鸡球虫病免疫学研究进展

鸡球虫病是严重危害养禽业的一种寄生虫病。一直以来,鸡球虫病主要依靠药物来进行防治。但是,随着球虫抗药性问题的日益严重,抗球虫新药开发困难及人们对食品安全的关注,药物在球虫病控制中的作用越来越受到限制,因而用免疫方法来控制鸡球虫病日益受到重视,并有望成为主要的技术手段。目前鸡球虫免疫学研究主要集中在鸡球虫免疫原性、宿主免疫应答及寻找有效的鸡球虫保护性抗原等方面。近年来随着分子生物学和现代生物技术的发展,鸡球虫基因工程疫苗以其独特的优势显示其在未来球虫病控制中的诱人前景,并可能取代传统疫苗而成为鸡球虫病防治的主要手段。     

鸡球虫疫苗的免疫机理和正确使用

鸡球虫病是肉仔鸡的一种最常见的寄生虫病。通常采用抗球虫药物防治能有效控制。但随着抗球虫药物的广泛、大剂量、长期应用,引起了耐药虫株的广泛产生、药物残留和停药易复发等问题,引起了全世界的警觉。球虫苗免疫预防球虫病具有效果确实、操作简单、一次免疫终身保护、费用低、生产性能不受影响、饲料中不需添加抗球虫药等优点。随着绿色畜牧业的到来,使用球虫苗免疫预防鸡球虫病是大势所趋。1鸡球虫苗的免疫机理艾美耳球虫在肠道的发育能使宿主迅速产生免疫应答,保护宿主免受同种球虫的再次侵袭。接种一定数量(约几千个)的球虫疫苗(强毒…     

3种中药对鸡球虫病四价活疫苗卵囊繁殖的影响

正鸡球虫病是我国养鸡生产中常见且危害大的疾病。近年来,由于球虫耐药性问题以及严峻的食品安全形势,采用疫苗代替抗球虫药来预防鸡球虫病的人越来越多。然而,目前的鸡球虫病疫苗均为活卵囊疫苗,免疫接种后需在鸡体发育繁殖,刺激机体免疫应答。所以,在小鸡阶段鸡体建立抗球虫免疫力期间,要避免使用抗球虫药和广谱抗菌抗球虫类药物,比如磺胺类、四环素类药物。为了解一些中药对鸡球虫病活疫苗卵囊繁殖的影响,特此进行本试验,以便为接种球虫病疫苗的鸡群选用药物提供依据。1材料与方法1.1供试药物     

鸡球虫药物防治及耐药性研究进展

鸡球虫病的防治长期以来仍依赖于抗球虫药的应用,由于球虫极易产生耐药性,球虫耐药性的越来越突出,给球虫病的防治带来困扰。本文从防治鸡球虫病的药物,鸡球虫耐药性主要特点、产生机制,及鸡球虫病的药物防治方法等方面做一综述。     

鸡球虫耐药性的研究

鸡球虫病（Coccidiosis）是严重危害现代化养鸡业发展的重要疾病之一。目前,防治鸡球虫病主要依赖于药物,近年来,由于大量抗球虫药的长期使用,鸡球虫耐药性的产生已成为无法避免的问题,给鸡球虫病的防治带来严重障碍。文中就鸡球虫耐药性概述、耐药性产生的机制、耐药性的特点、耐药性的检测方法、耐药性的延缓等方面进行论述,提...     

