首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献，搜索用时 187 毫秒
1.
应用日本血吸虫两种抗原疫苗免疫水牛的减虫率、肝组织虫卵的减少率和攻击前及解剖前的平均增重分别为：日本血吸虫冻融苗（Ｆ／Ｔ苗）组为６４．８％ 、８１．８％ 和２８．５ｋｇ、５５．３ｋｇ;日本血吸虫提纯抗原苗天然谷胱甘肽Ｓ－转移酶（ｎＧＳＴ 苗）组为３３．１９％ 、７９．７％ 和３７．８ｋｇ、６３．７ｋｇ  相似文献   

2.
从非流行区购进无蜱寄生的健康黄牛５头与水牛犊１头，其中３头成年黄牛（２～８岁）在畜舍内用从流行区水牛身上采得的镰形扇头蜱Ｒｈｉｐｉｃｅｐｈａｌｕｓｈａｅｍａｐｈｙｓａｌｏｉｄｅｓｈａｅｍａｐｈｙｓａｌｏｉｄｅｓ成虫，置于牛耳壳内叮咬；１头运至流行区放牧，让蜱上身叮咬；１头黄牛犊（１０年龄）去蜱后２周，用液氮保存的患病水牛染虫血４ｍｌ（４×１０ ８个虫体）皮下注射；另一头去蜱水牛犊亦同时注射相同剂量的染虫血，作为对照。５头黄牛在试验期间其体温、精神、食欲正常，未出现任何临床症状，感染后１０～１２ｄ外周血液中出现少量不典型的牛巴贝斯虫，红细胞染虫率在０．１％以下，持续３～５６消失；对照牛则体温升高（３９．８～４１．１℃），出现贫血、黄疸等症状，红细胞压积（ＰＣＶ）降至２６％，外周血液中出现典型的牛巴贝斯虫，红细胞染虫率（ＰＰＥ）高达１２％。对采用蜱叮咬及注射来自病水牛的染虫血为何不能使黄牛感染发病，文中进行了讨论。  相似文献   

3.
应用冷冻血清对１株采自自然感染的水牛牛巴贝斯虫进行了长达７２ｄ的体外连续培养，共继代２０次，培养７２ｈ红细胞染虫率最高达１４．１％，平均为８％～１０％。培养２０ｄ和３０ｄ的牛巴贝斯虫经液氮保存复苏后，接种于去脾水牛犊均引发了严重的牛巴贝斯虫病，从而说明已建立了水牛牛巴贝斯虫的体外连续培养，且经培养后的牛巴贝斯虫致病力没有改变。本试验利用６头份的冷冻健康水牛血清同时进行培养，结果发现，并非所有的健康水牛血清均适合于体外培养牛巴贝斯虫。这一发现对建立水牛牛巴贝斯虫的体外培养和研究水牛牛巴贝斯虫病均具有重要意义  相似文献   

4.
鸡Eimeria tenella致弱虫苗的实验研究及田间试验   总被引：1，自引：1，他引：0  
对双重致弱球虫疫苗(DLV虫苗)进行了实验室的安全试验。通过对380羽3日龄小鸡的3批毒力测定,强毒虫株2.5×10~4接种小鸡,死亡率均超过50％;DLV虫苗2.5×10~4剂量接种3批小鸡,未见明显临床表现。在鸡体连续5次传代,也未出现明显返强现象。通过对260羽3日龄小鸡的3批免疫试验证明,DLV虫苗对10×10~5强毒株的攻击有100％的保护率。又用ELISA法测定抗体效价消长发现,免疫后7周左右抗体效价达高峰,至14周抗体效价仍可保持在一定高度,足以对再感染具有保护力。该虫苗易于保存,一般在4℃可保存6个月以上,仍有良好的免疫效果。通过在上海、浙江、江苏、安徽等地区的田问试验,发现免疫鸡的平均发病率为2.8％,死亡率为0.48％。常规用药鸡平均发病率为11.8％,死亡率为2.9％。空白对照鸡(不用苗,不用药)平均发病率为80％,死亡率为28％(经及时抢救治疗减少了死亡率)。免疫鸡比常规用药鸡节省耗药费用0.20元/羽。在大批量扩大免疫试验中,对24,800羽鸡用苗后的平均保护率可达99.66％,死亡率为0.34％,效果十分显著。通过实验室和现场应用试验,证明DLV虫苗可靠、安全、稳定,且有高度免疫原性和足够的抗体水平及免疫期。  相似文献   

