2009～2010年乌鲁木齐市流行性感冒病原学监测分析

目的了解流行性感冒病毒（流感）的流行情况,探讨流感流行规律,为制订流感控制措施提供依据。方法对乌鲁木齐市监测门诊及疫情点的疑似流感样病例采集咽拭子标本,用核酸检测和接种狗肾传代细胞（MDCK）培养进行流感病毒分离及进行血凝试验,并对阳性者进行血凝抑制试验进行分型鉴定。结果 2009年10月-2010年3月监测流感样标本与咽拭子标本共1 218份,分离出流感病毒181株,分离率3.72%,分别为甲型H1N1亚型8株、H3N2亚型32株、新甲型H1N1 104株、B型37株。结论 2009年10月-2010年1月是以新甲型H1N1亚型流感病毒流行为主,2010年2月以B型流感流行为主。     

上海和无锡流感病毒病原学监测及血凝素基因变异

目的了解2004至2006年流感流行季节流感病毒型及亚型在上海及无锡两地流感样患者中流行情况及病毒型内血凝素（HA）基因变异状况。方法与上海及无锡市疾病预防控制中心合作，对门诊流感样患者及集体单位聚集性流感样暴发患者采集鼻咽拭标本，接种MDCK细胞，分离流感病毒，直接荧光免疫法鉴定阳性分离株型别，对甲型流感病毒采用RT-PCR鉴定亚型，并对部分H3、H1亚型流感病毒进行HA全基因片段测序，分析流感病毒HA基因变异状况。结果2004年8月至2006年9月，上海及无锡两地流感样患者中共分离到126株流感病毒，其中53株为H3N2亚型，43株为H1N1亚型，30株为B型。聚集性流感样疾病暴发多在2、3月份，分析7起聚集性流感样疾病暴发，分别为H3N2流感病毒感染2起，H1N1流感病毒感染1起，B型2起，及H3N2、B和H1N1、B混合感染各1起。HA序列分析，H1、H3与同期其他国家和地区的分离株近源。结论上海及无锡两地散发和局部暴发的甲型流感病毒感染仍主要为H1N1、H3N2亚型，未发现HA、NA重组株和新的HA、NA亚型；1～3月份为发病高峰；H1、H3型内变异状况与其他国家和地区相似。     

泰安市甲型H3N2流感病毒HA1氨基酸变异特点分析

目的了解2006~2008年泰安市甲型H3N2流感病毒HA1基因变异特征。方法采集本地区流感样病例咽拭子,分离病毒,选择甲型H3N2流感病毒,提取核酸,采用逆转录-聚合酶链反应(RT-PCR)扩增并测序,推导其编码氨基酸序列,进行基因进化特征分析。结果 2006~2008年共检测咽拭子524份,分离出流感病毒119株,分离阳性率为22.71%。119株流感病毒中H3N2亚型65株,H1N1亚型2株,B型Victoria系13株,B型Yamagata系39株。对8株H3N2病毒进行基因进化树分析,在其推导HA1蛋白分子抗原决定簇A上有3个氨基酸位点(R142G、N144D和I140K)发生突变。结论在近2个年度的流行季节中,本地区以H3N2亚型和B型Yamagata系为优势毒株,也有B型Victoria系和甲型H1N1亚型的存在。泰山分离株HA1区发生氨基酸替换的位点较少。WHO推荐A/Wisconsin/67/2005为北半球2006~2008年度的流感疫苗株,泰山分离株与此疫苗株的相似性较高,因此认为该流感疫苗对当年度优势株H3N2流感病毒的预防有一定效果。     

