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1.
1.猪是禽流感病毒变异获得侵害人体能力的宿主禽流感是由A型禽流感病毒引起禽类发病的一种急性高度致死性传染病。A型禽流感病毒属正黏病毒科,流感病毒属。其特性:变异性强,易形成新的病毒,使病毒毒力有所改变,称为抗原性漂移和抗原性转变。A型禽流感病毒可以感染多种动物,  相似文献   

2.
禽流感病毒不断重排和变异导致新型流感病毒不断出现,其中有些毒株已经获得了感染哺乳动物的能力,严重危害人类公共卫生安全。近年来,对于禽流感病毒致宿主特异性和致病性的研究取得了一定进展。病毒蛋白某些氨基酸位点的突变就能够改变病毒的宿主特异性,使病毒能够跨宿主传播。而且,病毒的RNA聚合酶、NS1非结构蛋白和几种新发现的病毒蛋白都与病毒的致病性密切相关。论文阐述了禽流感病毒宿主特异性与致病性的分子基础,为禽流感跨物种传播机制研究及防控工作提供参考。  相似文献   

3.
《中国家禽》2012,34(12):42-43
2005~2009年,浙江大学周继勇教授对青海湖地区的H5N1亚型高致病性禽流感暴发及其病原特点开展了一系列研究,涉及病原特性、自然宿主、病原遗传进化等方面,理清了青藏高原禽流感病毒的来源,为我国高致病性禽流感的  相似文献   

4.
禽流感(Avian Influenza, AI)是由正粘病毒科A型流感病毒引起的全身性或呼吸器官性传染病,为A类烈性传染病.主要引起禽类以呼吸系统疾病、产蛋下降乃至急性致死和高死亡率等为特征的烈性传染病,严重威胁着养禽业公共卫生安全.近年来禽流感病毒分子生物学研究取得了突破性进展,病毒编码的各种蛋白对病毒的致病性、宿主特异性起着关键性的决定作用.本文就禽流感病毒的生物学特性作简要的综述.  相似文献   

5.
禽流感概况     
正本文主要介绍了禽流感病毒的基本特性、流行病学特征和诊断方法。1总体介绍甲型流感病毒不仅感染禽类,还是全球重要的人兽病原体。这些病毒具有复杂的生态学和流行病学,涉及各种野生、圈养和驯养的禽类宿主以及各种野生和驯养的哺乳动物宿主,包括人、猪、马和狗等。甲型流感病毒会引起一系列临床疾病  相似文献   

6.
《《禽流感》 (第二版 )《禽流感》 (第二版 )是2004年最新出版的专著 ,由中国农业大学兽医学院甘孟侯教授主编。第一版《禽流感》出版时间较早 ,当时我国对禽流感了解较少 ,书中内容主要来自资料汇编 ,第二版增加了我国科研工作者对禽流感的科研成果和经验。《禽流感》 (第二版 )介绍了禽流感的发生历史与危害 ,病原分类、病毒的理化特性、病毒基因结构及其复制、病毒的增殖、流感病毒的遗传变异、流感病毒毒力和宿主特异性的分子生物学基础 ;禽流感的流行病学 ;禽流感的临床症状、病理变化 ;禽流感病原的分离、病毒鉴定、血清学试验 ,禽流…  相似文献   

7.
禽流感病毒可以感染多种动物,包括人、猪、鸟、马、海豹、鲸和雪貂等。流感病毒在不同的宿主存在一定的屏障,但禽流感毒株能突破宿主屏障直接感染人,造成死亡。因此流感病毒的变异和病毒如何选择物种跨越物种流行的机制,对预防和控制流感的爆发是非常重要的。本文综述病毒毒力的分子生物学基础、禽流感染人的分子机制研究进展及在控制禽流感方面的研究。  相似文献   

8.
2013年3月31日,国家卫生与计划生育委员会通报了上海和安徽确诊3例人感染H7N9亚型禽流感病例,顿时世界为之轰动,世界卫生组织(WHO)对此也高度关注。截止2013年4月25日,全国共确诊H7N9禽流感病例113人,分布在浙江、上海、江苏、河南等多个省份。历史上,美国、蒙古、韩国等多个国家都曾从野鸟和水禽中检出过H7N9亚型禽流感病毒,但从未有过人感染发病的报道。这次发生首次展现了H7N9具有夸宿主传播的能力。病毒基因组遗传进化分析表明这次流行的H7N9亚型禽流感病毒不同于以往的任何一株H7N9病毒,其HA 基因与我国南方水禽近年来分离到的H7亚型禽流感病毒密切相关,NA 基因则与2011年韩国野鸟分离到的H7N9亚型禽流感病毒遗传关系较近,其余6个基因则与国内地方流行的H9N2亚型禽流感病毒高度同源。因此,该病毒可能是不同亚型禽流感病毒在同一宿主体内经二元或三元重排而形成的新病毒。本文就H7N9亚型禽流感病毒的历史分布和国内新出现的H7N9亚型禽流感病毒的分子特性和遗传进化进行了分析。  相似文献   

