝素和神经氨酸酶分子流行特征

目的 分析2011年江苏省乙型流感病毒的血凝素(HA)和神经氨酸酶(NA)的分子流行特征.方法 选择13株2011年江苏省不同地区、不同流行时间的乙型流感毒株进行全基因组测序,通过生物信息学方法对HA、NA分子流行特征进行分析.结果 13株乙型流感毒株中,10株属于Victoria系,3株属于Yamagata系.10株Victoria系毒株的NA基因来源于Yamagata系病毒,是基因重配流行株.与疫苗株相比,10株Victoria系毒株和3株Yamagata系毒株的HA蛋白分别在197和196位增加一个糖基化位点.结论 2011年江苏省乙型流感Victoria系和Yamagata系病毒同时流行,其中重配的Victoria系病毒占优势.     

北京市门头沟区2015—2016年Victoria系乙型流感病毒HA1基因特征分析

目的 了解北京市门头沟区2015—2016年分离的Victoria系乙型流感病毒血凝素HA1基因变异特征,分析流行株与我国疫苗株的匹配情况,为乙型流感防控提供依据.方法 对狗肾传代细胞(MDCK)培养分离得到的14株Victoria系乙型流感病毒进行核酸提取,采用逆转录-聚合酶链反应(RT-PCR)扩增病毒HA1基因后进行核苷酸序列测定,采用邻接法进行遗传进化树分析.结果 2015—2016年北京市门头沟区流行的乙型流感病毒以Victoria系为主.分离并测序的14株Victoria系乙型流感病毒HA1基因与WHO推荐的2016—2017年流感疫苗株B/Brisbane/60/2008(FJ766842)和国内代表株B/JilinNanguan/1223/2016(EPI768805)亲缘性更近.与B/Brisbane/60/2008和B/JilinNanguan/1223/2016(EPI768805)的HA1区的氨基酸相比,所有毒株都在2个位点发生氨基酸替换,个别毒株也会在其他个别位点发生点突变,变异涉及1个抗原决定簇.而与WHO推荐的2015—2016年Yamagata系疫苗株B/Phuket/3073/2013(EPI608074)亲缘关系稍远一些.结论 在2015—2016年流感监测季中,北京市门头沟区乙型流感病毒以Victoria系为优势流行株.而WHO推荐的乙型流感疫苗株为Yamagata系,可见疫苗株与本区流行株匹配性不佳.     

2015年北京市房山区乙型Yamagata系流感病毒HA基因特性分析

目的 了解北京市房山区2015年乙型Yamagata系流感病毒HA1基因变异情况.方法 选取2015年流感病原学监测中分离到的乙型Yamagata系毒株共13株,采用RT-PCR法扩增病毒HA基因片段后进行序列测定,与WHO推荐的疫苗株进行比对并构建进化树.采用MEGA6软件对测序结果进行分析.结果 2015年房山区乙型Yamagata系流感病毒HA1基因片段序列测定拼接后核苷酸长度为1059bp,编码氨基酸为353个,与2014-2015年的疫苗株B/Massachusetts/02/2012比较,13株毒株的氨基酸均在第123、131、165、180、187、196、211、217、244、313、327位点有变异;与2012-2013年的疫苗株B/Wisconsin/01/2010比较,13株毒株的氨基酸在第187、313、327均有变异.做进化树分析,房山区2015年分离到的乙型Yamagata系流感病毒与疫苗株B/Wisconsin/1/2010在同一个分支上,距离较近,与B/Massachusctts/2/2012不在一个分支上,距离较远.结论 2015年北京市房山区乙型Yamagata系流感病毒HA1基因在抗原决定簇区已发生变异,但疫苗株B/Wisconsin/01/2010有保护作用,应继续关注氨基酸的替换.     

1994-2006年深圳市分离的B型流感病毒分子进化研究

目的 通过对深圳市分离的B型流感病毒HA1分子系统进化分析,初步了解深圳市B型流感病毒的流行变异规律.方法 选取深圳市1994-2006共13年间分离的50株B型流感毒株,通过RT-PCR将其HA1基因片段扩增后进行序列解析,然后,通过MEGA等软件对序列进行分子进化分析.结果 1994-2006年间深圳市流行的B型流感病毒分为Yamagata和Victoria两个亚系,两系的毒株分别是不同年份的主要流行株.两个亚系的HA1分子具有1个糖基化位点的差异,在4个抗原决定簇区域也分布有多个氨基酸位点的变异.结论 1994-2006年间深圳市B型流感病毒的两个亚系分别在不同年份主导流行,但变异均比较缓慢.

