安徽省5例人感染高致病性禽流感病例分析

目的分析安徽省5例人感染高致病性禽流感病例特点,为防治提供科学依据。方法按照《人禽流感流行病学调查方案》,对病例进行个案调查,调查发病经过、治疗情况,实验室检测,可能的感染来源,传播途径及暴露因素等。结果 5例人感染高致病性禽流感初期临床表现主要为流感样症状,4例病例的气管分泌物分离出H5N1禽流感病毒,5例病例的气管分泌物禽流感病毒H5N1核酸均为阳性。1例有明确的病死家禽接触史,死禽也被证实感染禽流感病毒;2例虽有明确的病死家禽接触史,但死禽未被证实感染禽流感病毒;2例病例未发现明确的病死禽接触史;结论 5例病例均为实验室确诊病例;对人禽流感病例的诊断不能完全依据禽流感疫情存在与否;经过对5例人禽流感病例密切接触者的医学观察,没有发现人传人的现象;人禽流感的感染来源、传播途径和影响因素等问题尚待进一步研究。     

1例人感染高致病性禽流感(H5N1)病例流行病学调查

目的研究1例人感染高致病性禽流感(H5N1)病例,为今后开展人禽流感防控工作提供科学依据。方法根据流行病学调查、临床表现、血清学检查、病毒分离及RT-PCR、Read-PCR法进行分析和诊断。结果此例患者为人感染高致病性禽流感(H5N1)实验室确诊病例,经抢救治疗无效因呼吸循环衰竭死亡。患者有明确病死禽接触史、典型临床症状与体征和实验室病原学依据。经采用隔离治疗、个人防护、医学观察、家禽捕杀和消毒等措施,疫情得到控制。结论加强禽流感疫情监测,禁止宰杀、食用病死家禽,采取综合性防控措施,是预防疫情发生的关键。     

卫生部要求进一步做好禽流感疫情现场防控工作

据青海省卫生厅报告，青海湖鸟岛野生候鸟发生禽流感疫情后，当地卫生部门立即对有关人员开展了疫情监测等各项工作。截至5月25日．尚未发现不明原因肺炎病例、人感染高致病性禽流感病例或与病死禽有接触史的流感病例。     

南宁市首例人感染高致病性禽流感病例的流行病学调查

目的对南宁市首例人感染高致病性禽流感病例进行流行病学调查分析,为进一步科学防控人禽流感提供依据。方法采用现场流行病学调查方法对病例和密切接触者进行个案调查,采用RT—PCR方法对病例呼吸道标本进行人感染高致病性禽流感病毒（H5N1）检测。结果确诊南宁市首例人感染高致病性禽流感病例,该病例经抢救无效死亡,病例有明确病死禽接触史。在采取病例隔离治疗、医护人员个人防护、密切接触者医学观察、消毒等综合控制措施后,疫情得到有效控制,密切接触者中未出现异常情况,未出现二代病例。结论需加强人禽流感疫情监测,加强医务人员培训,预防疫情发生。     

广东省农村首例人禽流感H5N1病例的流行病学分析

目的 确定人感染高致病性禽流感疫情,查明感染来源,以采取相应措施控制疫情.方法 采用现场流行病学调查和实验室检测相结合的方法 对广东省海丰县1 例不明原因肺炎病例进行诊断和分析.结果 该患者女性,44岁,于2008年2月16日开始发病,病初表现为流感样症状,持续发热,1周内胸片出现两肺大片浸润阴影,病情进展迅速,抗生素治疗无效,全身多器官功能衰竭,于2月25日死亡.患者痰液标本禽流感病毒(H5N1)核酸阳性,病毒分离阳性,基因序列分析显示,分离的H5N1病毒 [A/Guangdong/1/ 2008(H5N1)]仍为禽源性特征.患者居住广东省海丰县海城镇某村,发病前后未离开过居住地,未接触过类似病人.海丰县是候鸟迁徙栖息地,2004年曾发生禽流感疫情.患者发病前1周曾接触与进食自养的病死鸡.病家附近见有水鸟(麻雀和白鹭)活动.经医学观察8 d,所有密切接触者(包括患者的丈夫共91人)均未出现类似症状.参照卫生部<人感染高致病性禽流感应急预案>,采取一系列控制措施后,疫情没有扩散.结论 该病例确诊为广东省农村首例人感染高致病性禽流感病例,感染来源可能是禽流感病毒(H5N1)从病死禽直接传给人,但未发现人传人的现象.今后应继续加强不明原因肺炎监测,加强人感染高致病性禽流感的应急贮备、培训和健康教育.     

