Epidemiology and control of trematode infections in cattle in Zimbabwe: a review

In this paper the main epidemiological aspects of the major domestic ruminant trematode infections in Zimbabwe are reviewed and discussed with regard to the available options for control. Seasonal occurrence of amphistomes, Fasciola gigantica and Schistosoma mattheei are considered both in the definitive and intermediate hosts. The regional distribution of the trematodes is reviewed in relation to the distribution patterns of their snail intermediate hosts. Based on the epidemiological features of the trematodes, practical control measures are suggested.     

Detection of bovine respiratory syncytial virus using a heterologous antigen-capture enzyme immunoassay

Based on the marked antigenic similarities that exist between antigens of the human and bovine strains of respiratory syncytial virus (RSV), an enzyme immunoassay (EIA) designed to detect human RSV was used to detect bovine RSV. The commercial test kit (RSV EIA) consists of a solid phase (beads) coated with a capture antiserum prepared against the Long strain of human RSV. The RSV EIA test was compared with the method of inoculation of cell cultures and fluorescent antibody (FA) staining of lung tissue for the detection of bovine RSV. Using a cell culture-propagated stock of strain 375 of bovine RSV, the threshold of sensitivity of the EIA test for the cattle strain of RSV was determined to be less than or equal to 10(2.3) CCID50/ml. In addition, RSV EIA detected the bovine RSV in nasal samples obtained from 3 experimentally inoculated cattle. The RSV EIA exhibited a sensitivity of greater than or equal to 80% during the period that shedding of infectious virus took place. All of the bovine RSV FA-positive lung samples (n = 37) were positive by the RSV EIA. Twenty-six of the remaining 214 bovine RSV FA-negative lung samples were positive by the RSV EIA. The RSV EIA was also used to test 137 nasal swabs obtained from cases of bovine respiratory disease. Of these, 38 tested positive by RSV EIA. All samples that tested positive by EIA were confirmed by blocking assays using hyperimmune serum anti-bovine RSV and a pool of monoclonal antibodies specific for that virus.     

Vaccination of dogs against heterologous Babesia canis infection using antigens from culture supernatants

Soluble parasite antigens (SPA) from European Babesia canis can be used to protect dogs against a homologous but not heterologous challenge infection. In this study it is shown that when dogs are vaccinated with a mixture of SPA from both, a European B. canis isolate and a South African Babesia rossi isolate, protective immunity against heterologous B. canis infection is induced. Three groups of five beagle dogs each were vaccinated twice with graded doses of SPA derived from in vitro cultures of B. canis and B. rossi, with a 3-week interval. Saponin was used as adjuvant. Three weeks after booster vaccination immunological responsiveness against heterologous B. canis antigen was measured by seroconversion against infected erythrocytes and lymphocyte transformation using SPA. Upon vaccination dogs produced antibodies against infected erythrocytes and lymphoblastogenic responses against SPA in a dose-dependent manner. Dogs were then challenged with heterologous B. canis parasites. Dogs appeared to be protected against challenge infection, which was reflected in less severe decrease of packed cell volume (PCV) and reduced clinical signs. The level of protection to clinical signs (but not excessive PCV drop) was related to the level of SPA in plasma and spleen size, and not related to peripheral parasitaemia. The results suggest that vaccination with this bivalent vaccine primes T-helper cells that recognise common epitopes on SPA from an antigenically distinct B. canis isolate. These cells provide the essential Th signal to mount an effective and timely antibody response against SPA and parasites or parasitised erythrocytes, which prevents the further development of clinical babesiosis.     

Immunity following use of Australian tick fever vaccine: a review of the evidence

OBJECTIVE: To review the evidence available on the degree and duration of immunity provided by Australian tick fever vaccines against Babesia bovis, B. bigemina and Anaplasma marginale infections in Australia and overseas. BACKGROUND: Vaccines containing attenuated strains of B bovis and B bigemina as well as A. centrale grown in splenectomised calves have been used in Australia since 1964 to immunise cattle against tick fever. About 800,000 doses of vaccine are supplied annually and much of the evidence for protection is field evidence rather than conventional immunological measures or pen trials. CONCLUSIONS: Immunity to Babesia bovis and B. bigemina--A single inoculation generally provides sound, long-lasting protection both in Australia and overseas. No evidence was found of a loss of immunity with time. Vaccine failures to B. bovis do occur, but are uncommon and evidently caused by a number of factors, including immune responsiveness of the vaccinated animals, and immunogenicity of the vaccine strain. Immunity to Anaplasma marginale--The vaccine containing A. centrale provides partial, variable protection against A. marginale. Protection against challenge in Australia is adequate in most cases to prevent disease and use of the vaccine in this country appears to be justified. Protection against antigenically diverse, highly virulent stocks of A. marginale in other countries is, at times, clearly inadequate and better vaccines are required in situations where the challenge is severe.     

家禽免疫抑制与免疫失败的原因

改革开放后 ,我国的养禽业高速发展 ,已步入世界禽业大国行列。但我国禽病防疫水平不高 ,禽病的发生和危害仍十分严重。各种引起家禽免疫抑制和免疫失败的因素目前越来越多 ,导致抗体对外来抗原应答能力降低、消失 ,增加了家禽的发病率和治疗难度 ,给养鸡业带来很大的经济损失。1　免疫抑制性疾病的发生原因1.1　应激因素对家禽免疫的影响应激因素是机体对不同刺激的非特异反应的总和 ,是处于健康和疾病之间的过度状态。因此 ,如对应激状态放之任之 ,就有可能发展为疾病 ,如果重视它 ,及时消除 ,就可以恢复健康。所以 ,应激对以预防疾病为主…     

An apparatus for the restraint of sheep during infestation with schistosomes.

