当前新城疫的国际流行状况及我们在防控中应注意的问题

新城疫也称亚洲鸡瘟或伪鸡瘟,是由病毒引起的鸡和火鸡急性高度接触性传染病,常呈败血症经过。主要特征是呼吸困难,下痢、神经紊乱,黏膜和浆膜出血。在国际动物卫生法典中,新城疫(ND)属于A类病。1999年农业部发布的动物疫病病种目录中将其列为I类疫病。新城疫不仅会给禽类带来灾难性损害,而且还严重影响着禽及禽类制品的国际贸易。因此,世界各国都非常关注本病,对该病的发生和流行采取了极为严格的防控措施。为了做好我国防控新城疫的工作,我们对最近新城疫在其他国家的发生与控制情况及国内对新城疫病毒的研究状况作了总结,并提出了防制工…     

陆良县畜禽主要传染病血清学调查

2010年动物疫病预防控制中心对陆良县10个乡镇、县种猪场、华侨农场3424份血清进行了主要传染病血清学检测,包括猪瘟、猪圆环病毒、猪伪狂犬病、猪细小病毒病、口蹄疫、犬狂犬病、禽流感和新城疫抗体检测。结果表明:陆良县猪瘟、禽流感和新城疫整体免疫抗体水平较理想;未免疫猪圆环病毒、猪伪狂犬病、猪细小病毒疫苗猪群,存在该病抗体阳性结果,说明部分猪场感染过该病。通过主要疫病抗体检测及分析,为陆良县主要动物疫病防控提供了科学依据。     

鸡新城疫流行特点与预防控制

<正>新城疫(ND)是禽类一种急性、高度接触性、致死性的传染病,虽然目前采取了一系列的防控措施,但它仍然是威胁我国家禽生产的主要传染病之一,而且症状由典型转为非典型,防治工作也越来越复杂。1病原及流行特点新城疫病毒(NDV)为副黏病毒,只有一个血清     

新城疫流行病学变化及综合防制进展

新城疫(ND)是由新城疫病毒(NDV)引起的一种禽类急性、高度接触性、致死性传染病,被国际动物卫生组织(OIE)列为危害禽类的两种A类传染病之一.尽管世界各国对ND采取了严格的防控措施,如对强毒感染的扑杀措施、限制使用中等毒力疫苗及强制性免疫等措施,但它仍然是危害禽类的主要传染病,并且呈现新的流行趋势,使防制工作变得复杂化.     

新城疫病毒分子生物学研究进展

新城疫是由新城疫病毒引起禽类的高度接触性传染病。该病表现为发病较急、死亡率较高,给养禽业造成巨大的经济损失。该病被世界动物卫生组织(OIE)列为A类传染病。本文主要叙述了新城疫病毒基因组的结构和功能,以及新城疫疫苗的最新进展。     

禽新城疫疫情的处理与防范

新城疫是由副粘病毒科副粘病毒亚科腮腺炎病毒属的禽副粘病毒I型引起的高度接触性禽类烈性传染病。世界动物卫生组织（OIE）将其列为必须报告的动物疫病,我国将其列为一类动物疫病。但近年来在这方面报道不多,其潜在的威胁还是存在的,因此做好防控工作尤为重要。     

我国当前鸡新城疫的流行病学特点与防控

新城疫(ND)是由新城疫病毒(NDV)引起禽的一种急性高度接触性传染病。临床上该病常呈败血症经过,主要特征是呼吸困难、下痢、神经机能紊乱、黏膜和浆膜出血。该病是目前严重危害我国养禽业、必须通过疫苗进行防控的重大动物疫病之一。     

新城疫病毒分子生物学研究进展

新城疫(Newcastle Disease,ND)是由新城疫病毒(NDV)引起的一种急性、高度接触性禽类传染病,被世界动物卫生组织(OIE)定为法定必报传染病,我国也将其列为一类动物疫病,本文从新城疫病毒的形态及分子结构、致病力的分子基础、分子流行病学特征和基因工程疫苗等分子生物学相关研究进展进行了综述。     

新城疫病毒检测方法研究进展

新城疫(Newcastle disease,ND)是由新城疫病毒(NDV)引起的一种禽类急性、高度接触性、致死性传染病,被国际动物卫生组织(OIE)列为危害禽类的A类传染病之一.由于该病毒毒力存在差异,容易出现毒力返强或是导致发生非典型症状,快速、可靠、准确的诊断方法对于新城疫的监测和控制具有重要意义.本文从病毒的分离与鉴定、电镜技术、血清学方法以及分子生物学诊断技术4个方面介绍了新城疫病毒的检测技术,为今后兽医临床上检测新城疫病毒提供一定的参考.     

