2009—2010年宜宾市翠屏区甲型H1N1流感流行特征分析

目的分析宜宾市翠屏区2009—2010年甲型H1N1流感流行特征,为科学防控提供依据。方法利用中国疾病预防控制系统和现场调查资料进行分析。结果翠屏区2009—2010年共报告甲型H1N1流感确诊病例43例,年发病率分别为5．03／10万,0．24／10万;2009年发病高峰为11～12月份;男女比例为1．26：1,58．14％病例为学生,发病年龄以10～14岁居多,56．00％为初中生。结论翠屏区2009—2010年甲型H1N1流感出现疫情较迟,病例以城区学生为主。安排学生及早接种甲型H1N1流感疫苗,采取综合措施防范学校的暴发疫情是控制该病的关键。     

北京市2009年甲型H1N1流行性感冒危重症与死亡病例流行病学特征及其影响因素分析

目的 了解北京市2009年甲型H1N1流行性感冒(流感)危重症与死亡病例的流行病学特征,探讨影响甲型H1N1流感病情严重程度的主要因素.方法 利用北京市2009年甲型H1N1流感病例个案信息进行描述性分析和多因素Logistic回归分析.结果 北京市2009年甲型H1N1流感感染率为66.1/10万,25～60岁组人群感染率最高,为86.8/10万.0～5岁组和60岁以上年龄组危重症感染率(12.5/10万,3.9/10万)、死亡率(0.9/10万,0.7/10万)和病死率(2.4%,3.3%)较高.549例危重症病例中学龄前儿童110例,比例最高,占20.0%,69例死亡病例中离、退休人员17例,比例最高,占24.6%.超过70.0%的危重症和死亡病例均在发病后2 d内到医院就诊.危重症病例和死亡病例中,均以有心血管疾病的病例比例最高,其次为慢性肺部疾病.多因素Logistic回归分析显示,甲型H1N1流感病例中,60岁以上、慢性肺部疾病及心血管疾病可能导致其病情较重,OR值分别为3.586(95%CI 1.586～8.117)、2.126(95%CI 1.178～3.835)和1.954(95%CI 1.126～3.391).结论 60岁以上、伴心血管疾病及慢性肺部疾病等因素可能加重甲型H1N1流感病例病情.     

北京市2009年甲型H1N1流行性感冒危重症与死亡病例流行病学特征及其影响因素分析

目的 了解北京市2009年甲型H1N1流行性感冒(流感)危重症与死亡病例的流行病学特征,探讨影响甲型H1N1流感病情严重程度的主要因素.方法 利用北京市2009年甲型H1N1流感病例个案信息进行描述性分析和多因素Logistic回归分析.结果 北京市2009年甲型H1N1流感感染率为66.1/10万,25～60岁组人群感染率最高,为86.8/10万.0～5岁组和60岁以上年龄组危重症感染率(12.5/10万,3.9/10万)、死亡率(0.9/10万,0.7/10万)和病死率(2.4%,3.3%)较高.549例危重症病例中学龄前儿童110例,比例最高,占20.0%,69例死亡病例中离、退休人员17例,比例最高,占24.6%.超过70.0%的危重症和死亡病例均在发病后2 d内到医院就诊.危重症病例和死亡病例中,均以有心血管疾病的病例比例最高,其次为慢性肺部疾病.多因素Logistic回归分析显示,甲型H1N1流感病例中,60岁以上、慢性肺部疾病及心血管疾病可能导致其病情较重,OR值分别为3.586(95%CI 1.586～8.117)、2.126(95%CI 1.178～3.835)和1.954(95%CI 1.126～3.391).结论 60岁以上、伴心血管疾病及慢性肺部疾病等因素可能加重甲型H1N1流感病例病情.     