5.
在对当地黄牛采取人工杂交改良过程中,根据不同品种公牛的冻精将母牛群分组,并统计各组母牛的受胎率、牛犊的难产率、繁殖成活率和出生时的体尺、体重。统计结果表明:各组间母牛的受胎率均无明显差异 (P>0.05);牛犊的繁殖成活率也具有相同的结果。但各组杂种牛犊的难产率均高于土种黄牛值,并且F1 (西门塔尔×黄牛 )和F1 (荷斯坦×黄牛)的值与对照组差异显著(P<0.05),F1 (皮埃蒙特牛×黄牛)的值与对照组差异不显著 (P>0.05)。牛犊额头宽度与牛犊的难产率之间呈正相关(r=0. 830 4)。  相似文献   

6.
为了从7 d童虫cDNA文库筛选出童虫发育阶段特异性表达抗原基因。本研究首先构建了日本血吸虫7 d童虫cDNA文库,其次再采用日本吸血虫感染血清进行筛选。结果显示:建立的文库插入片段为0.5~3.0 kb,文库重组率为98%,初始文库滴度为2.4×10~6 pfu/mL,扩增后滴度为1.6×10~9 pfu/mL,利用感染日本血吸虫10 d和42 d的小鼠血清免疫筛选该文库,初筛和复筛后获得17条有效EST序列,其编码7个基因,分别为复制蛋白(2 ESTs)、肝再生增强因子(3 ESTs)、血小板活化因子(6 ESTs)、钙调理蛋白基因(3 EST)、丝束蛋白(1 ESTs)、核糖体RNA(1 EST)和还原型辅酶脱氢酶基因(1 EST)。该研究结果对今后探讨血吸虫的生长发育机制及筛选血吸虫早期诊断抗原具有重要意义。  相似文献   

7.
用于预防畜禽传染病和寄生虫病的免疫制剂 ,简称为“苗” ,目前共有三大类 ,即疫苗、菌苗和虫苗。疫苗有广义、狭义两种概念 ,广义泛指疾病免疫制剂和非疾病免疫制剂 ,狭义指用病毒免疫物质制成的免疫制剂 ;菌苗是指用细菌免疫物质制成的免疫制剂 ;虫苗是指用寄生虫免疫物质制成的免疫制剂。虫苗的研制是近十几年的事 ,由于起步较晚 ,目前国内外的定型产品尚寥寥无几。但由于是养殖业急需的防病制剂 ,故有强大的市场竞争力。目前国内已研制出的虫苗有以下几种 :(1)鸡柔嫩艾美耳球虫弱毒虫苗　是预防鸡柔嫩艾美耳球虫病的虫苗 ,系上海农科院…  相似文献   

8.
以小鼠为模型评价了利什曼原虫灭活苗的免疫保护效果。将利什曼原虫甲醛灭活后制备灭活疫苗,单独或与质粒pVAX/mIL-18联合经肌肉注射免疫小鼠,共免疫2次,间隔2周;同时以PBS作为对照。ELISA检测抗体表明,利什曼原虫灭活疫苗单独或与pVAX/mIL-18联合免疫可以诱导小鼠产生较强的抗利什曼原虫的IgG。免疫接种4周后通过尾静脉攻击利什曼原虫,联合免疫的减虫率达47.7%,单独免疫组减虫率达到31.4%;质粒pVAX/mIL-18组减虫率达到29.1%,灭活苗与pVAX/mIL-18联合免疫组肝脏负荷都要显著低于其它组(P0.05)。表明灭活苗与pVAX/mIL-18联合免疫组对Balb/c小鼠有一定的保护力,具有一定预防利什曼原虫感染的作用。  相似文献   

