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1.
不同禽源新城疫病毒强毒株对鹅的致病性研究   总被引:2,自引:1,他引:1  
分别采用鸽、鸡、鸭、鹅源新城疫病毒(NDV)强毒株和NDV国内标准强毒株F48E8进行鹅的人工感染试验,对感染鹅的临床症状、增重、抗体水平和排毒情况进行详细观察,探讨不同禽源NDV强毒株对鹅的致病性以及鹅在家禽新城疫(ND)流行中的意义。结果表明,鸽源强毒株JSP0204对鹅无致病性或致病性很弱,感染鹅未表现临床症状,增重也未受到显著影响(P0.05)。而鸡源JSC0804、鸭源JSD0812、鹅源JSG0210和F48E8株均可致鹅发病和死亡,尤以鸭源JSD0812和F48E8株致病性最强,致死率高达100%。所有感染鹅均可排毒,排毒时间因毒株不同而异。研究结果表明目前流行的NDV强毒株对鹅的致病性普遍增强,并进一步证实鹅在ND流行病学中具有重要的作用。  相似文献   

2.
对来自吉林地区疑似新城疫感染死亡的不同禽源(鸡、鸭、鹅、鸽)病料进行病毒的分离鉴定,分析其主要基因序列,测定其毒力及对雏鸡的致病性。结果表明,分离出的4株病毒均为新城疫病毒(NDV),F蛋白裂解位点处序列均为112 R-R-Q-K-R-F117,与典型强毒株一致,且相互之间的同源性为98.4%~99.8%,均属Ⅱ类Ⅶd型新城疫强毒。毒力测定和对雏鸡的致病性试验,亦证明这4株NDV分离株为强毒株,且毒力差异不显著。由此推测,近年来吉林省流行的NDV以Ⅱ类Ⅶd型为主。短期内,NDV在不同禽源宿主间的种间传播对病毒的毒力和变异没有造成较大的影响。  相似文献   

3.
鸭是新城疫病毒(NDV)重要的自然宿主,在NDV的传播和进化中起着重要作用。为研究鸭对不同NDV株易感性及在NDV传播中的作用,本研究选取5株不同禽源及基因型NDV,以不同剂量经滴鼻点眼途径接种15日龄番鸭,鉴定对鸭的致病性、排毒情况、血清抗体变化以及病毒的组织脏器分布;并设立同居鸭、鸡测定NDV水平传播能力。结果显示,疫苗病毒株La Sota和WB383(基因Ⅰ型)株能够在番鸭体内有限复制;La Sota仅诱导产生低水平抗体,而WB383诱导的抗体水平较高,未检测到这2株病毒的水平传播;F48E9对番鸭致病性强,具有较强水平传播能力;同为基因Ⅶ型病毒,鸭源MD株呈现出对番鸭高致病性,野鸭源WB363株则对番鸭致病性较低,但其水平传播能力高于MD株。实验结果显示,5株NDV对番鸭致病性差异较大,La Sota和WB383株对番鸭无致病性,排毒和水平传播能力弱;F48E9对番鸭具有高致病性;同属于基因Ⅶ型的强毒株对番鸭致病性差异较大,这种差异原因尚需进一步研究。本研究结果表明番鸭感染NDV的F48E9、WB363、MD株后水平传播能力较强,应重视其在NDV传播和进化过程中的作用研究。  相似文献   

4.
为了科学理解家鸭在新城疫病毒(NDV)流行和传播中的作用,对贵州不同地区分离的5株鸭源NDV强毒株进行遗传变异分析以及对鸭和SPF鸡的致病性研究。结果显示:5株NDV分离株均属于基因Ⅶd亚型,其F蛋白裂解位点基序均为112 RRQKRF117,符合强毒株序列特征,与病毒致病性指数测定结果相符;F和HN蛋白中功能性氨基酸位点均高度保守,但在HN蛋白线性表位区有3株发生E347K突变。交叉血凝抑制试验发现分离株与传统疫苗株LaSota的抗原同源性较低(为83.3%~87.0%),而与新型基因Ⅶ型疫苗株A-Ⅶ的抗原同源性较高(为93.5%~100%)。将5株NDV分离株以0.5mL病毒尿囊液原液通过肌肉注射感染鸭后未见明显发病死亡和病理变化,并且除脾外在其他多个组织脏器未能检测到病毒复制;而以106.0 ELD50·0.1mL-1剂量通过滴鼻点眼感染SPF鸡后6d内100%发病死亡,病死鸡表现出新城疫典型的临床症状和病理变化,病毒在多个组织脏器中均能复制且对脾、胸腺和法氏囊等免疫器官损伤严重。另外,SPF鸡攻毒后喉头和泄殖腔棉拭病毒分离率明显高于试验鸭。本研究结果表明,贵州省鸭群中流行的基因Ⅶd亚型NDV强毒株HN蛋白发生E347K突变的变异株呈上升趋势,并与传统疫苗株产生抗原差异;5株鸭源NDV强毒株对鸭和鸡致病性差异显著,虽然对鸭无明显致病性,但鸭感染后可在较长时间内通过喉头或泄殖腔向体外排毒,因此必须采取有效措施防止NDV强毒由鸭群向鸡群的传播。  相似文献   

