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.     

湖北省首例人感染H5N6禽流感病例流行病学调查

目的 对湖北省首例人感染H5N6禽流感病例的流行病学资料进行分析,探讨病例发现过程、调查处理措施、实验室检测方法,为防控人感染H5N6禽流感疫情提供依据.方法 采用描述性流行病学方法,分析湖北省首例人感染H5N6禽流感病例诊治过程、密切接触者信息,开展现场流行病学调查,并采集病例、密切接触者、活禽市场外环境标本进行实验室检测分析.结果 患者2016年4月9日发病,体温40℃,有活禽市场暴露史.发病早期采集的下呼吸道标本(痰液、气管分泌液)为H5N6禽流感病毒核酸阳性,而上呼吸道标本H5N6禽流感病毒核酸检测均为阴性.患者无外出史和H5N6禽流感病例接触史.患者经两个月的治疗痊愈出院.密切接触者58人均未出现发热和呼吸道感染症状.采集病例经常路过的两家活禽市场和一家土鸡专卖店外环境标本共36份,其中检出H5N6禽流感病毒核酸1 1份,阳性率为30.56％.结论 该病例为湖北省首例人感染H5N6禽流感病例,属本地感染的散发病例,未出现人传人.传播途径可能为:活禽市场通过禽-环境-人的途径传播.在病例诊断中,下呼吸道标本(尤其是痰液、气管分泌液)具有重要意义.另外,尽早应用奥司他韦对病例的成功救治起到了重要的作用.     

一起人感染H7N9禽流感家庭聚集性疫情的流行病学调查分析

目的 调查一起人感染H7 N9禽流感聚集性疫情的流行病学特征,分析病例的感染来源和传播途径.方法 对病例开展现场流行病学调查和实验室检测,对病例感染来源进行调查和外环境采样检测.结果 共发现两名病例,病例为父女关系.两病例发病前有可疑活禽暴露史,居住地附近可疑暴露市场标本检测出H7N9禽流感病毒.病例1在潜伏期内即发病,判断为环境暴露感染;其女儿的发病时间距脱离暴露环境已经10天,而在其父亲发病后曾共同生活,判断由其父亲传染给她的可能性大.结论 本起家庭聚集性疫情中,病例1的感染来源可能为被H7 N9禽流感病毒污染的环境,病例2被病例1传染的可能性更大.     

2016—2018年长沙市人群及活禽市场环境H5N6亚型禽流感病毒监测分析

目的:开展2016—2018年长沙市人群感染和活禽市场(live poultry markets, LPMs)环境污染H5N6亚型禽流感病毒(avian influenza virus, AIV)监测,为防控人感染H5N6亚型AIV提供实验室数据。方法:采集2016—2018年长沙市流感样病例和不明原因肺炎病例咽拭子6...     

北京市通州区外环境禽流感病毒的流行分布及基因特征分析

目的通过对2021—2022年北京市通州区农贸市场的外环境及相关人员标本的禽流感病毒检测结果及基因特征分析, 为我市禽流感防控策略提供依据。方法 2021—2022年共采集外环境及食品涂抹标本2 184例, 相关人员咽拭子标本124例。利用实时荧光RT-PCR法对标本进行核酸检测, 采用illumina二代测序平台对病毒载量高的阳性标本进行全基因组测序, 分析其基因特征。结果实时荧光RT-PCR核酸检测结果显示, 外环境及食品涂抹标本检出2例H5N8阳性、78例H7N9阳性、177例H9N2阳性、2例H5N8和H9N2共感染、1例H7N9和H9N2共感染, 124例人员标本检测结果均为阴性。对病毒载量高的阳性标本进行全基因组测序分析, 1例H5N8病毒的HA基因属于为2.3.4.4分支, HA基因的HA0裂解位点序列为多个连续性碱性氨基酸(REKRRKR/ GLF), 2例H7N9病毒的HA基因与Yangtza river delta属于同一分支, HA基因的HA0裂解位点序列为多个连续性碱性氨基酸(VPKRKRTAR/GLF), 均属于高致病性禽流感病毒。遗传进化树分析提示, H5N...     

2015—2016年济南市活禽市场禽流感病毒监测分析

目的 了解济南市活禽市场外环境样本中甲型禽流感病毒动态分布状况,分析禽流感病毒污染特征.方法 2015年11月至2016年10月,选择济南市所属槐荫区活禽批发市场与历城区活禽零售市场进行外环境样本采集,样本类型包括禽处理台表面擦拭物、笼具表面擦拭物、粪便标本、清洗禽类的污水、禽类饮用水等.应用荧光定量RT-PCR方法对样本进行甲型流感病毒核酸检测,阳性样本进一步进行H5、H7及H9亚型检测.采用x2检验比较不同类型活禽市场、不同类型样本各亚型禽流感病毒核酸阳性率差异.结果 全年共采集2943份禽流感外环境样本,甲型禽流感病毒核酸阳性样本检出率为13.73%(404份),H5、H7与H9亚型检出率分别为4.52%(133份)、0.07%(2份)和8.49%(250份).五种不同类型样本中,甲型禽流感病毒阳性率最高的为禽处理台表面擦拭物(21.88%),最低的为禽类粪便(9.64%)(x2=38.535,P<0.001).但在活禽批发市场中,甲型禽流感病毒阳性率最高的样本为禽类饮用水(46.60%),零售市场中阳性率最高的样本为禽处理台表面擦拭物(18.65%).环境样本中甲型禽流感病毒的波动呈季节性趋势,冬春季节阳性率较高,最高为12月份,5—9月呈低发平缓趋势.结论 济南市活禽市场环境存在禽流感病毒的污染,并以H5和H9亚型为主.活禽市场中禽类饮用水与零售市场中禽类处理台面的病毒检出率最高.     