9.
高致病性禽流感及其病毒的分子生物学特性   总被引:6,自引:0,他引:6  
笔者对1959-2005年46年内全世界高致病性禽流感的发生情况,以及病毒的基因和编码蛋白、病毒宿主特异性和病毒致病性的分子生物学基础进行了综述。旨在为防制高致病性禽流感提供资料参考。  相似文献   

10.
世界家禽饲养业普遍面临着禽流感的威胁。禽流感病毒分布广泛,其宿主包括野禽、迁栖鸟类,以及诸多非商业化饲养的鸟类。该病毒具有不断变异能力,特别当侵入高密度饲养的商品家禽群落时,常表现较高的致病性,故应提高对此病的重视。未来对禽流感的控制将结合早期诊断、利用先进的分子生物学技术进行病毒分离鉴定、隔离检疫、有选择的淘汰及对鸡群进行免疫接种等措施。1禽流感病毒的特性11众多的禽流感血清型禽流感是由正粘病毒科中A型流感病毒引发,并可按病毒粒子表面的血凝素(HA)和神经氨酸酶(NA)的糖蛋白进行分类,禽流…  相似文献   

11.
三聚体自转运黏附素(trimeric autotransporter adhesin,TAA)是近年来发现的参与猪胸膜肺炎放线杆菌(Actinobacillus pleuropneumoniae,APP)黏附宿主细胞的重要毒力因子。本研究比较了5b adh基因缺失株(△adh)与5b野生株的生物学特性及其对仔猪的致病性。结果表明,在BHI液体培养基中,△adh生长速度明显高于5b野生株;△adh在液体培养基中细菌集聚性明显减弱;仔猪感染后临床症状典型,猪肺脏病理组织切片结果表明,△adh致病性弱于野生株。本研究结果证实adh在APP黏附宿主过程中发挥重要作用,为下一步探究APP致病机制奠定基础。  相似文献   

12.
Most isolates of foot-and-mouth disease virus (FMDV) display a broad host range. Since the late 1990s, the genetic lineage of PanAsia topotype FMDV serotype O has caused epidemics in the Far East, Africa, the United Kingdom, France, the Netherlands, and numerous other countries throughout Europe and Asia. In contrast, there are several FMDV isolates that exhibit a more restricted host range. A Cathay topotype isolate of FMDV serotype O from the 1997 epizootic in Taiwan (O/TAW/97) demonstrated restricted host specificity, only infecting swine. Methods used to evaluate infectivity and pathogenicity of FMDV isolates in cattle are well-documented, but there has been less progress studying transmission and pathogenicity of FMDV isolates in pigs. In previous studies designed to examine pathogenicity, various chimeric viruses derived from O/TAW/97 were intradermally inoculated in the heel bulb of pigs. Subsequent quantitative scoring of disease and evaluation of virus released into nasal secretions and blood was assessed. Here we prove the usefulness of this method in direct and contact inoculated pigs to evaluate infectivity, pathogenicity and transmission of different Asian FMDV isolates. Virus strains within the Cathay topotype were highly virulent in swine producing a synchronous disease in inoculated animals and were efficiently spread to in-contact naive pigs, while virus strains from the PanAsia topotype displayed more heterogeneous properties.  相似文献   

13.
Bovine herpesvirus 1 (BHV1) and caprine herpesvirus 1 (CapHV1) are useful models to study virus-host interactions, as well as pathogenicity and latency, when comparing the outcome of infection in the natural and the foreign hosts. Molecular seroepidemiological analyses revealed that cross-reacting antibodies were mainly induced by glycoprotein gI (gB analogue), by the major capsid protein and by nonstructural proteins, whereas the most virus-specific antibodies were elicited by glycoproteins gIII and gIV. These glycoproteins, especially gIII (gC analogue), might therefore play an important role in the virus-host-interactions. As a basis for further studies, we re-evaluated observations concerning experimental infections with BHV1 and CapHV1 in the natural and the foreign hosts. All parameters indicated that both viruses were able to infect either host, but that the pathogenicity was restricted to the natural host. Latent virus could be reactivated exclusively from cows infected with BHV1. It was possible neither to reactivate BHV1 from goats, nor to reactivate CapHV1 from either species. The experiments indicated that the outcome of infection in the natural and the foreign host is dependent on host and viral factors, whereby gIII is only one important virus component involved. Further investigations in the host and host cell range of BHV1 and CapHV1 will help to clarify the role of factors responsible for virus-host-interactions.  相似文献   

