2009年泉州市H1N1流感监测及基因特性分析

目的 了解2009年泉州地区H1N1流感监测情况,分析泉州市H1N1流感病毒的HA和NA基因特征,探讨该病毒的遗传变异及分子特性.方法 对泉州市H1N1流感监测期间的病人咽拭子采用real-time RT-PCR方法检测病毒核酸,MDCK细胞培养进行病毒分离、鉴定,并提取其中2株代表性毒株病毒RNA;采用RT-PCR扩增病毒HA和NA基因,纯化产物进行核苷酸序列测定;用DNAStar Megalign软件进行序列分析.结果 1020份咽拭子中有200份为H1N1流感病毒核酸阳性,70份季节性流感病毒核酸阳性,其中53份为H3N2亚型,14份为H1N1亚型,3份为B型,并分离到29株甲型H1N1流感病毒株.HA基因经核苷酸序列测定显示,该毒株与北美流行株高度同源,由HA基因核苷酸序列推导的氨基酸系列与疫苗株A/Brisbane/59/2007相比,有22个位于抗原决定簇的氨基酸位点发生变异,但受体结合特异性仍为人样受体.NA基因耐药性位点分析,显示对达菲药物依然敏感.结论 2009年泉州市H1N1流感流行毒株与北美流行株高度同源,相对于疫苗代表株出现了HA蛋白抗原性的改变.     

甘肃省2000-2007年度流感监测结果分析

目的 掌握我省流感流行情况,为流感防治提供依据.方法 按照国家流感监测方案,在6所国家级哨点医院门诊内、儿科开展流感样病例的监测和在全省开展流感暴发疫情的监测,采集流感样患者的鼻咽拭子标本,用MDCK细胞或鸡胚进行流感病毒分离与鉴定.结果 2000-2007年,哨点医院流感样病例占门诊就诊人数的5.16%,从国家级监测哨点医院及暴发疫情共采集标本6383份,分离出流感病毒943份,分离率14.77%,其中H1N1亚型218株,H3N2亚型352株,B型(Victoria系)312株,B型(Yamagata系)61株;全省发生的61起疑似流感疫情暴发,经实验室检测44起确定为流感暴发,其中38起为B(victoria)亚型流感病毒,3起为H3N2亚型、2起为B型(Yamagata系)、1起为H1N1亚型.结论 流感每年均会在人群中活动,冬季以甲型流感为主;2005-2007年,每年3-6月份B型(Victoria系)是造成学校、幼儿园等集体单位暴发的主要病毒.     

无锡地区流感病毒病原学监测及H3亚型血凝素基因变异研究

目的 监测无锡地区2005年至2008年季节性流感型与亚型分布并了解2008年部分A/H3N2分离株血凝素(8A)基因变异状况.方法 无锡地区医院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,采用标准抗血清鉴定阳性分离株型与亚型,并对2008年部分H3亚型流感病毒进行HA全基因测序,分析HA基因变异状况.结果 2005年至2008年9月,在无锡地区流感样患者中共分离到435株流感病毒,其中164株为A/H1N1亚型,80株为MH3N2亚型,B型191株.型与亚型有明显季节性分布强弱特征.H3亚型HA序列分析,无锡地区9株分离株与上海地区同期分离株接近,有很多序列相互穿插归属于进化树的同一分支,与WHO 2008-2009年疫苗推荐株相近.结论 近年无锡地区散发和局部暴发流感病毒感染仍主要为A/H1N1、A/H3N2和B型,A/H3N2 HA基因与上海地区同期分离株接近,与WHO 2008-2009年疫苗推荐株相近.     

无锡地区流感病毒病原学监测及H3亚型血凝素基因变异研究

目的 监测无锡地区2005年至2008年季节性流感型与亚型分布并了解2008年部分A/H3N2分离株血凝素(8A)基因变异状况.方法 无锡地区医院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,采用标准抗血清鉴定阳性分离株型与亚型,并对2008年部分H3亚型流感病毒进行HA全基因测序,分析HA基因变异状况.结果 2005年至2008年9月,在无锡地区流感样患者中共分离到435株流感病毒,其中164株为A/H1N1亚型,80株为MH3N2亚型,B型191株.型与亚型有明显季节性分布强弱特征.H3亚型HA序列分析,无锡地区9株分离株与上海地区同期分离株接近,有很多序列相互穿插归属于进化树的同一分支,与WHO 2008-2009年疫苗推荐株相近.结论 近年无锡地区散发和局部暴发流感病毒感染仍主要为A/H1N1、A/H3N2和B型,A/H3N2 HA基因与上海地区同期分离株接近,与WHO 2008-2009年疫苗推荐株相近.     