甲型H1N1流感62例临床诊治分析

2009年3月以来,墨西哥、美国暴发了甲型H1N1流感,疫情迅速蔓延。我院2009年6月～9月共收治甲型H1N1流感病例62例,现将其临床表现及治疗情况报道如下。     

某中学甲型H1N1流感暴发疫情调查

目的 描述洪雅县某中学甲型H1N1流感暴发疫情的流行病学特征,为学校甲型H1N1流感暴发防控提供参考.方法 应用现场流行病学方法开展调查,用RT - PCR检测病例标本,用Epidata录入数据,用Excel、Epiinfo软件进行结果分析.结果 该校共发现流感病例151例,罹患率6.31％,学生病例149例,首发病例为高一学生,高一年级罹患率最高(11.19％),住校生罹患率9.1％,走读生为2.83％.病原学检测,采集25例病例的咽拭子标本,甲型H1N1流感病毒阳性率20％.结论 此次疫情是为甲型H1N1流感暴发疫情,住校学生罹患率较高,住宿条件较差和学生接触密切是此次疫情的危险因素.     

2009年广东省甲型流行性感冒暴发流行期间首株甲型H1N1流行性感冒病毒血凝素基因分析

目的 检测和分析2009年广东省甲型流行性感冒(流感)暴发流行期间首株甲型H1N1流感病毒血凝素(HA)基因.方法 对2009年广东省首例确诊的甲型H1N1流感患者的咽拭子进行病毒分离,取细胞培养上清液提取病毒核酸,采用HA基因的特异性引物进行RT-PCR,PCR产物进行克隆、测序和同源性分析.结果 获得2009年广东省首株甲型H1N1流感病毒的HA基因,大小为1710 bp,命名为A/GuangzhouSB/01/2009(H1N1)HA,GenBank登录号为GQ268003.与疫情发源地近期报告的277株甲型H1N1流感病毒的HA基因比对,同源性为99.0%～99.8%;其中与美国报告的病毒株的同源性高达99.8%,与患者发病前曾到美国旅游的流行病学史一致.与25株中国季节性甲型H1N1流感病毒的HA基因比对,同源性为72.3%～85.6%.结论 2009年广东省甲型流感暴发流行期间首株甲型H1N1流感病毒与目前流行的甲型H1N1流感病毒同源性高,与中国季节性甲型H1N1流感病毒同源性较低.     

四川省2009甲型H1N1流感的流行病学特征

目的分析四川地区甲型H1N1流感流行病学特点,为今后新发传染病的防控提供参考。方法回顾性分析我院2009年收治的271例甲型H1N1流感病例的来源、年龄及时间分布。结果 1.271例甲型H1N1流感病例,男∶女为1.09∶1,随着病情加重发病年龄逐渐增加,病程亦逐渐延长;2.轻症患者均无基础疾病,危重症患者基础疾病较重症患者多且重;3.绝大多数患者年龄在10~30岁（211例,77.87%）,轻症及重症中无≤2岁及≥65岁的患者,危重症中≥65岁者2例;4.疫情早期（5~9月）患者均为轻症,以输入病例为主（52例,19.19%）,疫情后期以本土暴发病例为主（9月以后）有危重症出现。结论新发传染病疫情早期以轻症、输入病例为主,后期随着社区聚集性疫情,有重危症患者出现;患者年龄、基础疾病是该疾病严重程度的重要影响因素。     

甲型H1N1流感96例临床观察

目的探讨辽阳地区甲型H1N1流感的临床特点。方法分析2009年9—10月我市收治的96例甲型H1N1流感患者的临床表现、实验室检查结果、治疗及预后特点。结果辽阳地区甲型H1N1流感以青少年学生多发;绝大多数病例临床表现类似于普通感冒,少数病例出现CK、AIJT、AST升高,极少数病例可出现口周疱疹及皮疹;重症发生率为4．2％;连花清瘟胶囊和（或）痰热清注射液治疗有效。结论辽阳地区甲型H1N1流感临床经过良好,无危重症病例,治愈率为100％。中西医结合治疗有效。     

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。     

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.     

Influenza surveillance from November 2008 to 2011; including pandemic influenza A(H1N1)pdm09 in Bhutan