14.
为了进一步了解根腐病病原菌的生物学特性以及不同病原菌对苜蓿的致病性,本研究以苜蓿根腐病病原BF1(Fusarium equiseti)、BF28(F.oxysporum)、BF36-2(F.solani)三种镰孢菌菌株为试验材料,观测菌落的外观特征与产孢量,并对WL343、金皇后、阿尔冈金、WL525四个苜蓿品种以菌液和菌饼两种方式接种,比较不同菌株对苜蓿的致病性。结果表明,菌液接种方式,苜蓿感病较快,感病程度较重。不同菌株在苜蓿根系的定植能力不同,BF1菌丝在根系附近聚集;而BF28及BF36-2菌丝则均匀分布于培养基表面。菌饼接种方式,不同菌株对苜蓿的致病性存在较大差异,产孢能力强的菌株致病力强。BF28对苜蓿的致病性最强,BF36-2次之,而BF1的致病性较弱。通过对感病植株进行解剖构造与致病过程观察,病菌以厚垣孢子入侵根系及叶片表皮细胞,以菌丝体及孢子形式在细胞间隙扩展,并向植物组织中释放细胞壁溶解物质,植物细胞壁溶解,根髓部腐烂中空,根颈部缢缩,叶部出现溃烂斑,植株的生长受阻。  相似文献   

15.
日本血吸虫童虫经24h到2年冻藏后,其活力和感染率与冻藏时间长短不相关,与冻存培养液的pH相关,最佳pH为7。冻藏50d传至F4,冻藏2年传至F1。童虫及其子代在终宿主小鼠和中间宿主钉螺体内的移行、生长、发育、繁殖、传代、性别比率及对终宿主的致病力,同相应对照组无明显差异,由此证明日本血吸虫童虫可用液氮冻藏长期保种。  相似文献   

16.
Mycoplasmas are a diverse group of pathogens responsible for disease in a wide range of animal species. In recent years there have been considerable advances in knowledge of the proteins and structures involved in adherence in some mycoplasmas, but understanding of the biochemical functions and roles in virulence of another central feature of mycoplasmas, their lipoproteins, continues to develop. The aim of this review is to examine current knowledge of the roles of lipoproteins in the pathogenicity and the evolution of virulence in those mycoplasmas causing disease in domestic animals. Those lipoproteins that have been characterised have roles in adherence, in transport of nutrients into the mycoplasma cell, and in enzymatic interactions with the host. Furthermore they appear to play a prominent role in both inducing the host immune response to infection and in facilitating evasion of this response, particularly through the generation of dramatic levels of antigenic variation on the cell surface. Recent genomic comparisons of several pathogenic mycoplasmas have identified a further level of interaction between lipoproteins and pathogenicity. In several pathogens large scale horizontal gene transfer between distantly related mycoplasma species has resulted in the acquisition of a large number of genes, including those encoding lipoproteins thought to play a role in virulence, by one mycoplasma from another inhabiting the same host species. The interactions between these horizontally transferred genes, their new mycoplasma host and the animal that it infects may be an important contributing factor in the pathogenesis of some mycoplasmoses.  相似文献   

17.
雷玉明  张建文 《草地学报》2006,14(3):284-286
经田间采集、分离培养、室内鉴定及致病性测定。本文报道了寄生于菊科Compositae和桑科Moraceae等9种草本植物上的3种尾孢菌及其病害:蒿褐斑病(Cercospora artenmisiae Y.L.Guo&Y.Jiang)、蓟褐斑病(Cercospora cirsii Ellis &E verh.)和蓓草褐斑病(Cercospora humuligena Y.L.Guo&L.Xu)。上述病害在国内外均未见报道,属国内3种新病害,其中9种草本植物为国内新纪录寄主。并对每一种病害的症状和病原形态进行了描述。  相似文献   

18.
Cryptosporidium infections in man, animals, birds and fish   总被引:3,自引:0,他引:3  
SUMMARY: The protozoan parasite Cryptosporidium has gained better recognition over the last decade as an enteropathogen in a wide variety of host animals. Prior to 1975, infections were thought to occur infrequently and to be largely asymptomatic in nature. However, recent studies have revealed the organism to be more prevalent and pathogenic than previously thought. Infections producing clinical disease have been recorded in numerous host species including man, and the organism is now regarded as a newly-emergent zoonosis. This paper collates information currently available on the host range and specificity, life cycle and pathogenicity of the parasite and summarises the various techniques used to diagnose infections. Aust. vet. J. 62: 253–258  相似文献   

19.
Problems dealing with common parasites--oxyurids, which affect laboratory mice colonies are discussed and reviewed. Their life histories, pathogenicity and immunity are examined. The attention is paid to the influence of age, sex, strain and status of the host in the infection. It is agreed that helminth infections are usually more severe in male than in female vertebrate hosts.  相似文献   

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