甲型H1N1流行性感冒病毒血凝素基因变异状况及序列分析

目的 了解2009年度甲型H1N1流行性感冒(流感)病毒的检测情况和血凝素(HA)基因变异情况.方法 选择国家级流感监测哨点医院以及暴发疫情的疫点,采集流感样病例的鼻咽拭子标本,通过实时(RT)-PCR进行病毒分型及甲型H1N1流感病毒检测,对阳性标本采用狗肾细胞(MDCK)进行病原分离,采用红细胞凝集试验测定病毒效价,用血凝抑制实验进行型别鉴定,通过RT-PCR扩增毒株HA1片段的基因并进行序列测定,利用生物信息学技术进行序列分析.结果 共检测咽拭子样本996份,其中核酸检测阳性病例包括甲型H1N1 337份,季节性H1N1亚型1份,季节性H3N2亚型67份,B型12份,流感核酸检测阳性率为41.87％,其中甲型流感核酸检测阳性率为33.84％.分离出甲型H1N1病毒36株,选择18株.测序成功的10株甲型H1N1流感病毒在多个氨基酸位点发生变异,与疫苗株A/California/07/2009(H1N1)比较,有6个位点发生突变,其中1个位点位于抗原决定簇的B区.结论 2009年度分离到的流感病毒株中以甲型H1N1为绝对的优势毒株,毒株的血凝素基因与世界卫生组织(WHO)提供的疫苗株相比有变异,与疫苗株相比,抗原决定簇B区有改变,但关键位点第222位没有变化.     

2007—2008年新疆流感监测结果分析

目的分析2007—2008年新疆流行性感冒（流感）流行特征和流感病毒优势株的情况。方法收集、分析监测哨点医院流感样病例及实验室病原学资料,用细胞培养分离并用血球凝集抑制试验对流感病毒进行分型。结果监测哨点医院2007—2008年流感样病例处于较为平稳的水平,无明显的流行高峰,病例相对集中在2007年12月-2008年1月,此监测年度无疫情暴发报告;共收集流感样病例标本589份,分离病毒60株,阳性率为10．19％;其中B（Yamagata）型52株（86％）,H3N2亚型7株（12％）,H1N1亚型1株（2％）。结论2007—2008年新疆流感活动较为平稳,流行毒株以B（Yamagata）型病毒为主,并有向H3N2亚型转化的趋势。     

上海地区2004年至2008年甲型流行性感冒病毒亚型的分布

目的 分析近5年上海地区甲型流行性感冒(流感)病毒亚型的分布并探究其原因.方法 对上海地区流感监测哨点流感样患者和聚集性流感暴发患者,采集咽拭子标本接种犬肾细胞(MDCK),直接荧光免疫法鉴定阳性分离株型别,多重RT-PCR鉴定亚型.结果 2004年至2005年初的季节性流感以A/H3N2为主;2005年末至2006年中期的季节性流感以A/H1N1为主;2006年末到2007年10月份分离到的流感毒株基本为A/H3N2亚型;2008年1月至5月份,人群流感病毒分离株仍以A/H3N2处于优势地位,但从2008年7月开始的季节性流感则以A/H1N1占绝对优势.结论 近5年上海地区季节性流感主要为甲型流感病毒H3N2和H1N1亚型,但在不同年份的季节性流感中流行强度有所不同.     

2008～2009年烟台市流感病原学监测结果分析

对烟台市2008和2009年度流感病毒病原学监测结果进行对比分析。两年间2个国家级流感样病例监测哨点医院共采集流感样病例标本(排除甲流)930份,分离流感病毒130株,分离率13.98%。2008～2009年度共检测标本426份,分离流感病毒62株,分离率14.55%;2009年度检测504份,分离流感病毒68株,分离率13.49%。2008～2009年度以甲型H1N1亚型为优势毒株,占95.16%(59株);2009年则以甲型H3N2亚型为流行的优势毒株,占76.47%(52株)。     

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

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.     

磷酸奥司他韦对上海及周边地区不同流行性感冒病毒亚型的体外抗病毒效果

目的 了解上海及周边地区近年来流行性感冒(流感)病毒流行株对磷酸奥司他韦的敏感度及是否存在耐药株.方法 从2004-2006年上海市、江苏省无锡市和浙江省德清县流感监测和暴发病例分离到的流感病毒中,随机抽取B型、H1亚型、H3亚型的部分流感病毒,用中性红吸收法在体外检测磷酸奥司他韦的抗病毒作用,以50%抑制浓度(IC50)表示药物的抗病毒效果.方差分析检验药物对各亚型流感株IC50的差异.结果 磷酸奥司他韦对研究使用的50株不同型和亚型流感病毒皆有抑制病毒感染细胞的效果,IC50均＜25 mg/L.药物对B亚型病毒的效果较差,IC50为19.97 mg/L(15.16～22.36 mg/L),高于A/H1N1亚型的8.15 mg/L(0.02～22.36 mg/L,P＜0.05)和A/H3N2亚型的10.92 mg/L(0.08～19.72 mg/L,P＞0.05);对于不同年份分离的流感病毒,药物效果有所变化.结论 磷酸奥司他韦对上海及周边地区的流感病毒具有较好的体外抗病毒效果,需要建立监测网络来监控药物的效果和病毒的耐药情况.     