干休所春季防控高致病性禽流感的探讨

随着春季的到来，候鸟北迁活动逐渐频繁，高致病性禽流感传播机率增加。从近日国际疫情形势看，全球禽流感疫情扩散速度加快，科威特、伊朗、德国、法国、意大利等亚欧各国陆续发现境内野生候鸟感染H5N1和H7亚型高致病性禽流感疫情。人感染病例也持续增加，死亡率不断上升。防疫工作面临的形势仍然十分严峻。总结干休所秋冬季疫情防控经验，结合新的情况，笔者认为应主要做好以下方面的工作。     

四川省3例人禽流感分析

目的 分析四川省3例人禽流感病例特点，为防治提供科学依据。方法 按照《人禽流感流行病学调查方案》，对病例进行个案调查，调查发病经过、治疗情况，实验室检测，可能的感染来源，传播途径及暴露因素等。结果 3例人禽流感病例初期临床表现主要为流感样症状，2例病例的气管分泌物分离出禽流感病毒H5N1,1例病例的气管分泌物禽流感病毒H5N1核酸阳性，3例病例咽拭子样核酸均为阴性。1例病例未发现明确的病死禽接触史；2例虽有明确的病死家禽接触史，但死禽未被证实感染禽流感病毒。结论 3例病例均为实验室确诊病例；应尽量采集患者的气管分泌物样进行检测；对人禽流感病例的诊断不能完全依据禽流感疫情存在与否；人禽流感的感染来源、传播途径和影响因素等问题尚待进一步研究。     

1例人感染高致病性禽流感死亡病例的流行病学调查

[目的]为查明人感染高致病性禽流感病例发生的原因,为今后预防和控制人感染高致病性禽流感提供科学依据。[方法]2009年1月26日对该市1例人感染高致病性禽流感患者进行流行病学调查分析。[结果]采集病人的鼻咽拭子和下呼吸道吸取物经广西壮族自治区疾病预防控制中心检测、中国疾病预防控制中心复检,H5N1禽流感病毒核酸阳性。人感染高致病性禽流感为北流市首次发现,经采取预防措施有效地控制了疫情。[结论]该病例感染来源为禽类。加强医务人员的培训和医疗机构不明原因肺炎监测,切断传播途径,采取有效的环境消毒及隔离措施是预防控制人感染高致病性禽流感的主要措施。     

云南省首例人感染H5N6禽流感病例的 临床与流行病学特征分析

摘要:目的　开展云南省首例人感染H5N6禽流感病例流行病学调查,探索可能的感染来源,为制定防控措施提供依据。方法　按照《人禽流感疫情预防控制技术指南（试行）》进行流行病学调查,通过收集病例诊疗经过、密切接触者信息、现场调查病例暴露情况,结合实验室检测结果综合诊断病例;采集患者、密切接触者、外环境标本进行检测分析。结果　云南省首例人感染H5N6禽流感确诊病例有明确禽类接触史,密切接触者中无不明原因肺炎病例,未发现人与人之间传播病例,相关外环境标本H5N6禽流感病毒核酸检测阳性。结论　云南省首例人感染H5N6禽流感病例属本地感染,属个案病例,感染来源可能与直接接触野禽暴露有关。加强不明原因肺炎监测工作,扩大人间和禽间流感病毒监测是早期发现和及时控制人感染高致病性禽流感疫情的关键。     