新城疫血凝和血凝抑制试验(HA/HI)中红细胞浓度对结果的影响

新城疫是由新城疫病毒引起禽的一种急性、热性、败血性和高度接触性传染病,具有很高的发病率和病死率。除家禽外,至少有200多种鸟类可以自然或实验感染新城疫病毒,此病是危害养禽业的一种主要传染病,被世界动物卫生组织列为A类动物疫病,我国将其列为一类动物疫病。由于新城疫对畜牧业的危害和对国家政治、经济的影响     

A survey of Newcastle disease in Swiss laying-hen flocks using serological testing and simulation modelling

Newcastle disease (ND) is a highly contagious viral disease of birds particularly domestic poultry. Switzerland is currently declared free from ND; since vaccination is prohibited, the detection of antibodies against ND virus (NDV) results in the destruction of the respective flock (stamping-out policy). However, in 1995 and 1996, antibody-positive flocks were detected and sporadic ND outbreaks even occurred in Switzerland. Therefore, a serosurvey was done to look for evidence of NDV infections in Swiss laying-hen flocks. The survey was designed to provide 95% confidence of detecting at least one seropositive flock if the flock prevalence were 1%. Thirty blood samples from each of 260 commercial laying-hen flocks were collected during 1996 in a central poultry slaughterhouse. Sera were screened for NDV antibodies with a commercial blocking enzyme-linked immunosorbent assay (ELISA). Samples with a questionable or positive test result were retested with the same ELISA. A stochastic computer model was applied to define a cut-off number of test-positive samples to help to differentiate between true- and false-positive flocks and to estimate the true flock prevalence of infection. Four flocks were identified as NDV-seropositive and the NDV true seroprevalence among commercial laying-hen flocks in Switzerland was most likely between 1.35 and 1.55%. This indicates that Swiss laying-hen and parental flocks with more than 150 animals have been in contact with strains of NDV that cause subclinical infection in chicken, because no clinical symptoms have been observed. In this context, computer simulation was a useful technique to interpret survey results.     

Newcastle disease--seroepidemiologic study of a highly contagious epizootic in poultry and in wild birds in Switzerland

Newcastle disease (ND) is a highly contagious viral disease particularly of domestic poultry. Switzerland is currently declared free from ND. A serosurvey using an ELISA was performed to investigate infections with ND-Virus (NDV) in 260 Swiss laying hen flocks, 169 backyard poultry flocks and 1576 wild birds. For laying hen flocks, a stochastic model was applied to analyse the results from serological testing. Four laying hen flocks were identified as NDV-seropositive, and the true NDV seroprevalence in this population was most likely between 1.3 and 1.5%. NDV antibodies were also detected in five of the 169 backyard poultry-flocks. ND-antibody positive birds were found in 10% of all wild birds examined, with the highest proportions among cormorants, grebes, birds of prey, owls, and swifts. The study indicated that positive flocks must have been in contact with NDV strains causing sub-clinical infection, since no clinical signs had been observed. Moreover, trade of poultry or poultry eggs was considered to be an important factor associated with seropositivity in backyard poultry flocks. Contact to wild birds did not seem to be of major importance.     