一例儿童轻型人感染H7N9禽流感确诊病例调查

目的 分析2013年北京市海淀区一例人感染H7N9禽流感病例的发病、诊治和感染来源情况,提出疫情控制措施.方法 采集患儿标本进行实验室检测,应用《人感染H7N9禽流感个案调查表》对患儿及其家属开展面对面问卷调查,获得现场资料.结果 患儿以上呼吸道症状为首发症状,经门诊治疗痊愈,传染源不明.患儿无肺部感染,未服用达菲,经过抗炎、抗病毒治疗.结论 人感染H7 N9禽流感是一种新出现的传染病,传染和流行特征未明,要加强流感样病例监测、流感病原学监测、不明原因肺炎监测等传染病监测工作,及时发现病例,及早采取防治措施.     

一例儿童轻型人感染H7N9禽流感确诊病例调查

目的 分析2013年北京市海淀区一例人感染H7N9禽流感病例的发病、诊治和感染来源情况,提出疫情控制措施调整意见.方法 采集患儿标本进行实验室检测,应用《人感染H7 N9禽流感个案调查表》与患儿及其家属面对面问卷调查,获得现场资料.结果 患儿以上呼吸道症状为首发症状,经门诊治疗痊愈,传染源不明.患儿无肺部感染,经过抗炎、抗病毒治疗,未服用达菲.结论 人感染H7 N9禽流感是一种新出现的传染病,传染和流行特征未明,要加强流感样病例监测、流感病原学监测、不明原因肺炎监测等传染病监测工作,及时发现病例,及早采取防治措施.     

儿童甲型H1N1流感和季节性流感患者的病毒载量及相关临床症状研究

目的 分析并比较儿童甲型H1N1流感和季节性流感患者咽拭子标本的病毒载量及相关临床症状.方法 应用荧光PCR方法对采集的咽拭子标本进行检测,并通过建立核酸标准品,绘制标准曲线,测定标本中的病毒载量,同时结合所收集的患者临床症状数据资料应用随机区组方差和卡方检验方法进行统计分析.结果 2009年9月至2010年9月期间收集的1,040份咽拭子标本中,共检出甲型H1N1流感病毒阳性标本120份,甲型H3N2流感病毒阳性标本61份,乙型流感病毒阳性标本99份;对收集的流感阳性标本病毒载量测定结果显示:不同型别,不同发病时间流感患者咽拭子标本的病毒载量差异无统计学意义(P＞0.05);甲型H1N1流感、季节性流感感染者的性别比例差异无统计学意义,甲型H1N1流感感染者出现咳嗽,流涕临床症状者明显高于与乙型流感感染者.结论 甲型H1N1流感患者咳嗽,流涕症状比季节性乙型流感患者多见,而甲型H1N1流感和季节性流感患者咽拭子标本的病毒载量无显著性差异.     

中国职业暴露人群感染H6N6禽流感病毒血清学调查

目的 系统评估我国职业暴露人群感染H6N6禽流感病毒的状况.方法 本研究利用我国2009-2011年开展的高致病性H5N1禽流感病毒职业暴露人群血清学监测所采集的近15 000份血清标本,开展H6N6禽流感病毒血清学调查.结果 本研究中检测到H6N6禽流感病毒阳性血清共10份,分别来自不同的职业暴露人群,包括活禽市场、家禽规模养殖场、家禽散养户、屠宰加工场和野生候鸟栖息地.从地域上看该10份阳性血清来自8个不同的省份,分布在我国的南北方.结论 这是我国大陆地区首次报道人感染H6亚型禽流感病毒.     

Clinical and epidemiological survey and analysis of the first case of human infection with avian influenza A(H7N9) virus in Hangzhou, China

To investigate and report on the clinical and epidemiological characteristics of the first case of human infection with avian influenza A(H7N9) virus in Hangzhou, China. A field epidemiological survey was used to study the first case in Hangzhou. The patient was a 39-year-old male chef with a history of exposure to a farm product market and to poultry prior to the onset of disease on 15 March 2013. He had diarrhea, chills, pyrexia, and intermittent cough with freshly red foamy bloody sputum early in his disease. His fever > 39 °C continued for a week with rapid progression. Computed tomography findings showed extensive bilateral consolidation, followed by multiorgan failure. The patient died on the morning of 27 March. His infection was eventually confirmed 1 week later on 3 April. Flu-like symptoms including fever and cough were found in 46 of his 138 close contacts. This was the first case of human infection with avian influenza A(H7N9) virus in Hangzhou. None of the close contacts had onset of the disease. The case patient’s condition progressed rapidly. The source of infection might be his exposure to the farm product market, but the mode of exposure remains unclear.     