Objective Describe the influenza A(H1N1) pandemic in Bhutan. Design Observational study from sentinel surveillance sites. Setting Bhutan remains isolated, with only one to two flights a day at the lone airport, no trains, and only three major roads that enter from India. Main outcome measures PCR positive human respiratory samples Results The first case of A(H1N1)pdm09 infection was detected in Bhutan in July 2009, 3 months after the virus was first reported in Mexico in April 2009. During the official WHO pandemic period (11 June 2009 to 8 August 2010), a total of 2149 samples were collected and tested by RT‐PCR of which 22.7% (487) were confirmed A(H1N1)pdm09; H3N2, H1N1, and B were positive in 2.2%, 1.1%, and 7.2%, respectively. The highest rate of A(H1N1)pdm09 cases (57.4%) was detected in the 6‐20 year‐old age group. Importantly, Bhutan increased from 3 sentinel sites in April 2009 to 11 a year later, and in April 2010 established PCR capability for influenza. Conclusions Despite relative isolation, the A(H1N1)pdm09 reached Bhutan within 3 months of identification in Mexico. The H1N1 pandemic has made Bhutan more prepared for epidemics in the future.     

Transmission of pandemic influenza H1N1 (2009) in Vietnamese swine in 2009-2010

Please cite this paper as: Trevennec et al. (2012) Transmission of pandemic influenza H1N1 (2009) in Vietnamese swine in 2009–2010. Influenza and Other Respiratory Viruses 6(5), 348–357. Background The pandemic of 2009 was caused by an H1N1 (H1N1pdm) virus of swine origin. This pandemic virus has repeatedly infected swine through reverse zoonosis, although the extent of such infection in swine remains unclear. Objective This study targets small and commercial pig producers in North Vietnam, in order to estimate the extent of H1N1pdm infection in swine and to identify the risk factors of infection. Methods Virologic and serologic surveillance of swine was carried out in 2009–2010 in pig farms (38 swabs and 1732 sera) and at a pig slaughterhouse (710 swabs and 459 sera) in North Vietnam. The sera were screened using a influenza type A‐reactive ELISA assay, and positive sera were tested using hemagglutination inhibition tests for antibody to a panel of H1‐subtype viruses representing pandemic (H1N1) 2009 (H1N1pdm), triple reassortant (TRIG), classical swine (CS), and Eurasian avian‐like (EA) swine lineages. Farm‐level risk factors were identified using a zero‐inflated negative binomial model. Results We found a maximal seroprevalence of H1N1pdm of 55·6% [95% CI: 38·1–72·1] in the slaughterhouse at the end of December 2009, 2 weeks after the peak of reported human fatalities with H1N1pdm. Farm‐level seroprevalence was 29% [95% CI: 23·2–35·7]. In seropositive farms, within‐herd seroprevalence ranged from 10 to 100%. We identified an increased risk of infection for farms that specialized in fattening and a decreased risk of infection in farms hiring external swine workers. Conclusions Our findings suggest extensive reverse‐zoonotic transmission from humans to pigs with subsequent onward transmission within pig herds.     

Perspectives of Allergists/Immunologists on the 2009–2010 H1N1 Vaccination Effort

Background. Persons with high-risk conditions such as asthma were a target group for national H1N1 vaccine recommendations. Allergists/immunologists (allergists) are a provider group that could vaccinate persons with asthma and other high-risk conditions. Their level of participation in and experiences with the 2009–2010 H1N1 vaccination campaign are unknown. Objective. To describe the experiences of allergists related to the 2009–2010 H1N1 vaccination campaign. Methods. A cross-sectional, mailed survey of a national sample of 1955 allergists providing outpatient care was conducted in June–September 2010. Results. The overall response rate was 72%. Most allergists “strongly recommended” H1N1 vaccine for children, and most “recommended” or “strongly recommended” vaccine for adults. The majority (71%) agreed to participate in the H1N1 vaccine campaign and received vaccine. Vaccine supply was a significant challenge, but otherwise few major problems were experienced with administering H1N1 vaccine. The majority of respondents, particularly among those who participated in the 2009–2010 H1N1 vaccination campaign, felt they would be very likely to vaccinate in the event of future influenza pandemic. Conclusions. The experiences of allergists in the H1N1 vaccine campaign were generally positive. Most allergists are willing to serve as vaccinators in future influenza pandemics, which will help facilitate broad access to vaccine for patients with asthma and other high-risk conditions.     

