Vaccination of pregnant cows with K99 antigen of enterotoxigenic Escherichia coli and protection by colostrum in newborn calves

The immune response to the K99 was tested in 45 pregnant cows, subcutaneously vaccinated, for protecting the newborn calves. Serological tests were performed in the blood sera of all animals and in the milk and colostrum sera; hemogram, inhibition of the adhesion to the brush border and histological tests were performed. The calves from vaccinated cows survived the experimental infection after the suction of colostrum in spite of the fact that the calves from control dams died with diarrhea.     

Diagnosing feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) infection: an update for clinicians

With the commercial release in Australia in 2004 of a vaccine against feline immunodeficiency virus (FIV; Fel‐O‐Vax FIV®), the landscape for FIV diagnostics shifted substantially. Point‐of‐care (PoC) antibody detection kits, which had been the mainstay for diagnosing FIV infection since the early 1990s, were no longer considered accurate to use in FIV‐vaccinated cats, because of the production of vaccine‐induced antibodies that were considered indistinguishable from those produced in natural FIV infections. Consequently, attention shifted to alternative diagnostic methods such as nucleic acid detection. However, over the past 5 years we have published a series of studies emphasising that FIV PoC test kits vary in their methodology, resulting in differing accuracy in FIV‐vaccinated cats. Importantly, we demonstrated that two commercially available FIV antibody test kits (Witness? and Anigen Rapid?) were able to accurately distinguish between FIV‐vaccinated and FIV‐infected cats, concluding that testing with either kit offers an alternative to PCR testing. This review summarises pertinent findings from our work published in a variety of peer‐reviewed research journals to inform veterinarians (particularly veterinarians in Australia, New Zealand and Japan, where the FIV vaccine is currently commercially available) about how the approach to the diagnosis of FIV infection has shifted. Included in this review is our work investigating the performance of three commercially available FIV PoC test kits in FIV‐vaccinated cats and our recommendations for the diagnosis of FIV infection; the effect of primary FIV vaccination (three FIV vaccines, 4 weeks apart) on PoC test kit performance; our recommendations regarding annual testing of FIV‐vaccinated cats to detect ‘vaccine breakthroughs’; and the potential off‐label use of saliva for the diagnosis of FIV infection using some FIV PoC test kits. We also investigated the accuracy of the same three brands of test kits for feline leukaemia virus (FeLV) diagnosis, using both blood and saliva as diagnostic specimens. Based on these results, we discuss our recommendations for confirmatory testing when veterinarians are presented with a positive FeLV PoC test kit result. Finally, we conclude with our results from the largest and most recent FIV and FeLV seroprevalence study conducted in Australia to date.     

Utility of two modified-live virus canine distemper vaccines in wild-caught fishers (Martes pennanti)

Background: Canine distemper virus (CDV) infects families in the order Carnivora. As a preventive measure, vaccinations against CDV are frequently given to mustelids in captive environments.

Objectives: Our objectives were to compare the utility between two modified-live virus canine distemper vaccines (MLV CDV's), Fervac-D® (no longer manufactured) and Galaxy-D® (now manufactured by MSD Animal Health as part of a multivalent vaccine), in developing an immune response in wild-caught fishers.

Animals and methods: The Pennsylvania Fisher Reintroduction Project (PFRP) used 14 wild-caught fishers during one year of the project to evaluate the utility of vaccinations against CDV as part of any reintroduction project. Fishers were injected subcutaneously in the nape of the neck with their designated vaccine.

Results: Fervac-D® did not effectively stimulate development of a serologic antibody response, whereas Galaxy-D® had adequate seroconversion or rise of titer levels to suggest that the general use of MLV CDV may be suitable in fishers pending further studies.

Conclusion: We recommend that future studies be conducted, evaluating the use of currently produced vaccines in fishers. Future research should also focus on the length of days required between administration of primary and booster vaccines to achieve sufficient immune response.

