鸡球虫病疫苗的研究进展

鸡球虫病是由艾美耳球虫感染鸡引起的一种危害极其严重的寄生原虫病。目前,控制球虫病主要还是依赖于药物,但由于球虫耐药株的频繁出现和人们对药物残留等问题的关注,使人们更加注重探讨从免疫预防的角度去控制球虫病。本文综述了鸡球虫病活疫苗(强毒疫苗和弱毒疫苗)的研究和应用现状及重组疫苗(DNA疫苗和重组蛋白疫苗)的研究进展,同时介绍了新型疫苗佐剂的研究情况。     

鸡球虫毒力致弱方法及其在鸡球虫病弱毒活疫苗研发上的应用

鸡球虫病是由艾美耳属球虫感染引起的一种危害严重的肠道寄生原虫病,每年给全球养鸡业造成巨大经济损失。活疫苗是替代抗球虫药防控鸡球虫病的有效手段,而减毒活疫苗安全性能更高,免疫原性更好,更加稳定,有效防控鸡球虫病的暴发。通过理化致弱、鸡胚传代和早熟选育方法诱导虫株毒力减弱是常用的鸡球虫毒力致弱手段,但目前尚缺乏相关方法的系统性综述。鉴于此,为综合了解当前鸡球虫毒力致弱方法的研究进展及其在鸡球虫病弱毒活疫苗的应用研究,本文通过查阅、搜集和整理国内外文献相关研究内容,对鸡球虫强毒株致弱措施和方法及其在鸡球虫病弱毒苗应用现状进行综述,为新一代鸡球虫病弱毒活疫苗的研究提供理论依据。     

影响鸡球虫病疫苗免疫效果的若干因素

鸡球虫病是一种呈全球性分布、侵害鸡体肠道继而出现以肿胀和出血等临床症状的原虫病,长期利用化学药物防治球虫病,造成了耐药和药物残留两大问题。由此,人们利用球虫疫苗预防球虫病愈加普遍,国内外相继问世一系列球虫病疫苗,主要以弱毒和强毒活疫苗为主。球虫疫苗免疫成功与否不仅仅与疫苗本身的质量有关,还和使用球虫疫苗的过程有关。本文结合临床经验主要作以下几个方面介绍。     

鸡球虫核酸疫苗的研究进展

鸡球虫病是一种重要的寄生原虫病,给养禽业带来严重的经济损失,鸡的病死率有时高达40%。传统的强毒苗、弱毒苗预防鸡球虫病因存在安全性差、免疫效果不理想等因素而得不到广泛应用;球虫基因工程疫苗是较为理想的疫苗,但免疫保护效果较差。核酸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,被称为第三代疫苗。随着球虫抗原基因的不断发现,鸡球虫核酸疫苗的研究引起人们的广泛关注。本文就近年来鸡球虫核酸疫苗的研究进展作一综述。     

检测鸡球虫四价弱毒疫苗抗体应答的ELISA方法的建立及初步应用

本研究旨在建立检测鸡球虫四价弱毒疫苗(柔嫩艾美耳球虫、毒害艾美耳球虫、堆型艾美耳球虫、巨型艾美耳球虫)抗体应答的酶联免疫吸附试验(ELISA),并初步阐明鸡免疫四价弱毒疫苗及攻虫后的抗体应答。将300羽岭南黄鸡分为A(免疫攻虫组)、B(不免疫不攻虫组)、C(不免疫攻虫组)共3个组。A组雏鸡在4日龄时进行首免,11日龄时鸡开始二免,二免完成后(17日龄时)对A组及C组的鸡进行攻虫(28万个4种球虫的混合卵囊/羽),7 d后检查A、C两组鸡的存活率。在鸡二免和三免完成后,分别对A、B组进行采血,通过优化最佳抗原包被浓度、酶结合物工作浓度及最佳血清稀释度,建立了ELISA方法来检测鸡体对球虫四价弱毒疫苗的抗体应答情况。A组鸡血清抗体的平均D值为0.870和0.904,明显高于B组鸡的平均D值0.261和0.270,证明了鸡体免疫疫苗后可以刺激产生相应抗体。免疫鸡攻虫后的存活率和抗体应答的检测结果,都充分说明了此鸡球虫弱毒四价疫苗具有良好的免疫原性,所建立的ELISA方法为今后评价鸡球虫弱毒四价疫苗的免疫效力提供了有效手段。     

信息撷采

鸡球虫弱毒疫苗研制成功 中国一年所产的70亿只商品鸡,如今只要注射鸡球虫弱毒疫苗,即可防病,还能生产出高质量、无药残的禽蛋产品。北京农学院动物科学技术系段嘉树教授为首席专家的课题组,历经15年艰苦探索,率先在国内研制成功鸡球虫弱毒疫苗。专家称,这项技术填补了国内空白,并达到世界先进水平,也为打破国际禽蛋贸易技术壁垒创造了条件。 鸡球虫病是艾美耳球虫寄生在肠道所引起的原虫病。它是工厂化养鸡危害最为严重的疫病之一,能引起鸡的消化功能障碍,生长发育迟缓,增重减慢,产蛋率下降。从20世纪40年代开始,各国主要采用抗球虫药为…     

