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1株野禽源H5N6亚型禽流感病毒的分离鉴定与遗传进化分析 总被引:1,自引:0,他引:1
《中国兽医杂志》2017,(5)
为了解野生鸟类禽流感病毒的流行情况,对2015-2016年广州地区野生鸟类进行流感监测,分离得到1株H5N6流感病毒。对病毒分离株进行基因克隆、测序和序列分析,结果显示,HA基因属于Clade2.3.4.4,HA蛋白的裂解位点处具有多个连续碱性氨基酸,具备高致病性禽流感病毒的典型分子特征。各基因片段分别与H5N6亚型的猫和家禽等的不同宿主病毒株相应片段具有较高相似性,揭示了野鸟作为流感病毒孵化器的可能性,提示需加强对野生鸟类禽流感监控。 相似文献
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禽流感病毒免疫研究进展 总被引:3,自引:0,他引:3
禽流感(avian influenza,AI)是由正粘病毒科A型流感病毒引起的禽类全身性或呼吸器官性疫病。禽流感病毒(avian influenza virus,AIV)为带包膜、分节段的单股负链RNA病毒。该病自然宿主是野生水禽、海鸥和各种海鸟,在野生鸟类中存在15种HA和9种NA亚型,大部分的HA和全部的NA亚型存在野鸭体内。从迁徙性水禽体内分离到的禽流感病毒是家禽流感的主要感染来源。在哺乳动物、鸡和火鸡体内感染的流感病毒,呈现出高进化率和高变异率,说明流感病毒在新的宿主体内生长而导致的适应性变化。鸭子在把流感病毒从自然宿主传播给家禽和哺乳动物中起着重要的作用。随着对流感病毒感染的宿主免疫反应研究的深入,可能为防治AI提供帮助。 相似文献
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禽流感(avian influenza,AI)是由A型流感病毒引起的家禽或野禽的疾病综合征。根据禽流感病毒(AIV)的致病力通常分为高致病性禽流感(HPAI)和低致病性禽流感(MPAI),HPAI传播快,具有高度致死性;MPAI多呈隐性感染或症状较轻,不导致严重病变或死亡。AI历来被认为是人类流感的最大基因库,是人流感病毒发生变异的新基因来源。1997年,中国香港H5N1 AIV及1999年中国大陆和香港H9N2AIV首次突破种间障碍直接感染人甚至致死。不但打破了自然条件下仅有H1、H2和H3亚型流感病毒可以感染人和其他哺乳动物的常规,而且为人流感增添了新的毒株亚型(H5和H9)。由此赋予了AIV(禽流感病毒)全新的公共卫生意义。 相似文献
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(接上期)A型流感病毒及禽流感对人的感染1 概述 流感自古以来就是动物与人共患的急性高度传染性疾病。流感病毒属正黏病毒科的病毒,根据病毒核蛋白抗原的特点可分为A、B、C三型,而A型除感染动物外,还可感染人类。A型流感病毒目前已明确有15个HA(血凝素)亚型和9个NA(神经氨酸苷酶)亚型,每个A型流感毒株只有1个HA亚型和1个NA亚型组合。2 A型流感病毒的宿主及其对人的感染情况(见表1)3 哺乳动物和人感染禽流感病毒情况3.1 猪:由于猪的流感在其体内具有禽流感病毒和人流感病毒,因此,通常都把猪作为A型流感病毒的“中间宿… 相似文献
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流感病毒受体识别以及流感病毒跨宿主感染的分子机理 总被引:4,自引:0,他引:4
近年来禽流感病毒在亚洲流行,使家禽养殖业受到很大冲击。令人担心的是,从东南亚疫情爆发地区还报道了人类感染禽流感病毒的病例,我国湖南等省也有人类感染禽流感病毒。目前疫情虽然已经得到控制,但是H5N1亚型禽流感病毒将长期在亚洲存在。由于流感病毒的自身基因组极易产生变异和亚洲地区家禽业的养殖模式特点,禽流感病毒极有可能进化成可以跨宿主感染的新型流感毒株。本文对流感病毒的受体识别和跨宿主感染的分子机理作一综述,并讨论若出现流感大流行时的药物控制措施。 相似文献
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野鸟在流感的生态学上具有重要的地位,从70年代起,美国、加拿大、英国、澳大利亚等国家对野生鸟类及候鸟的禽流感监测做了长期系统的研究工作。自1961年首次从野禽体内分离到H5N3禽流感病毒后,所有15个H亚型和9个N亚型的A型流感病毒都在野禽群体中分离到,特别是野鸭、海岸鸟及海鸥等水禽,从野生迁徙性水禽中分离到禽流感病毒的几率远远超过了其它禽种。经多年的调查和研究,已知水禽是禽流感病毒的天然宿主,其所携带的流感病毒是各型流感病毒的祖先,野生鸟尤其是鸭乃流感病毒巨大的储存库。故研究野生水禽及候鸟禽流感对防治禽流感具有重要… 相似文献
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A型流感病毒在温血动物中广泛存在,也是目前导致人类和各种动物流感疾病的主型。在自然情况下流感病毒感染的宿主范围有一定的特异性,分离自人的流感病毒一般不能在鸡、鸭等禽类体内复制,同样禽流感病毒在灵长类动物体内的复制能力也极差。但近年来不断发生禽流感病毒(包括H5N1,H9N2,H7N7亚型病毒)直接传染给人的事件,而2009年爆发的人类的H1N1流感的病原则是猪源流感病毒重组而来。研究证实,流感病毒的致病性及跨种间传播的深层原因是病毒分子结构差异及其与宿主细胞相互作用。病毒多种结构蛋白和非结构蛋白某些功能位点上氨基酸的差异是病毒致病性及其跨中传播的分子生物学基础。 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
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本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
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REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
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以国际标准强毒R株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离MG,并收集感染鸡所产蛋分离MG。结果表明,人工感染48小时后上、下呼吸道及肺已被全面感染,96小时气囊已被感染,120小时输卵管已能分离到MG,卵巢始终分离不到MG。人工感染鸡自144小时便能在其所产蛋中分离出MG。药物治疗能在72小时内消除感染,油乳剂苗则需24天后逐渐降低蛋内MG分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内MG,但以研制的种蛋浸泡剂药浴效果为最好。 相似文献
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Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献