鸡球虫病的肠道免疫反应

随着养禽业集约化程度的提高 ,鸡球虫病的危害日趋严重。通过饲料添加抗球虫药预防球虫病是目前控制该病的最主要方法 ,但随着田间球虫分离物对药物的抗性日趋严重及抗球虫新药开发速度的减缓 ,使鸡球虫病的药物防治遇到新的困难 ,因此促使科学工作者不得不寻找其它更为有效的控制球虫病的方法。本文旨在讨论在球虫感染过程中的免疫机制及相关的一些因素 ,为用免疫学方法控制鸡球虫病提供理论基础。1　抗球虫免疫概况鸡自然感染球虫过程中能迅速形成强烈的保护性免疫。强毒虫株、减毒虫株 (Ｓｈｉｒｌｅｙ ,1 989;Ｊｅｎｋｌｎｓ等 ,1 991ａ…     

细胞因子在抗鸡球虫感染中的作用及应用

鸡球虫病是由艾美耳球虫感染引起的一种严重危害养禽业的寄生虫病,被认为是对养禽业最具经济破坏力的疾病之一,每年可引起巨大的经济损失。目前鸡球虫病的防制主要依赖于药物,但由于抗药性、药物残留等问题,人们日益重视用免疫学方法来预防和控制鸡球虫病。细胞因子在免疫应答及抗感染过程中起重要作用,近30年来,随着对细胞因子种类及其功能的不断发现,它们在抗球虫方面的作用也引起研究者的重视。研究细胞因子的产生和作用有利于深入了解抗球虫感染的免疫调控和免疫效应机制,为免疫增强剂、免疫佐剂的使用和提高免疫效果提供依据。     

鸡球虫抗药性的特点及其对策

到目前为止,鸡球虫病的防治仍以药物控制为主,大量抗球虫药物的长期使用,导致了鸡球虫抗药性的产生,给鸡球虫病的防治带来很大困难。作者根据鸡球虫抗药的特点,认为制定合理用药程序,开发研制新的抗球虫药物,营养调控以及免疫预防是减少球虫抗药性产生和控制鸡球虫病的主要措施。其中研制高效、低毒、广谱、无残留的抗球虫新制剂,采用基因工程疫苗免疫是今后的主攻方向。      

鸡球虫耐药性研究进展

到目前为止，鸡球虫病的防治仍以药物控制为主，大量抗球虫药的长期使用，导致了鸡球虫耐药性的产生，给鸡球虫病的防治带来很大的困难。本文总结近年来国内外学者研究的成果，在鸡球虫耐药性概述、抗球虫药及其作用机制、耐药性产生的机制、耐药性的特点、耐药性的检测方法、耐药性的获得及敏感性恢复，耐药性的延缓或解决措施等方面进行了综述，提出对鸡球虫耐药性的展望，为消除耐药性，更好地防治鸡球虫病提供依据。     

鸡球虫DNA疫苗研究进展

鸡球虫病是严重危害养禽业的一种寄生虫病。一直以来,鸡球虫病主要依靠药物来进行防制。但是,随着球虫抗药性问题的日益严重、抗球虫新药开发困难及人们对食品安全的关注,药物在球虫病控制中的作用越来越受到限制,因而人们期望用更好的手段来控制鸡球虫病。DNA疫苗是近年发展起来的一种新型疫苗,因其安全、稳定、高效和易于制备而得到广泛研究。随着鸡球虫保护性抗原基因的不断发现,以及对细胞因子等免疫佐剂在抗球虫感染中的作用不断深入探索,鸡球虫DNA疫苗的研究引起人们的广泛关注和极大兴趣。本文就鸡球虫DNA疫苗作用机理、抗原基因、载体、免疫佐剂、免疫途径、免疫剂量、免疫程序及DNA疫苗研究进展方面展开一系列论述。     

鸡球虫病免疫学研究进展

鸡球虫病是严重危害养禽业的重要寄生虫病之一 ,长期以来对其防治主要依靠药物 ,并发挥了一定的积极效果。近年来因耐药虫株不断出现 ,尤其是药物残留对环境的污染及其对人类健康的威胁等一系列问题日益突出。因此 ,寻找防治球虫病的新方法是广大学者关注的焦点。在众多防治本病的措施中 ,免疫学方法因其安全、有效、无毒副作用等特点 ,倍受人们的青睐。但该方法目前仍然存在许多尚未阐明和有待解决的问题。文章对近年来鸡球虫病细胞免疫和体液免疫等方面的研究进展作了较全面系统的阐述 ,为兽医临床球虫病的有效防治提供科学的理论依据     