Influenza disease burden in adults by subtypes following the initial epidemic of pandemic H1N1 in Singapore

Peaks of influenza activity in July 2009 and January 2010 were >90% pandemic H1N1 (pH1N1), but by May 2010, H3N2 predominated in hospital attendances (46·5%, versus 38·9% pH1N1); H3N2 hospital attendances were older (72·9% aged ≥60 years versus 13·5% for pH1N1), but the age-stratified proportions admitted for pneumonia ]were similar. As at the end of the third epidemic wave in Singapore, pH1N1 cases in hospital attendances were still markedly younger than cases of H3N2 or influenza B, with little evidence for any changes in severity.     

Original Article: A primary school outbreak of pandemic 2009 influenza A (H1N1) in China

Please cite this paper as: Huai et al. (2010) A primary school outbreak of pandemic 2009 influenza A (H1N1) in China. Influenza and Other Respiratory Viruses DOI: 10.1111/j.1750‐2659.2010.00150.x. Background  We investigated the first known outbreak of pandemic 2009 influenza A (H1N1) at a primary school in China. Objectives  To describe epidemiologic findings, identify risk factors associated with 2009 H1N1 illness, and inform national policy including school outbreak control and surveillance strategies. Methods  We conducted retrospective case finding by reviewing the school’s absentee log and retrieving medical records. Enhanced surveillance was implemented by requiring physicians to report any influenza‐like illness (ILI) cases to public health authorities. A case–control study was conducted to detect potential risk factors for 2009 H1N1 illness. A questionnaire was administered to 50 confirmed cases and 197 age‐, gender‐, and location‐matched controls randomly selected from student and population registries. Results  The attack rate was 4% (50/1314), and children from all grades were affected. When compared with controls, confirmed cases were more likely to have been exposed to persons with respiratory illness either in the home or classroom within 7 days of symptom onset (OR, 4·5, 95% CI: 1·9–10·7). No cases reported travel or contact with persons who had traveled outside of the country. Conclusions  Findings in this outbreak investigation, including risk of illness associated with contacting persons with respiratory illness, are consistent with those reported by others for seasonal influenza and 2009 H1N1 outbreaks in school. The outbreak confirmed that community‐level transmission of 2009 H1N1 virus was occurring in China and helped lead to changes in the national pandemic policy from containment to mitigation.     

Increased symptom severity but unchanged neuraminidase inhibitor effectiveness for A(H1N1)pdm09 in the 2010–2011 season: comparison with the previous season and with seasonal A(H3N2) and B

Background No studies of the clinical symptoms before starting therapy or of the effectiveness of neuraminidase inhibitors (NAIs) have been carried out of the 2009–2010 and 2010–2011 seasons that compare A(H1N1)pdm09 or the three circulating types of influenza virus. Methods The clinical symptoms and duration of fever (body temperature ≥37·5°C) after the first dose of an NAI (oseltamivir, zanamivir, laninamivir) were analyzed. PCR was carried out for 365 patients with A(H1N1)pdm09 in the 2009–2010 season and for 388 patients with one of the three types of influenza circulating in the 2010–2011 season. IC₅₀ for the three NAIs was also analyzed in 51 patients in the 2010–2011 season. Results The peak body temperature was significantly higher in 2010–2011 than in 2009–2010 for patients under 20 years with A(H1N1)pdm09, and in the 2010–2011 season for children 15 years or younger with A(H1N1)pdm09 than for those with other virus types. The percentage of A(H1N1)pdm09 patients with loss of appetite or fatigue was significantly higher in 2010–2011 than in the previous season. The duration of fever was not affected by the kind of NAI or by age in multiple regression analysis. The percentage of patients afebrile at 48 hours after the first dose of NAI was significantly higher for A(H1N1)pdm09 than for A(H3N2) (laninamivir) or B (oseltamivir and laninamivir). Conclusion Although the clinical symptoms of A(H1N1)pdm09 were slightly more severe in the 2010–2011 season, the effectiveness of the NAIs remained high in comparison with 2009–2010 and with other types of seasonal influenza.     

