非典型新城疫的发生与防制

近年来 ,随着新城疫 (ND)免疫密度的提高 ,典型新城疫的发病率明显下降 ,而非典型新城疫 (CND)的发病率则上升 ,由于CND缺乏特征性的临床症状和病理变化 ,导致误诊 ,延误处理时机 ,造成病原得不到及时清除 ,致使ND难以扑灭的严重后果。1　非典型ND发生特点1.1　流行特点CND主要发生于免疫接种ND疫苗的鸡群 ,雏鸡易发 ,尤以 30～ 4 0日龄雏鸡更易发生。病鸡呈非典型经过 ,不表现明显的临床症状和病理变化 ,其发病率和死亡率都低于ND。非典型ND病程持续时间长 ,期间鸡群中总有少数鸡不断地零星死亡。1.2　临床症状患病鸡主要表现为明…     

鸡的主要传染病及防制对策

ND只有一个血清型，现有传统疫苗可抵抗强毒的攻击，而很少有典型的嗜内脏型ND爆发。生产实践中常见的是非典型ND，表现为以呼吸道症状为主、绿便、偏高的死亡率等，剖检一些病死鸡可见腺胃乳头出血，小肠扣状肿出血等病变。有的鸡群虽多次接种过ND疫苗，但仍有非典型ND的发生，可能与下列因素有关：     

鸡非典型新城疫的发生机理及诊治

鸡新城疫 ( Newcastle Disease,ND)是由新城疫病毒 ( NDV)引起鸡的急性、高度接触性传染病 ,是严重危害养鸡业的疾病之一。近年来 ,随着养鸡户对 ND危害性认识的不断提高和各种 ND疫苗的使用 ,ND的发生得到了一定的控制。 80年代末 ,其发生出现了新的变化 ,即所谓的非典型 ND的发生情况越来越严重 ,在国内外均有报道 ,已成为养禽业的突出问题。由于本病缺乏典型新城疫的特有症状和病理变化而很难诊断 ,并且如果有其他疾病并发时 ,死亡数量明显增加 ,危害极大。1　发病特点1 .1　有母源抗体的雏鸡群或免疫鸡群多发　非典型新城疫多发于…     

鸡新城疫防治中的误区

随着对鸡ND病认识的不断深入,防治的手段日趋科学,典型的ND(鸡新城疫)已很少发生。取代的是广泛的非典型ND。由于非典型ND的病理变化不典型,极易被误诊为其它疾病,造成人们在ND防治方面思想上的麻痹。     

非典型新城疫的防控工作

非典型新城疫是指在家禽中发生的临床表现和解剖变化不典型的新城疫（ND）,是在商业禽群中广泛应用ND疫苗以后出现的ND发病形式。虽然中国家禽业的典型ND已经得到较好的控制,但非典型ND时有发生。幼龄鸡发生时,可表现精神沉郁、羽毛松乱、翅膀下垂、瘫痪或站立不稳、食欲减退或废绝、呼吸急促、咳嗽、口流粘液、拉黄绿或黄白色粪便等症状,随着病程的延长可表现歪脖、腿麻痹等神经症状,死淘率明显增加;     

当前鸡新城疫的发生特点及防制措施

近年来随着鸡新城疫(ND)免疫的普及,鸡典型新城疫已很少见到,而非典型ND的发生很普遍.由于非典型ND缺乏特征的临床症状和病理变化,极易造成误诊,使病鸡得不到及时救治,造成死淘率上升、生长性能降低、产蛋量下降,给养殖户造成很大损失.     

鸡新城疫防治中的误区

随着对鸡ND（鸡新城疫）病认识的不断深入,防治的手段日趋科学,典型的ND已很少发生。取代的是广泛的非曲型ND。由于非典型ND的病理变化不典型,极易被误诊为其它疾病,造成人们在ND防治方面思想上的麻痹。（1）对防治非典型ND认识上的误区。非典型ND在实际生产中的常见并给生产所造成的潜在巨大损失,目前仍是威胁养鸡业发展严重的疫病之一。对ND病的不重视正是鸡病防治中的一大误区。（2）诊断误区。非典型ND一般在临诊症状上先表现为呼吸道症状,其后出现典型的神经症状。剖检常见有腺胃乳头的少量出血和肠道某段（特别是卵黄蒂…     

非典型新城疫的防控工作

非典型新城疫是指在家禽中发生的临床表现和解剖变化不典型的新城疫(ND),是在商业禽群中广泛应用ND疫苗以后出现的ND发病形式.     