5.
不同基因型新城疫病毒对美国白羽王鸽的致病性研究   总被引:1,自引:0,他引:1  
为比较鸽源Ⅵb亚型新城疫病毒(NDV)与其它不同基因型NDV对鸽的致病性差异,本研究选取JS-7-05-Ch(基因Ⅲ型)、WX-10-07-Pi(基因Ⅵb型)、JS-5-05-Go(基因Ⅶd型)和F48E8(基因Ⅸ型)4个病毒株,分别人工感染2月龄实验鸽。接种后,观察实验鸽临床症状、病理剖解变化、同时检测HI抗体水平变化、喉气管和泄殖腔排毒以及病毒在组织分布情况。4株NDV均能导致接种鸽的发病,但死亡率分别为0、0、100%、50%。WX-10-07-Pi接种组鸽泄殖腔排毒时间最长、而且病毒检出率比其它组高。另外,在接种组鸽的多种组织器官中均可检测出病毒。实验结果表明,不同基因型NDV对鸽均有致病性,但致病力强弱与NDV毒株特性有关;基因Ⅵb型NDV在鸽体内可长期的带毒与排毒,与其它基因型NDV相比更易在鸽群中传播。  相似文献   

6.
新城疫病毒致病性和免疫原性研究概况   总被引:3,自引:1,他引:3  
新城疫病毒(NDV)长期以来一直是危害我国养禽业主要病原之一。而且,近年来NDV感染并致病的宿主范围还有扩大的趋势。用NDV经典毒力测定方法对各种禽源NDV分离株毒力研究及用分子生物学方法对其主要毒力相关基因(F和HN)研究结果表明,分离株大部分为强毒株。不同禽源分离株致病性试验结果表明,各种禽源NDV致病性存在差异。免疫保护试验结果表明,各种禽源NDV分离株间抗原免疫原性也存在差异。目前NDV致病性试验和免疫保护试验主要是在同源禽类或在异源1~2种禽类进行,因此,很有必要进行不同禽源分离株在主要家禽品种间的交叉致病性试验和免疫保护试验。  相似文献   

7.
不同基因型新城疫病毒株对鹅的致病性   总被引:4,自引:1,他引:4  
用不同基因型(Ⅳ、Ⅵb、Ⅵg、Ⅶd(坞源)、Ⅶd(鹅源)、Ⅷ、Ⅸ)新城疫病毒(NDV)强毒株分别人工感染23日龄隆昌鹅,观察了其对鹅的致病性。结果:各株病毒均可使接种鹅感染、发病,发病串为10%~100%,死亡率分别为0%、20%、30%、70%、50%、40%、50%。接种Ⅵg、ⅦdI、Ⅶ和Ⅸ型NDV强毒株可使鹅严重发病、死亡,症状和病变都与Ⅶd亚型鹅源毒株感染鹅相似,接种Ⅳ型(Herts/33)及Ⅵb亚型(PB9601)毒株的鹅轻微发病。免疫组化检检测发现,攻毒鹅多种组织器官中都能检测到病毒抗原。在能检测到病毒抗原的器官中,病毒抗原主要定位于淋巴细胞、网状细胞、巨噬细胞、肝细胞及各种上皮细胞的胞浆内;与Ⅵg、ⅦCl、Ⅶ和Ⅸ型NDV感染鹅组织相比,Herts/33、PB9601感染鹅大部分组织内的阳性染色较弱。本试验结果表明,不同基因型NDV强毒株对鹅的致病性存在明显差异。  相似文献   

