广州市甲型H1N1流感病例密切接触者调查及医学观察结果分析

目的对广州市甲型H1N1流感病例密切接触者进行调查,并对隔离医学观察情况进行分析,为制定甲型H1N1流感防控措施提供科学依据。方法对确诊病例进行流行病学调查,确定密切接触者名单并对其进行追踪调查,采取定点医院和定点宾馆集中隔离医学观察的方法对密切接触者进行隔离观察,出现症状者采集咽拭子用real-time RT-PCR方法检测甲型H1N1流感病毒核酸。结果对223例密切接触者进行调查和观察,对其中23例出现症状者进行排查,及时发现3例甲型H1N1流感病例,其余220例均顺利解除隔离。在入境检疫时发现4例输入病例,其密切接触者104人,未发现甲型H1N1流感病例;在自行前往医院就诊时发现2例输入病例,其密切接触者共60人,发现了3例病例。密切接触者追踪调查与集中隔离时发现的3例病例,其密切接触者59人未发现甲型H1N1流感病例。结论对密切接触者进行调查和隔离医学观察是及时发现续发病例,防止疫情进一步传播和扩散的有效措施,病例不同发现方式影响密切接触者的转归。     

中国首例甲型H1N1流感二代病例的临床特征

目的了解2009年我国首例甲型H1N1流感二代病例的流行病学、临床、病原学检查特点及预后转归。方法对患者流行病学及临床资料进行回顾性分析,并采用实时荧光聚合酶链反应测定甲型H1N1流感病毒核酸。结果患者与甲型H1N1流感输入病例接触1天后发病。以发热、咽痛、咳嗽起病,白细胞及CD4＋T淋巴细胞计数降低,无肺炎等并发症。多级机构检测咽拭子甲型H1N1流感病毒核酸阳性确诊甲型H1N1流感。RT-PCR测序证实其病毒核苷酸序列与一代输入病例的一致,同源性为100%。经奥司他韦抗病毒及对症治疗痊愈出院。结论本病例的传染源明确,为我国首例报告的甲型H1N1流感二代确诊病例,其临床表现轻,病情恢复快。未发生院内感染,早隔离早诊断等防控措施有效。     

一起由3C.2a1分支甲型H3N2亚型流感病毒引起的医院暴发疫情分析

目的 通过对某医院一起甲型H3N2亚型流感暴发疫情进行调查和分析,为有效防控医院内发生的流感暴发疫情提供科学依据和经验借鉴.方法 采用现场流行病学调查方法,对某医院流感暴发疫情中病例进行个案调查,采集发热病例咽拭子标本,采用实时荧光PCR方法检测流感病毒核酸,应用MDCK细胞分离流感病毒,并采用全基因组测序方法对分离到的流感病毒进行序列分析.结果 2017年8月1日至7日,某医院呼吸科病区共报告发热病例30例,罹患率为28.58%.现场采集15例发热病例的咽拭子标本,经检测14例(94.3%)病例的标本为甲型H3N2亚型流感病毒核酸阳性;其中3例成功分离到甲型H3N2亚型流感病毒;对分离到的3株毒株进行基因测序分析,HA序列均属于3C.2a1分支,存在N171K、N121K突变.结论 此次疫情为北京市首起由3C.2a1分支甲型H3N2亚型流感病毒引起的医院内流感暴发疫情,提示医院也是流感疫情发生的重点场所.     

广州市甲型H1N1流感暴发疫点与监测人群病毒抗体检测

目的通过分析广州市甲型H1N1流感暴发疫点与监测人群病毒的抗体水平,了解甲型H1N1流感的流行趋势,为预防甲型H1N1流感疫情提供科学依据。方法应用红细胞血凝抑制（HI）方法检测流感甲型H1N1抗体,对比分析1570名疫区学生与1326名监测人群血清标本H1N1流感病毒的抗体水平。结果疫区学生甲型H1N1流感病毒感染率、流感罹患率分别为32.17%、22.23%,明显高于市区监测人群的22.62%、15.38%（P=0.000,P=0.000）。疫点学生与市区监测人群甲型H1N1流感隐性感染率分别为9.94%、7.24%,差异有统计学意义（P=0.012）。在已感染甲型H1N1流感病毒的疫点学生和市区监测人群中,甲型H1N1流感隐性感染率（30.89%、32.00%）差异无统计学意义（P=0.754）。疫点人群显性感染者的抗体滴度明显高于隐性感染者（t=4.701,P=0.000）,监测人群中显性感染与隐性感染者的抗体滴度无显著差异（t=0.248,P=0.804）。结论疫点学生甲型H1N1流感隐性感染率明显高于监测人群。提示隐性感染人群具有潜在的传染力,应加强隐性感染者的监测。     