甲型H1N1与季节性H1N1流感病毒血凝素基因比较分析

目的分析泰安市2008～2009年度季节性流感与2009年度甲型H1N1流感病原学检测结果 ,比较季节性H1N1与甲型H1N1血凝素基因变异情况。方法选择国家级流感监测哨点医院以及暴发疫情的疫点,采集流感样病例的鼻咽拭子标本,通过RealtimePCR进行病毒检测,用MDCK细胞进行病毒分离,通过RT-PCR扩增血凝素HA1片段的基因并测序,利用生物信息学进行序列分析。结果 2008～2009年共检测鼻咽拭子标本283份,分离出流感病毒33株,分离阳性率为11.67%,其中季节性H1N1亚型31株。2009年5月1日～12月31日,检测鼻咽拭子标本996份,流感核酸检测阳性417份,阳性率为41.86%,其中甲型H1N1337份,季节性H1N1亚型1份。6株季节性H1N1病毒均在多个氨基酸位点上发生变异,与疫苗株A/Brisbane/59/2007(H1N1)比较,有11个位点发生了突变,其中5个位点位于抗原决定簇上;测序成功的6株甲型H1N1病毒在多个氨基酸位点发生变异,与疫苗株A/California/07/2009(H1N1)比较,有6个位点发生突变,其中1个位点位于抗原决定簇的B区。结论 2008～2009年度季节性H1N1为优势株,甲流暴发后,甲型H1N1成为绝对优势毒株。季节性H1N1分离株有多处氨基酸替换,抗原决定簇B区变异频繁;甲型H1N1病毒分离株的基因有变异,但关键位点第222位仍为D(天冬氨酸),与疫苗株相比抗原决定簇的关键位点变化不大。     

Sensitivity and specificity of rapid diagnosis kit detecting separately influenza A and B viruses

Sensitivity and specificity of the Directigen Flu A + B kit, a rapid test for influenza virus A and B, were evaluated. This test detects influenza A and B viruses separately by EIA. Reactivity of the kit was tested using a total of 23 isolates: 13 isolates of human influenza virus A (H1N1, H3N2) and 10 isolates of human influenza virus B. All of the isolates were tested positive and no difference in reactivity was found in antigenic variables and subtypes. The kit was only reactive to influenza virus A and B, not reactive to other viruses. Typical influenza A and B strains were tested for detection limit. 7.8 x 10(3) pfu/ml was a detection limit for influenza virus A (H1N1: Beijing/262/95), 4.7 x 10(4) pfu/ml for influenza virus A (H3N2: Kitakyusyu/159/93), and 3.1 x 10(4) pfu/ml for influenza virus B (Guangdong/05/94). The Directigen Flu A + B kit was a easy-to-use, rapid detection device and the kit has sensitivity and specificity equivalent to other diagnostic devices, suggesting the kit are useful in medical institutions.     

Mild to moderate influenza activity in Europe and the detection of novel A(H1N2) and B viruses during the winter of 2001-02

Influenza activity in Europe during the 2001-02 influenza season was mild to moderate. Compared to historical data, the intensity was low in six countries, medium in eleven and high in one country (Spain). The dominant virus circulating in Europe was influenza A(H3N2). Two novel influenza virus strains were isolated during the 2001-02 season: influenza A(H1N2) viruses (mainly isolated in the United Kingdom and Ireland, but also in Belgium, France, Germany, the Netherlands, Portugal, Sweden, Switzerland and Romania), and influenza B viruses belonging to the B/Victoria/2/87 lineage (mainly isolated in Germany, but also sporadically in France, Italy, the Netherlands and Norway). With the exception of H1N2 virus detections in England, and Ireland and the influenza B viruses belonging to the B/Victoria/2/87 lineage in Germany, these two viruses did not circulate widely in Europe and did not play an important role in influenza activity during the 2001-02 season. An influenza B virus belonging to the B/Victoria/2/87 lineage will be included in the 2002-03 influenza vaccine. The new subtype influenza A(H1N2) is covered by the 2002-03 vaccine, as the haemagglutinin and neuraminidase components of the H1N2 viruses are antigenically similar to the vaccine components (H1N1 and H3N2).     

