鸭甲肝病毒鸡胚化弱毒MY株Vp1重组蛋白的免疫保护效果试验

将鸭甲肝病毒鸡胚化弱毒MY株Vp1基因原核表达工程菌(pET32a+Vp1,BL21(DE3)PlysS)对基因Yp1进行大量表达和纯化,得到鸭甲肝弱毒MY株Vp1重组蛋白作为抗原制备亚单位疫苗,免疫雏鸭,用间接ELISA检测方法对免疫后抗体生成水平进行监测,并通过动物攻毒试验评价免疫保护效果.结果显示:Vp1重组蛋白免疫家兔后血清检测琼扩效价≥1∶64,细胞中和试验效价为1/45;雏鸭免疫后抗体生成水平呈明显上升趋势,对攻毒起到了保护作用.首次揭示了DHAV-1结构蛋白Vp1刺激机体产生抗体使雏鸭获得保护的能力.     

鸭瘟与鸭坦布苏病毒病活疫苗联合免疫效果研究

鸭瘟鸡胚化弱毒活疫苗与鸭坦布苏病毒病活疫苗通过肌肉注射途径,同时接种21日龄健康易感肉鸭,检测两种活疫苗联合免疫的安全性和免疫效力。将两种活疫苗同时免疫雏鸭,免疫后14d检测血清抗体值,并在14d时采用鸭瘟强毒和鸭坦布苏病毒强毒株同时攻毒,观察试验组与对照组的攻毒保护情况。结果表明:两种活疫苗联合免疫健康易感雏鸭后,血清抗体上升快,可同时抵御鸭瘟强毒与鸭坦布苏病毒强毒株的攻击,保护效果良好。结论:鸭瘟与鸭坦布苏病毒病活疫苗联合免疫,对雏鸭安全,免疫保护效果好,避免多次免疫对雏鸭带来的应激反应,提高养殖经济效益。     

间接ELISA检测鸭肝炎病毒抗体的研究

以蔗糖密度梯度离心法纯化的病毒作为包被抗原，建立了检测鸭肝炎病毒（ＤＨＶ）抗体的间接ＥＬＩＳＡ方法。经特异性及重复性试验，效果良好。ＥＬＩＳＡ效价与琼扩、中和效价存在平行关系。经ＥＬＩＳＡ检测，１日龄雏鸭免疫后，４日龄可检出ＥＬＩＳＡ抗体，１０日龄达到峰值。ＤＨＶ高免血清在雏鸭体内作用维持时间为１０ｄ左右。攻毒保护试验表明，攻毒前雏鸭的血清抗体水平与攻毒后雏鸭存活率具直接相关性。     

血清3型鸭甲型肝炎病毒弱毒疫苗株培育及免疫原性研究

近年来鸭甲型肝炎病毒血清3型引起的小鸭肝炎在我国广泛流行,严重危害着肉鸭养殖业.本研究采用鸭胚连续传代对血清3型鸭甲型肝炎病毒分离株进行致弱,通过检测不同代次的鸭胚组织毒的毒力、稳定性及免疫原性,结果发现该病毒在鸭胚中连续传代至第53代以后对雏鸭无致病性,在雏鸭体内连续继代不出现毒力返强.雏鸭经颈部皮下接种5×105.9ELD50的第54代病毒后可刺激机体产生坚强的免疫力.1日龄雏鸭免疫后4 d对强毒感染的保护指数为81.4%,免疫后6天的保护指数为100%.3日龄雏鸭免疫后5 d攻毒保护率为100%.1日龄雏鸭免疫后1周,血清中和抗体水平为10-3.29,至第4周达到高峰,之后开始缓慢下降.试验结果表明,3型鸭甲型肝炎病毒株第54代弱毒具有良好的免疫原性、毒力稳定,雏鸭接种后诱导产生的免疫力完全可以保护小鸭渡过鸭肝炎易感期,可作为疫苗候选株     

