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1.
目的 探索全球高致病性禽流感(highly pathogenic avian influenza,HPAI)H5N1疫情的空间分布特征,识别高风险聚集区,为禽流感疫情监测、发展趋势提供科学依据.方法 收集和整理世界动物卫生组织和粮农组织疫情监测报告中的2004年1月~2009年12月间的HPAI H5N1疫情,运用空间扫描统计量和空间聚类方法分析全球HPAI H5N1的空间分布.结果 空间扫描统计量分析显示疫情呈现非随机分布的特征,在空间分布上存在聚集性,共检测出15个高风险聚集区,主要集中在中欧、南欧、非洲东北部地区以及亚洲的东南部地区.空间聚类分析显示高风险聚集区主要集中于欧洲的德国、法国、瑞士和意大利,以及亚洲的东南部地区.结论 全球HPAIH5N1呈现空间聚集分布,高风险聚集区主要位于中欧、南欧以及东南亚,为重点监控区域.候鸟迁徙可能是跨洲远距离传播的重要途径.  相似文献   

2.
  目的  以中国31个省(自治区、直辖市)为研究区域,探究其2004—2019年H5N1亚型高致病禽流感发生次数时空分布特征。  方法  基于ArcGIS 10.5软件和SPSS 26.0软件,应用聚类分析和χ2检验研究H5N1疫病的时间分布特征和影响因素。应用空间自相关方法研究H5N1疫病的空间分布特征。  结果  通过时间聚类分析,得到在疫情流行阶段(2004—2005年)和平稳阶段(2006—2019年),H5N1疫情暴发次数在时间分布上都存在聚集性,其中1月、2月、6月和11月为疫病的高发期。通过全局空间自相关分析,发现疫情流行阶段H5N1空间分布呈聚集性,疫情平稳阶段呈现随机分布。通过局部自相关分析,表明流行阶段H5N1热点地区集中在中国中部地区,主要包括乌鲁木齐、咸宁、岳阳、安庆、九江等市,平稳阶段的热点地区主要集中在中国西北部。χ2检验显示疫病发生与候鸟迁徙具有相关关系。  结论  中国H5N1禽流感在流行阶段具有时空聚集性,在平稳阶段仅具有一定的时间聚集性。  相似文献   

3.
中国大陆地区438例人感染H7N9禽流感空间聚集性分析   总被引:8,自引:0,他引:8       下载免费PDF全文
目的 了解中国大陆438例人感染H7N9禽流感空间分布特征及发展趋势。方法 建立438例人感染H7N9禽流感发病数据库(2013年2月至2014年5月),利用ArcGIS 10.0软件对疫情分布进行趋势及空间自相关分析,应用SPSS 16.0软件分析人口学特征。结果 2013年6月至2014年5月中国大陆人感染H7N9禽流感总体呈增长趋势,但上海地区病例明显减少;建立的趋势面分析显示其发病由北向南呈明显上升趋势,自西向东直线斜率有所减小。2013年2-5月省级水平和2013年6月至2014年5月市级水平的全局Moran''s I值分别为0.144 718、0.117 468(P<0.05),差异有统计学意义。由局部Moran''s I和热点分析显示浙江省北部、广东省南部是人感染H7N9禽流感发病的主要高聚集区域(Z>2.58)。结论 2013年2月至2014年5月中国大陆地区人感染H7N9禽流感疫情表现为省级水平空间聚集性下降,但地市级水平的空间聚集性和局部热点数量有所增加,应根据空间分布相关特点,科学制定防控疫情传播的措施。  相似文献   

4.
一起高致病性禽流感爆发现场处置情况分析   总被引:1,自引:0,他引:1  
禽流感是由甲型流感病毒引起的禽类从亚临床症状、轻度呼吸系统感染直到急性死亡等一系列综合病征,分为高致病性与低致病性两种。2004年2月,我区在禽间发生高致病性禽流感,我们立即进行了处置,很快将疫情控制,未发生人感染禽流感,现将处置情况报道如下。  相似文献   

5.
刘德坚  邱星元  郑磊 《职业与健康》2012,28(14):1748-1749
目的明确人感染高致病性禽流感疫情的发生,探讨感染来源,以采取相应措施控制疫情的发生。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深圳宝安区1例人感染高致病性禽流感病例个案疫情进行分析。结果该例病例无明确的家禽接触及进食史,病人发病前经常在有大量各类野生候鸟活动的栖息地附近晨练。实验室检测发现该例病毒与香港2011年禽流感死亡的野鸟病毒基因接近,与家禽较远。结论该病例是2011年中全国唯一的1例人禽流感确诊病例,感染途径很可能与野生候鸟有关,建议在冬春季节提醒群众尽量避免直接接触野生候鸟及其排泄物。  相似文献   