无锡地区流感病毒病原学监测及H3亚型血凝素基因变异研究

目的 监测无锡地区2005年至2008年季节性流感型与亚型分布并了解2008年部分A/H3N2分离株血凝素(8A)基因变异状况.方法 无锡地区医院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,采用标准抗血清鉴定阳性分离株型与亚型,并对2008年部分H3亚型流感病毒进行HA全基因测序,分析HA基因变异状况.结果 2005年至2008年9月,在无锡地区流感样患者中共分离到435株流感病毒,其中164株为A/H1N1亚型,80株为MH3N2亚型,B型191株.型与亚型有明显季节性分布强弱特征.H3亚型HA序列分析,无锡地区9株分离株与上海地区同期分离株接近,有很多序列相互穿插归属于进化树的同一分支,与WHO 2008-2009年疫苗推荐株相近.结论 近年无锡地区散发和局部暴发流感病毒感染仍主要为A/H1N1、A/H3N2和B型,A/H3N2 HA基因与上海地区同期分离株接近,与WHO 2008-2009年疫苗推荐株相近.     

无锡地区流感病毒病原学监测及H3亚型血凝素基因变异研究

目的 监测无锡地区2005年至2008年季节性流感型与亚型分布并了解2008年部分A/H3N2分离株血凝素(8A)基因变异状况.方法 无锡地区医院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,采用标准抗血清鉴定阳性分离株型与亚型,并对2008年部分H3亚型流感病毒进行HA全基因测序,分析HA基因变异状况.结果 2005年至2008年9月,在无锡地区流感样患者中共分离到435株流感病毒,其中164株为A/H1N1亚型,80株为MH3N2亚型,B型191株.型与亚型有明显季节性分布强弱特征.H3亚型HA序列分析,无锡地区9株分离株与上海地区同期分离株接近,有很多序列相互穿插归属于进化树的同一分支,与WHO 2008-2009年疫苗推荐株相近.结论 近年无锡地区散发和局部暴发流感病毒感染仍主要为A/H1N1、A/H3N2和B型,A/H3N2 HA基因与上海地区同期分离株接近,与WHO 2008-2009年疫苗推荐株相近.     

无锡地区流感病毒病原学监测及H3亚型血凝素基因变异研究

目的 监测无锡地区2005年至2008年季节性流感型与亚型分布并了解2008年部分A/H3N2分离株血凝素(8A)基因变异状况.方法 无锡地区医院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,采用标准抗血清鉴定阳性分离株型与亚型,并对2008年部分H3亚型流感病毒进行HA全基因测序,分析HA基因变异状况.结果 2005年至2008年9月,在无锡地区流感样患者中共分离到435株流感病毒,其中164株为A/H1N1亚型,80株为MH3N2亚型,B型191株.型与亚型有明显季节性分布强弱特征.H3亚型HA序列分析,无锡地区9株分离株与上海地区同期分离株接近,有很多序列相互穿插归属于进化树的同一分支,与WHO 2008-2009年疫苗推荐株相近.结论 近年无锡地区散发和局部暴发流感病毒感染仍主要为A/H1N1、A/H3N2和B型,A/H3N2 HA基因与上海地区同期分离株接近,与WHO 2008-2009年疫苗推荐株相近.     

无锡地区流感病毒病原学监测及H3亚型血凝素基因变异研究

目的 监测无锡地区2005年至2008年季节性流感型与亚型分布并了解2008年部分A/H3N2分离株血凝素(8A)基因变异状况.方法 无锡地区医院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,采用标准抗血清鉴定阳性分离株型与亚型,并对2008年部分H3亚型流感病毒进行HA全基因测序,分析HA基因变异状况.结果 2005年至2008年9月,在无锡地区流感样患者中共分离到435株流感病毒,其中164株为A/H1N1亚型,80株为MH3N2亚型,B型191株.型与亚型有明显季节性分布强弱特征.H3亚型HA序列分析,无锡地区9株分离株与上海地区同期分离株接近,有很多序列相互穿插归属于进化树的同一分支,与WHO 2008-2009年疫苗推荐株相近.结论 近年无锡地区散发和局部暴发流感病毒感染仍主要为A/H1N1、A/H3N2和B型,A/H3N2 HA基因与上海地区同期分离株接近,与WHO 2008-2009年疫苗推荐株相近.     