8.
不同宿主源NDV毒株对SPF鸡致病性研究   总被引:4,自引:2,他引:2  
为阐明不同宿主及不同基因型新城瘦病毒(NOV)对SPF鸡致病性,选择分离自鸡、番鸭、鹅、健康野鸟的基因VIId亚型NDV 6株,鸡源基因Ⅲ型和鸽源基因VIb型毒株各1株,以及基因Ⅸ型强毒F48E9,共9株NDV毒株进行致病性试验.在对各毒株的EID50及主要致病指数MDT、ICPI测定基础之上,以相同剂量感染15日龄SPF鸡,观察临床症状及剖检病变,计算发病率和死亡率,并在攻毒后不同时间采集主要组织样品.以SYBR Green I Real-time PCR检测病毒最早出现时间及病毒载量.结果表明,6株基因VIId亚型NDV毒株导致SPF鸡100%发病,死亡率90%以上,属于高致病性毒株;基因Ⅲ、VIb型毒株导致SPF鸡发病但不死亡,属于中等毒力毒株.VIId亚型毒株与F48E9株攻毒后SPF鸡在病理变化、组织嗜性及病毒载量上没有显著差异.根据毒株的MDT、ICPI指数及攻毒鸡病程综合判断,VIId亚型毒株在致病性上与F48E9株差异不显著.健康野鸟携带基因VIId亚型高致病性NDV,在NDV的自然生态传播过程中起重要作用,提示应该加强对野鸟的流行病学监测及相关研究.  相似文献   

9.
从山东潍坊某发病鸭场分离到1株病毒,经分离、鉴定为鸭新城疫。对该分离病毒进行了毒力和致病性等生物学特性分析。结果,该分离病毒连续传3代后,HA效价稳定在9log2以上,MDT为124.5h,ICPI为0.292,F基因核苷酸和转译氨基酸与传统Lasota株的同源性最高,与Kuwait256株最低。而F基因裂解位点的氨基酸组成与NDV强毒株的特征性结构一致("112R-R-Q-K-R-F117")。结论:(1)该病例为鸭Ⅰ型新城疫弱毒株感染;(2)F基因的裂解位点的特征性结构不完全决定鸽新城疫的毒力。  相似文献   

10.
对鸭源新城疫病毒(NDV)强毒株JSD0812对鸭的致病性进行了研究。结果显示,对于15日龄雏鸭,JSD0812株病毒尿囊液的半数致死剂量(LD50)为101mL。15,30,45,60。110日龄鸭肌肉注射感染试验结果表明,所有日龄鸭感染JSD0812株后均可发病,但死亡率随日龄的增长而下降,110日龄鸭感染后未见死亡。鸭感染后可经咽喉和/或泄殖腔短期排毒,感染鸭组织器官中病毒分离率较低。  相似文献   

11.
12.
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   

13.
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   

14.
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   

15.
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   

16.
用硝酸和高氯酸消化蜂蜜,使硒游离出来,在微酸性环境下,硒和2,3-二氨基萘(DAN)生成有较强荧光的物质,用环己烷萃取,在激发波长378nm,荧光波长518nm处测定其荧光强度。蜂蜜中硒含量范围:0.10~0.82μg/g。表明:蜂蜜应视为天然富硒营养品。  相似文献   

17.
Fractures of the anconeal process of 5 pigs ranging in age from 4 to 8 months were studied radiographically and histologically. Clinically, animals with a fracture of the anconeal process had a "tight," restricted gait. In pigs at 4.5 months of age, a radiolucent line through the base of the anconeal process was composed of fibrocartilage, fibrous connective tissue, and hyaline cartilage. Subperiosteal proliferation of woven bone was located along the cranial surface of the olecranon, adjacent to the base of the anconeal process. In older animals, the radiolucent line through the anconeal process contained variable amounts of fibrous connective tissue and fibrocartilage. The proliferation of subperiosteal bone at the base of the anconeal process formed a "buttress callus" which retained a radiolucent area between the callus and the proximal surface of the anconeal process. The latter region of radiolucency was continuous with the transversely oriented line that traversed the base of the anconeal process.  相似文献   

18.
为贯彻落实《兽药生产质量管理规范》(简称《兽药GMP》),进一步推动兽药GMP实施进程,我部制定了《兽药生产质量管理规范检查验收办法》,现予公告。本公告自2003年6月1日起施行。附件:兽药生产质量管理规范检查验收办法二○○三年四月十日第一章 总则 第一条 为推动《兽药生产质量管理规范》(以下简称兽药GMP)的实施,规范兽药GMP检查验收工作,制定本办法。 第二条 农业部负责全国兽药GMP管理和检查验收工作;负责制修订兽药GMP检查验收管理规定;负责兽药GMP检查员队伍建设和监督管理工作,负责国际兽药贸易中GMP互认工作。 …  相似文献   

19.
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   

20.
乳酸杆菌益生作用机制的研究进展   总被引:2,自引:0,他引:2  
乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和 Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。  相似文献   

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