羊痒病研究进展

羊痒病(scrapie,SC)是世界上流行传播非常广泛的传染性海绵状脑病(transmissible spongiform encephalopathy,TSE)之一.而牛的传染性海绵状脑病,又称疯牛病(bovinespongiform encephalopathy,BSE)的爆发让人们意识到必须控制TSE的流行来保护动物和人类的健康.为此,不同国家的兽医当局都有针对羊痒病的根除计划,加强对动物的监管,同时培育对羊痒病有抗性的羊.在我国,羊痒病在2012年被列入重大外来动物疫病监测计划的动物疫病.小反刍兽疫、非洲猪瘟、牛海绵状脑病和羊痒病等重大疫病的病原传入我国并播散到辽宁省只是时间问题,我们应该尽快开展有关这些疫病的研究工作,做好相应的技术战略储备[1].本文就羊痒病当前的研究进展做一综述,为该病的进一步研究和针对该病的防治提供理论依据.     

传染性海绵状脑病实验室检测方法研究进展

传染性海绵状脑病(TSE)是人和动物共患的一类慢性、进行性、致死性、传染性和神经系统退行性脑病，在人类主要包括库鲁病(kuru)、克雅氏病(Creutzfeldt—Jakob Disease，CJD)、格施谢三氏症(Gerstmann Straussier Scheinker Disease，GSSD)、致死性家族失眠症(Fatal Familiar Insomnia．FFL)和变异性克雅氏病(Viriant Creutzfeldt—Jakob Disease，vCJD)；动物上主要有羊痒病(Scrapie)，牛海绵状脑病(Bovine Spongiform Encephalopathy．     

骡朊病毒基因克隆与序列分析

传染性海绵状脑病（TSEs）是一种可引起人和动物一系列神经退化性疾病的一种新型传染病,包括羊痒病（scrapie）、牛海绵状脑病（BSE）、鹿的慢性消耗性疾病（CWD）,水貂海绵状脑病（MSE）,猫的疯猫病（FSE）,人克雅氏病（CJD）。疾病的致病机理并不清楚,但是朊蛋白被认为是感染性因子。1986年暴发的疯牛病给英国造成很大的损失,而且变异型克雅氏病（vCJD）被认为是人类食用了被疯牛病污染的牛肉发生的,引起了全世界的恐慌。     

羊痒病病原学特点与流行病学特征的研究进展

羊痒病是由羊痒病病毒在绵羊和山羊体内相互作用引起的一种中枢神经系统渐进性退化的疾病。该传染病的临床症状以潜伏期长、剧痒、中枢神经系统变性、共济失调和病死率高为主要特征。本病对养羊业危害较大,是最早所知的动物传染性海绵状脑病。羊痒病疫情虽然在中国发生较少,但目前在世界各地均有流行,对中国的潜在威胁也越来越大。因此,加强对该病的病原学、流行病学特征的认识对其综合防控具有十分重要的意义。作者主要介绍了目前国内外羊痒病病原学和流行病学特征的研究进展及综合性防控措施,以期为其防控提供一定的理论依据。     

饲料中动物源性成分的检测技术研究进展

痒病和牛海绵状脑病（疯牛病）都属于传染性海绵状脑病，其病原是蛋白质侵染颗粒——朊毒体（Prion）。痒病是羊的一种比较古老的疾病，而疯牛病是最早在英国出现的一种新病，1987年Weels等正式报道，然后迅速传播到欧洲多个国家和地区，给英国和欧洲的养牛业造成了巨大损失，并影响到相关产业。     

羊痒病的诊断与防控措施

<正>羊痒病是由亚病毒中的朊病毒所致,是一种长期的进行性、衰竭性与致死性神经性疾病。传统的羊痒病是一种绵羊和山羊自然发生的疾病,世界上除了澳大利亚和新西兰外,其他国家均有发生。它是传染性海绵状脑病(TSE)之一,与牛海绵状脑病、鹿的慢性消耗性疾病相关,这些疾病都是由脑部细胞内部结构异常的蛋白所导致的。羊痒病可以在各品种羊中发生,但尚未发现本病能由羊传播给其他动物的报道。     