6.
合肥市部分中学生禽流感防治知识态度和行为调查   总被引:3,自引:0,他引:3  
禽流感(avian influenza)是由甲型流感病毒引起的一种禽类疾病综合征[1] .禽流感病毒一旦在人群中传播后,就有可能发生基因变异,或与人流感病毒发生基因重配形成新的重配株,从而获得对人的致病性和更大的传播能力,在人群中引起流感流行甚至大流行 [2].2004年春季以来,东南亚地区越南、泰国均出现高致病性禽流感的流行,并且发现临床患者;在我国,部分地区也发现家禽感染高致病性禽流感.安徽省在2004年1月2 9日和2月5日分别在阜阳市颖州区、界首市、广德县和马鞍山市雨山区出现高致病性禽流感疫情.为了解省会市中学生对禽流感的认识情况,笔者于2004年4月开展了一次禽流感知识、行为、态度等相关问题的调查,现将结果报告如下.  相似文献   

7.
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。  相似文献   

8.
《肉品卫生》2005,(7):i012-i013
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。  相似文献   

9.
目的分析广州市荔湾区首起高致病性禽流感疫情应急监测情况,为探讨禽流感疫情预防控制措施提供科学依据。方法按照《人感染高致病性禽流感应急监测方案》,对2008年3月13日广州市荔湾区农贸市场发生的一起H5NI亚型动物高致病性禽流感疫情的密切接触者进行采样、医学观察;对监测医院上报的发热伴流感样症状病例进行追踪和排查,在疫点周围开展入户搜索。结果对19名密切接触者和160名一般接触者进行健康监测未发现发热、咳嗽等异常临床表现。19名密切接触者咽拭子标本H5N1核酸及血标本禽流感病毒H5抗体均为阴性,其中有4份血标本H9抗体呈阳性,3份来自市场鸡档人员,1份来自卫生处理厂工人。6家哨点监测医院共报告门诊流感样病例3971例,未发现不明原因肺炎及疑似人禽流感病例。结论此次广州市荔湾区农贸市场动物高致病性禽流感疫情未造成人群感染。发生高致病性禽流感疫情时,在处理疫点的同时立即开展应急监测,是及时发现病人、切断传播途径、有效控制疫情传播和蔓延的重要措施。  相似文献   

10.
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.  相似文献   

11.
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.  相似文献   

12.

Objectives

This study describes the outbreaks of H5N8 highly pathogenic avian influenza (HPAI) in Korea during the first wave, from January 16, 2014 through July 25, 2014. Its purpose is to provide a better understanding of the epidemiology of H5N8 HPAI.

Methods

Information on the outbreak farms and HPAI positive wild birds was provided by the Animal and Plant Quarantine Agency. The epidemiological investigation sheets for the outbreak farms were examined.

Results

During the 7-month outbreak period (January–July 2014), H5N8 HPAI was confirmed in 212 poultry farms, 38 specimens from wild birds (stools, birds found dead or captured). Ducks were the most frequently infected poultry species (159 outbreak farms, 75.0%), and poultry in 67 (31.6%) outbreak farms was asymptomatic.

Conclusion

As in the previous four H5N1 epidemics of HPAI that occurred in Korea, this epidemic of H5N8 proved to be associated with migratory birds. Poultry farms in Korea can hardly be free from the risk of HPAI introduced via migratory birds. The best way to overcome this geographical factor is to reinforce biosecurity to prevent exposure of farms, related people, and poultry to the pathogen.  相似文献   

13.
Highly pathogenic avian influenza (HPAI) H5N1 expanded considerably during 2005 and early 2006 in both avian host species and geographic distribution. Domestic waterfowl and migratory birds are reservoirs, but lethality of this subtype appeared to initially limit migrant effectiveness as introductory hosts. This situation may have changed, as HPAI H5N1 has recently expanded across Eurasia and into Europe and Africa. Birds could introduce HPAI H5N1 to the Western Hemisphere through migration, vagrancy, and importation by people. Vagrants and migratory birds are not likely interhemispheric introductory hosts; import of infected domestic or pet birds is more probable. If reassortment or mutation were to produce a virus adapted for rapid transmission among humans, birds would be unlikely introductory hosts because of differences in viral transmission mechanisms among major host groups (i.e., gastrointestinal for birds, respiratory for humans). Another possible result of reassortment would be a less lethal form of avian influenza, more readily spread by birds.  相似文献   