人感染甲型H1N1流感病毒的研究进展

2009年4月以来,包括墨西哥、美国和加拿大在内的许多国家发生了人感染甲型H1N1流感病毒疫情,WHO已于2009年4月29日将此次流感流行的预警级别不断提升至5级。现已基本明确,引起此次流感疫情的甲型H1N1流感病毒是猪流感病毒（swine influenza virus,SIV）的一种新型变异株。     

2009-2010年山西省流感／甲型H1N1流感的病原学监测分析

目的分析掌握山西省2009--2010年流感／甲型H1N1流感的流行特征,为预测和防控流感／甲型H1N1流感流行提供科学依据。方法对哨点医院和集体发热疫情进行监测采样,采用病毒核酸检测法和细胞培养法分离鉴定流感／甲型H1N1流感病毒,并对2009年5月至2010年4月山西省录入“中国流感监测信息系统”的流感样病例监测报告数据及其样本病原学监测数据进行统计分析。结果山西省全年均有流感病毒活动,2009年流行优势毒株为甲型H1N1流感病毒,流行最高峰在11月（阳性率为58．1％,甲型H1N1占88．1％）,主要导致59岁以下人群发病,其中5-24岁年龄组阳性率较高,进入2010年后乙型（Victoria系）流感病毒的活动有所增加,成为流行株。结论流感样病例监测和病原学监测,可以及时反映流感活动状况,对于掌握该省流感／甲型H1N1流感流行规律有着重要意义。     

河北省2009-2014年甲型H1N1流感流行特征分析

目的 分析河北省2009-2014年度甲型H1N1流感的流行特征.方法 采用描述性流行病学方法对2009年4月1日-2014年3月31日的流感监测结果进行分析.结果 采集的47949例流感样病例(influenza-like illness,ILI)标本经流感病毒核酸检测,8248例阳性(阳性率为17.20％),其中甲型H1N1 4168例,季节性H3 2006例,B型1820例,季节性H1等254例.各年度优势病原不同,除2010-2011年度外,其他年度均存在甲型H1N1流感病毒流行.对4168例甲型H1N1病例进一步分析显示:全省11个地市均有该病例检出,男女性别比1.09:1.自2009年甲流大流行后,2011年11月至2014年3月共出现3次流行,具有明显的季节性,且呈单峰分布.结论 河北省甲型N1N1流感的流行趋势已趋于季节性,无明显的地域性,除2010-2011年度外,其他年度都是优势病原之一,近年来感染以25-59岁年龄组为主.     

2011-2017年河北省甲型H1N1流感流行特征分析

目的掌握河北省甲型H1N1流感的流行特征,为流感防控提供科学依据.方法通过中国流感监测信息系统收集河北省2011年4月至2017年3月流感及流感样病例(influenza-likeillness,ILI)监测数据进行统计分析.结果共检测ILI标本77 008份,甲型H1N1流感病毒核酸阳性2 699份,阳性率3.50％.对2 699例甲型H1N1流感病例进一步分析显示:全省11个地市均有该病例检出,男女比例为1.09:1,各年龄组均可发病,检出率最高的是25～59岁组,最低0～4岁组.2011年11月至2017年3月共出现4次流行,具有明显的季节性,且呈单峰性.各年度均有甲型H1N1流感病例检出,甲型H1N1流感分别是2012-2013、2013-2014和2016-2017年度的优势病原.结论河北省甲型N1N1流感流行具有明显的季节性,冬春季流行,近年来感染以5～14岁年龄组为主.     

应用SEIR模型预测2009年甲型H1N1流感流行趋势

目的 探讨SEIR模型预测甲型H1N1流感流行趋势的功效.方法 利用国庆前北京市流感样病例数、流感样病例中甲型H1N1流感阳性率及二级以上医院流感样病例就诊率等参数估算甲型H1N1流感实际感染人数,基于传染病传播动力学,建立SEIR模型,对国庆后甲型H1N1流感的流行趋势及高峰达到时间进行预测,与甲型H1N1流感病原学...     

