Evolution of H5N1 avian influenza viruses in Asia

An outbreak of highly pathogenic avian influenza A (H5N1) has recently spread to poultry in 9 Asian countries. H5N1 infections have caused > or =52 human deaths in Vietnam, Thailand, and Cambodia from January 2004 to April 2005. Genomic analyses of H5N1 isolates from birds and humans showed 2 distinct clades with a nonoverlapping geographic distribution. All the viral genes were of avian influenza origin, which indicates absence of reassortment with human influenza viruses. All human H5N1 isolates tested belonged to a single clade and were resistant to the adamantane drugs but sensitive to neuraminidase inhibitors. Most H5N1 isolates from humans were antigenically homogeneous and distinct from avian viruses circulating before the end of 2003. Some 2005 isolates showed evidence of antigenic drift. An updated nonpathogenic H5N1 reference virus, lacking the polybasic cleavage site in the hemagglutinin gene, was produced by reverse genetics in anticipation of the possible need to vaccinate humans.  

郑州地区988例甲型H1N1流行性感冒临床特征分析

目的 了解郑州地区新型甲型H1N1流行性感冒(流感)的临床特征,提高临床医师对本病的认识.方法 采用描述性流行病学方法对河南省传染病医院2009年5月1日～12月30日收治确诊的988例甲型H1N1流感患者资料进行回顾性分析.结果 本组患者男546例,女442例,年龄0.4 ～77岁.临床主要表现为流感样症状,包括发热、咳嗽、流涕、咽痛,其他症状有头痛、全身酸痛、恶心呕吐、腹泻等,体征有咽部充血及扁桃体肿大等.外周血WBC总数正常或偏低,单核细胞增多.胸部X线检查主要表现为肺纹理增多、肺炎、胸膜炎等.治疗首选奥司他韦,不良反应少见,可作为常规用药.本病预后良好,死亡率0.71％.危重病人多合并呼吸系统并发症,常需要机械辅助呼吸.结论 新型甲型H1N1流感传染性强,但症状轻微,死亡率不高.  

奥司他韦联合痰热清治疗疑似甲型H1N1流感疗效观察

[目的]观察奥司他韦联合痰热清治疗疑似甲型H1N1流感疗效。[方法]138例疑似甲型H1N1流感病例,随机分对照组69例,单纯用奥司他韦75mg,每日2次口服,治疗组69例,在对照组基础上,联合痰热清20ml加入液体中静脉滴注,每日1次;两组常规给予对症、支持治疗,均用药5d。[结果]根据发热、流感样症状、转为重症病例的多少、判断。治疗组治愈48例,显效11例,好转7例,无效3例,1例T﹥39℃持续3d视为重症,总有效率为95.65%;对照组治愈40例,显效8例,好转13例,无效7例,其中4例T﹥39℃持续3d视为重症,1例药疹退出观察,总有效率为89.71%。[结论]应用奥司他韦联合痰热清治疗疑似甲型H1N1流感,疗效优于单纯用奥司他韦。  

磷酸奥司他韦治疗甲型H1N1流行性感冒的临床疗效观察

目的观察我院用磷酸奥司他韦治疗甲型H1N1流行性感冒的临床疗效和不良反应。方法对临床确诊的40例甲型H1N1流行性感冒患者均用磷酸奥司他韦进行治疗。结果除2例患者要求中途停止治疗外,38例患者均治愈出院,其中出现不良反应有3例,不良反应发生率为7.89%。结论磷酸奥司他韦对甲型H1N1流行性感冒有效,不良反应发生率相对较高。  

34例确诊甲型H1N1流感临床分析

目的 了解我国甲型H1N1流感患者的临床表现及相关实验室检查和治疗情况.方法 采用描述性流行病学方法对医院2009年10月25日-12月20日收治的34例确诊甲型H1N1流感患者的临床资料进行回顾性分析.结果 34例患者临床以轻症为主,重症患者仅1例;主要症状为发热34例(100.0%),最高体温平均(38.8±0.68)℃,咳嗽27例(79.4%),咽痛22例(64.7%),咳痰15例(44.1%),全身酸痛13例(38.2%),头痛12例(35.3%),乏力8例(23.5%),流涕8例(23.5%);主要体征为咽部充血30例(88.2%),扁桃体肿大15例(44.1%);实验室检查外周血白细胞总数正常32例(94.1%),降低2例(5.9%),中性粒细胞分类升高14例(41.2%),淋巴细胞分类降低12例(35.3%),58.8%的患者血清C-反应蛋白不同程度升高;国产奥司他韦治疗24 h内,＞80.0%的患者体温恢复正常,临床症状和体征明显改善,未发现明显不良反应.结论 34例确诊甲型H1N1流感患者外周血白细胞总数正常,中性粒细胞分类升高,近60.0%的患者血清C-反应蛋白增高,可能是有别于其他季节性流感的临床特征;国产奥司他韦治疗安全、有效.  