鸡球虫疫苗研究进展

鸡球虫病是生产中严重危害养禽业的寄生虫病,长期以来以药物防治为主。目前,由于球虫耐药性的普遍存在,加上消费者对禽产品药物残留问题的关注,采用疫苗防治球虫病为人心所向。球虫活苗在实际生产中发挥了一定的作用,但由于球虫活苗存在“复壮”的可能且使用麻烦,人们将目光转向了分子疫苗。球虫基因组学研究为基因工程苗开发奠定了基础,目前已经筛选了上百个功能抗原基因。受表达系统的限制,原核表达的重组蛋白抗原性较差,虽有较多尝试,但鲜有成功。人们在探索体外真核表达(如酵母、杆状病毒表达系统等)的同时,核酸疫苗以其独特的诱发高水平细胞免疫反应的能力而倍受青睐,近几年发展较快。     

Coccidiosis control with toltrazuril in conjunction with anticoccidial medicated or nonmedicated feed

A 42-day broiler floor pen study was conducted comparing the anticoccidial efficacy of toltrazuril (Baycox) as a stand alone treatment and as an additional treatment to in-feed anticoccidial programs. Toltrazuril was administered on days 18 and 19 in the drinking water at 7 mg/kg of body weight. The treatments were 125 ppm nicarbazin (days 0-14) to 66 ppm salinomycin (SAL) (days 15-35) with and without toltrazuril, SAL (days 0-35) with and without toltrazuril, nonmedicated (NM) to SAL with toltrazuril, and NM with and without toltrazuril. The controls were NM noninfected and infected. The treatments were replicated in five blocks of eight pens each in a randomized complete block design. All withdrawal feed was nonmedicated. On day 14, birds, except noninfected, were exposed to coccidial oocysts (Eimeria acervulina, Eimeria maxima, and Eimeria tenella) seeded litter. On days 21, 28, 35, and 42, birds and feed were weighed, four birds per pen were coccidial lesion scored, and litter oocyst counts were performed. The coccidial infection in the NM infected treatment caused a significant (P < 0.05) coccidiosis infection. Coccidiosis was moderately controlled in the anticoccidial treatment birds without toltrazuril. Performance in the NM with toltrazuril was equal to or better (P < 0.05) than the anticoccidial programs without toltrazuril. Toltrazuril was equal to the noninfected birds in performance. Toltrazuril most completely eliminated all coccidial lesions and dramatically reduced oocyst shedding. The performance data, lesion scores, and oocyst counts showed that a 2-day treatment with toltrazuril successfully controlled the coccidiosis with no relapse of infection. Toltrazuril can thus be used for supplemental control with in-feed anticoccidials or as a primary anticoccidial with nonmedicated feed.     

Use of hybridoma antibodies and recombinant DNA technology in protozoan vaccine development

The use of hybridoma antibodies developed against the sporozoite stage of avian coccidia, coupled with genetic-engineering techniques, has made it possible to begin bird-immunization studies utilizing an Escherichia coli-elicited coccidial protein. The coccidia are currently controlled in the poultry industry by use of anticoccidial compounds, but it now may be possible to use the bird's own immune system for defense against the parasitic infection. Since the sporozoite stage, which initiates the infection in poultry, is quite complex and is made up of hundreds of proteins or antigens, hybridoma antibodies were produced to identify specific antigens. These antigens, once identified, were found in such minute amounts that it became necessary to utilize genetic engineering in order to produce enough protein for immunization studies. One such protein, designated 5401, has been shown to stimulate an antibody response in immunized birds and to impart partial protection against a coccidial challenge infection. The results of these studies indicate that development of a vaccine against coccidial parasites may someday be possible.     

