猪支原体肺炎活疫苗(RM48株)的最小免疫剂量测定及活菌滴度与免疫保护率平行关系试验

为确定猪支原体肺炎活疫苗(RM48株)的最小免疫剂量,使用两批该疫苗(活菌滴度均为108CCU/m L)分别用原倍、10倍、100倍和1000倍稀释,以胸腔注射和鼻腔接种两种方式各免疫4头仔猪,45 d后攻毒,70 d后剖杀观察结果。结果表明其中一批疫苗4个稀释度胸腔注射组的攻毒保护率分别为78%、77.6%、68.8%和55.2%,鼻腔接种组分别为70.6%、68.1%、58.4%和18.4%;另一批的胸腔注射组攻毒保护率分别为80.6%、78.8%、67.6%和52.4%,鼻腔接种组分别为71.6%、68.4%、53.5%和28.4%。按照判定标准,可将该疫苗的胸腔注射接种最小免疫剂量确定为106CCU/头,鼻腔接种最小免疫剂量确定107CCU/头,同时结果也证明免疫保护率与活菌滴度间在测定范围内具有很好的平行关系。     

关于制订种鸭场免疫程序的几点建议

使用多种疫苗来预防不同的传染病时,需要根据各种疫苗的免疫特性来合理地制订预防接种的次数和间隔时间,即免疫程序,其主要内容包括疫苗种类、接种时间或接种动物日龄、接种方法、剂量、不同疫苗之间的间隔时间、同一种疫苗二次接种间隔的时间等。     

浅谈疫苗的使用

接种疫苗是有效控制动物传染性疾病的主要手段,通过注意疫苗选择、疫苗质量、疫苗接种方法、接种注意事项等,使其达到最佳的免疫效果。     

如何使用好猪口蹄疫疫苗

近几年来,国内外动物疫情不断发生,我国对口蹄疫等重大疫病实施了强制免疫。随着动物免疫的全面开展,提高了免疫密度,但是相对疫苗反应增多。疫苗反应一般在接种口蹄疫疫苗后1min至24h出现过敏反应。如何接种猪口蹄疫疫苗、接种后的过敏反应主要症状是什么,应如何处理？笔者根据临床实际的情况总结如下。     

如何使用好猪口蹄疫疫苗

近几年来,国内外动物疫情不断发生,我国对口蹄疫等重大疫病实施了强制免疫。随着动物免疫的全面开展,提高了免疫密度,但是相对疫苗反应增多。疫苗反应一般在接种口蹄疫疫苗后1min至24h出现过敏反应。如何接种猪口蹄疫疫苗、接种后的过敏反应主要症状是什么,应如何处理？笔者根据临床实际的情况总结如下。     

正确接种疫苗 呵护孩子健康（防疫知识问答之二）

9、问：国家扩大免疫规划的内容有哪些？ 答：国家扩大免疫规划,通俗地讲就是根据疾病控制需要．政府免费提供更多种类的疫苗供公众主要是儿童进行接种．而家长也必须按照国家规定的免疫程序及时为自己的孩子接种这些疫苗。国家下一步实施的扩大免疫规划的内容主要为：     

畜禽免疫失败的原因调查及应对措施

在生产实践中,畜禽接种疫苗后免疫效果不佳或出现免疫失败的情况时有发生,给畜禽疫病防控带来一定的困难.主要从疫苗质量、疫苗稀释过程、免疫程序、接种途径、免疫操作、疫苗间的干扰作用及药物干扰等方面分析了导致免疫失败的原因,并提出了相应的应对措施,以期为有效预防免疫失败的发生提供参考.     

影响生猪免疫效果的因素及应对措施

在生猪免疫工作中,经常遇到接种了某种疫苗后,仍发生该传染病。因此,如何加强疫苗的生产、运输、保管、使用等环节上的管理,不断提高疫苗的效价、免疫质量已成为当前防疫工作亟待解决的问题。     

雏鸡禽流感不同免疫方式的研究

目前,我国广泛应用禽流感疫苗来预防禽流感的发生和传播,但就不同种疫苗免疫效果、不同免疫方式以及与其他疫苗同时接种的免疫效果的研究较少.     

