以兽类为例探讨我国陆生野生动物疫病监管中面临的问题与对策

近年来, 新型冠状病毒、SARS病毒和鼠疫等新发和再发性动物源疫病多是由兽类及其媒介携带的病原生物直接或间接感染而引发的, 不仅对人类健康和生态系统平衡造成了重大威胁, 而且威胁全球公共卫生安全、粮食安全和生物安全。结合我国重要陆生兽类疫源疫病发生的新情况和新特点, 本文重点总结了我国以陆生野生及非野生兽类(家畜为主)为重点的24种重要人兽共患病的监管情况, 并对这些疫源疫病的监管空缺进行了分析。由于病原生物的种类多及其感染传播方式多样, 我国人间和动物间疫情呈现多发态势, 新发和再发疫病防控面临严峻挑战。从目前情况来看, 我国重要野生动物疫源疫病呈现为多部门、多层监管的局面。全球化贸易剧增、非法猎杀、非法交易、违法违规养殖、滥食野生动物陋习、检疫环节失察等导致了当前我国野生动物疫源疫病的传染源头和传播链错综复杂, 加剧了人类与野生动物所携带的病原接触、感染和传播的风险。极端气候或灾害事件频发以及对新发再发传染病的认知不足导致难以从源头做好疫病防控。针对上述问题, 本文提出了从源头加强基础研究和全链条监管来积极防范陆生野生动物疫病疫情的对策和建议。     

沈阳桃仙国际机场鸟类夜间迁徙规律

在鸟类迁徙季节,夜间鸟击事故频发是机场鸟击发生的一个显著特点.了解鸟类的夜间迁徙规律对于改进夜间鸟击防范措施具有重要的指导意义.本研究综合采用网捕法和声音记录法对沈阳桃仙机场夜间鸟类迁徙物种组成和迁徙规律进行研究.结果表明: 56种鸟类(占比88.9%)具有夜间迁徙习性,且以后半夜迁徙为主;鸟类夜间迁徙具有明显的时间动态和迁徙次序,春季鸟类迁徙较为集中,迁徙高峰在5月中旬,主要鸟类由鹌鹑、红尾伯劳、栗耳鹀、黑喉石鵖、普通夜鹰、黄眉柳莺等组成,秋季迁徙较为分散,迁徙高峰出现在9月下旬至10月上旬,主要由鹌鹑、灰背鸫、红喉鹨、丘鹬、矛斑蝗莺和灰头鵐等组成.对夜间迁徙鸟类的危险等级评估发现,春季严重危险物种是鹌鹑和红尾伯劳,秋季严重危险物种是鹌鹑、纵纹腹小鸮、灰背鸫和丘鹬.分别从夜间迁徙鸟类组成、迁徙动态、时间节律和物种危险等级等角度提出了相应的鸟击防范对策,为桃仙机场鸟击防范提供参考.     

迁徙鸟类对中途停歇地的利用及迁徙对策

中途停歇地是迁徙鸟类在繁殖地和非繁殖地之间的联系枢纽,对于迁徙鸟类完成其完整的生活史过程具有重要作用。从鸟类的迁徙对策、中途停歇地的选择、鸟类在中途停歇地的停留时间、体重变化和种群特征以及中途停歇地的环境状况等方面,回顾了中途停歇生态学在近年来的研究进展,并提出了在迁徙对策理论的实验研究,小型鸟类在中途停歇地的停歇时间及体重变化的准确确定等目前有待解决的问题。     

鸟类迁徙的研究方法和研究进展

鸟类的迁徙长期以来一直是人类最感兴趣的自然现象之一。随着科技的不断发展,各种先进的仪器设备和研究方法被应用到鸟类迁徙的研究中,为深入了解鸟类的迁徙活动起到了重要作用。介绍了野外观察、雷达监测、环志、卫星跟踪、稳定同位素和室内控制实验等鸟类迁徙的主要研究方法、并介绍了近年来在鸟类的迁徙停歇地和迁徙路线以及鸟类迁徙的能量代谢方面的研究成果,供广大读者参考和借鉴。     