Coccidiosis in poultry: anticoccidial products, vaccines and other prevention strategies

Coccidiosis in chickens is a parasitic disease with great economic significance, which has been controlled successfully for decades using mainly anticoccidial products. However, large-scale and long-term use of anticoccidial drugs has led to the worldwide development of resistance against all these drugs. In order to minimize the occurrence of resistance, the rotation of various anticoccidial drugs in single and/or shuttle programmes is used. Unfortunately, this has not solved the anticoccidial resistance problem. Recently, live anticoccidial vaccines have been incorporated into rotation programmes, resulting in an increasing incidence of anticoccidial drug-sensitive Eimeria spp. field isolates, which may ameliorate the efficacy of anticoccidial drugs. Nevertheless, possible upcoming bans restricting the use of anticoccidials as feed additives, consumer concerns on residues and increasing regulations have prompted the quest for alternative coccidiosis control strategies. Although management and biosecurity measures could halt the introduction of Eimeria spp. to a farm, in practice they do not suffice to prevent coccidiosis outbreaks. Phytotherapy, aromatherapy and pre- and probiotics either show conflicting, non-consistent or non-convincing results, and have therefore not been applied at a large scale in the field. So far, live attenuated and non-attenuated anticoccidial vaccines have proved to be the most solid and successful coccidiosis prevention and control strategy. Despite the drawbacks associated with their production and use, their popularity is increasing. If with time, the immunogenicity of subunit vaccines can be improved, they could represent the next generation of highly efficient and low-cost anticoccidial strategies.     

鸡球虫耐药性的研究进展

长期以来，人们对鸡球虫病的防治以药物控制为主要手段，但是大量抗球虫药的长期使用，导致了鸡球虫耐药性的产生，给鸡球虫病的防治带来严重的障碍，通过对鸡球虫耐药性的产生、作用机理、主要特点、耐药性的检测方法、球虫耐药性虫株的诱导以及对耐药性虫株敏感性的恢复等方面的研究，进一步提出对鸡球虫耐药性的展望，为消除球虫的耐药性，更好地防治鸡球虫病提供科学依据。     

鸡球虫病药物防治的研究现状

鸡球虫病是一种对养鸡业造成严重危害的寄生性原虫病,其防治已成为养鸡业的重要课题。目前,对鸡球虫病的防治主要还是依赖药物。本文综述了鸡球虫病药物防治的研究现状,主要阐述了聚醚类载体抗生素、化学合成类抗球虫药研究情况,同时分析了目前药物防治存在的问题,诸如耐药性、药物残留、防治费用支出较大等,最后简单综述了制定合理给药程序、开发中草药、应用疫苗免疫等解决方案与对策。     

Recent advances in immunomodulation and vaccination strategies against coccidiosis

Coccidiosis is a ubiquitous intestinal protozoan infection of poultry seriously impairing the growth and feed utilization of infected animals. Conventional disease control strategies rely heavily on chemoprophylaxis, which is a tremendous cost to the industry. Existing vaccines consist of live virulent or attenuated Eimeria strains with limited scope of protection against an ever-evolving and widespread pathogen. The continual emergence of drug-resistant strains of Eimeria, coupled with the increasing regulations and bans on the use of anticoccidial drugs in commercial poultry production, urges the need for novel approaches and alternative control strategies. Because of the complexity of the host immunity and the parasite life cycle, a comprehensive understanding of host-parasite interactions and protective immune mechanisms becomes necessary for successful prevention and control practices. Recent progress in functional genomics technology would facilitate the identification and characterization of host genes involved in immune responses as well as parasite genes and proteins that elicit protective host responses. This study reviews recent coccidiosis research and provides information on host immunity, immunomodulation, and the latest advances in live and recombinant vaccine development against coccidiosis. Such information will help magnify our understanding of host-parasite biology and mucosal immunology, and we hope it will lead to comprehensive designs of nutritional interventions and vaccination strategies for coccidiosis.