无锡地区流感病毒病原学监测及H3亚型血凝素基因变异研究

目的 监测无锡地区2005年至2008年季节性流感型与亚型分布并了解2008年部分A/H3N2分离株血凝素(8A)基因变异状况.方法 无锡地区医院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,采用标准抗血清鉴定阳性分离株型与亚型,并对2008年部分H3亚型流感病毒进行HA全基因测序,分析HA基因变异状况.结果 2005年至2008年9月,在无锡地区流感样患者中共分离到435株流感病毒,其中164株为A/H1N1亚型,80株为MH3N2亚型,B型191株.型与亚型有明显季节性分布强弱特征.H3亚型HA序列分析,无锡地区9株分离株与上海地区同期分离株接近,有很多序列相互穿插归属于进化树的同一分支,与WHO 2008-2009年疫苗推荐株相近.结论 近年无锡地区散发和局部暴发流感病毒感染仍主要为A/H1N1、A/H3N2和B型,A/H3N2 HA基因与上海地区同期分离株接近,与WHO 2008-2009年疫苗推荐株相近.     

无锡地区流感病毒病原学监测及H3亚型血凝素基因变异研究

目的 监测无锡地区2005年至2008年季节性流感型与亚型分布并了解2008年部分A/H3N2分离株血凝素(8A)基因变异状况.方法 无锡地区医院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,采用标准抗血清鉴定阳性分离株型与亚型,并对2008年部分H3亚型流感病毒进行HA全基因测序,分析HA基因变异状况.结果 2005年至2008年9月,在无锡地区流感样患者中共分离到435株流感病毒,其中164株为A/H1N1亚型,80株为MH3N2亚型,B型191株.型与亚型有明显季节性分布强弱特征.H3亚型HA序列分析,无锡地区9株分离株与上海地区同期分离株接近,有很多序列相互穿插归属于进化树的同一分支,与WHO 2008-2009年疫苗推荐株相近.结论 近年无锡地区散发和局部暴发流感病毒感染仍主要为A/H1N1、A/H3N2和B型,A/H3N2 HA基因与上海地区同期分离株接近,与WHO 2008-2009年疫苗推荐株相近.     

Characterization of epidemic influenza virus A(H3N2) strains circulating in Russia in the 2003-2004 epidemic season

Studies indicated that the epidemic rise in the incidence of influenza was caused by its virus A (H3N2) circulation in Russia in the 2003-2004 season. The Center of Influenza Ecology and Epidemiology investigated 101 epidemic strains isolated the MDCK culture. Antigenic analysis showed that all viruses A(H3N2) were similar to the reference virus A/Fujian/411/02(H3N2) and only 5 strains slightly differed from the latter. Twelve (14%) strains resistant to rimantadine at a concentration of 0.5 mg/ml were identified. Investigation of paired sera from the patients demonstrated a rise of antibodies to the references of influenza virus A(H3N2) in 68.7% of cases and a less increase in those to influenza viruses A(H1N1) and B. The active circulation of A(H3N2) viruses was due not only to changes in their antigenic structure, but also to the low level of antibodies to these viruses, as shown by the analysis of donor sera.     

Genetic analysis of avian influenza A viruses isolated from domestic waterfowl in live-bird markets of Hanoi, Vietnam, preceding fatal H5N1 human infections in 2004