鸡场免疫失败的原因及其对策

鸡场免疫失败的原因主要有雏鸡母源抗体的干扰、疫苗质量问题、接种方法不合适、疫苗联合应用不当、传染性疾病的干扰、免疫空白期、免疫程度不合理等。为了保证免疫效果,在生产实践中应做到制订合理的切实可行的免疫程序、减少应激、采用正确的免疫操作方法和接种途径,以及实行综合性防治等措施。     

Vaccinal control of Marek's disease: current challenges, and future strategies to maximize protection

Marek's disease is an economically important lymphoid neoplasm of chickens, caused by oncogenic strains of Marek's disease herpesvirus. The disease can be successfully controlled by vaccination with attenuated or non-pathogenic MDV strains. However, vaccine failures do occur as field strains continue to evolve towards pathotypes of greater virulence, and this evolution is likely to be driven by the vaccines themselves. Two general strategies can be considered to improve protection by vaccination. Firstly by the development of novel vaccines, and secondly by maximizing the potential of existing vaccines. This second goal requires investigation of optimal timing and vaccine delivery route, and optimal vaccination regimes for different breeds of chick. Accurate quantitation of Marek's disease vaccine virus in vaccinated chicks will contribute significantly to our understanding of vaccinal protection. We recently developed a real-time polymerase chain reaction (PCR) assay for quantitation of CVI988 vaccine virus in the feather tips, a rich source of viral DNA which can easily be sampled in a non-invasive manner. This PCR test is now used commercially to confirm the successful vaccination of chicks. We have also used the PCR to examine various aspects of vaccination in experimental chicks and commercial chicks with a view to determining how vaccine level in feathers correlates with protection against challenge, and for identifying optimal timing and vaccine delivery route, and optimal vaccination regimes for different breeds of chick. In this article we review some aspects of the current vaccinal control of Marek's disease, before highlighting some of the problems associated with current vaccines and vaccination strategies, and the challenges for the future. We go on to discuss the development and use of our real-time PCR feather test, its current applications and potential opportunities in Marek's disease vaccine research.     

禽类DNA疫苗研究进展

新型疫苗的研究对于禽类传染病的防制意义重大。传统疫苗是基于抗原刺激机体产生特异性抗体的原理,它们大多数激发机体的体液免疫,很难启动细胞免疫。脱氧核糖核酸(DNA)疫苗作为第3代疫苗,具备传统疫苗和其它基因工程苗不可比拟的优点,能够诱导全方位的免疫反应且使用更安全更方便,DNA疫苗是将外源基因与真核质粒重组后直接导入细胞内,使外源基因在宿主细胞内表达合成保护性抗原蛋白。这是模拟病毒自然感染提呈过程,既能产生细胞免疫,又能产生体液免疫。文章对DNA疫苗在禽类应用的可行性和应用研究新进展作了综述。     

NALT (nasal cavity-associated lymphoid tissue) in the rabbit

Due to its many advantages, interest in intranasal vaccination of domestic mammals and humans is currently increasing. Successful stimulation of the immune system by intranasal vaccines requires, however, the presence of lymphoid tissue in the nasal cavity. This nasal cavity-associated lymphoid tissue (NALT) has already been described in humans and many laboratory rodents, but data about rabbits are very scarce. For this purpose, histological sections of the nasal cavities of 10 female adult New Zealand White rabbits were examined for the presence of lymphoid tissue. Primary (I) and secondary (II) lymphoid follicles divided by interfollicular regions were mainly present at the bottom of the ventral nasal meatus and the nasopharyngeal meatus from 1 to 3.3 cm from the tip of the nose. In this region intraepithelial and lamina propria lymphocytes, and isolated lymphoid follicles (ILF's) were additionally seen at the dorsal and dorsolateral sides of the nasopharyngeal meatus and within the mucosae of the nasal conchae and the lateral nasal walls. Intraepithelial and lamina propria lymphocytes, and ILF's were, just like in humans, randomly distributed along the entire nasal mucosa. The rabbit NALT is more voluminous compared to rodents in which lymphoid tissue is only present at the bottom of the nasopharyngeal meatus. Since the relative volume of the rabbit nasal cavity is also similar to that of humans, the rabbit could be a valuable research model not only for animal but also for human intranasal vaccine development.     