阳江市2009年甲型H1N1流行性感冒暴发疫情分析

目的了解阳江市甲型H1N1流感暴发的流行特征和影响因素,探索预防控制流感的方法。方法分析阳江市2009年甲型H1N1流感暴发疫情,并对社区人群按年龄分层抽样进行血清学回顾性调查。结果阳江市共报告甲型H1N1流感暴发疫情42起;10下旬至11月为发病高峰期;暴发疫情中小学占50.00%,中学占38.10%;患者男性占53.38%,女性占46.42%;社区人群甲型H1N1流感感染率为30.63%。结论学生群体为甲型H1N1流感暴发疫情的高危人群,针对疫情发生的不同时期相应地调整防控策略的防控效果显著;防控措施采取时间越早,暴发疫情持续时间就越短,发病率就越低。     

深圳市罗湖区住院病人新型甲型H1N1流感感染情况分析

目的分析深圳市罗湖区住院病人新型甲型H1N1流感的感染情况,为辖区住院病人的甲流防控工作提供依据。方法采用描述性流行病学研究方法对深圳市罗湖区2009年11月至2010年2月期间深圳市人民医院和罗湖区人民医院的住院病人新型甲型H1N1流感的感染情况进行分析。结果在2009年11月至2010年2月期间共检测了292份疑似甲流的住院病人的咽拭子样本,共检出甲流感染者93例。2009年11月份住院病人感染甲流的人数最多,感染率高达68.18%。30岁以下的住院病人感染甲流的人数占住院病人感染甲流总数的81.7%。男女住院病人甲流的感染率比为1.21：1.结论甲流主要感染30岁以下住院病人,因此,需要加强对该年龄段有流感症状的住院病人的甲流排查和管理。     

Changes in epidemiology,clinical features and severity of influenza A (H1N1) 2009 pneumonia in the first post-pandemic influenza season

Although the influenza A (H1N1) 2009 virus is expected to circulate as a seasonal virus for some years after the pandemic period, its behaviour cannot be predicted. We analysed a prospective cohort study of hospitalized adults with influenza A (H1N1) 2009 pneumonia at 14 teaching hospitals in Spain to compare the epidemiology, clinical features and outcomes of influenza A (H1N1) 2009 pneumonia between the pandemic period and the first post-pandemic influenza season. A total of 348 patients were included: 234 during the pandemic period and 114 during the first post-pandemic influenza season. Patients during the post-pandemic period were older and more likely to have chronic obstructive pulmonary disease, chronic kidney disease and cancer than the others. Septic shock, altered mental status and respiratory failure on arrival at hospital were significantly more common during the post-pandemic period. Time from illness onset to receipt of antiviral therapy was also longer during this period. Early antiviral therapy was less frequently administered to patients during the post-pandemic period (22.9% versus 10.9%; p 0.009). In addition, length of stay was longer, and need for mechanical ventilation and intensive-care unit admission were significantly higher during the post-pandemic period. In-hospital mortality (5.1% versus 21.2%; p <0.001) was also greater during this period. In conclusion, significant epidemiological changes and an increased severity of influenza A (H1N1) 2009 pneumonia were found in the first post-pandemic influenza season. Physicians should consider influenza A (H1N1) 2009 when selecting microbiological testing and treatment in patients with pneumonia in the upcoming influenza season.     

Pediatric hospital admissions from influenza A (H1N1) in Brazil: effects of the 2010 vaccination campaign

In 2009, the influenza A (H1N1) virus spread rapidly around the world, causing the first pandemic of the 21^st Century. In 2010, there was a vaccination campaign against this new virus subtype to reduce the morbidity and mortality of the disease in some countries, including Brazil. Herein, we describe the clinical and epidemiological characteristics of patients under 19 years of age who were hospitalized with confirmed influenza A (H1N1) infection in 2009 and 2010. We retrospectively reviewed files from the pediatric patients who were admitted to a university hospital with real-time polymerase chain reaction (RT-PCR) confirmed influenza A (H1N1) infection in 2009 and 2010. There were 37 hospitalized patients with influenza A (H1N1) in 2009 and 2 in 2010. In 2009, many of the hospitalized children had an underlying chronic disease and a lower median age than those not hospitalized. Of the hospitalized patients, 78% had a chronic disease, primarily pneumopathy (48%). The main signs and symptoms of influenza were fever (97%), cough (76%), and dyspnea (59%). Complications occurred in 81% of the patients. The median length of hospitalization was five days; 27% of the patients required intensive care, and two died. In 2010, two patients were hospitalized with influenza A (H1N1): one infant with adenovirus co-infection who had received one previous H1N1 vaccine dose and presented with respiratory sequelae and a 2-month-old infant who had a hospital-acquired infection. An impressive reduction in hospital admissions was observed in 2010 when the vaccination campaign took place in Brazil.     