辽宁老铁山雀形目鸟类秋季迁徙初探

2000~2004年秋在辽宁旅顺老铁山自然保护区,通过鸟类环志和直接观察的方法,对该地区雀形目(Passeriformes)鸟类秋季迁徙规律进行了研究。5年共环志11 040只雀形目鸟类,发现8种保护区新记录种。结果表明,鸟类迁徙高峰大都集中在10月中下旬;气候条件与鸟类迁徙关系密切;不同年份优势种及种群数量均不同;鸟类的迁徙具有一定的顺序性和集群现象,但不同种类迁徙的种群大小又有差别;2004年雀形目鸟类的种类和数量都明显少于前4年,略有下降趋势。     

遥感与GIS支持下的崇明东滩迁徙鸟类生境适宜性分析

崇明东滩鸟类自然保护区位于长江入海口,是国际迁徙鸟类重要的栖息地.受自然和社会因素影响,该地区鸟类栖息环境正处于快速变化.研究采用面向对象的图像分割方法提取鸟类生境适宜性多边形评价单元,根据近年来野外调查数据分析了影响迁徙鸟类生存的地类、植被、潮沟、底栖生物等关键环境因素,建立了鸟类与关键环境影响因素的定性定量关系.在此基础上利用GIS空间分析方法和技术,进行了崇明东滩鸟类保护区内主要四大鸟类种群雁鸭类、鸻鹬类、鹭类以及鸥类的生境适宜性分析.结果表明:(1)崇明东滩迁徙鸟类生境较适宜的面积占保护区总面积40%左右;(2)光滩区域、与光滩邻近的海三棱藨草带以及潮沟地带是鸟类生境适宜性较好的地理区域;(3)基于面向对象的遥感分析技术和GIS空间分析技术,能有效且简便地对生态环境处于快速动态变化中的物种生境适宜性进行快速、客观准确的分析评价,其结果可为崇明东滩鸟类种群及其生存环境规划、保护和管理提供基础科学依据.     

怎样开展鸟类环志

环志是了解鸟类迁徙规律最有效的方法,通过环志活动可掌握鸟类迁徙时间、路线、范围及迁徙鸟的性比、种群数量、年龄等方面的情况,环志工作对保护珍稀鸟类,科学地利用鸟类资源,监测环境,降低鸟害等方面都有重要的科研意义。鸟类环志于本世纪２０年代初始于丹麦,目前...     

基于机场鸟情特点的驱鸟设备使用探讨

鸟击是随着飞机诞生而出现的一个全球性问题,具有突发性和多发性的特点。中国民航面临鸟击风险逐渐上升的趋势。根据重庆江北国际机场的鸟情数据,对比中国民航、部分国内机场和美国民航鸟击数据发现,机场具有飞行区集群活动鸟类、迁徙季节、飞行区及周边区域鸟击高发的特点。为加强对飞行区及周边区域鸟情的干扰和驱赶,笔者对目前市场上常见的声音、视觉、物理、化学等各类驱鸟设备（措施）作用原理及有效性进行分析,指出机场面临关键区域、重要时段驱鸟措施使用受限,驱鸟设备本身效果不足以及即时驱鸟设备对鸟情处置后果不确定等问题,并就此提出机场驱鸟设备配置与安装使用的建议,以期为机场驱鸟设备配置与使用提供参考。     

四川黑竹沟国家级自然保护区的鸟类多样性

鸟类多样性是区域生物多样性价值和保护管理成效评价的重要指标。2015—2019年利用样线法和样点法对四川黑竹沟国家级自然保护区的鸟类多样性进行调查,结合红外相机数据和文献资料,统计出保护区鸟类16目54科286种。其中,国家Ⅰ级重点保护野生鸟类3种、国家Ⅱ级重点保护野生鸟类21种。世界自然保护联盟(IUCN)濒危物种红色名录列为濒危的1种、易危3种、近危2种;划分的5类生境(常绿阔叶林、常绿落叶阔叶混交林、针阔混交林、亚高山针叶林和亚高山灌丛或草甸)中,鸟类多样性最高的是常绿阔叶林,其次是常绿落叶阔叶混交林,最低的是亚高山灌丛或草甸。群落组成相似性结果显示,针阔混交林与亚高山针叶林中的鸟类群落相似性最高;鸟类多样性的垂直分布格局呈中峰模式,峰值出现在海拔1 600～2 400 m。建议保护区加强对珍稀鸟类和迁徙鸟类的调查监测力度,增加对重点生境的巡护,加强在保护区周边乡镇的宣传力度,提高当地居民的生态保护意识。     