球虫疫苗研究进展

本文对疫苗类型、疫苗的研制方法、展望三个方面进行了阐述。其中,疫苗类型有强毒活疫苗、弱毒活疫苗、灭活疫苗、基因工程苗等。疫苗的研制方法,强毒活疫苗主要通过控制球虫卵囊量,弱毒疫苗的致弱方法有鸡胚传代致弱、早熟选育致弱、物理和化学方法致弱。     

应用生物安全法预防鸡球虫病

在养鸡行业,鸡球虫病是危害性较大的一种疾病,造成的经济损失难以估计.到目前为止,虽然人们不断研制出对防治球虫有较好效果的药物以及球虫弱毒疫苗,但是离彻底控制或较好地控制球虫病发生的目标仍相距甚远.笔者在长期从事防治鸡球虫病的实践中,采用生物安全法预防球虫病,取得了良好的效果.     

通过活球虫卵囊疫苗免疫控制家禽的球虫病

自50年代以来，养禽业对球虫病的防洽一直是以药物为主。然而，由于球虫的抗药性日趋严重，从而导致了近来人们对使用活球虫疫苗重新感兴趣和疫苗使用规模的不断扩大。实际上，球虫疫苗已被家禽业有效的使用了40多年。目前，养禽业使用的商品化球虫疫苗主要有4种（其疫苗商品名分别为：COCCIVAC、IMMUCOX、LIVACOX和PARACOX）。所有这四种疫苗都为含有多个艾美耳球虫种和种株的多价球虫疫苗，其中有些疫苗是采用鸡胚传代的方法或选择球虫的早熟株而制成的弱毒球虫疫苗。特别是在较好的饲养管理条件下，使用这些疫苗都会对鸡提供…     

肉鸡球虫病综合防治技术探讨

肉鸡的饲养周期虽然较短，但球虫病的危害仍十分严重，其造成的经济损失是难以估计的。到目前为止，虽然人们不断研制出对防治球虫有较好效果的药物和球虫弱毒疫苗，但是仍不能彻底控制或较好地控制球虫病发生。本文就在长期从事防治鸡球虫病的实践中，总结出预防球虫病的方法，供广大肉鸡饲养场借鉴。     

球虫抗药性检测方法评述

抗药性是药物预防鸡球虫病的主要障碍,鸡球虫抗药性的检测方法主要包括笼饲试验法(鸡体测定法)、鸡胚试验法、细胞培养法、聚丙烯酰胺凝胶电泳法、同工酶测定法、PCR测定法等,本文对上述各种检测方法及其判定标准进行了综述.     

抗鸡球虫药物的合理应用

鸡球虫种类很多,目前世界公认的有8 种,其中危害最大的有艾美耳属的柔嫩艾美耳球虫、毒害艾美耳球虫2种,是养鸡业中严重多发,且防制困难的疾病之一,其死亡率达40%～50%。近几年来由于各养殖户缺乏疾病防制知识,使用药物防治球虫病时并不能做到合理选用和科学应用,导致球虫的耐药性不断增加,球虫病在一定区域仍然广泛流行。作者阐述了如何合理应用抗球虫药物来减少药物产生耐药性,使其更有效地治疗鸡球虫病。     

Application of polymerase chain reaction based on ITS1 rDNA to speciate Eimeria

A method was developed to recover Eimeria spp. oocysts directly from poultry litter and determine which species of Eimeria were present using polymerase chain reaction (PCR) based on the ITS1 rDNA sequence. The species composition of Eimeria oocysts was also compared before and after propagation in susceptible chickens to determine if the relative proportion of each species changed after expansion. In samples from two broiler operations, ITS1-PCR was able to detect Eimeria spp. oocysts recovered from litter, with Eimeria acervulina, Eimeria maxima, and Eimeria praecox being the predominant species present therein. Although Eimeria tenella was found in one sample, the other species--Eimeria brunetti, Eimeria necatrix, and Eimeria mitis-were not detected. The species composition as determined by ITS1-PCR did not appear to appreciably alter after expansion in susceptible chickens. The described method represents a rapid means for determining the major Eimeria species in a poultry operation and may be helpful in choosing a particular live oocyst vaccine formulation to protect chickens against coccidiosis.     