A SYBR Green I real-time RT-PCR assay for detection and differentiation of influenza A(H1N1) virus in swine populations

The novel influenza A(H1N1) virus that emerged recently in Mexico has spread rapidly to many countries and initiated a human pandemic. It would be interesting to determine whether the virus has existed in, or will spread to, the swine population. However, it is difficult to differentiate the virus from some swine influenza viruses. In this study, a SYBR Green I real-time RT-PCR assay was designed for detection and differentiation of influenza A(H1N1) virus from some swine influenza viruses, by comparing the amplification of two pairs of primers corresponding to influenza A(H1N1) virus and some swine influenza viruses, respectively. The assay was evaluated using online analysis, identified influenza viruses and clinical samples. The results indicated that the assay has high sensitivity and specificity to detect influenza A(H1N1) virus, and is able to differentiate it from some swine influenza viruses. This, in turn, could provide essential epidemiological information for risk analysis and decision making in combating the disease, and stimulate research to differentiate pathogens similar to each other using the same method.     

北京市1例人感染H9N2禽流感病例的流行病学调查与分析

目的 分析北京市人感染H7N9禽流感疫情强化监测中发现的1例人感染H9N2禽流感病例流行病学调查情况,为今后科学防控人感染H9N2禽流感疫情提供参考.方法 采用现场流行病学和实验室检测相结合的方法,收集病例流行病学资料,采集并检测病例、暴露环境和密切接触者等标本,分析流行病学特征和可能的感染来源.结果 病例发病第3日和第7日咽拭子标本检测均为H9N2禽流感病毒核酸阳性.病例发病前10天内无禽类接触史,但病例平时活动有暴露于H9N2禽流感病毒污染环境的可能.密切接触者在医学观察期内均未出现流感样症状.结论 该病例为北京市首例成人感染H9N2禽流感确诊病例,同时也是北京市第二例H9N2禽流感确诊病例.医疗机构加强流感样病例监测是及时发现人感染H9N2禽流感病例的重要手段.     

2009年深圳市某街道甲型H1N1流感流行病学分析

目的探讨深圳市某街道2009年甲型H1N1流感的流行病学特征。方法将2009年流感样病例建立数据库进行统计学分析,对死亡病例进行个案分析。结果 2009年甲型H1N1流感实验室确诊65例,其中重症患者10例（死亡1例）;病例主要集中在10-11月（333例）;学校和托幼机构为高发场所（363例,98.9%）;5～14岁青少年为易感人群（293例,79.8%）。结论深圳市某街道2009年甲型H1N1流感发病高峰出现在11月,主要在封闭、人群集中、接触密切的学校和托幼机构暴发。     

重庆市九龙坡区2009年甲型H1N1流感暴发疫情流行病学分析

目的了解重庆市九龙坡区甲型H1N1流感暴发疫情的流行病学特征,为更好地制定有针对性的控制措施提供依据。方法对重庆市九龙坡区2009年甲型H1N1流感暴发疫情处理资料进行描述性分析。结果 16起甲型H1N1流感暴发疫情累计确诊64例,平均罹患率为0.36%（64/17778）;疫情集中发生在9月,发病人群主要是中专职校学生;男女性别比为3：1。结论甲型H1N1流感暴发疫情均发生在学校,学校是控制甲型H1N1流感疫情的关键,应及时报告疫情、有效落实控制措施。     

Serologic Evidence of Pandemic Influenza Virus H1N1 2009 Infection in Cats in China

Infection of domestic cats with (H1N1) pandemic 2009 (pdm09) influenza A virus has recently been documented. In this paper, we report for the first time the sporadically current seroprevalence of (H1N1) pdm09 influenza A virus infection in cats in China. Thirteen of 1,080 sera were found positive by nucleoprotein (NP)-specific enzyme-linked immunosorbent assays (ELISAs) in different cat populations in southern China. It is very important to stress further surveillance of pandemic (H1N1) 2009 influenza A virus in cats in southern China.