ClassⅠ新城疫病毒概述

新城疫病毒是影响养禽业健康发展的主要病原之一。新城疫病毒只有一个血清型,但根据亲源关系可以划分为ClassⅠ和ClassⅡ两大类。ClassⅠ新城疫病毒于2006年被证实存在,当前可被细分为9个基因型(1～9)。ClassⅠ所有自然分离株均为无毒株或弱毒株,但有经人工传代返强的报道,由于其分布广泛,数量庞大,对养禽业有巨大的潜在威胁。为了更好的了解ClassⅠ新城疫毒株的生物学特性,为研究ClassⅠ新城疫病毒提供参考,现将其基因组结构、分子流行病学及检测方法等综述如下。     

新城疫病毒classⅠ和classⅡ微型基因组的构建及其复制效率差异性的比较

为研究新城疫病毒(NDV)微型基因组的复制效率,本实验分别以NDV 9a5b(ClassⅠ)病毒株和La Sota(ClassⅡ)病毒株基因组骨架为平台,插入绿色荧光蛋白(GFP)作为报告基因替代病毒的整个编码区,只保留与病毒复制、转录和病毒包装相关的调控区域Leader和Trailer,构建获得的微型基因组DNA片段反向插入反向遗传载体TVT(0.0)中,从而构建了两株病毒的微型基因组质粒。同时,将相应病毒株的NP、P和L 3个基因分别克隆至pCI-neo载体中,构建3个辅助质粒的真核表达系统。通过将微型基因组和辅助质粒共转染BSR T7/5T7-5细胞,表明在相同转染条件下,无论使用哪一种辅助质粒,ClassⅡ型微型基因组的报告基因的表达效率均高于ClassⅠ型微型基因组。实验结果显示ClassⅠNDV转录复制系统的运行效率明显低于ClassⅡNDV。     

Molecular characterization of a recent Newcastle disease virus outbreak in Jordan

Newcastle disease (ND) is a highly contagious viral disease and is a continuous threat to the poultry industry worldwide. In the early months of 2011, several devastating ND outbreaks occurred in Jordan affecting broilers, layers and breeders. The fusion gene of the isolated Newcastle disease virus (NDV) was partially amplified by RT-PCR, then directly sequenced. The NDV isolates were found to have the motif(112)RRQKRF(117). This motif and a mean death time (MDT) of 46h are indicative of the velogenic nature of these NDV isolates. Phylogenetic analysis showed that the new NDV strain belongs to the lineage 5d (Aldous et al., 2003) and is closely related to the Chinese strain SG/Liaoning/2009. NDV outbreaks in 2010 and 2011 have been noted in neighboring countries. Based on the high nucleotide similarity between our isolated NDV isolates and the Chinese NDV strain, the origin of these recent NDV isolates might be from China.     

新城疫病毒M蛋白细胞核定位的机制与功能研究进展

新城疫病毒（Newcastle disease virus,NDV）M蛋白一种非糖基化膜相关蛋白,主要位于病毒囊膜内表面,构成了病毒囊膜和核衣壳连接的支架。研究表明,M蛋白是一种细胞核-细胞质穿梭蛋白。在NDV感染早期,M蛋白可通过自身携带的核定位信号进入细胞核。根据已报道的相关RNA病毒M蛋白功能的研究结果,推测NDV M蛋白早期的细胞核定位有利于细胞质中病毒基因组的复制和转录,并且可能会抑制细胞基因的转录和蛋白质合成。目前,国内外对M蛋白的研究主要集中在M蛋白与NDV毒力和复制的关系以及以M蛋白为核心的病毒样颗粒形成机制和利用方面,而对M蛋白细胞核定位的机制和功能研究相对较少。鉴于M蛋白细胞核定位在NDV复制和致病过程中的重要作用,本文主要从NDV M蛋白的细胞定位特征、M蛋白细胞核定位的分子机制和功能方面进行阐述,以期为NDV M蛋白细胞核定位的功能及其作用机制研究提供理论参考。     

Molecular characterization of Newcastle disease viruses isolated from rural chicken in northwest Ethiopia reveals the circulation of three distinct genotypes in the country