Clinical importance: If only primary doses are required, then hard-release reintroduction projects for fishers could be recommended. If primary and booster vaccines are required then soft-release reintroduction projects should be recommended that include captive management periods, allowing for appropriate vaccination intervals needed to maximize the probability of protection against CDV.     

现代化规模猪场猪伪狂犬病防控探讨

猪伪狂犬病是目前规模猪场主要防控的病毒病之一,2018年12月华北地区某现代化规模猪场,妊娠母猪出现流产现象。通过发病背景、临床症状及死胎剖解、现场情况、实验室血清学及病原学检测,此次妊娠母猪流产是由伪狂犬病毒野毒感染所致。采用优质伪狂犬基因缺失疫苗进行紧急接种、改善通风、消除贼风引起的应激措施后,得到了有效的控制。该措施从猪场的饲养管理角度并结合疫苗防控来控制疫病,以期为现代化规模猪场伪狂犬病的防控提供参考。     

基于SIR传染病模型的不同控制策略比较

研究了SIR模型在连续接种、脉冲接种、治疗等不同策略下平衡点的稳定性,获得了疾病灭绝的阈值条件.通过比较各种控制策略的有效性,说明接种比治疗更能有效控制疾病,同时应用两种控制策略比单独应用一种更有效.     

新城疫病毒接种后气管黏膜损伤研究

为了研究新城疫弱毒疫苗的免疫机理,用rlasota(重组lasota野毒株)免疫2日龄SPF雏鸡,接种后分别在第1,3,5,7,15,18 d取气管,进行电镜、光镜观察,利用免疫组化染色方法检测病毒在气管内的分布;结果发现rlasota接种后第1 d纤毛细胞有脱纤毛现象。接种第3 d杯状细胞破碎,黏液成分增多,黏膜下层的纤维裸露到表面;接种后第7 d,可以看到纤毛细胞纤毛上有球形粒子,杯状细胞、基细胞大量增生;接种后第18 d,纤毛细胞脱纤毛区域进一步增大。光镜观察结果发现,接种后第5 d黏膜下层水肿,淋巴细胞、粒细胞、浆细胞浸润,黏膜上皮形成空泡状,表层有数层不成熟的细胞组成;接种后第7 d,腺体腔闭塞。免疫组化染色气管固有层细胞呈阳性反应,棕色颗粒出现在胞浆中。这说明气管黏膜的损伤可能是机体重要的防御机制和免疫机制的表现。     

我国土地资源开发利用存在的若干问题及对策

分析阐述了我国土地资源开发利用上存在的诸多问题：耕地面积减少、土地质量下降、山林乱垦等，这已危及到我国粮食生产安全和现代农业的发展。为了保护和拯救有限的土地资源，实现土地利用效益的最大化，应从土地资源合理开发利用的工作出发，走土地资源适度规模经营的道路。本着因地制宜、保护环境、节约用地原则，全面规划综合利用，建立良性的生态系统，促进现代农业可持续发展。     

固定顶油罐大型化的技术经济问题

论述了建造大型化固定顶油罐的必要性，大型油罐良好的经济性能是推动油罐大型化的直接接动因。对金属油罐建设费用的构成进行了分析，并以实例对油罐在钢材方面，土地使用方面，各项费用指标，辅助工程费用及操作费用等方面分析了讨论，指出增大油罐容积，可降低工程项目的建设和操作费用，减少投资提高工程项目的经济效益。     

规模化畜牧养殖对生态环境的影响及防治

目前,人们对物质生活的享受要求越来越高,对饮食要求质量逐渐增大,家禽养殖业在高速发展,以满足市场需要。家禽养殖和畜牧业在我国农业产值的占比迅速扩大,但是也带来很多问题。人们在重视物质生活资料的丰富性时,更加关注生存环境的质量健康。但是,由于养殖带来的生态污染问题不断在干扰人们生活的健康环境,如何更好协调规模化养殖业和生态环境和谐相处成为更多人关注的焦点。