Abstract：

Objective To study the prevalence and variation of influenza B viruses of Shenzhen. Methods Fifty strains influenza B viruses in Shenzhen from 1994 to 2006 were selected. HA1 gene were amplified by RT-PCR and sequenced. Phylogenetic analysis of HA1 was conducted by MEGA program. Results The influenza B viruses of Shenzhen were divided into Yamagata and Victoria lineage. The two lineages prevailed respectively in different years from 1994 to 2006. The variance of glycosylation site and some mutations of antigenic determinants were detected in the two lineages. Conclusion The viruses of Yamagata and Victoria lineage prevailed respectively in different years in Shenzhen but the mutation rates of the two lineages were slowly.     

武汉市2003年流感监测及当前优势流行毒株的抗原性和基因特性分析

目的 探讨2003年武汉市流感流行概况，分析优势流行毒株抗原性和基因特性变异特征。方法 每周在流感监测哨点医院统计流行病学资料，采样分离流感病毒标本，对其中3株H3病毒做血凝抑制试验并对其编码HA1区基因进行序列测定和分析。结果 从418份咽拭标本中分离到流感病毒58株，其中5，7株为H3亚型，1株为乙型；全年月分离率和门诊流感样病例数的变化有冬、夏两个高峰，最高峰均出现在7月；新分离到的3株H3病毒的抗原性与本年度疫苗组分株A／Panama／2007／99有较大差异，编码HA1区的氨基酸序列有14个位点发生了变异，基因种系发生树分析也证实他们的HA1基因存在较大差异。结论 2003年武汉市流感活动呈双峰型增强，H3病毒活动显著加强，其抗原性和基因特性与疫苗株相比均发生了较大的变异。     

江苏省2019—2022年乙型流感病毒Victoria系HA基因特征分析

目的分析江苏省2019—2022年乙型流感病毒Victoria系流行特征, 了解其基因变异情况, 监测江苏省流感活动水平和流行趋势。方法通过"中国流感监测信息系统"收集的江苏省2019—2022年流感样病例监测数据, 选取16株乙型流感病毒Victoria系毒株进行全基因组测序, 利用MEGA 7软件构建进化树并进行HA基因序列特征分析。结果江苏省2019—2022年监测到的流感病毒中乙型流感病毒Victoria系占绝对优势。16株标本株中2019—2020年度的毒株在V1A.3早期分支, 而2021—2022年度的毒株则聚类在3a.2亚型分支。与疫苗株相比, 2019—2020及2020—2021年度的毒株发生了1个氨基酸位点的改变并增加了1个糖基化位点, 而2021—2022年度的毒株则存在多个位点变异, 其中H122Q、A127T、R133G、P144L、N150K、S194D及K200R位于抗原决定簇上。结论江苏省乙型流感病毒Victoria系在多处基因位点发生了变异, 提示对该亚型变异的持续监测至关重要, 可为疫苗的更新提供重要依据。     

2021—2022年流感监测季北京市乙型Victoria系流感病毒血凝素基因特性和抗原性分析

目的分析2021—2022年流感监测季北京市乙型Victoria系流感病毒(BV)的血凝素(hemagglutinin, HA)基因特性、抗原性及与流感疫苗组分株的匹配性。方法采集2021—2022年流感监测季流感样病例(influenza like-illness, ILI)咽拭子样本经MDCK和鸡胚培养分离流感病毒, 提取病毒核酸后测序。应用MEGA5.0进行病毒HA基因的核苷酸和氨基酸变异, 采用maximum likelihood方法构建HA基因的遗传进化树, 在线预测N-糖基化位点。SWISS-MODEL同源建模, 建立BV毒株HA的蛋白质三维空间模拟图。通过血凝抑制(hemagglutination inhibition, HI)试验, 进行毒株的抗原性分析。结果共收集402株BV毒株, 选取58株测序获得HA基因全长序列, 与本年度的疫苗组分BV株(B/Washington/02/2019)HA基因相比较显示, 有27个氨基酸位点发生变异, 其中11个变异位点位于4个不同的抗原决定簇。遗传进化树分析显示:3个进化分支的毒株共同流行, 其中54株(54/58, 93.10%...     