“疯牛病”浅说

牛海绵状脑病 (ＢＳＥ)俗称“疯牛病” ,是传染性海绵状脑病的一种。是一种特殊病毒———朊病毒引起人和动物的一组具有共同特征的非炎性、亚急性、渐进性、致死性中枢神经系统变性的疾病 ,故又称朊病毒病。自从 2 0世纪 80年代英国出现疯牛病以来 ,已在欧洲一些国家扩大流行 ,引起世界各国的恐慌和关注。我国虽未发现疯牛病 ,但为了预防疯牛病的发生 ,笔者将有关知识简述如下。1　疯牛病的病因是由有传染性海绵状脑病的一种即绵羊、山羊痒病病羊的骨、肉被加工成粉 ,作为牛的饲料添加剂进入牛的饲料中 ,这种痒病羊的骨肉粉中间含一种特殊…     

免疫印迹法检测绵羊朊蛋白prpc的研究

蛋白免疫印迹法在目前已有的朊病检测方法中具有敏感性和特异性高的特点，是检测痒病的金标准。本实验室为国家动物海绵状脑病实验室，负责检测北方地区的牛羊海绵状脑病，自2003年成立以来，在羊痒病流行病学调查、痒病易感性相关分子机理方面及病理组织学检查、免疫组织化学检测法等领域进行了广泛深入的研究，同时基本建立了羊痒病免疫印迹检测方法。     

2005年3-4月全球重大动物疫情综述

2005年3—4月，全球通报发生的重大动物疫情主要有水泡性口炎、高致病性禽流感、新城疫、牛海绵状脑病、痒病、马传染性贫血和牛传染性鼻气管炎等。     

2004年6-7月全球重大动物疫情综述

2004年6—7月，全球报告发生重大动物疫情有口蹄疫、水泡性口炎、牛传染性胸膜肺炎、高致病性禽流感、牛海绵状脑病和痒病等。     

PrP genetics in ruminant transmissible spongiform encephalopathies

Scrapie, bovine spongiform encephalopathy (BSE), and chronic wasting disease (CWD) are prion diseases in ruminants with considerable impact on animal health and welfare. They can also pose a risk to human health and control is therefore an important issue. Prion protein (PrP) genetics may be used to control and eventually eradicate animal prion diseases. The PrP gene in sheep and other representatives of the order Artiodactyles has many polymorphisms of which several are crucial determinants of susceptibility to prion diseases, also known as transmissible spongiform encephalopathies (TSE). This review will present the current understanding of PrP genetics in ruminants highlighting similarity and difference between the species in the context of TSE.     

Prion biology relevant to bovine spongiform encephalopathy

Bovine spongiform encephalopathy (BSE) and chronic wasting disease (CWD) of deer and elk are a threat to agriculture and natural resources, as well as a human health concern. Both diseases are transmissible spongiform encephalopathies (TSE), or prion diseases, caused by autocatalytic conversion of endogenously encoded prion protein (PrP) to an abnormal, neurotoxic conformation designated PrPsc. Most mammalian species are susceptible to TSE, which, despite a range of species-linked names, is caused by a single highly conserved protein, with no apparent normal function. In the simplest sense, TSE transmission can occur because PrPsc is resistant to both endogenous and environmental proteinases, although many details remain unclear. Questions about the transmission of TSE are central to practical issues such as livestock testing, access to international livestock markets, and wildlife management strategies, as well as intangible issues such as consumer confidence in the safety of the meat supply. The majority of BSE cases seem to have been transmitted by feed containing meat and bone meal from infected animals. In the United Kingdom, there was a dramatic decrease in BSE cases after neural tissue and, later, all ruminant tissues were banned from ruminant feed. However, probably because of heightened awareness and widespread testing, there is growing evidence that new variants of BSE are arising "spontaneously," suggesting ongoing surveillance will continue to find infected animals. Interspecies transmission is inefficient and depends on exposure, sequence homology, TSE donor strain, genetic polymorphism of the host, and architecture of the visceral nerves if exposure is by an oral route. Considering the low probability of interspecies transmission, the low efficiency of oral transmission, and the low prion levels in nonnervous tissues, consumption of conventional animal products represents minimal risk. However, detection of rare events is challenging, and TSE literature is characterized by subsequently unsupported claims of species barriers or absolute tissue safety. This review presents an overview of TSE and summarizes recent research on pathogenesis and transmission.     