2019—2020年山东省H3N2流感病毒抗原性及血凝素基因特征分析

目的 了解2019—2020年流感监测年度山东省分离的H3N2亚型流感病毒抗原性及血凝素(hemagglutinin,HA)基因遗传进化规律与氨基酸变异情况。方法 用免疫雪貂后的抗血清进行红细胞凝集抑制试验,对2019年4月至2020年3月山东省分离的40株H3N2亚型流感毒株进行抗原性分析,并对其中19株待检病毒的HA基因进行序列测定及分析。结果 抗原性分析结果显示检测的H3N2亚型流感病毒中仅仅35%(14/40)与疫苗株A/Kansas/14/2017抗原性类似。系统进化树显示,19株H3N2亚型流感病毒分离株血凝素基因在进化树上全部属于3C.2a分支,与处于3C.3a分支的疫苗株A/Kansas/14/2017亲缘关系较远;与疫苗株相比,所有待检毒株A抗原决定簇有3个位点,B抗原决定簇有2个位点发生改变;受体结合位点均发生T135K位和S137F位变异;19株分离株全部发生133位糖基化位点缺失。结论 抗原性分析及HA基因序列分析结果显示,WHO推荐的 2019—2020 年疫苗株保护效果有可能不理想。应继续密切关注 H3N2 亚型流感病毒的流行与基因变异情况,为流感病毒疫苗株推荐及防控提供科学依据。     

Seasonal influenza virus strains circulating in Malaysia from 2005 to 2009

From 2005 to 2009, the Institute for Medical Research (IMR), Kuala Lumpur received a total of 7,117 respiratory specimens from patients with influenza-like illness (ILI) for influenza screening. Seasonal influenza virus was isolated from 17.3% of patients with ILI in 2005, 31.6% in 2006, 12.8% in 2007, 10.2% in 2008 and 13.5% in 2009. There were one or more influenza A and B virus strains circulating in Malaysia throughout the year, with distinctly a peak in May to August. The predominant circulating strains of seasonal influenza A were A/California/7/2004-like (H3N2) in 2005, A/New Caledonia/20/99-like (H1N1) in 2006, A/ Brisbane/10/2007-like (H3N2) in 2007 and 2008, and A/Perth/16/2009-like (H3N2) virus in 2009. The predominant circulating strains of influenza B were B/Hong Kong/330/2001-like in 2005, B/Malaysia/2506/2004-like in 2006, B/Florida/4/2006-like in 2007 and 2008, and B/Brisbane/60/2008-like in 2009.     

Zoonotic studies on influenza in pigs and birds, India, 1980-81

Five hundred and twenty pig sera collected from Pune, Maharashtra State, India during 1980 were examined in Haemagglutination Inhibition (HI) tests to determine the antibody prevalence to nine human influenza virus strains covering the subtypes A(HON1), A(H1N1), A(H2N2), A(H3N2), type B and one swine influenza virus strain A(Hsw1N1). This study indicated considerable prevalence of antibodies to the four H3N2 strains isolated from 1973 onwards, particularly to the two recent H3N2 strains, limited prevalence of antibodies to H1N1 strain and absence of antibodies to the Hsw1N1 and HON1 influenza strains in the pig sera. Three hundred and eleven cloacal swab specimens collected from different species of domestic and wild birds from Kolar district, Karnataka State, India during 1980 and 1981 were investigated for influenza virus prevalence. No influenza virus was isolated from any of the specimen, but one strain of Newcastle disease virus was isolated from a chicken.     