9.
本文介绍对广东顺德市两个球虫病重病区鸡场的苗鸡进行了两批试验,每个场的试验苗鸡均分为3个组,组1应用DLV虫苗(为球虫病三价双重致弱活疫苗)拌料口服免疫,不再服药。组2于服苗后期采用优化组合配伍用药连续2天,优化组合用药, 为球R0.5×10-6 氨丙啉合剂(20 2)×10-6, 为球R1.0×10-6 巴卡巴嗪80×10-6。组3为空白对照组。结果:两批试验中两组用苗组不用药的死亡率分别为4.5%、4.3%;两组用苗免疫后再连续2天分别应用 、 两种优化组合药后,即完全控制了球虫病。结论:在虫苗免疫效果较差的鸡中给予短期小剂量优化组合用药即可提高DLV虫苗防治球虫病的效果。  相似文献   

10.
水牛巴贝斯虫病病原—牛巴贝斯虫体外培养的研究   总被引：7，自引：1，他引：6  
本研究采用微气静相培养技术,对一株采自人工感染的去脾脏水牛犊的牛巴贝斯虫(Babesia bovis)进行了80天的连续体外培养·继代26次,累积增殖6.51×10~((?))倍;累积稀释2.19×10~(35)倍。培养24小时红细胞的染虫率为2.63±0.50％;48小时为7.18±1.39％;72小时为20.78±4 52％。最高红细胞染虫率达33.50％。体外培养的牛巴贝斯虫与采自病牛血液内的牛巴贝斯虫形态一致,说明已建立了水牛巴贝斯虫病病原——牛巴贝斯虫的体外培养。 对影响牛巴贝斯虫体外培养的几种因素进行的实验结果表明:培养液pH值显著地影响虫体的繁殖,最适的体外连续培养的pH为7.2;合适的血清浓度为40％;血清灭活后,支持牛巴贝斯虫生长繁殖的能力明显降低;脱纤血分离的血清和自然凝固血析出的血清用于培养的效果相同;RPMI-1640和TCM-199培养液支持牛巴贝斯虫生长繁殖的能力没有差异。  相似文献   

11.
Progress in the development of tuberculosis vaccines for cattle and wildlife   总被引：11，自引：0，他引：11  
Vaccination against bovine tuberculosis is likely to become an important disease control strategy in developing countries, which cannot afford a test and slaughter control programme, or in countries which have a wildlife reservoir of Mycobacterium bovis infection. In the past decade, considerable progress has been made in the development and evaluation of tuberculosis vaccines for cattle and for a range of wildlife maintenance hosts including possums, badgers, deer and African buffaloes. Experimental challenge systems have been established for the different target species and the resulting disease process has mimicked that seen in the field. In cattle, neonatal vaccination with BCG appeared to be more effective than vaccination of 6-month-old calves and in most situations no other vaccine has been shown to be better than BCG. However, prime-boost strategies involving combinations of BCG with a protein or DNA vaccine, to improve on BCG vaccination alone, have produced very encouraging results. Differential diagnostic tests have been developed using mycobacterial antigens that are only present in virulent M. bovis to differentiate between BCG-vaccinated and M. bovis-infected cattle. BCG vaccine has been shown to reduce the spread of tuberculous lesions in a range of wildlife species and a prototype oral bait delivery system has been developed. Prospects for the development of improved vaccines against bovine tuberculosis are promising and vaccination approaches could become very valuable in the control and eradication of bovine tuberculosis.  相似文献   

12.
The safety, efficacy and cross-protectivity of a live intranasal aerosol haemorrhagic septicaemia vaccine containing Pasteurella multocida serotype B:3,4 were tested in young cattle and buffaloes in Myanmar, where more than 1.5 million animals had been inoculated with this vaccine between 1989 and 1999. A recommended dose of 2 x 10(7) viable organisms was used for the efficacy test. The administration of 100 times the recommended dose to 50 cattle and 39 buffalo calves was innocuous. Seven months after they were vaccinated, three of three buffaloes were protected and 12 months after they were vaccinated, three of four buffaloes were protected against a subcutaneous challenge with serotype B:2 which killed three of three unvaccinated buffaloes. Twelve months after they were vaccinated, eight of eight cattle survived a serotype B:2 challenge, which killed four of four unvaccinated controls. The vaccinated cattle had developed serum antibodies detectable by the passive mouse protection test. Indirect haemagglutination tests on sera taken from cattle 10 days and five weeks after they were vaccinated showed high titres of antibodies. The serum of vaccinated cattle cross-protected passively immunised mice against infection with P. multocida serotypes E:2, F:3,4 and A:3,4.  相似文献   