朊蛋白在物种内、物种间的致病机理

朊蛋白(prion)是传染性海绵状脑病(transmissible spongiform encephalopathy,TSE)的唯一致病因子。在细胞内存在两种形式的朊蛋白,即正常形式PrP~c和致病形式PrP~(sc)(PrP~(res))。PrP~(sc)的出现是TSE发生的关键因素。本文阐述了朊蛋白的发现与意义及其在物种内、物种间的致病机理。     

Atypical scrapie in a Swiss goat and implications for transmissible spongiform encephalopathy surveillance.

Different types of transmissible spongiform encephalopathies (TSEs) affect sheep and goats. In addition to the classical form of scrapie, both species are susceptible to experimental infections with the bovine spongiform encephalopathy (BSE) agent, and in recent years atypical scrapie cases have been reported in sheep from different European countries. Atypical scrapie in sheep is characterized by distinct histopathologic lesions and molecular characteristics of the abnormal scrapie prion protein (PrP(sc)). Characteristics of atypical scrapie have not yet been described in detail in goats. A goat presenting features of atypical scrapie was identified in Switzerland. Although there was no difference between the molecular characteristics of PrP(sc) in this animal and those of atypical scrapie in sheep, differences in the distribution of histopathologic lesions and PrP(sc) deposition were observed. In particular the cerebellar cortex, a major site of PrP(sc) deposition in atypical scrapie in sheep, was found to be virtually unaffected in this goat. In contrast, severe lesions and PrP(sc) deposition were detected in more rostral brain structures, such as thalamus and midbrain. Two TSE screening tests and PrP(sc) immunohistochemistry were either negative or barely positive when applied to cerebellum and obex tissues, the target samples for TSE surveillance in sheep and goats. These findings suggest that such cases may have been missed in the past and could be overlooked in the future if sampling and testing procedures are not adapted. The epidemiological and veterinary public health implications of these atypical cases, however, are not yet known.     

The prion hypothesis and the human prion diseases

Our understanding of the pathogenesis of the transmissible spongiform encephalopathies (TSE) has made terrific headway over the past 40 years and some scientists are even of the opinion that this group of diseases belongs to the neurodegenerative syndromes best understood. On the other hand, the investigation of TSE has led to a multitude of unexpected and surprising results and consequently has initiated impassioned discussions among scientists. Although the human forms of TSE are very rare, the wildfire-like spread of the bovine spongiform encephalopathy (BSE) raises the pressing question as to whether BSE is communicable to humans. This overview summarizes some current hypotheses about the nature of the infectious agent and about the pathogenesis of the damage of the central nervous system.     

TSE pathogenesis in cattle and sheep

Many studies have been undertaken in rodents to study the pathogenesis of transmissible spongiform encephalopathies (TSE). Only a few studies have focused on the pathogenesis of bovine spongiform encephalopathy (BSE) and scrapie in their natural hosts. In this review, we summarize the most recent insights into the pathogenesis of BSE and scrapie starting from the initial uptake of TSE agents and crossing of the gut epithelium. Following replication in the gut-associated lymphoid tissues (GALT), TSE agents spread to the enteric nervous system (ENS) of the gut. Infection is then carried through the efferent fibers of the post-ganglionic neurons of the parasympathetic and sympathetic nervous system to the pre-ganglionic neurons in the medulla oblongata of the brain and the thoracic segments of the spinal cord. The differences between the pathogenesis of BSE in cattle and scrapie in sheep are discussed as well as the possible existence of additional pathogenetic routes.     