Serologic evidence of avian influenza virus infections among Nigerian agricultural workers

Nigeria has had multiple incursions of highly pathogenic avian influenza A (HPAI) H5N1 virus into its poultry population since 2006. This study aimed to determine if Nigerians exposed to poultry had evidence of avian influenza virus transmission to man. Between 2008 and 2010, 316 adult farmers and open market workers and 54 age‐group matched, non‐animal exposed controls were enrolled in a prospective, population‐based study of zoonotic influenza transmission in four towns in southeastern Nigeria. Questionnaire data and sera obtained at the time of enrollment were examined for evidence of previous infection with 10 avian influenza virus strains. Serologic studies on sera collected at the time of enrollment showed modest evidence of previous infection with three avian‐origin influenza viruses (H5N1, H5N2, and H11N1) and one avian‐like H9N2 influenza virus, with eight (2.4%) of animal‐exposed subjects and two (3.7%) unexposed subjects having elevated microneutralization assay antibody titer levels (ranging from 1:10 to 1:80). Statistical analyses did not identify specific risk factors associated with the elevated antibody titers observed for these zoonotic influenza viruses. These data suggested only occasional virus transmission to humans in areas thought to have been enzootic for avian influenza virus. Prospective data from this cohort will help the authors to better understand the occurrence of zoonotic infections due to avian influenza viruses in Nigeria. J. Med. Virol. 85:670–676, 2013. © 2013 Wiley Periodicals, Inc.     

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.     

Pandemic threat posed by avian influenza A viruses

Influenza pandemics, defined as global outbreaks of the disease due to viruses with new antigenic subtypes, have exacted high death tolls from human populations. The last two pandemics were caused by hybrid viruses, or reassortants, that harbored a combination of avian and human viral genes. Avian influenza viruses are therefore key contributors to the emergence of human influenza pandemics. In 1997, an H5N1 influenza virus was directly transmitted from birds in live poultry markets in Hong Kong to humans. Eighteen people were infected in this outbreak, six of whom died. This avian virus exhibited high virulence in both avian and mammalian species, causing systemic infection in both chickens and mice. Subsequently, another avian virus with the H9N2 subtype was directly transmitted from birds to humans in Hong Kong. Interestingly, the genes encoding the internal proteins of the H9N2 virus are genetically highly related to those of the H5N1 virus, suggesting a unique property of these gene products. The identification of avian viruses in humans underscores the potential of these and similar strains to produce devastating influenza outbreaks in major population centers. Although highly pathogenic avian influenza viruses had been identified before the 1997 outbreak in Hong Kong, their devastating effects had been confined to poultry. With the Hong Kong outbreak, it became clear that the virulence potential of these viruses extended to humans.     

Seroprevalence of avian influenza H9N2 among poultry workers in Shandong Province, China

H9N2 avian influenza virus has been circulating widely in birds, with occasional infection among humans. Poultry workers are considered to be at high risk of infection with avian influenza due to their frequent exposure to chickens, but the frequency of H9N2 avian influenza virus infections among them is still indistinct. This study was carried out in order to identify the seroprevalence of H9N2 avian influenza virus among poultry workers in Shandong, China. During the period from December 2011 to February 2012, a total of 482 subjects took part in this study, including 382 poultry workers and 100 healthy residents without occupational poultry exposure. Serum samples were collected and tested for the presence of antibodies against H9N2 avian influenza virus by hemagglutination inhibition (HI) and microneutralization (MN) assays. Nine subjects (9/382?=?2.3 %) were positive for antibodies against H9N2 avian influenza virus among poultry workers by either HI or MN assays using ≥40 cut-off, while none of the 100 healthy residents were seropositive. In conclusion, our study identified H9N2 avian influenza infections among poultry workers in Shandong, China, and continuous surveillance of H9N2 avian influenza virus infection in humans should be carried out to evaluate the threat to public health.     

Evidence for human infection with avian influenza A(H9N2) virus via environmental transmission inside live poultry market in Xiamen,China

H9N2 avian influenza virus (AIV) has become prevalent in the live poultry market (LPM) worldwide, and environmental transmission mode is an important way for AIVs to infect human beings in the LPM. To find evidence of human infection with the influenza A(H9N2) virus via environmental contamination, we evaluated one human isolate and three environmental isolates inside LPMs in Xiamen, China. The phylogeny, transmissibility, and pathogenicity of the four isolates were sorted out systematically. As for the H9N2 virus, which evolved alongside the “Avian-Environment-Human” spreading chain in LPMs from the summer of 2019 to the summer of 2020, its overall efficiency of contact and aerosol transmissibility improved, which might contribute to the increasing probability of human infection. This study indicated that environmental exposure might act as an important source of human infection in LPMs.