A novel electrochemical device to differentiate pandemic (H1N1) 2009 from seasonal influenza

Please cite this paper as: Straight et al. (2010) A novel electrochemical device to differentiate pandemic (H1N1) 2009 from seasonal influenza. Influenza and Other Respiratory Viruses 4(2), 73–79. Background One of the challenges of the recent pandemic (H1N1) 2009 influenza outbreak was to differentiate the virus from seasonal influenza when confronting clinical cases. The determination of the virus has implications on treatment choice, and obvious epidemiologic significance. Objectives We set out to apply a novel electrochemical device to samples derived from clinical cases of pandemic (H1N1) 2009 influenza to examine the ability of the device to differentiate these samples from cases of seasonal influenza. Patients/Methods An IRB approved protocol allowed for the use of original nasal wash samples from 24 confirmed human cases pandemic (H1N1) 2009 influenza. Clinical samples from cases of seasonal influenza (Influenza A/H1N1, A/H3N2, and B) were included as controls. Nucleic acids were extracted and samples examined by the ElectraSense^® Influenza A assay (CombiMatrix, Inc). Samples were also examined by RT-PCR or Luminex assays as a comparator. Results and Conclusions The ElectraSense^® Influenza A assay correctly identified 23 of 24 samples of laboratory-confirmed pandemic (H1N1) 2009 Influenza. The assay correctly identified all samples of influenza A/H1N1 and A/H3N2, and differentiated these from pandemic (H1N1) 2009 Influenza in all cases. The ElectraSense^® Influenza A assay proved to be a useful assay to quickly and accurately differentiate pandemic (H1N1) 2009 influenza from seasonal influenza.     

Experimental inoculation of pigs with pandemic H1N1 2009 virus and HI cross-reactivity with contemporary swine influenza virus antisera

Please cite this paper as: Vincent et al. (2010) Experimental inoculation of pigs with pandemic H1N1 2009 virus and HI cross-reactivity with contemporary swine influenza virus antisera. Influenza and Other Respiratory Viruses 4(2), 53–60 Background A novel A/H1N1 was identified in the human population in North America in April 2009. The gene constellation of the virus was a combination from swine influenza A viruses (SIV) of North American and Eurasian lineages that had never before been identified in swine or other species. Objectives The objectives were to (i) evaluate the clinical response of swine following experimental inoculation with pandemic H1N1 2009; (ii) assess serologic cross-reactivity between H1N1 2009 and contemporary SIV antisera; and (iii) develop a molecular assay to differentiate North American-lineage SIV from H1N1 2009. Methods Experiment 1: Weaned pigs were experimentally infected with A/California/04/2009 (H1N1). Experiment 2: The cross-reactivity of a panel of US SIV H1N1 or H1N2 antisera with three isolates of pandemic A/H1N1 was evaluated. Experiment 3: A polymerase chain reaction (PCR)-based diagnostic test was developed and validated on samples from experimentally infected pigs. Results and Conclusions In experiment 1, all inoculated pigs demonstrated clinical signs and lesions similar to those induced by endemic SIV. Viable virus and antigen were only detected in the respiratory tract. In experiment 2, serologic cross-reactivity was limited against H1N1 2009 isolates, notably among virus antisera from the same HA phylogenetic cluster. The limited cross-reactivity suggests North American pigs may not be fully protected against H1N1 2009 from previous exposure or vaccination and novel tests are needed to rapidly diagnose the introduction of H1N1 2009. In experiment 3, an RT–PCR test that discriminates between H1N1 2009 and endemic North American SIV was developed and validated on clinical samples.     

Influenza A/H1N1 2009 pneumonia in kidney transplant recipients: characteristics and outcomes following high‐dose oseltamivir exposure

S.P. Watcharananan, T. Suwatanapongched, P. Wacharawanichkul, W. Chantratitaya, V. Mavichak, S.B. Mossad. Influenza A/H1N1 2009 pneumonia in kidney transplant recipients: characteristics and outcomes following high‐dose oseltamivir exposure.
Transpl Infect Dis 2010: 12: 127–131. All rights reserved Abstract: We report 2 cases of severe pneumonia due to the novel pandemic influenza A/H1N1 2009 in kidney transplant recipients. Our patients initially experienced influenza‐like illness that rapidly progressed to severe pneumonia within 48 h. The patients became hypoxic and required non‐invasive ventilation. The novel influenza A/H1N1 2009 was identified from their nasal swabs. These cases were treated successfully with a relatively high dose of oseltamivir, adjusted for their renal function. Clinical improvement was documented only after a week of antiviral therapy. Despite early antiviral treatment, we showed that morbidity following novel pandemic influenza A/H1N1 2009 infection is high among kidney transplant recipients.