鸭抗鹅细小病毒抗血清的制备

为了研究鸭抗鹅细小病毒抗血清对鹅细小病毒病的防治效果,试验采用鹅细小病毒98E株鹅胚胚毒(活毒)免疫成年鸭,检测其抗体效价和并描绘抗体消长规律,利用琼扩效价为1∶32的鸭抗鹅细小病毒抗血清进行鹅细小病毒病预防和治疗试验。结果表明:首免第1周即可在血清中检测到抗体,加强免疫后第1周血清抗体琼扩效价即达到1∶128;攻毒后第25天,在预防试验中雏鹅死亡率为0,在治疗试验中雏鹅死亡率为56%。说明鸭抗鹅细小病毒抗血清对雏鹅细小病毒病的防治具有很好的效果。     

鸭病毒性肠炎间接ELISA诊断方法的建立及应用

本研究以鸭病毒性肠炎(DVE)病毒作为包被抗原,建立了检测DVE抗体的间接ELISA诊断方法.应用该ELISA诊断方法检测DVE阳性对照血清,当血清稀释至12800 倍时,结果仍为阳性;检测其它7种鸭病阳性血清结果均为阴性;批内重复性试验和批间重复性试验的变异系数均小于10%;该检测方法与血清中和试验的符合率为100%.DVE 活疫苗皮下免疫鸭抗体监测结果表明:鸭免疫后第7d 可以在血清中检测出DVE特异性抗体.本试验建立的诊断方法具有良好的特异性、敏感性和重复性,为DVE免疫鸭的抗体监测和DVE流行病学调查提供了一种快速、简便的血清学诊断方法.     

鸭病毒性肝炎Ⅰ型疫苗中和抗体效果实验

鸭病毒性肝炎是由鸭肝炎病毒(DHV)引起的一种雏鸭高度致死性传染病;该病主要侵害4周龄以内的雏鸭,特别是不足一周龄的无母源抗体的雏鸭最易感,病鸭突然发病,病程短促,数小时即死亡,死亡率高达90％。DHV有三种血清型,无交叉保护作用。目前,I型呈世界性分布,II型和III型鸭病毒性肝炎分别局限于英国和美国,在国内,以I型鸭病毒性肝炎流行为主,目前国内对鸭病毒性肝炎主要是以治疗为主,当雏鸭发病时使用鸭肝炎抗体进行治疗,这样会增加饲养成本并影响雏鸭的生长性能。由于此病发病急,死亡率高,目前最好的方法还是以预防为主。本实验通过鸭病毒性肝炎I型疫苗（CH60株）在临床上的应用,使用鸡胚中和试验对不同剂量鸭病毒性肝炎I型疫苗（CH60株）雏鸭的血清进行抗体检测,,以确定该疫苗株在临床应用的效果情况,同时确定鸭病毒性肝炎I型疫苗（CH60株）适用于该地区雏鸭的最佳免疫剂量。     

鸭病毒性肝炎高免血清对雏鸭保护力的测定

国内外大量资料表明,目前世界上流行的鸭病毒性肝炎有Ⅰ、Ⅱ、Ⅲ三个血清型,国内各地流行的鸭肝炎经鉴定均属Ⅰ型。该型的特点是发病快、死亡率高,有时可达90％以上。其预防方法包括用弱病毒疫苗直接免疫雏鸭,或免疫母鸭,雏鸭通过母源抗体获得被动保护,或给雏鸭直接注射高免血清等三种     

1型鸭疫里氏杆菌抗体间接ELISA检测方法的建立

以1型鸭疫里氏杆菌(RA)全基因组保守区域ompA基因的重组表达产物为包被抗原,建立了检测RA血清抗体的间接ELISA方法。原核表达的重组ompA蛋白经纯化后作为包被物,以方阵滴定法确定抗原最佳包被浓度为1.5μg/mL,待检血清最佳稀释度为1∶100。与普通的微量凝集试验相比较,该方法灵敏度高于凝集试验约16倍～128倍。与鸭源大肠埃希菌、鸭源多杀性巴氏杆菌、鸭链球菌、鸭源呼肠病毒、鸭肝炎病毒和鸭瘟病毒感染鸭血清均无交叉反应,表明该方法特异性好。利用该方法检测了雏鸭免疫RA灭活油乳剂疫苗之后血清抗体水平。     