牛传染性鼻气管炎疫苗的研究进展

牛传染性鼻气管炎(infectious bovine rhinotracheitis,IBR)是由牛传染性鼻气管炎病毒(infectious bovine rhinotracheitis virus,IBRV)即牛疱疹病毒1型(BoHV-1)感染所引起的一种高度接触性传染病。该病给我国养牛业带来了巨大的经济损失。由于缺乏有效的治疗性药物,疫苗免疫仍然是防控该病的有效措施。当前,牛传染性鼻气管炎疫苗主要包括灭活疫苗、弱毒疫苗2种常规疫苗和亚单位疫苗、DNA疫苗、IBRV基因缺失疫苗、病毒活载体疫苗4种基因工程疫苗,各种疫苗各有优点。现对上述疫苗的最新研究进展进行综述,以期为IBRV疫苗的研究与开发提供参考。     

Rationale and perspectives on the success of vaccination against bovine herpesvirus-1

Several characteristics of BHV-1 have contributed to the successful development of both conventional and marker vaccines. BHV-1 is a stable virus, which grows to high titers in vitro, has a limited host range and causes acute viremic infections. Furthermore, the protective antigens, as well as the antigens that are suitable as marker, are present in the predominant virus isolates and induce significant and long-lasting immune responses, both in na?ve and in previously vaccinated animals. In many parts of the world including North-America control of BHV-1 is achieved by vaccination with conventional attenuated or inactivated vaccines. With parts of Europe being BHV-1 free, the ability to differentiate infected from vaccinated animals has become critical as a trading tool. Live and killed gE-deleted marker vaccines are now widely used in Europe, in combination with gE-based diagnostic tests to monitor cattle. However, several issues remain to be resolved. BHV-1 causes latency, which creates a need for stringent management practices in case eradication is to be achieved. Since intramuscular delivery with a syringe and needle leads to considerable tissue damage, needle-free delivery methods should be adopted for beef cattle. Furthermore, conventional inactivated and attenuated vaccines are less efficacious in neonates, so alternative vaccine types such as CpG adjuvanted protein vaccines or DNA vaccines are required for effective vaccination of this age group.     

Mucosal vaccination: lung versus nose

The induction of potent mucosal immune responses able to prevent the establishment of infection at the onset of mucosal pathogen colonisation represents a desirable but challenging goal for vaccine development. Here we compare nasal vaccine delivery with intra-pulmonary vaccination using a sheep lymphatic cannulation model. Our results demonstrate that nasal delivery of a non-infective ISCOMATRIX(?) influenza vaccine does not induce primary immune responses in the lymph draining the nasal lymph nodes, suggesting that local immune responses in the lymph nodes draining the nasal cavity are relatively weak. However, this mode of delivery can boost existing immunity in the nasal lymph. Using the same adjuvant we were able to induce very potent immune responses in both blood and bronchoalveolar lavage (BAL), following intra-pulmonary delivery of ISCOMATRIX(?) influenza vaccine, even when very small doses of antigen were employed. Lung delivery could also induce comparable immune responses against other recombinant antigens mixed with ISCOMATRIX(?) adjuvant and could therefore become a method of choice for the induction of immunity to mucosal pathogens infecting the lower respiratory tract.     

A study on latency in calves by five vaccines against bovine herpesvirus-1 infection

Four bovine herpesvirus-1 (BHV-1) commercial vaccines, three of which (vaccines B, D, E) were modified live vaccines (MLV) and one (vaccine A) identified as a live strain of BHV-1 gE negative, were used for vaccination of calves, using three calves for each vaccine. Three months after vaccination calves were subjected to dexamethasone (DMS) treatment following which virus was recovered from calves inoculated with vaccine B and from those given vaccine D. No virus reactivation was obtained in calves, which received vaccines A or E. The DNA extracted from the two reactivated viruses was subjected to restriction endonuclease analysis. The restriction pattern of the isolate obtained from calves vaccinated with vaccine D differs significantly from that of the original vaccine, whereas the reactivated virus from calves given vaccine B conserved the general pattern of the original vaccine strain. For each reactivated virus in this experiment (B and D) as well as for the isolate obtained from calves vaccinated with a further MLV (vaccine C) in a previous trial, three calves were inoculated. No clinical signs of disease were detected in any of the inoculated calves during the observation period. When the nine calves were exposed 40 days later to challenge infection with virulent BHV-1, they remained healthy and no virus was isolated from their nasal swabbings. These results indicate that some BHV-1 vaccines considered in the project can establish latency in the vaccinated calves, however, the latency does not appear to interfere with the original properties of the vaccines in terms of safety and efficacy.     