14.
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.  相似文献   

15.
16.
The recent introductions of highly pathogenic avian influenza (HPAI) H5N1 virus in wild birds and its subsequent spread throughout Asia, the Middle East, Africa and Europe has put a focus on the role of wild birds in the geographical spread of HPAI H5N1 virus. Large-scale surveillance programs are ongoing to determine a potential role of wild birds in H5N1 virus spread and to serve as sentinel systems for introductions into new geographical regions. The unprecedented scale and coverage of these surveillance programs offer a unique opportunity to expand our current knowledge on the ecology of LPAI in wild migratory birds. We provide an update on the current knowledge on the relation between host and virus ecology.  相似文献   

17.
An overview of the epidemiology of avian influenza   总被引:15,自引:0,他引:15  
Alexander DJ 《Vaccine》2007,25(30):5637-5644
Only viruses of the Influenzavirus A genus have been isolated from birds and termed avian influenza [AI] viruses, but viruses with all 16 haemagglutinin [H1-H16] and all 9 neuraminidase [N1-N9] influenza A subtypes in the majority of possible combinations have been isolated from avian species. Influenza A viruses infecting poultry can be divided into two groups. The very virulent viruses causing highly pathogenic avian influenza [HPAI], with flock mortality as high as 100%. These viruses have been restricted to subtypes H5 and H7, although not all H5 and H7 viruses cause HPAI. All other viruses cause a milder, primarily respiratory, disease [LPAI], unless exacerbated. Until recently HPAI viruses were rarely isolated from wild birds, but for LPAI viruses extremely high isolation rates have been recorded in surveillance studies, with overall figures of about 11% for ducks and geese and around 2% for all other species. Influenza viruses may infect all types of domestic or captive birds in all areas of the world, the frequency with which primary infections occur in any type of bird usually depending on the degree of contact there is with feral birds. Secondary spread is usually associated with human involvement, either by bird or bird product movement or by transferring infective faeces from infected to susceptible birds, but potentially wild birds could be involved. In recent years there have been costly outbreaks of HPAI in poultry in Italy, The Netherlands and Canada and in each millions of birds were slaughtered to bring the outbreaks under control. Since the 1990s AI infections due to two subtypes have been widespread in poultry across a large area of the World. LPAI H9N2 appears to have spread across the whole of Asia in that time and has become endemic in poultry in many of the affected countries. However, these outbreaks have tended to have been overshadowed by the H5N1 HPAI virus, initially isolated in China, that has now spread in poultry and/or wild birds throughout Asia and into Europe and Africa, resulting in the death or culling of hundreds of millions of poultry and posing a significant zoonosis threat.  相似文献   

18.
《Vaccine》2017,35(9):1316-1322
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.  相似文献   

19.
Understanding of ecologic factors favoring emergence and maintenance of highly pathogenic avian influenza (HPAI) viruses is limited. Although low pathogenic avian influenza viruses persist and evolve in wild populations, HPAI viruses evolve in domestic birds and cause economically serious epizootics that only occasionally infect wild populations. We propose that evolutionary ecology considerations can explain this apparent paradox. Host structure and transmission possibilities differ considerably between wild and domestic birds and are likely to be major determinants of virulence. Because viral fitness is highly dependent on host survival and dispersal in nature, virulent forms are unlikely to persist in wild populations if they kill hosts quickly or affect predation risk or migratory performance. Interhost transmission in water has evolved in low pathogenic influenza viruses in wild waterfowl populations. However, oropharyngeal shedding and transmission by aerosols appear more efficient for HPAI viruses among domestic birds.  相似文献   

20.
Migratory birds have been implicated in the long-range spread of highly pathogenic avian influenza (HPAI) A virus (H5N1) from Asia to Europe and Africa. Although sampling of healthy wild birds representing a large number of species has not identified possible carriers of influenza virus (H5N1) into Europe, surveillance of dead and sick birds has demonstrated mute (Cygnus olor) and whooper (C. cygnus) swans as potential sentinels. Because of concerns that migratory birds could spread H5N1 subtype to the Western Hemisphere and lead to its establishment within free-living avian populations, experimental studies have addressed the susceptibility of several indigenous North American duck and gull species. We examined the susceptibility of Canada geese (Branta canadensis) to HPAI virus (H5N1). Large populations of this species can be found in periagricultural and periurban settings and thus may be of potential epidemiologic importance if H5N1 subtype were to establish itself in North American wild bird populations.  相似文献   

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