甘肃黑河内陆河湿地自然保护区候鸟多样性

甘肃黑河为我国第二大内陆河,位于其中游的黑河湿地自然保护区为内陆河流湿地生态系统自然保护区。2008年分季节采用样线法和样点法调查该保护区湿地、农田村庄、人工林和荒漠4种生境的鸟类种类和数量。调查共记录保护区分布的鸟类17目35科116种,其中夏候鸟73种(占鸟类种类的62.93%),迁徙过路鸟20种(占17.24%),留鸟17种(占14.66%),冬候鸟6种(占5.17%)。其中,属于《湿地公约》的水禽56种。在湿地生境共记录鸟类70种,占保护区鸟类种数的60.34%,其中繁殖期在湿地生境栖息的鸟类有50种,绝大部分为夏候鸟(47种),留鸟只有3种;迁徙季节分布有44种鸟类,其中迁徙过路鸟(只在迁徙季节见到)有17种,占迁徙季节鸟类种类数的38.64%。村庄农田、人工林以及荒漠生境中,繁殖期和迁飞期共记录鸟类57种,夏候鸟有33种,留鸟有17种,迁徙过路鸟只有3种。甘肃张掖黑河湿地保护区是众多水禽在我国西北地区的重要繁殖地和迁徙停歇地,是我国候鸟迁徙西部路线上的关键区域。     

Novel H7N7 avian influenza viruses detected in migratory wild birds in eastern China between 2018 and 2020

Wild birds are the natural reservoirs of avian influenza viruses, and surveillance and assessment of these viruses in wild birds provide valuable information for early warning and control of animal diseases. In this study, we isolated 19 H7N7 avian influenza viruses from wild bird between 2018 and 2020. Full genomic analysis revealed that these viruses bear a single basic amino acid in the cleavage site of their hemagglutinin gene, and formed four different genotypes by actively reassorting other avian influenza viruses circulating in wild birds and ducks. The H7N7 viruses bound to both avian-type and human-type receptors, although their affinity for human-type receptors was markedly lower than that for avian-type receptors. Moreover, we found that the H7N7 viruses could replicate efficiently in the upper respiratory tract and caecum of domestic ducks, and that the H5/H7 inactivated vaccine used in poultry in China provided complete protection against H7N7 wild bird virus challenge in ducks. Our findings demonstrate that wild bird H7N7 viruses pose a substantial threat to the poultry industry across the East Asian-Australian migratory flyway, emphasize the importance of influenza virus surveillance in both wild and domestic birds, and support the development of active control strategies against H7N7 virus.     

Flying Over an Infected Landscape: Distribution of Highly Pathogenic Avian Influenza H5N1 Risk in South Asia and Satellite Tracking of Wild Waterfowl

Highly pathogenic avian influenza (HPAI) H5N1 virus persists in Asia, posing a threat to poultry, wild birds, and humans. Previous work in Southeast Asia demonstrated that HPAI H5N1 risk is related to domestic ducks and people. Other studies discussed the role of migratory birds in the long distance spread of HPAI H5N1. However, the interplay between local persistence and long-distance dispersal has never been studied. We expand previous geospatial risk analysis to include South and Southeast Asia, and integrate the analysis with migration data of satellite-tracked wild waterfowl along the Central Asia flyway. We find that the population of domestic duck is the main factor delineating areas at risk of HPAI H5N1 spread in domestic poultry in South Asia, and that other risk factors, such as human population and chicken density, are associated with HPAI H5N1 risk within those areas. We also find that satellite tracked birds (Ruddy Shelduck and two Bar-headed Geese) reveal a direct spatio-temporal link between the HPAI H5N1 hot-spots identified in India and Bangladesh through our risk model, and the wild bird outbreaks in May-June-July 2009 in China (Qinghai Lake), Mongolia, and Russia. This suggests that the continental-scale dynamics of HPAI H5N1 are structured as a number of persistence areas delineated by domestic ducks, connected by rare transmission through migratory waterfowl.     