当前流行的乙型流感病毒血凝素蛋白抗原性及其基因特性

通过抗原性分析弄清了近年来连续２次乙型流感病毒在我国人群中造成流感流行，是由于乙型流感病毒株发生抗原性变异所造成。通过毒粒基因分析发现，我国人群中流行的Ｂ／Ｐａｎａｍａ／４５／９０类毒株，其ＨＡ１区氨基酸序列比国际代表性毒株Ｂ／Ｐａｎａｍａ／４５／９０病毒在１６５位点上多一个氨基酸，乙型流感病毒流行株可能具有地区性差异。     

当前流行的乙型流感病毒血凝素蛋白的抗原性及其基因特性

通过抗原性分析弄清了近年来连续２次乙型流感病毒在我国人群中造成流感流行，是由于乙型流感病毒株发生抗原性变异所造成。通过毒粒基因分析发现，我国人群中流行的Ｂ／Ｐａｎａｍａ／４５／９０类毒株，其ＨＡＩ区氨基酸序列比国际代表性毒株Ｂ／Ｐａｎａｍａ／４５／９０病毒在１６５位点上多一个氨基酸（天冬酰胺），乙型流感病毒流行株可能具有地区性差异。     

当前我国流行的乙型流感病毒血凝素蛋白抗原性及基…

通过病毒血凝素蛋白抗原性分析，弄清楚了近年来连续几年在我国人嫩中造成乙型流感病毒流行和局部暴发由于乙型流感病毒发生抗原性变异和在我国人群中至少有两第抗原性明显不同的乙型流感病毒同时并存所造成。同时还发现乙型流感病毒的流行具有地区性差异。通过对乙型流感病毒血凝素重键区核甘酸和氨基酸序列的分析发现，近年来在我国分离的两系乙型流病毒毒株之间有高达３０－４２个氨基酸的差异，Ｂ／Ｙａｍａｇａｔａ／１６／８８     

Increasing appearance of reassortant influenza B virus in Taiwan from 2002 to 2005

Genetic and antigenic analyses of influenza B virus field strains isolated in Taiwan from 1998 to 2005 were performed. To investigate the molecular evolution of influenza B viruses, sequence analysis of the hemagglutinin (HA1 subunit) and neuraminidase genes was performed. All influenza B viruses isolated between 1998 and 2000 belonged to the B/Yamagata/16/88 lineage. The B/Victoria/2/87 lineage, which was cocirculating with the Yamagata lineage, was identified in Taiwan in March 2001. Concurrently, there was an increasing prevalence of this lineage in many parts of the world, including North America and Europe, during the 2001-2002 season. Since 2002, genetic reassortants of influenza B virus with the Victoria lineage of hemagglutinin and the Yamagata lineage of neuraminidase have been found at a rate of 46%. Therefore, in 2002, at least three sublineages of influenza B virus strains, the B/Shanghai/361/2002-like strain (Yamagata lineage), the B/Hong Kong/330/01-like strain (Victoria lineage), and the B/Hong Kong/1351/02-like strain (B reassortant lineage), were identified in Taiwan. The results showed that genetically distinct lineages can cocirculate in the population and that the reassortment among these strains plays a role in generating the genetic diversity of influenza B viruses. Interestingly, from January to April 2005, B reassortant viruses became dominant (73%) in Taiwan, which indicated that a mismatch had occurred between the influenza B vaccine strain recommended for the 2004-2005 season in the Northern hemisphere by the World Health Organization and the epidemic strain.     

Genetic analysis and evaluation of the reassortment of influenza B viruses isolated in Taiwan during the 2004-2005 and 2006-2007 epidemics

Influenza B viruses were predominant in Taiwan during the 2004-2005 epidemic and both Victoria and Yamagata lineage viruses co-circulated. A reassortant influenza B virus that contained a Victoria lineage hemagglutinin (HA) gene and Yamagata lineage neuraminidase (NA) gene appeared first in 2002 and became predominant during the 2004-2005 epidemic. During the 2006-2007 epidemic, an influenza B outbreak occurred in Taiwan and only Victoria lineage viruses circulated. We characterized the viruses isolated in the 2006-2007 epidemic and found that the HA genes of influenza B viruses from that epidemic were highly similar to those from the 2004-2005 epidemic. We also analyzed the NA genes of isolates from the 2006-2007 epidemic and found that they all belonged to the Yamagata lineage and formed a new genetic subclade. Comparison of isolates from the 2004-2005 and 2006-2007 epidemics revealed four substitutions, N220K, E320D, K343R and E404K in NA genes. Although the HA sequences from the 2006-2007 epidemic were similar to those from the 2004-2005 epidemic, the NA sequences differed, suggesting distinct patterns of evolution of the HA and NA genes from 2004-2007 in Taiwan. This study emphasizes that the evolution of the NA genes may contribute to reemergence of influenza B viruses.     