Cross-protection against H5N1 influenza virus infection is afforded by intranasal inoculation with seasonal trivalent inactivated influenza vaccine

BACKGROUND: Avian H5N1 influenza A virus is an emerging pathogen with the potential to cause substantial human morbidity and mortality. We evaluated the ability of currently licensed seasonal influenza vaccine to confer cross-protection against highly pathogenic H5N1 influenza virus in mice. METHODS: BALB/c mice were inoculated 3 times, either intranasally or subcutaneously, with the trivalent inactivated influenza vaccine licensed in Japan for the 2005-2006 season. The vaccine included A/NewCaledonia/20/99 (H1N1), A/NewYork/55/2004 (H3N2), and B/Shanghai/361/2002 viral strains and was administered together with poly(I):poly(C(12)U) (Ampligen) as an adjuvant. At 14 days after the final inoculation, the inoculated mice were challenged with either the A/HongKong/483/97, the A/Vietnam/1194/04, or the A/Indonesia/6/05 strain of H5N1 influenza virus. RESULTS: Compared with noninoculated mice, those inoculated intranasally manifested cross-reactivity of mucosal IgA and serum IgG with H5N1 virus, as well as both a reduced H5N1 virus titer in nasal-wash samples and increased survival, after challenge with H5N1 virus. Subcutaneous inoculation did not induce a cross-reactive IgA response and did not afford protection against H5N1 viral infection. CONCLUSIONS: Intranasal inoculation with annual influenza vaccine plus the Toll-like receptor-3 agonist, poly(I):poly(C(12)U), may overcome the problem of a limited supply of H5N1 virus vaccine by providing cross-protective mucosal immunity against H5N1 viruses with pandemic potential.     

2009年广东省新型甲型H1N1流行性感冒病毒神经氨酸酶基因进化分析

目的 探讨2009年广东省新型甲型H1N1流行性感冒(流感)病毒神经氨酸酶(NA)基因的进化及NA基因编码蛋白抗原性、酶活性位点、糖基化位点变异情况.方法 从2009年广东省新型甲型H1N1流感患者中分离到病毒毒株共69株,提取病毒总RNA,RT-PCR扩增NA基因,并测序分析;同时从美国国立生物技术信息中心基因库检索获得 52株不同年代、不同地域甲型流感病毒NA基因序列,用MEGA 4.0软件进行基因进化分析和氨基酸序列分析.结果 2009年广东省新型甲型H1N1流感病毒NA基因与禽H5N1流感病毒同源性较高,为87.1%,潜在抗原位点氨基酸分布相同;所有毒株的酶活性中心位点高度保守;具有8个糖基化位点,其中5个位点有不同程度的氨基酸替换,但与2001年禽H5N1毒株的糖基化位点的氨基酸相同.结论 2009年广东省新型甲型H1N1流感病毒NA基因与禽H5N1流感病毒高度同源,与NA抑制剂的特异性结合位点未发生变化.     

Evaluation of Wondfo influenza A&B fast test based on immunochromatography assay for rapid diagnosis of influenza A H1N1

Influenza viruses cause significant morbidity and mortality in both children and adults during local outbreaks or epidemics. Therefore, a rapid test for influenza A&B would be useful. This study was conducted to evaluate the clinical performance of the Wondfo influenza A&B test for rapid diagnosis of influenza A H1N1 Infection. The rapid testing assay could distinguish infection of influenza A and B virus. The reference viral strains were cultured in MDCK cells while TCID50 if the viruses were determined. The analytical sensitivity of the Wondfo kit was 100 TCID50/ml. The Wondfo kit did not show cross reactivity with other common viruses. 1928 suspected cases of influenza A (H1N1) virus infection were analyzed in the Wondfo influenza A&B test and other commercially available products. Inconsistent results were further confirmed by virus isolation in cell culture. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 100%, 98.23%, 92.45%, and 100% for flu A, and 96.39%, 99.95%, 98.77%, and 99.84% for flu B respectively. 766 suspected cases of influenza A (H1N1) virus infection were analyzed in the Wondfo influenza A&B test and RT-PCR. The sensitivity, specificity, PPV and NPV were 56.5%, 99.75%, 99.52% and 71.04% for flu A, 25.45%, 99.86%, 93.33% and 94.54% for flu B respectively. These results indicate that the Wondfo influenza A&B test has high positive and negative detection rates. One hundred fifty-six specimens of influenza A (H1N1) confirmed by RT-PCR were analyzed by the Wondfo influenza A&B test and 66.67% were positive while only 18.59% were positive by the reference kit. These results indicate that our rapid diagnostic assay may be useful for analyzing influenza A H1N1 infections in patient specimen.