13.
This study was completed to determine the prevalence and distribution of Toxocara vitulorum infection in cattle and buffalo calves and investigate its clinical impact in northern Lao PDR (Peoples Democratic Republic). The results aim to assist decisions on disease control measures that can contribute to increasing cattle and buffalo productivity within smallholder farming systems in tropical areas. A prevalence survey for T. vitulorum in buffalo and cattle calves aged <3 months was conducted between September 2009 and June 2010 in five provinces of northern Lao PDR using a two-stage sampling technique to select 69 villages and 899 calves, with faecal samples collected and examined for T. vitulorum eggs at a local laboratory. At the time of sampling, data on calf morbidity and anthelmintic treatment was also collected. Factors potentially associated with infection and severity of infection were analyzed at univariable and multivariable levels, using T. vitulorum status (positive/negative) and on the positive calves only, faecal egg count levels as outcome variables. The estimated prevalence of T. vitulorum in northern Lao was 22.6 % (95 % confidence interval [CI], 0.17–0.28), and 76.8 % of villages had at least one positive calf. Province was the only significant (p?<?0.05) variable investigated associated with calf infection status. Species (buffalo) was the only variable significantly (p?<?0.05) associated with higher egg per gram of faeces levels among infected calves. Prevalence in calves aged 1–21 days, the reported prepatent period, was 17.5 % (CI 0.11–0.24). Treatment levels were very low (8.2 %) and if treatment occurred it was mostly unsuccessful. The high and wide spread infection of T. vitulorum in cattle and buffalo calves identified in this survey is likely to result in suboptimal cattle and buffalo productivity. Improved management of T. vitulorum infection in cattle and buffalo calves in northern Lao PDR is indicated to reduce potential negative production impacts and enable more efficient development of large ruminant livestock industry as a pathway from rural poverty for smallholder farmers in northern Lao PDR. In addition to quantifying this disease problem in calves, the conduct of this applied participatory research study provided an important opportunity to improve animal health services by increasing the parasite, large ruminant handling and research knowledge and capacity of government animal health staff and farmers.  相似文献   

14.
The infectivity of a Theileria parva lawrencei stabilate, from a stock derived from an African buffalo (Syncerus caffer) in the Serengeti National Park, Tanzania, was investigated. In the first experiment a buffalo and three cattle were inoculated with a stabilate from a stock passaged three times in cattle. All cattle developed fatal theilerial infections. Isolations from the buffalo by tick feeding and cell culture isolation showed that it was infected with T p lawrencei at the time of inoculation, but the second isolation made 19 days after inoculation behaved like T p parva in cattle, developing a high parasitosis, while the third isolation made three months later behaved like T p lawrencei with low parasitosis. It was concluded that two biological types of T parva could exist in a buffalo at one time, but it was not shown that the buffalo had become a carrier of T p lawrencei adapted to cattle. In the second experiment two buffaloes and three cattle were inoculated with T p lawrencei (Serengeti) stabilate which had been passaged six times through cattle and ticks. The two buffaloes had mild theilerial infections and developed serological titres in the indirect fluorescent antibody test, but the cattle had fatal infections. Tick and cell culture isolations of T parva were possible during the clinical reactions of the buffaloes, but no carrier state was demonstrated. Theileria-infected cell lines were established from the buffaloes and the cattle and were examined using monoclonal antibodies against T parva schizonts.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