广西3例人禽流感病例的临床与流行病学特征

目的对广西2005～2009年确诊报告的3例人感染高致病性禽流感病例进行临床和流行病学分析,为进一步科学防控人禽流感提供依据。方法对确诊病例和病例的密切接触者进行个案调查,采用RT-PCR方法对病例的呼吸道标本进行人感染高致病性禽流感病毒(H5N1)核酸检测。结果3例病例表现为重症肺炎并呈进行性加重,最后均死亡,发病至首次就诊平均时间为2天,首次住院为3天,确诊时间为7天,死亡时间为8天,其中确诊至死亡时间仅1天。3病例呈高度散发,病例之间无流行病学关联,发病时间均为冬春季,有明确的病死禽暴露史,传播模式为禽—人传播。对病例采取隔离治疗、医护人员加强个人防护、对密切接触者进行医学观察、疫点应急消毒等综合措施后,疫情得到有效控制。结论3例人感染高致病性禽流感病例发病与接触病死禽有关,冬春季多见,未发现人传人的证据。早期发现和救治病人是提高病人预后的关键,要加强人禽流感疫情监测,及时科学处置疫情,以控制疫情扩散。     

Avian influenza H5NI in Europe: little risk as yet to health in the Netherlands

Since 2004, outbreaks of fowl plague caused by a highly pathogenic avian influenza virus of the subtype A/H5NI have been reported from various countries in Southeast Asia. To date, 118 cases with 61 deaths have been documented in humans, due to close contact with infected poultry or raw poultry meat. Although efficient human-to-human transmission has not occurred, in a few cases transmission to blood relatives could not be ruled out. In October 2005, outbreaks of A/H5NI in poultry and wild fowl have been confirmed from Turkey, Romania and Russia, due probably to infection via migratory birds. The direct risk of infection in humans in Europe is very low and is associated with direct exposure to infected poultry. In order to address the long-term risk of a pandemic due to recombination of human and avian viruses or to mutations in the avian virus itself, guidelines for pandemic preparedness have been developed and implemented in the Netherlands.     

河南省首例人感染H7N9禽流感病例的流行病学调查

[目的]通过对1例人感染H7N9禽流感病毒患者的调查分析,为人感染H7N9禽流感的科学防控提供依据。[方法]采用流行病学调查方法,调查病例的发病经过、可能的感染来源、传播途径及暴露因素等,医学观察患者的密切接触者,同时对患者进行临床诊治、实验室检测。[结果]确诊1例人感染HTN9禽流感病毒,经救治后痊愈出院。患者有明确的活禽接触史,咽拭子检测H7N9禽流感病毒核酸阳性。患者的密切接触者中均未发现异常临床表现。通过扩大监测流感病例160例和职业人群858例,均未发现H7N9禽流感病毒核酸阳性。当地活禽交易市场鸡咽拭子标本检出2份H7N9禽流感病毒核酸阳性,阳性鸡来源于外省。[结论]活禽暴露是人感染H7N9禽流感病毒的关键风险因素,暂无证据人传人,未发现人群隐性感染和轻症病例。仍需开展扩大监测和流行病学调查,以完善对感染谱的认识。     

Efficacy of clade 2.3.2 H5 commercial vaccines in protecting chickens from clade 2.3.4.4 H5N8 highly pathogenic avian influenza infection

Emerging clade 2.3.4.4 of the highly pathogenic avian influenza (HPAI) virus strain H5N8, which had been detected sporadically in domestic poultry in China, started to affect wild birds and poultry in South Korea in 2014. The virus was spread to Germany, Italy, the Netherlands, United Kingdom, and even United States by migratory birds. Here, we tested currently used commercial clade 2.3.2 H5 vaccines to evaluate mortality, clinical signs, virus shedding, and histological damage after experimental infection of chickens with the clade 2.3.4.4 HPAI H5N8 virus. Although the vaccination protected chickens from death, it failed to prevent chickens from shedding the virus and from tissue damage according to histological examination. These results suggest that the use of appropriate vaccines that match the currently epidemic HPAI virus is recommended, and continuous HPAI surveillance and testing of currently used commercial vaccines should be performed.     