The first known cases of human infection with highly pathogenic avian influenza (HPAI) H5N1 viruses in Vietnam occurred in late 2003. However, HPAI H5N1 and low-pathogenic avian influenza (LPAI) H5N2 and H9N3 viruses were isolated from domestic waterfowl during live-bird market (LBM) surveillance in Vietnam in 2001 and 2003. To understand the possible role of these early viruses in the genesis of H5N1 strains infecting people, we performed sequencing and molecular characterization. Phylogenetic analysis revealed that the hemagglutinin (HA) genes of two geese HPAI H5N1 strains belonged to clade 3, and their surface glycoprotein and replication complex genes were most closely related (98.5–99.7% homologous) to A/duck/Guangxi/22/01 (H5N1) virus, detected contemporarily in southern China, whilst the M and NS genes were derived from an A/duck/Hong Kong/2986.1/00 (H5N1)-like virus. The H5 HA gene of the duck HPAI H5N1 strain belonged to clade 5 and acquired a gene constellation from A/quail/Shantou/3846/02 (H5N1), A/teal/China/2978.1/02 (H5N1) and A/partridge/Shantou/2286/03 (H5N1)-like viruses. The phylogenetic analysis further indicated that all eight gene segments of goose and duck HPAI H5N1 and LPAI H5N2 viruses were distinct from those of H5N1 clade-1 viruses known to have caused fatal human infections in Vietnam since late 2003. The duck H9N3 isolates derived genes from aquatic-bird influenza viruses, and their H9 HA belonged to the Korean lineage. The PB2 gene of A/duck/Vietnam/340/01 (H9N3) virus had lysine at position 627. Based on the molecular characterization of specific amino acid residues in the surface and relevant internal protein-coding genes, the Vietnamese H5N1 and H9N3 virus isolates indicated specificity to avian cell surface receptor and susceptibility for currently licensed anti-influenza A virus chemotherapeutics. Our findings suggest that the H5N1 and H5N2 viruses that circulated among geese and ducks in LBMs in Hanoi, Vietnam, during 2001 and 2003 were not the immediate ancestors of the clade-1 viruses associated with fatal human infections in Vietnam. The clade-1 HPAI H5N1 viruses were independently introduced into Vietnam.     

The rimantadine sensitivity spectrum in influenza A viruses circulating in the 2002-2004 epidemic seasons

A total of 200 influenza A virus strains were studied. Among them there 32 strains of A(H1N1) and 84 strains of A(H3N2) from the 2002-2003 epidemic season and 84 strains of A(H3N2) from the 2003-2004 epidemic season. Most rimantadine-sensitive strains whose infectivity and hemagglutinating activity were found to decrease by the drug given at a concentration of 0.5 microg/ml. In terms of infectivity and hemagglutinating activity, the number of rimantadine-resistant strains of A (H1N1) was equal to 9.0% for A(H1N1) influenza viruses and to 10.0 and 14.0% for A (H3N2) influenza viruses in different seasons, respectively.     

2009年泉州市流感监测结果分析

目的了解泉州市2009年流感活动情况及其型别特征。结论通过流行病学和病原学监测,对泉州市流感流行情况进行分析。结果 2009年全市流感样病例占就诊人数的0.26%～2.34%;全年采集监测标本1392份,经RT-PCR法检测样本阳性率为22.34%;经MDCK细胞分离流感毒株134株,其中季节性H3N2和HINl型各占60.45%和11.19%,甲型H1N1流感占21.64%,B型占6.70%。结论 2009年泉州市流感春夏季以季节性H3N2亚型流感为优势毒株,秋冬季以甲型H1N1流感为流行株,需加强泉州市流感监测和流感病毒抗原变异研究。     

1999-2007年佛山市流感病毒活动情况及甲3亚型病毒HA1基因分析

目的总结1999-2007年佛山市流感病毒流行情况,分析甲3亚型（H3N2）毒株流行与其HA1基因进化的关系。方法用MDCK细胞分离流感病毒,培养后血凝阳性者进行型别鉴定。随机抽取每年2～3株甲3亚型毒株的细胞培养物提取RNA后进行HA1基因的逆转录,对其核苷酸和氨基酸序列及亲缘关系进行分析。结果甲型和乙型流感病毒在佛山市人群中同时流行。甲型流感毒株是人群感染流感的主要型别。HA1区氨基酸序列与历年的流感疫苗推荐株相比,点突变率为0.3%～6.08%。发生替换的重要位点包括了抗原决定簇的17个位点、抗体结合部位的10个位点和1个糖基化位点。结论佛山市的甲1和甲3亚型流感毒株活动呈此起彼伏的优势株转换现象。甲3亚型新旧毒株交替迅速,大致按照毒株分离的年代聚类成进化树的不同小侧枝,表明新的流行株出现后可能迅速突破地域局限。提示地区实验室及时监测和研究流感毒株的发生和发展是流感监测网络建设的基础。     