Genetic diversity of influenza B virus: the frequent reassortment and cocirculation of the genetically distinct reassortant viruses in a community

To characterize the genetic diversity of influenza B viruses isolated during one influenza season, the antigenic and genetic relationships among 20 strains of influenza B virus isolated in February and March 2001 at one pediatric clinic in Yamagata City, Japan, were investigated. The HA gene and seven other gene segments were phylogenetically divided into three distinct sublineages (Harbin/7/94-, Tokyo/6/98-, and Shiga/T30/98-related lineage) of the Yamagata/16/88-like lineage. The NS genes of the viruses belonging to the Harbin/7/94-related lineage have additional three nucleotides at positions 439-447, and were phylogenetically distinguishable from those of the currently circulating Yamagata/16/88- and Victoria/2/87-like lineages, but were closely related to that of the Yamagata/16/88-like lineage isolated before 1994. Moreover, four strains of influenza B virus isolated in the same community between 2002 and 2003 were further examined. Phylogenetic analysis revealed that a virus of Victoria/2/87-like lineage isolated in 2003 had acquired the NA, NS, M, and PA gene segments from a Shiga/T30/98-like virus, and two strains of Harbin/7/94-related lineage had acquired the various gene segments from Shiga/T30/98-like virus through a reassortment event. These results indicate that genetically distinct multiple viruses can combine to cause an influenza B epidemic in a community and that the frequent reassortment among these viruses plays a role in generating the genetic diversity of influenza B viruses.     

Clinical and genetic characterization of severe influenza B-associated diseases during an outbreak in Taiwan.

BACKGROUND: Mismatches between circulating and vaccine strains of influenza virus had been observed in Taiwan. A comprehensive clinical and genetic analysis of influenza B viruses-associated important diseases was lacking. OBJECTIVES: Clinical and phylogenetic analysis of influenza B viruses during an outbreak in Taiwan. STUDY DESIGNS: Clinical manifestations of hospitalized, culture-confirmed patients were analyzed from July 2004 to June 2005. Partial genome sequence analysis of hemagglutinin (HA), neuraminidase (NA), and nonstructural (NS) genes were performed in 54 influenza B isolates during the study period, and nine srandomly chosen isolates during 2000 and 2003. RESULTS: Three specific diseases were found in these patients, including 13 of encephalitis/encephalopathy, 28 of influenza-associated myositis (IAM), and one of acute respiratory distress syndrome (ARDS). Three phylogenetic groups were identified, including reassortant strains-group 1 (Victoria lineage of HA, Yamagata lineage of NA, clade A of NS), group 2 (Yamagata lineage of HA, Yamagata lineage of NA, clade A of NS), and group 3 (Yamagata lineage of HA, Yamagata lineage of NA, clade B of NS). CONCLUSIONS: Severe influenza B-associated disease in children was not rare and might be fatal. We offered the evidence of co-circulation of the two HA lineages in the same outbreak.     

B型流感病毒Yamagata系和Victoria系双重荧光PCR诊断方法的建立与应用

目的 建立一种新型的双重荧光PCR诊断方法,用于B型流感病毒By (B/Yamagata)和Bv(B/Victoria)亚系的准确分子分型.方法 从GenBank随机下载By和By HA(hemagglutinin)基因各50条序列,通过MEGA分析,利用Primer Primer软件设计亚系特异性引物和通用探针,建立双重荧光PCR诊断方法.用HAI(hemagglutination inhibition)实验确认的B型流感病毒亚系分离毒株和A型流感病毒进行特异性验证,用体外转录核酸拷贝数进行灵敏度实验.结果 2006-2010流感监测年份,对17 765份流感样病例咽拭标本中分离到B型流感病毒793株,本方法鉴定有152株By和641株Bv病毒,与HAI鉴定结果一致.本诊断方法的检测特异性达100％,灵敏度达102拷贝/μl,重复性变异系数＜3.5％.结论 本研究所建立的荧光PCR方法为流感实时监测提供了有力的技术支撑,适合于流感监测实验室对流感病毒的快速分子诊断.     