陕西省杨陵区鸡球虫病原种类的调查研究

对杨陵区四乡一镇的６８组鸡群进行了鸡球虫病的调查研究。结果表明，杨陵区鸡球虫病比较普遍，１５￣５０日龄雏鸡的球虫病特别严重。全区鸡的球虫平均感染率为５８．３％，在所检查的青年，成年鸡群中，笼养鸡群的球虫感染率为３５．１％，散养鸡群的球虫感染率为５７．４％。雏鸡的球虫感染率为６８．４％。经实验室鉴定，共查见柔嫩艾美耳球虫，毒害艾美耳球虫，巨型艾美耳球虫，堆型艾美耳球虫和缓艾美耳球虫和哈氏艾美耳球虫等     

柔嫩艾美耳球虫广西南宁株的分离及鉴定

利用从南宁市郊养鸡场球虫病鸡粪便中收集的球虫混合种卵囊感染小鸡,再应用单卵囊分离感染技术,从感染鸡盲肠中收集的卵囊分离纯化获得1株纯种球虫,经鸡体传代增殖,对该虫株的卵囊大小和卵形指数、潜在期、排卵高峰期、最短孢子化时间、寄生部位、致病性等指标进行观察和测定。结果测得该虫株卵囊的平均大小为(25.743±1.94126)μm×(21.4±1.85985)μm,平均卵型指数为1.2067±0.07;潜在期为140 h;其排卵囊峰期在第6～9天,最高峰在第7天;最短孢子化时间为19 h;寄生部位在盲肠;对两周龄的艾维茵鸡,当使用5×104的孢子化卵囊感染剂量时死亡率为7.5%。根据这些测定和观察到的指标综合鉴定该分离株球虫为柔嫩艾美耳球虫,并命名为柔嫩艾美耳球虫广西南宁株(Eimeria.tenella-GXNN),该研究结果为进一步研究本地区鸡球虫病的药物治疗和免疫预防等奠定了基础。     

鸡球虫入侵相关分子的研究进展

鸡球虫病是由艾美耳球虫寄生于肠道所引起的一种危害极其严重的寄生虫病,给养鸡业造成巨大的经济损失.艾美耳球虫属于顶复器门原虫,在入侵宿主细胞过程中需要通过入侵虫体顶端的顶复器分泌蛋白发挥作用.目前已报道与鸡球虫入侵相关的重要蛋白,包括微线蛋白、蛋白激酶、热激蛋白以及糖酵解酶等.这些蛋白主要参与了鸡球虫入侵宿主细胞以及在宿主细胞内的生长发育、参与了虫体的细胞周期活动以及参与了糖酵解提供虫体入侵需要的能量等,进一步对这些分子进行研究,对了解鸡球虫入侵宿主细胞的相关机理及发展抗球虫病疫苗和治疗药物将有积极的意义.     

Gel-Bead Delivery of Eimeria oocysts protects chickens against coccidiosis

Vaccines composed of either virulent or attenuated Eimeria spp. oocysts have been developed as an alternative to medication of feed with ionophore drugs or synthetic chemicals. The purpose of this study was to evaluate the use of gel-beads containing a mixture of Eimeria acervulina, Eimeria maxima, and Eimeria tenella oocysts as a vaccine against coccidiosis. Newly hatched chicks (Gallus gallus domesticus) were either sprayed with an aqueous suspension of Eimeria oocysts or were allowed to ingest feed containing Eimeria oocysts-incorporated gel-beads. Control day-old chicks were given an equivalent number of Eimeria oocysts (10(4) total) by oral gavage. After 3 days, chicks were randomly assigned to individual cages, and feces were collected between days 5 and 8 postinfection. All samples were processed for total Eimeria oocysts. At 4 wk of age, all chickens and a control nonimmunized group received a high-dose E acervulina, E maxima, and E. tenella challenge infection. Oocyst excretion by chicks fed gel-beads or inoculated by oral gavage was 10- to 100-fold greater than that of chicks spray-vaccinated with the Eimeria oocysts mixture (log 6.3-6.6 vs. log 4.8). Subsequent protection against challenge as measured by weight gain and feed conversion efficiency was significantly greater (P < 0.05) in gel-bead and oral gavage groups compared with spray-vaccinated or nonimmunized groups. Also, gel-bead and oral gavage groups showed no significant difference (P > 0.05) in weight gain and feed conversion efficiency compared with nonchallenged controls. These findings indicate that incorporation of Eimeria spp. oocysts in gel-beads may represent an effective way to deliver live oocyst vaccines to day-old chicks for preventing subsequent outbreaks of coccidiosis in the field.     

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.     

Interleukin-2 production in SC and TK chickens infected with Eimeria tenella

SC and TK inbred chicken strains display differential protective immunity to coccidiosis, SC being more resistant and TK susceptible to disease. In this study, the association between interleukin (IL)-2 and disease phenotype was assessed by cytokine quantification in serum, duodenum, cecum, and spleen cell cultures of SC and TK chickens experimentally infected with Eimeria tenella. In general, after primary infection, SC and TK strains produced equivalent amounts of IL-2 in all sources examined. However, after secondary infection, SC animals displayed significantly greater IL-2 levels in serum and the duodenum compared with strain TK. IL-2 production after reinfection with Eimeria may be an important factor contributing to the genetic differences in coccidiosis between SC and TK chickens and provides a rational foundation for cytokine-based immunotherapeutic approaches to disease control strategies.