Newcastle disease (ND) is a highly contagious disease that affects many species of birds and causes significant economic losses to the poultry industry worldwide. Fifteen Newcastle disease virus (NDV) isolates obtained from rural chickens in northwest Ethiopia in 2011 and 2012 were characterized genotypically. The main functional region of the F gene was amplified and sequenced (260 nucleotides). Among the Ethiopian NDV isolates, 2 isolates had the virulent motif ¹¹²R-R-Q-K-R-F¹¹⁷ at the cleavage site of the fusion protein while 13 isolates contained the lentogenic motif ¹¹²G-G/R-Q-G-R-L¹¹⁷. Phylogenetic analysis based on the variable region of the F gene indicated that the two isolates exhibiting the virulent motif belonged to lineage 5 (genotype VII) subgenotype d and the remaining 13 isolates were grouped into lineage 2 (genotype II). The nucleotide sequences of lineage 5 isolates were genetically related to the Sudanese NDV isolates, suggesting potential epidemiological link of ND outbreaks between neighbouring countries. The lentogenic strains shared similarities with La Sota vaccine strain and probably originated from the vaccine strain either through direct exposure of birds to the live vaccine or to infectious La Sota-like strains circulating in rural poultry. This study provides genetic evidence on the existence of different NDV genotypes circulating in the rural poultry in Ethiopia. The virulent NDV continues to be a problem in poultry sector in Ethiopia, and their continuous circulation in rural and commercial poultry calls for improved surveillance and intensified vaccination and other control measures.     

Newcastle disease virus outbreaks: Vaccine mismatch or inadequate application?

Newcastle disease (ND) is one of the most important diseases of poultry, and may cause devastating losses in the poultry industry worldwide. Its causative agent is Newcastle disease virus (NDV), also known as avian paramyxovirus type 1. Many countries maintain a stringent vaccination policy against ND, but there are indications that ND outbreaks can still occur despite intensive vaccination. It has been argued that this may be due to antigenic divergence between the vaccine strains and circulating field strains. Here we present the complete genome sequence of a highly virulent genotype VII virus (NL/93) obtained from vaccinated poultry during an outbreak of ND in the Netherlands in 1992-1993. Using this strain, we investigated whether the identified genetic evolution of NDV is accompanied by antigenic evolution. In this study we show that a live vaccine that is antigenically adapted to match the genotype VII NL/93 outbreak strain does not provide increased protection compared to a classic genotype II live vaccine. When challenged with the NL/93 strain, chickens vaccinated with a classic vaccine were completely protected against clinical disease and mortality and virus shedding was significantly reduced, even with a supposedly suboptimal vaccine dose. These results suggest that it is not antigenic variation but rather poor flock immunity due to inadequate vaccination practices that may be responsible for outbreaks and spreading of virulent NDV field strains.     

新城疫病毒样颗粒研究进展

新城疫(Newcastle disease,ND)是由新城疫病毒(Newcastle disease virus,NDV)引起的一种急性、高度接触性禽类烈性传染病,以呼吸道、消化道及神经系统症状为主要特征,在易感家禽中死亡率高达100%,给中国及世界养禽业和贸易往来带来了严重的经济损失。病毒样颗粒(virus-like particles,VLPs)是由病毒蛋白在感染过程中体外表达或自发组装而形成的不含病毒基因组、不能复制、不具有感染能力的病毒样蛋白颗粒。VLPs适宜的大小及独特的表面结构可被天然免疫细胞和分子有效识别,诱导良好的先天性免疫应答和适应性免疫应答,且VLPs不含病毒的感染性核酸,安全性较高,近年来成为疫苗领域中的研究热点。树突状细胞(dendritic cells,DCs)作为专职抗原递呈细胞,在连接天然免疫与适应性免疫之间具有独特功能,是目前抗原递呈能力最强的专职免疫细胞。成熟DCs (mature DCs,mDCs)迁移至次级淋巴组织能刺激初始型T细胞活化和增殖,被认为是特异性免疫应答的始动者,体外培养的不成熟DCs (immature DCs,imDCs) 也可辅助增强抗原递呈能力。NDV-VLPs主要是以NDV-M蛋白为骨架,来装配HN、F和NP蛋白,可表现出与活的NDV颗粒相似的外观和免疫原性。可见通过NDV-VLPs制成的疫苗同样具备安全、稳定、可刺激体液和细胞免疫应答、作为载体表达其他抗原及可设计成区分自然感染与免疫接种等诸多优点。文章主要就NDV-VLPs的相关内容展开探讨,以期为后续研究提供参考。