鸭传染性浆膜炎母源抗体消长规律及其对后代雏鸭的保护

为研究鸭传染性浆膜炎母源抗体消长规律及其对后代雏鸭是否具有保护力,本研究采用鸭传染性浆膜炎疫苗于产蛋前免疫种鸭,并利用间接ELISA方法检测不同时间点收集的鸭蛋中卵黄抗体和对应批次孵育出的雏鸭血清抗体变化规律,以及后代雏鸭从出壳开始母源抗体的变化规律。结果表明,接种疫苗后卵黄抗体和传递到雏鸭体内血清抗体变化规律一致,接种后第6 d检测到抗体出现,27 d抗体达到峰值,之后缓慢下降。后代雏鸭母源抗体随日龄的增加逐渐降低,1日龄最高,21日龄后母源抗体消失。攻毒试验表明母源抗体对雏鸭具有一定的保护力。本研究为防治鸭传染性浆膜炎制定合理的疫苗免疫程序提供了实验依据。     

白术、微米白术和白术多糖对断奶仔猪生长性能和肠道形态及微生态区系的影响

试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。     

Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia

Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Y‐chromosomal variation of local goat breeds of Turkey close to the domestication centre

Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Feline intracranial neoplasia: retrospective review of 160 cases (1985-2001)

The purpose of this study was to determine the frequency of different tumor types within a large cohort of cats with intracranial neoplasia and to attempt to correlate signalment, tumor size and location, and survival time for each tumor. Medical records of 160 cats with confirmed intracranial neoplasia evaluated between 1985 and 2001 were reviewed. Parameters evaluated included age, sex, breed, FeLV/FIV status, clinical signs, duration of signs, number of tumors, tumor location(s), imaging results, treatment, survival times, and histopathologic diagnosis. Most of the cats were older (11.3 +/- 3.8 years). Primary tumors accounted for 70.6% of cases. Metastasis and direct extension of secondary tumors accounted for only 5.6 and 3.8% of cases, respectively. Twelve cats (7.5%) had 2 or more discrete tumors of the same type, whereas 16 cats (10.0%) had 2 different types of intracranial tumors. The most common tumor types were meningioma (n = 93, 58.1%), lymphoma (n = 23, 14.4%), pituitary tumors (n = 14, 8.8%), and gliomas (n = 12, 7.5%). The most common neurological signs were altered consciousness (n = 42, 26.2%), circling (n = 36, 22.5%), and seizures (n = 36, 22.5%). Cats without specific neurological signs were common (n = 34, 21.2%). The tumor was considered an incidental finding in 30 (18.8%) cats. In addition to expected relationships (eg, meninges and meningioma, pituitary and pituitary tumors), we found that lesion location was predictive of tumor type with diffuse cerebral or brainstem involvement predictive of lymphoma and third ventricle involvement predictive of meningioma.     

A brief history of the prevention of infectious diseases by immunisations

Infectious diseases have always been a terrible scourge for humans. The appearance of these plagues, as they were called without distinction, was generally connected to various conditions: asters, climatic changes or religious reasons. The concept of contagious, and then infectious, diseases came slowly. Variolation, i.e. transmission of ‘virulent’ matter to induce a natural disease and the immunity against it, was brought from Constantinople to England by Lady Montague, in 1721. This ‘variolation’ technique was also often performed in veterinary medicine against diseases like sheep-pox or pleuropneumonia. As ‘vaccination’ is the term generally accepted for ‘immunisation’, variolation can be the word designating such a technique. The second period of the history of immunisation began, in 1880, with the studies of Pasteur and his collaborators. A great number of bacterial vaccines were developed: dead, live but attenuated or only parts of pathogens. The viruses were produced in animals, then in eggs and at last, in tissue cultures. Second generation vaccines appeared with genetic engineering: recombinant vaccines, vector vaccines, nucleic acids vaccines, and markers vaccines, among others. These novel technologies can permit the development of new ones and improve the quality of the vaccines already existing.