Evidence of infection with H4 and H11 avian influenza viruses among Lebanese chicken growers

Human infections with H5, H7, and H9 avian influenza viruses are well documented. Exposure to poultry is the most important risk factor for humans becoming infected with these viruses. Data on human infection with other low pathogenicity avian influenza viruses is sparse but suggests that such infections may occur. Lebanon is a Mediterranean country lying under two major migratory birds flyways and is home to many wild and domestic bird species. Previous reports from this country demonstrated that low pathogenicity avian influenza viruses are in circulation but highly pathogenic H5N1 viruses were not reported. In order to study the extent of human infection with avian influenza viruses in Lebanon, we carried out a seroprevalence cross-sectional study into which 200 poultry-exposed individuals and 50 non-exposed controls were enrolled. We obtained their sera and tested it for the presence of antibodies against avian influenza viruses types H4 through H16 and used a questionnaire to collect exposure data. Our microneutralization assay results suggested that backyard poultry growers may have been previously infected with H4 and H11 avian influenza viruses. We confirmed these results by using a horse red blood cells hemagglutination inhibition assay. Our data also showed that farmers with antibodies against each virus type clustered in a small geographic area suggesting that unrecognized outbreaks among birds may have led to these human infections. In conclusion, this study suggests that occupational exposure to chicken is a risk factor for infection with avian influenza especially among backyard growers and that H4 and H11 influenza viruses may possess the ability to cross the species barrier to infect humans.     

Recent expansion of highly pathogenic avian influenza H5N1: a critical review

Wild birds, particularly waterfowl, are a key element of the viral ecology of avian influenza. Highly pathogenic avian influenza (HPAI) virus, subtype H5N1, was first detected in poultry in November 1996 in southeast China, where it originated. The virus subsequently dispersed throughout most of Asia, and also to Africa and Europe. Despite compelling evidence that the virus has been dispersed widely via human activities that include farming, and marketing of poultry, migratory birds have been widely considered to be the primary source of its global dispersal. Here we present a critical examination of the arguments both for and against the role of migratory birds in the global dispersal of HPAI H5N1. We conclude that, whilst wild birds undoubtedly contribute to the local spread of the virus in the wild, human commercial activities, particularly those associated with poultry, are the major factors that have determined its global dispersal.     

野生鸟类传染性疾病研究进展

由于具有独特的飞行能力和极强的地理扩散能力,鸟类活动为某些传染性疾病的快速传播和扩散带来了潜在风险.自20世纪以来,以禽霍乱、禽波特淋菌病、西尼罗河热、禽流感等为代表的鸟类疾病频繁暴发,导致为数众多的野生鸟类、家禽甚至人类死亡,给社会造成巨大的经济损失.因此,有关鸟类传染性疾病的研究已引起了国内外学者的广泛关注.从鸟类传染性疾病的生态学特征、疾病对鸟类与人类社会的影响、鸟类对疾病的传播、鸟类疾病的监测、预警和防控等方面对野生鸟类的传染性疾病研究进展进行了综述.不同疾病导致的鸟类死亡量、易感物种数量、暴发频率和地理扩散等特征差异显著.20世纪以来,疾病已成为全球生物多样性的七大威胁因子之一.疾病可能造成鸟类大量死亡,从而对鸟类种群,特别是濒危鸟类种群造成严重影响.其中,人畜共患病还会导致家禽家畜甚至人类的死亡,从而对社会产生严重的影响.野生鸟类作为多种疾病传播的媒介,其移动和迁徙可能会导致疾病的传播与扩散.开展全面的监测活动和建立疾病预警体系,对于疾病的防控具有重要意义.     

北京野生水鸟迁徙规律及其监测策略初探

2005年全球暴发的禽流感疫情备受世界关注,候鸟带毒且野生水鸟是禽流感病毒的天然储库已被世界公认,我国野生动物疫源疫病监测工作已被提到重要议事日程.通过对2006～2008年监测数据的分析,发现北京市野生水鸟春季迁徙从2月下旬开始,4月初达到迁徙高峰;9月下旬开始秋季南迁,11月下旬达到迁徙高峰.并分别对北京地区雁鸭类、鹬鸻类、鹭类的迁徙规律进行了分析;根据北京的气候特点分析了野生水鸟的分布和迁徙特点;根据禽流感病毒与温度的关系,提出了北京的重点监测时期及物种.     