With this adjustable apparatus sheep aged from five months to five years and varying in mass from 16-95 kg could be restrained effectively. Cercarial suspension was split by only 2/44 sheep during infestation with Schistosoma mattheei. Using a battery of seven cages, it was possible to infest 23 sheep, each for 30 minutes, in one day. No cercariae were more than 4-1/2 hours old at the end of exposure.     

鸡球虫病的免疫防治

鸡球虫病是一种危害性较大的肠道寄生虫病，多发于3个月以内的仔鸡，尤以15～45日龄的雏鸡最易感染。其发病率高达50％～70％，死亡率为20％～30％．严重者可达80％t~。我国是养鸡大国，每年因球虫病造成的直接和间接经济损失难以估计。迄今为止，鸡球虫病的防治主要依赖药物预防，但是目前药物防治球虫病遇到了两大难题．首先是球虫极易产生耐药性．其次是药物残留，一些国家对禽肉、蛋制品中球虫药物含量有着严格的限制，我国已经加入WTO．解决禽蛋制品的药物残留已成当务之急。因此，利用免疫预防来代替药物防治控制球虫病已成为寄生虫学界的共识。近年来，球虫疫苗的应用进一步完善．为我们防治球虫病提供了一种新的途径．比较好地解决了抗药性和药物残留等问题。     

浅谈鸡球虫病的免疫

鸡球虫病是养禽业中重要的常见病之一,在鸡的各种疾病中,球虫病的发病率最高,占20%以上。而目前肉鸡大规模集约化饲养方式,也为鸡球虫病的发生提供了合适的条件。据Bhogal报道,每年世界养禽业因为鸡球虫病造成的损失达到20亿美元以上。目前防治鸡球虫病的方法主要有药物和疫苗。其中抗球虫药一直是主要的防治手段。随着耐药性和人类健康等问题的出现,抗球虫药的使用受到了很大的限制,球虫疫苗的使用逐步增加。无论哪种方法,都是对球虫生活史的某一阶段或几个阶段产生杀灭或抑制,从而达到控制发病的目的。1生活史球虫的生活史包括:从感染鸡…     

促益素雏鸡IBD疫苗免疫后局部体液的免疫变化

本研究分别将两种促益素“禽福”和“亿妙灵”与鸡传染性法氏囊病中等毒力活疫苗配合应用,通过间接ELISA法检测免疫雏鸡泪液、气管液,胆汁、肠液的IgG、IgM、IgA含量的动态变化。结果表明：应用促益素雏鸡IBD疫苗免疫后局部体液的上述三种免疫球蛋白含量较IBD疫苗单独免疫雏鸡有不同程度地升高：IBD强毒攻击后,疫苗单独免疫雏鸡局部体液的上述指标明显低于应用促益素的疫苗免疫雏鸡。表明使用促益素后,可提高疫苗增强机体局部免疫的功能,有效抵抗强毒攻击,使疫苗的免疫保护率显著提高：在两种促益素中,“禽福”的局部体液免疫增强效果强于“亿妙灵”。     

Immunity of rodents to malaria

This study reviews recent work in our laboratory on the immune response of rats to Plasmodium berghei infection. It gives special emphasis to our studies on the mechanisms for implementation of the immune response by humoral antibody and phagocytes and to our studies of the changes in the cellular systems upon which the development of the immune response depends.     

家禽的营养与免疫

家禽营养是建立免疫的物质基础,营养物质直接或间接地调控机体的免疫应答并对免疫功能产生影响。本文综述了营养是建立免疫的物质基础,营养调控免疫应答的机制及营养对免疫功能的影响,最后提出家禽营养与免疫对养禽生产的指导意义。     

蚯蚓抗菌的免疫生态学机制

 蚯蚓具有独特的抗菌免疫防御体系,论文从蚯蚓的防御屏障、蚯蚓的细胞免疫和蚯蚓的体液免疫三个方面对蚯蚓的免疫防御体系进行了综述。     

通过营养调节免疫（续完）

上一期回顾：上期文章介绍营养素可通过多种机制影响免疫力,包括：作为免疫系统的底物;调节白细胞的信号传递;影响激素环境;影响肠动力学以及为病原体提供关键的营养成分,通过对营养和免疫应答之间相互作用的了解,营养学家和生产商就能够制定出饲喂策略,在获得最高生产力和动物福利的同时,最大程度地减少传染病的发生。     

Immunity and potential of vaccination

This article will focus on current information available on the equine immune response to helminth parasites as it relates to acquired resistance, hypersensitivity reactions, and vaccine development.     

免疫牛乳的研制

在已杀菌的牛乳中添加0．5％的牛初乳粉，然后再经巴氏杀菌，制得的免疫牛乳蛋白质高达4．0％左右，免疫球蛋白含量在1000mg／L以上，产品具有调节免疫的功效，经毒性试验证实产品属无毒物。