Response of calves to challenge exposure with virulent bovine respiratory syncytial virus following intranasal administration of vaccines formulated for parenteral administration

OBJECTIVE: To determine whether single-fraction and combination modified-live bovine respiratory syncytial virus (BRSV) vaccines commercially licensed for parenteral administration could stimulate protective immunity in calves after intranasal administration. DESIGN: Randomized controlled trial. ANIMALS: 39 calves. PROCEDURES: Calves were separated from dams at birth, fed colostrum with a minimal concentration of antibodies against BRSV, and maintained in isolation. In 2 preliminary experiments, 9-week-old calves received 1 (n = 3) or 2 (3) doses of a single-component, modified-live BRSV vaccine or no vaccine (8 control calves in each experiment), and were challenged with BRSV 21 days after vaccination. In a third experiment, 2-week-old calves received combination modified-live virus (MLV) vaccines with or without BRSV and calves were challenged with BRSV 8 days later. Calves were euthanized, and lung lesions were measured. Immune responses, including serum and nasal antibody and nasal interferon-alpha concentrations, were assessed. RESULTS: BRSV challenge induced signs of severe clinical respiratory tract disease, including death and pulmonary lesions in unvaccinated calves and in calves that received a combination viral vaccine without BRSV. Pulmonary lesions were significantly less severe in BRSV-challenged calves that received single or combination BRSV vaccines. The proportion of calves that shed virus and the peak virus titer was decreased, compared with control calves. Protection was associated with mucosal IgA antibody responses after challenge. CONCLUSIONS AND CLINICAL RELEVANCE: Single and combination BRSV vaccines administered intranasally provided clinical protection and sparing of pulmonary tissue similar to that detected in response to parenteral delivery of combination MLV and inactivated BRSV vaccines previously assessed in the same challenge model.     

Duration of immunity (DOI) and booster vaccination--dealing with the issue at practice level in the UK

The presentation offers a UK veterinary practitioners viewpoint on issues of DOI and booster vaccination with reference to both dog and cat vaccines. The current use of vaccines and issues surrounding their use are discussed, including motivations for and against vaccinating in a climate of reduced fear of disease, and increased suspicion of vaccines. Attitudes to extended DOI and routine booster vaccinations are explored, and specific disease and prevention issues concerning leptospirosis in particular are presented. The strategy and tactics of implementation of extended DOI vaccines at general practice level are discussed based on the author's own experiences, and thoughts offered on how vaccine manufacturers might support the process at local and national levels, as well as communicating a positive message for continued routine vaccination of dogs and cats, and the advantages that extended DOI offers.     

Bordetella rhinitis in pigs: serum and nasal antibody response to Bordetella bacterins.

The nasal and serum antibody response of two groups of pigs, vaccinated with adjuvant containing formalinized or sonicated Bordetella bronchiseptica bacterins was compared with the response of a nonvaccinated group. The tube agglutination test was used to determine agglutinin titers. Following vaccination, all pigs were challenged intranasally with the vaccine strain of Bordetella, after which the nasal Bordetella flora of vaccinated and nonvaccinated pigs was investigated. Sera and nasal secretions from both vaccinated groups exhibited markedly higher agglutinin titers than the control group and serum titers were higher than those in nasal secretions. No differences in agglutinating antibody response were evident between the two vaccines. Serum antibody titers exceeded nasal titers and persisted over a longer period of time. Systemic vaccination resulted in an increased nasal clearance of the vaccine strain by the groups of pigs vaccinated with sonicated or formalined bacterin, whereas no such clearance was evident in the nonvaccinated control group.