Human infection with an avian H9N2 influenza A virus in Hong Kong in 2003

Avian H9N2 influenza A virus has caused repeated human infections in Asia since 1998. Here we report that an H9N2 influenza virus infected a 5-year-old child in Hong Kong in 2003. To identify the possible source of the infection, the human isolate and other H9N2 influenza viruses isolated from Hong Kong poultry markets from January to October 2003 were genetically and antigenically characterized. The findings of this study show that the human H9N2 influenza virus, A/Hong Kong/2108/03, is of purely avian origin and is closely related to some viruses circulating in poultry in the markets of Hong Kong. The continued presence of H9N2 influenza viruses in poultry markets in southern China increases the likelihood of avian-to-human interspecies transmission.     

Evaluation of a rapid test for detection of H5N1 avian influenza virus

The performance of H5 Dot ELISA, a rapid test for detection of avian H5N1 influenza virus, was evaluated using 30 H5N1 strains belonging to 10 major genetic groups of H5N1 influenza virus, 14 strains of non-H5N1 influenza virus and 652 field samples collected from healthy and diseased chickens from markets and poultry farms. The detection limit of the test for all 30 strains of H5N1 virus was < or = 0.1 hemagglutinin (HA) units and the test yielded a negative result when tested against 100 HA units of the non-H5N1 viruses. The test gave a positive result for 87 of the 106 poultry samples from which H5N1 virus was isolated by culture and 3 of 546 culture-negative poultry samples. Compared with virus culture, the overall prediction rate of the test was determined to be 96.6%; the positive prediction rate was 96.7% and negative prediction rate, 96.6%. The false positive rate was 0.5% and false negative rate 17.9%. Considering that the test is also convenient to use, it was concluded that H5 Dot ELISA is suitable for field use in the investigation of H5N1 influenza outbreaks and surveillance in poultry.     

Virologic and serologic surveillance for human, swine and avian influenza virus infections among pigs in the north-central United States

Summary.  Influenza virus infection in pigs is both an animal health problem and a public health concern. As such, surveillance and characterization of influenza viruses in swine is important to the veterinary community and should be a part of human pandemic preparedness planning. Studies in 1976/1977 and 1988/1989 demonstrated that pigs in the U.S. were commonly infected with classical swine H1N1 viruses, whereas human H3 and avian influenza virus infections were very rare. In contrast, human H3 and avian H1 viruses have been isolated frequently from pigs in Europe and Asia over the last two decades. From September 1997 through August 1998, we isolated 26 influenza viruses from pigs in the north-central United States at the point of slaughter. All 26 isolates were H1N1 viruses, and phylogenetic analyses of the hemagglutinin and nucleoprotein genes from 11 representative viruses demonstrated that these were classical swine H1 viruses. However, monoclonal antibody analyses revealed antigenic heterogeneity among the HA proteins of the 26 viruses. Serologically, 27.7% of 2,375 pigs tested had hemagglutination-inhibiting antibodies against classical swine H1 influenza virus. Of particular significance, however, the rates of seropositivity to avian H1 (7.6%) and human H3 (8.0%) viruses were substantially higher than in previous studies. Received December 1, 1999 Accepted January 21, 2000     

The 2009 pandemic influenza in Russia. I. Diagnosis and molecular biological characteristics of the virus

The analysis of 1558 clinical samples revealed influenza virus A(H1N1v) RNA in 339 patients with influenza and 163 fatal cases,which was made in May to December 2009. Data on the antigenic properties of more than 250 of pandemic virus strains isolated at the Research Institute of Influenza and the molecular genetic characteristics of 31 strains are presented. All the test isolates were found to have the S203 substitution in hemagglutinin, which was characteristic of one of 5 minor genome A(H1N1v) virus variants found in the United States and Mexico in 2009. All the test strains contain the S31N substitution in the M2 protein, which determines viral resistance to adamantine, and have no H275Y substitution in neuraminidase, which determines oseltamivir resistance. The substitution of amino acid residue of Asp to Gly at position 222 of HA was found in 8 (73%) of 11 isolates from postmortem lung and trachea samples and in 2 (10%) of 20 isolates from nasopharyngeal swabs. The determination of the pathogenic role of this substitution calls for further investigations.