非典型新城疫的发生原因及防疫

在生产实践中经常出现接种鸡新城疫(ND)疫苗后的鸡群仍有非典型新城疫的发生,且以二免前后的鸡发病最多,发病率、死亡率一般不高,临诊以呼吸道症状、神经症状、产蛋量急剧下降为主要特征。1非典型新城疫的发生原因非典型新城疫的发生原因很复杂,主要有以下几个方面:1.1ND强毒多重污染我国大、中、小鸡场及农村散养鸡群饲养管理与防疫水平参差不齐,防制ND的漏洞很多。如ND活疫苗不合理使用,对ND病死鸡、粪便、污水等污染物不能进行无害化处理,使ND污染越来越严重,而空气和带毒野鸟对ND病毒的传播使ND的防制工作难上加难。ND强毒感染…     

我国鸡新城疫免疫程序的概况

预防鸡新城疫(ND)目前虽然有多种有效的ND疫苗,但接种疫苗后还常有ND的发生。许多兽医工作者为防制鸡ND进行了免疫程序的研究。其中包括疫苗,疫苗的接种途径,鸡首次免疫,加强免疫时间以及免疫接种次数等。现就此综述如下。     

禽类细胞因--新型免疫佐剂和免疫治疗剂

在食用性动物中使用抗生素饲料添加剂和抗微生物的化学药品就像一把双刃剑!一方面．它可以防止疾病的爆发、促进动物的生长;但另一方面,耐药性细菌的出现也引起了人们广泛的关注。因此,一些国家已经禁止在饲料中使用抗生素,为此,为了有效地控制疾病,肉类生产商正急于寻找一种新的替代物。细胞因子是在机体被感染或接种疫苗后产生的一类蛋白质．能够影响免疫应答的类型和水平．是一种绝佳的替代物。随着越来越多的禽类细胞因子基因的发现,在家禽中使用细胞因子成为可能。下面就禽类细胞因子最近的进展做一综述．并侧重阐述细胞因子作为免疫治疗剂和疫苗佐剂的功能及前景。     

蜂胶与蜂胶疫苗

蜂胶是蜜蜂群体的一种副产物,是一种有较强粘性的固体状、棕黑色、有芳香气味的物质。蜂胶是一种纯天然的广谱抗菌素。它有树脂、蜂腊、芳香油、花粉及黄酮类的物质。其高强度和黏度、杀菌防腐能力都是其他天然品无法比拟的。它是天然药材、辅料及兽药、医药、植物和肉食品加工、食品防腐保鲜的好材料。     

猪蓝耳病灭活疫苗与弱毒疫苗免疫后的抗体水平比较

为比较猪蓝耳病灭活疫苗与弱毒疫苗的免疫抗体水平,本试验在惠城区某猪场随机选取100头仔猪,分成两组,分别免疫猪蓝耳病灭活疫苗与弱毒疫苗,采用ELISA方法检测血清中的抗体水平,并对两组抗体的S/P值进行比较。结果表明,猪蓝耳病弱毒疫苗产生的抗体水平比灭活疫苗高,灭活疫苗免疫效果较差,且抗体持续时间短。本研究为猪场蓝耳病的防控及免疫程序的制定提供参考依据。     

Concomitant turkey herpesvirus-infectious bursal disease vector vaccine and oil-adjuvanted inactivated Newcastle disease vaccine administration: consequences for vaccine intake and protection