15.
Toxocara vitulorum, a nematode parasite in the small intestine of cattle and water buffaloes, causes high morbidity and mortality of 1-3 months old buffalo calves. This research evaluated the specific perieneteric antigens (Pe) reactivity of anti-T. vitulorum-Pe antibody (Tv-Pe-Ab) in both immune sera and colostrum from buffalo cows immediately post-partum from buffalo cows. The presence of Tv-Pe-Ab in sera of buffalo newborn calves was also examined at 1 day before and after suckling the colostrum as well as in sera from naturally infected calves at the beginning and peak of the maximum infection and then again during the period of rejection and post-rejection of the parasite. Pe antigens were characterized for Tv-Pe-Ab by SDS-PAGE and Western blot (WB). The SDS-PAGE showed that Pe contained nine protein bands (11, 14, 31, 38, 58, 76, 88, 112 and 165 kDa). All Pe bands were recognized by Tv-Pe-Ab in sera and colostrum of buffalo cows. Only the serum antibodies of buffalo calves at 1 day of age after suckling the colostrum and during the beginning of T. vitulorum infection recognized Pe antigen's nine bands. In contrast, serum antibodies from 1-day-old buffalo calves, taken before suckling colostrum, did not react with any protein band. In suckling calves, which reached peak egg output, rejection and post-rejection stages of the infection, serum Tv-Pe-Ab reactivity with lower molecular weight protein bands (11-76 kDa) was lost and only reactivity with the Pe protein bands of higher molecular weight (88, 112 and 165 kDa) remained.  相似文献   

16.
The protective capacity of an adult stage Ostertagia ostertagi globin antigen was tested in four vaccination experiments in cattle. In a preliminary experiment, calves were vaccinated three times intraperitoneally with 250 microg globin in Freund's adjuvant and challenged with a trickled infection of 25,000 infective larvae. In three subsequent field studies, calves were vaccinated twice or three times intramuscularly with 80-100 microg globin in Quil A and challenged with a natural gastrointestinal nematode infection on pasture. Higher globin-specific antibody levels were detected in the vaccinated calves than in the control animals in all vaccine trials. In the preliminary experiment, geometric mean cumulative egg counts in the globin group were reduced by 52% and total worm burdens were reduced by 28%, compared to the controls. In the first field trial cumulative faecal egg counts were reduced by 63% in the vaccinated calves. However, the reduction in faecal egg output in these two experiments was not statistically significant and no reduction in faecal egg counts was observed in the vaccinated animals in the two last field trials. In conclusion, vaccination of calves with O. ostertagi globin resulted in highly variable protection levels after challenge infection.  相似文献   

17.
Wu Z  Liu S  Zhang S  Tong H  Gao Z  Liu Y  Lin D  Liu Z  Wu G  Yi H  Song G  Xu Y 《Veterinary parasitology》2004,123(3-4):167-177
To observe the long lasting effect of the recombinant Sj26GST sub-unit vaccine against Schistosoma japonicum in cattle, animals aged from 5 to 12 months were vaccinated with reSjc26GST, and were challenged by natural infection 6 months or 12 months after vaccination. Worm burdens per cattle and egg burden in tissue (per gram) of cattle with or without vaccination were compared. The results showed that anti-reSjc26GST antibodies were produced in vaccinated cattle. Following natural infection, the vaccinated and the control non-vaccinated cattle were all found to be infected with S. japonicum. A 30% reduction in worm number was observed in the vaccinated cattle when compared with the control cattle. The anti-fecundity effect was characterized by an average of 60% decrease in eggs deposited in the liver of vaccinated cattle; such a decrease is obviously very significant. In addition to the anti-fecundity effect induced in the vaccinated cattle, the number of miracidum hatched per 50 g faeces and the number of eggs released in intestinal tissues per gram were reduced or decreased. Results suggested that the immune responses induced by reSjc26GST in cattle were similar to that in buffaloes and in pigs. In addition, our result demonstrated that the lasting effect of immunity to S. japonicum induced in cattle after vaccination with reSjc 26 GST could persist at least 12 months.  相似文献   