Exploration of the emergence of the Victoria lineage of influenza B virus

Summary. The Victoria lineage represented by B/Victoria/2/87 is one of the two major distinctive haemagglutinin (HA) lineages of influenza B virus, and its recent re-emergence has aroused great concerns. However, it remains unknown when, where, and how this HA lineage emerged in the world. In this study, the HA1 domain of the HA gene of fourteen influenza B viruses isolated in China in 1972–1984 was sequenced. The sequences were phylogenetically analyzed with the HA1 sequences of 41 other important influenza B isolates. The results unveiled some earlier footprints of the Victoria lineage in China, and the epidemic history of the Victoria lineage could be traced back from the year 1985 to 1975. Moreover, phylogenetic analysis, the history of China, and the epidemiology of influenza B virus indicated that the Victoria lineage possibly emerged in China in the 1970s through gradual evolution from a minor lineage.     

Evolutionary characteristics of influenza B virus since its first isolation in 1940: dynamic circulation of deletion and insertion mechanism

Summary.  New antigenic variants of B/Yamagata/16/88-like lineage which appeared in the season of 1997 as a minor strain tended to predominate in the following season. Also, we could observe for the first time, three peaks of activity caused by H3N2 virus and two variants of B influenza virus. Antigenic and phylogenetic analyses revealed that B/Victoria/2/87-like variants appeared again in Japan in 1997 after a nine-year absence. Influenza B viruses evolved into three major lineages, including the earliest strain (I), B/Yamagata/16/88-like variants (II), which comprised of three sublineages (II-(i), II-(ii), II-(iii)), and B/Victoria/2/87-like variants (III). Evolution of influenza B virus hemagglutinin was apparently distinguishable from that of influenza A virus, showing a systematic mechanism of nucleotide deletion and insertion. This phenomenon was observed to be closely related to evolutionary pathways of I, II-(i), II-(ii), II-(iii) and III lineages. It was noteworthy to reveal that the nucleotide deletion and insertion mechanism of influenza B virus completed one cycle over a fifty-year period, and that a three nucleotide deletion was again observed in 1997 strains belonging to lineage II-( iii). It was evident that amino acid substitutions accompanying nucleotide insertions were highly conserved. Received December 4, 1997 Accepted March 10, 1998     

北京市2015-2020年流感流行季流感样病例和流感病原学分析

目的了解2015-2020年流感流行季北京市流感流行特征。方法使用北京市2015-2020年流感样病例(influenza-like illness,ILI)和流感病原学监测数据,分析流感流行趋势和流感病毒流行特征。结果2015年第27周至2020年第26周共涉及5个流感流行季,流感样病例百分比(percentage of influenza-like illness,ILI%)为1.58%。共检测ILI标本96892件,流感病毒核酸阳性率为16.32%,其中A(H3N2)亚型6474件(40.89%)、甲型H1N14410件(27.86%)、乙型Victoria系3290件(20.78%)、乙型Yamagata系1597件(10.09%)。ILI周报告数、ILI%与流感病毒阳性率变化趋势基本一致(r=0.796,P<0.001;r=0.808,P<0.001)。2017-2018年和2018-2019年流行季活跃期较长。2017-2018、2018-2019年流行季ILI周报告数较高(49628人次和71555人次),核酸阳性率峰值较高(58.51%和57.08%)。结论2015-2020年北京市流感流行符合北半球流行特征,其中2017-2018和2018-2019流行季活跃期较长、流行水平较高,且各流行季优势毒株不同。     

A newly developed real-time PCR assay for discriminating influenza B virus Yamagata and Victoria lineages

Currently, two distinct lineages of influenza B virus (IBV), B/Victoria and B/Yamagata lineage, have been co-circulating in human beings. Assessment of the prevalent lineage is key for the recommendation of the seasonal influenza vaccine composition and the evaluation of its efficacy. In this study, a multiplex qRT-PCR assay for the discrimination of the IBV lineages was designed based on the genetic differences of the hemagglutinin genes between B/Yamagata and B/Victoria lineages. The assay was highly specific and able to discriminate the lineages of IBV without any non-specific reaction against other influenza A viruses. The detection limit of the assay was determined to be 10 genome-equivalent copies and 2.8 × 10^-2 50% tissue culture infectious doses (TCID₅₀) of live IBV per reaction. Moreover, our assay was able to discriminate the lineages of IBVs in clinical samples with 100% accuracy, when compared with pyrosequencing. Our results indicate that this assay may represent an update of the existing qRT-PCR assays and will be of great use for the rapid and accurate diagnosis and surveillance of the circulating IBVs.