11例甲型H1N1流感患者临床分析

目的 探讨甲型H1N1流感患者的临床特点及其转归.方法 对11例甲型H1N1流感患者进行隔离治疗,分析其流行病学、临床表现、实验室检查、治疗效果及临床转归等方面资料.结果 甲型H1N1流感好发于年轻人,发热、咳嗽及咽部不适为主要临床症状,部分患者出现白细胞减少及低钾血症,早期应用抗病毒治疗后,平均1.5 d后体温正常,平均6.6 d后咽拭子病毒转阴,8.3 d痊愈;治疗中未见明显药物不良反应出现.结论 甲型H1N1流感轻症患者早期抗病毒治疗有助于缩短病程,使用奥司他韦无论是进口的达菲,还是我国的军科奥韦治疗甲型H1N1流感均是安全、有效的.  

甲型H1N1流感患者临床特征及疗效分析

目的 总结甲型H1N1流感患者的临床特征,分析奥司他韦疗效.方法 回顾性收集了我院560例轻症甲型H1N1流感住院患者的临床资料,包括年龄、主要症状、实验室检查、发热至口服奥司他韦的时间、发热持续时间、病毒转阴时间;分析发热至口服奥司他韦的时间与发热持续时间及病毒转阴时间的相关性.患者按发热至口服奥司他韦的时间不同分三组,比较不同组间发热持续时间及病毒转阴时间是否有差异.结果 大部分患者症状为发热(97.0%)及咳嗽(90.0%);少数伴有胃肠道(1.8%)或神经系统症状(0.9%);部分患者血常规及生化异常;16.6%的患者心电图呈非特异性改变.患者从发热到起始服奥司他韦时间与发热持续时间及病毒转阴时间均呈正相关(r=0.83,P＜0.01;r=0.60,P＜0.01).各组之间比较其发热持续时间及病毒转阴时间差异有统计学意义(P＜0.01).结论 轻症甲型H1N1流感临床特征与季节性流感类似,发热患者早期口服奥司他韦治疗可能会缩短发热持续时间及病毒转阴时间.  

Structural basis for oseltamivir resistance of influenza viruses

Oseltamivir, one of the two anti-neuraminidase drugs, is currently the most widely used drug against influenza. Resistance to the drug has occurred infrequently among different viruses in response to drug treatment, including A H5N1 viruses, but most notably has emerged among recently circulating A H1N1 viruses and has spread throughout the population in the absence of drug use. Crystal structures of enzyme–drug complexes, together with enzymatic properties, of mutants of H5N1 neuraminidase have provided explanations for high level oseltamivir resistance due to the common H275Y mutation, with retention of zanamivir susceptibility, and intermediate level resistance due to the N295S mutation. Complementation of enhanced NA activity due to a D344N mutation by the H275Y mutation suggests an explanation for the recent emergence and predominance of oseltamivir-resistant influenza A H1N1 viruses.  

Determination of oseltamivir quality by colorimetric and liquid chromatographic methods

We developed a colorimetric and chromatographic assay for oseltamivir to assess the authenticity of Tamiflu (F. Hoffmann-La Roche Ltd., Basel, Switzerland) because of a growing concern about counterfeit oseltamivir. The colorimetric assay is quantitative and relies on an extractable colored ion-pair complex of oseltamivir with Congo red or bromochlorophenol blue. The reverse-phase chromatographic assay uses an alkaline mobile phase with UV detection. Both methods were evaluated for variability and selectivity and subsequently applied to batches of oseltamivir products acquired through the Internet. The Congo red test showed greater assay sensitivity, linearity, and accuracy. Colorimetric and chromatographic analysis showed all batches of oseltamivir product were within +/-15% of the stated amount of active ingredient.