Spatial, temporal, and species variation in prevalence of influenza A viruses in wild migratory birds

Although extensive data exist on avian influenza in wild birds in North America, limited information is available from elsewhere, including Europe. Here, molecular diagnostic tools were employed for high-throughput surveillance of migratory birds, as an alternative to classical labor-intensive methods of virus isolation in eggs. This study included 36,809 samples from 323 bird species belonging to 18 orders, of which only 25 species of three orders were positive for influenza A virus. Information on species, locations, and timing is provided for all samples tested. Seven previously unknown host species for avian influenza virus were identified: barnacle goose, bean goose, brent goose, pink-footed goose, bewick's swan, common gull, and guillemot. Dabbling ducks were more frequently infected than other ducks and Anseriformes; this distinction was probably related to bird behavior rather than population sizes. Waders did not appear to play a role in the epidemiology of avian influenza in Europe, in contrast to the Americas. The high virus prevalence in ducks in Europe in spring as compared with North America could explain the differences in virus-host ecology between these continents. Most influenza A virus subtypes were detected in ducks, but H13 and H16 subtypes were detected primarily in gulls. Viruses of subtype H6 were more promiscuous in host range than other subtypes. Temporal and spatial variation in influenza virus prevalence in wild birds was observed, with influenza A virus prevalence varying by sampling location; this is probably related to migration patterns from northeast to southwest and a higher prevalence farther north along the flyways. We discuss the ecology and epidemiology of avian influenza A virus in wild birds in relation to host ecology and compare our results with published studies. These data are useful for designing new surveillance programs and are particularly relevant due to increased interest in avian influenza in wild birds.     

Do crocodilians get the flu? Looking for influenza A in captive crocodilians

It is well established that several wild aquatic bird species serve as reservoirs for the influenza A virus. It has also been shown that the influenza A virus can be transmitted to mammalian species such as tigers and domestic cats and dogs through ingestion of infected birds. Another group of animals that should also be considered as potential hosts for the influenza A virus are the crocodilians. Many crocodilian species share aquatic environments with wild birds that are known to harbor influenza viruses. In addition, many large crocodilians utilize birds as a significant food source. Given these factors in addition to the close taxonomic proximity of aves to the crocodilians, it is feasible to ask whether crocodilian species may also harbor the influenza A virus. Here we analyzed 37 captive crocodilians from two locations in Florida (plus 5 wild bird fecal-samples from their habitat) to detect the presence of influenza A virus. Several sample types were examined. Real-time RT-PCR tests targeting the influenza A matrix gene were positive for four individual crocodilians--Alligator sinensis, Paleosuchus trigonatus, Caiman latirostris and Crocodylus niloticus. Of the seven serum samples tested with the avian influenza virus agar gel immunodiffusion assay, three showed a nonspecific reaction to the avian influenza virus antigen-A. sinensis, P. trigonatus and C. niloticus (C. latirostris was not tested). Viable virus could not be recovered from RT-PCR-positive samples, although this is consistent with previous attempts at viral isolation in embryonated chicken eggs with crocodilian viruses.     

Virus isolation and molecular epidemiology of highly pathogenic avian influenza A(H5N8) from an outbreak in free-ranging wild birds,India 2016

We report the molecular epidemiology of highly pathogenic avian influenza (HPAI) virus involved in an outbreak causing death in free-ranging wild birds at Mysore, Karnataka state of India. The virus was typed as HPAI A(H5N8) by conventional and TaqMan probe based real-time PCR assays. Six isolates of HPAI virus were recovered in 9-day-old embryonated chicken eggs. Haemagglutinin gene-based phylogeny of virus isolates showed >?99.9% nucleotide sequence identity with HPAI A(H5N8) isolates from migratory birds and domestic poultry from China and Korea indicating either these wild birds have routed their migration through Korea and/or eastern China or these dead birds must have directly or indirectly contacted with wild birds migrating from Eastern China and/or Korean regions. The study emphasises the role of migratory wild birds in spread of HPAI across the globe.     

Epizootic and epidemiological situation with the avian flu in Dovolensk and Kupinsk areas of Novosibirsk region and the preventive measures

Results of the analysis registered avian flu epizootia are submitted. Diseases were registered as among wild birds, and poultry. From a biological material from a poultry and wild bird of some villages of Novosibirsk region the influenza virus type A (H5N1) is allocated. Carrying out sanitary and antiepidemic measures is organized. It is established, that disease and a mass destruction of poultry have taken place after contact to a wild bird on lakes. It is revealed, that the degree of distribution of a mass destruction of poultry on farmsteads in the struck territories depends on terms of carrying out of necessary measures on localization of the foci. Occurrence of new cases of disease among wild birds and poultry in 2006 as lakes in this territory are a place of nesting of the wild birds being the reservoir of the influenza virus is predicted.