Hatchery vaccination protocols in day-old chicks are designed to provide early priming and protection against several poultry diseases including, but not limited to, Marek's disease (MD), infectious bursal disease (IBD), and Newcastle disease (ND). The constraint of concomitant administration of live MD and IBD vaccines plus ND inactivated oil-adjuvanted vaccines (IOAVs) requires improvements in vaccine technology. Single-needle concomitant subcutaneous (SC) application of IBD/MDV and killed NDV vaccine and the use of viral vectors for expression of immunogenic proteins are a current trend in the industry. The objective of this work was to assess the compatibility of a turkey herpesvirus (HVT)-infectious bursal disease (vHVT-IBD) vector vaccine applied simultaneously with IOAV and to evaluate the consequences for vaccine intake, the need for additional immunizations with the respective vaccines, and protection. Five separate trials were performed using double- and/or single-needle injectors. The levels and persistence of vaccine intake, serologic response, vHVT-IBD virus combination with the MD Rispens strain, and/or live NDV vaccination were also assessed. Histopathology and PCR at injection sites showed adequate vaccine intake detected up to 44 days postvaccination. Serologic evidence of vaccine priming was observed, and all vaccinated groups differed (P < 0.05) from the control at different time points. MD, NDV, and IBD protection results after concomitant double-shot single-needle vaccination were near 85%, 95%, and 100%, respectively. Taken together the results indicate no deleterious effects on the efficacy of the vHVT-IBD vaccine monitored by vaccine intake, serologic and challenge results, and combinations after concomitant live/killed vaccination, suggesting the suitability of its use in hatchery vaccination. All types of injectors used as well as injection techniques, vaccines injected separately or together, gave the same results.     

表位疫苗设计、优化策略及在动物疫苗研究中的应用

表位疫苗是依据抗原表位来设计的一种新型疫苗。由于具有安全性好、诱导产生特异性免疫反应强,在抗感染免疫、免疫逃避、抗肿瘤免疫中具有良好应用前景。本文就表位疫苗的设计、构建、优化及其在动物疫苗中的应用研究作一综述。     

Titration of Marek's disease cell-associated vaccine virus (CVI 988) of reconstituted vaccine and vaccine ampoules from Dutch hatcheries

Thirty-one outbreaks of Marek's disease (MD) were reported in the Netherlands and retrospectively analyzed. The outbreaks occurred mostly in vaccinated commercial layer and a few breeder flocks of several breeds; however, the cause of the outbreaks could not be established. Therefore, in a prospective study, the occurrence of true vaccine failures was assessed onfive hatcheries. The plaque-forming units (PFU) of MD vaccine per chicken dose were determined through in vitro assays on vacine ampoules (2 to 5 per hatchery) and samples of reconstituted vaccine (approximately 22 per hatchery). All forty reconstituted vaccine samples of hatcheries 1 and 4 showed PFU doses <10(3). In hatchery 4, 14 samples showed extreme low PFU (< or = 10 PFU). In hatcheries 2, 3, and 5, the numbers of MD vaccine suspensions with a titer > or = 10(3) PFU, which is the standard required, were 1 (5%), 17 (77%), and 3 (14%), respectively. Some vaccine ampoules showed < 10(3) PFU per chicken dose. This study shows the usefulness to assess the PFU per chicken dose of reconstituted MD vaccine and vaccine ampoules to unravel true vaccine failures, which could result in disease outbreaks in the field.     

An update on antileishmanial vaccine candidates and prospects for a canine Leishmania vaccine

Dogs are the domestic reservoir for Leishmania infantum, the parasite causing zoonotic visceral leishmaniasis (VL) in both the Old and New Worlds. Since the available methods for canine leishmaniasis treatment and control have limited efficacy, the development of a canine Leishmania vaccine is highly desirable. Mechanisms of antileishmanial immune responses in murine, human, and canine infections are briefly presented. Vaccine candidates, including live or killed parasites, Leishmania purified fractions, defined recombinant parasite antigens, live recombinant bacteria expressing Leishmania antigens and antigen-encoding DNA plasmids, are reviewed. Finally, some practical requirements for the evaluation of vaccine candidates in dogs are indicated.