18.
Mycobacterium bovis bacille Calmette-Guérin (BCG) delivered to calves by the oral route in a formulated lipid matrix has been previously shown to induce protection against bovine tuberculosis. A study was conducted in cattle to determine if a combination of a low dose of oral BCG and a protein vaccine could induce protective immunity to tuberculosis while not sensitising animals to tuberculin. Groups of calves (10 per group) were vaccinated by administering 2 × 10(7)colony forming units (CFU) of BCG orally or a combination of 2 × 10(7)CFU oral BCG and a protein vaccine comprised of M. bovis culture filtrate proteins (CFP) formulated with the adjuvants Chitin and Gel 01 and delivered by the intranasal route, or CFP formulated with Emulsigen and the TLR2 agonist Pam(3)CSK(4) and administered by the subcutaneous (s.c.) route. Two further groups were vaccinated with the CFP/Chitin/Gel 01 or CFP/Emulsigen/Pam(3)CSK(4) vaccines alone. Positive control groups were given 10(8)CFU oral BCG or 10(6)CFU s.c. BCG while a negative control group was non-vaccinated. All animals were challenged with M. bovis 15 weeks after vaccination and euthanized and necropsied at 16 weeks following challenge. Groups of cattle vaccinated with s.c. BCG, 10(8)CFU or 2 × 10(7)CFU oral BCG showed significant reductions in seven, three and four pathological or microbiological disease parameters, respectively, compared to the results for the non-vaccinated group. There was no evidence of protection in calves vaccinated with the combination of oral BCG and CFP/Emulsigen/Pam(3)CSK(4) or oral BCG and CFP/Chitin/Gel 01 or vaccinated with the protein vaccines alone. Positive responses in the comparative cervical skin test at 12 weeks after vaccination were only observed in animals vaccinated with s.c. BCG, 10(8)CFU oral BCG or a combination of 2 × 10(7)CFU oral BCG and CFP/Chitin/Gel 01. In conclusion, co-administration of a protein vaccine, administered by either systemic or mucosal routes with oral BCG did not enhance the protection conferred by administration of oral BCG alone.  相似文献   

19.
Bovine herpesvirus type 5 (BoHV-5) is the causative agent of bovine herpetic encephalitis. In countries where BoHV-5 is prevalent, attempts to vaccinate cattle to prevent clinical signs from BoHV-5-induced disease have relied essentially on vaccination with BoHV-1 vaccines. However, such practice has been shown not to confer full protection to BoHV-5 challenge. In the present study, an inactivated, oil adjuvanted vaccine prepared with a recombinant BoHV-5 from which the genes coding for glycoprotein I (gI), glycoprotein E (gE) and membrane protein US9 were deleted (BoHV-5 gI/gE/US9−), was evaluated in cattle in a vaccination/challenge experiment. The vaccine was prepared from a virus suspension containing a pre-inactivation antigenic mass equivalent to 107.69 TCID50/dose. Three mL of the inactivated vaccine were administered subcutaneously to eight calves serologically negative for BoHV-5 (vaccinated group). Four other calves were mock-vaccinated with an equivalent preparation without viral antigens (control group). Both groups were boostered 28 days later. Neither clinical signs of disease nor adverse effects were observed during or after vaccination. A specific serological response, revealed by the development of neutralizing antibodies, was detected in all vaccinated animals after the first dose of vaccine, whereas control animals remained seronegative. Calves were subsequently challenged on day 77 post-vaccination (pv) with 109.25 TCID50 of the wild-type BoHV-5 (parental strain EVI 88/95). After challenge, vaccinated cattle displayed mild signs of respiratory disease, whereas the control group developed respiratory disease and severe encephalitis, which led to culling of 2/4 calves. Searches for viral DNA in the central nervous system (CNS) of vaccinated calves indicated that wild-type BoHV-5 did not replicate, whereas in CNS tissues of calves on the control group, viral DNA was widely distributed. BoHV-5 shedding in nasal secretions was significantly lower in vaccinated calves than in the control group on days 2, 3, 4 and 6 post-challenge (pc). In addition, the duration of virus shedding was significantly shorter in the vaccinated (7 days) than in controls (12 days). Attempts to reactivate latent infection by administration of dexamethasone at 147 days pv led to recrudescence of mild signs of respiratory disease in both vaccinated and control groups. Infectious virus shedding in nasal secretions was detected at reactivation and was significantly lower in vaccinated cattle than in controls on days 11–13 post-reactivation (pr). It is concluded that the inactivated vaccine prepared with the BoHV-5 gI/gE/US9− recombinant was capable of conferring protection to encephalitis when vaccinated cattle were challenged with a large infectious dose of the parental wild type BoHV-5. However, it did not avoid the establishment of latency nor impeded dexamethasone-induced reactivation of the virus, despite a significant reduction in virus shedding after challenge and at reactivation on vaccinated calves.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号