一起无防护禽肉加工引起人感染H7N9禽流感病毒的流行病学调查

目的 分析1例人感染高致病性H7N9禽流感病例的感染模式及病原变异情况,为禽流感防控提供依据。方法 采用流行病学方法调查病例可疑暴露史及感染途径,追踪调查病例病情进展;使用核酸检测、病毒分离、基因测序及进化分析等技术对采集的相关标本展开病原学分析。结果 病例无活禽接触史,发病前一周在狭小通风不畅厨房内不带手套加工烹饪光鸡;病例下呼吸道提取物、病家剩余冷冻光鸡表面涂抹标本、活禽来源市场环境标本均检出高度同源的H7N9禽流感病毒,且均在HA基因的裂解位点出现多个碱性氨基酸（PEVPKRKRTAR/GL）插入的突变。结论 无防护禽肉操作是"禽-人"传播模式下的重要感染方式之一,现行的活禽限售区防控措施效果有限,应尽快推进规模化标准养殖,实现活禽全城限售、集中屠宰、冰鲜上市。     

Pathologic Changes in Wild Birds Infected with Highly Pathogenic Avian Influenza A(H5N8) Viruses,South Korea, 2014

In January 2014, an outbreak of infection with highly pathogenic avian influenza (HPAI) A(H5N8) virus began on a duck farm in South Korea and spread to other poultry farms nearby. During this outbreak, many sick or dead wild birds were found around habitats frequented by migratory birds. To determine the causes of death, we examined 771 wild bird carcasses and identified HPAI A(H5N8) virus in 167. Gross and histologic lesions were observed in pancreas, lung, brain, and kidney of Baikal teals, bean geese, and whooper swans but not mallard ducks. Such lesions are consistent with lethal HPAI A(H5N8) virus infection. However, some HPAI-positive birds had died of gunshot wounds, peritonitis, or agrochemical poisoning rather than virus infection. These findings suggest that susceptibility to HPAI A(H5N8) virus varies among species of migratory birds and that asymptomatic migratory birds could be carriers of this virus.     

Transboundary spread of highly pathogenic avian influenza through poultry commodities and wild birds: a review

The extensive circulation of the H5N1 highly pathogenic avian influenza (HPAI) virus in animals and the human health implications which it poses have led to extensive research in unexplored fields and thus a re-assessment of our understanding of this infection. Moreover, widespread infection of poultry has raised concerns about the food safety and trade implications of this infection, necessitating revised international trade regulations. The role of wild birds has been much debated and resources have been invested to clarify the role that they may play in the spread of infection. It is now clear that wild birds may be responsible for primary introduction in a previously free area. To date it is still unclear whether HPAI infection may be maintained in wild bird populations for extended periods of time. This paper reviews existing knowledge on the transboundary spread of HPAI through poultry and poultry commodities and summarises evidence of spread through wild birds.     

Antigenic evolution of contemporary clade 2.3.4.4 HPAI H5 influenza A viruses and impact on vaccine use for mitigation and control

Since 2003, highly pathogenic avian influenza (HPAI) viruses of the H5 subtype have been maintained in poultry, periodically spilling back into wild migratory birds and spread to other geographic regions, with re-introduction to domestic birds causing severe impacts for poultry health, production and food sustainability. Successive waves of infection have also resulted in substantial genetic evolution and reassortment, enabling the emergence of multiple clades and subtypes within the H5 2.3.4.4 HPAI viruses. Control of AI is principally through either culling or through vaccination using conventional vaccines. Here, we antigenically and genetically characterise the emerging 2020/21 H5NX clade 2.3.4.4 strains and assess cross-reactivity to putative vaccine strains using chicken antisera. We demonstrate significant antigenic differences between commercially available poultry vaccines and currently circulating viruses suggesting that vaccination options might be suboptimal in the current outbreaks.     

Anatidae migration in the western Palearctic and spread of highly pathogenic avian influenza H5NI virus

During the second half of 2005, highly pathogenic avian influenza (HPAI) H5N1 virus spread rapidly from central Asia to eastern Europe. The relative roles of wild migratory birds and the poultry trade are still unclear, given that little is yet known about the range of virus hosts, precise movements of migratory birds, or routes of illegal poultry trade. We document and discuss the spread of the HPAI H5N1 virus in relation to species-specific flyways of Anatidae species (ducks, geese, and swans) and climate. We conclude that the spread of HPAI H5N1 virus from Russia and Kazakhstan to the Black Sea basin is consistent in space and time with the hypothesis that birds in the Anatidae family have seeded the virus along their autumn migration routes.