Strain typing of German transmissible spongiform encephalopathies field cases in small ruminants by biochemical methods

Following the implementation of a large scale transmissible spongiform encephalopathies (TSE) surveillance programme of small ruminants, evidence for a natural transmission of bovine spongiform encephalopathy (BSE) to a French goat has been found. During the years 2002-2004, a massive TSE rapid testing programme on >250,000 small ruminants was carried out in Germany. In this national survey, 186 scrapie-affected sheep were found which originated from 78 flocks. The majority of these cases were of the classical TSE type (115 sheep belonging to 14 outbreaks). However, 71 cases coming from 64 flocks were of the novel atypical scrapie type. According to the regulation EU 999/2001, all TSE cases in small ruminants have to be examined by strain typing methods to explore any possibility of the existence of BSE cases in the field sheep population. Here we report on a biochemical typing strategy (termed FLI-test), which includes the determination of molecular masses, antibody binding affinities and glycosylation pattern of the TSE induced abnormal prion protein. Based on this typing approach none of the analysed German classical TSE outbreaks (total number of analysed sheep: 36) displayed biochemical features indicative for a BSE infection. However, in two cases distinct but BSE-unrelated PrP(Sc) types were found, which alludes to the existence of different scrapie strains in the German sheep population.     

Abnormal prion protein in ectopic lymphoid tissue in a kidney of an asymptomatic white-tailed deer experimentally inoculated with the agent of chronic wasting disease

Chronic wasting disease (CWD), a transmissible spongiform encephalopathy (TSE) of deer and elk, is one of a group of fatal, neurologic diseases that affect several mammalian species, including human beings. Infection by the causative agent induces accumulations of an abnormal form of prion protein (PrPres) in nervous and lymphoid tissues. This report documents the presence of PrPres within ectopic lymphoid follicles in a kidney of a white-tailed deer that had been experimentally inoculated by the intracerebral route with CWD 10 months previously. The deer was nonclinical, but spongiform lesions characteristic of TSE were detected in tissues of the central nervous system (CNS) and PrPres was seen in CNS and in lymphoid tissues by immunohistochemistry. The demonstration of PrPres in lymphoid tissue in the kidney of this deer corroborates a recently published finding of PrPres in lymphoid follicles of organs other than CNS and lymphoid tissues in laboratory animals with TSE (scrapie).     

Molecular profiling and comparison of field transmissible spongiform encephalopathy cases diagnosed in Catalunya

Molecular profiling of the proteinase K resistant prion protein (PrP(res)) is a technique that has been applied to the characterisation of transmissible spongiform encephalopathy (TSE) strains. An interesting example of the application of this technique is the ability to differentiate, at the experimental level, between bovine spongiform encephalopathy (BSE) and scrapie infection in sheep, and to distinguish between classical and atypical BSE and scrapie cases. Twenty-six BSE cases and two scrapie cases from an active TSE surveillance program and diagnosed at the PRIOCAT, TSE Reference Laboratory (Centre de Recerca en Sanitat Animal, Universitat Autònoma de Barcelona, Catalunya, Spain) were examined by Western blotting. Molecular profiling was achieved by comparing the glycosylation profile, deglycosylated PrP molecular weight and 6H4/P4 monoclonal antibody binding ratio. The results obtained during the characterisation of these field cases indicated an absence of atypical BSE cases in Catalunya.     

小脑颗粒神经元细胞模型材料制备

小脑颗粒神经元是动物传染性海绵状脑痛发生、发展过程中的主要反应性细胞之一，小脑颗粒神经元的体外分离、纯化和鉴定是建立动物传染性海绵状脑痛细胞作用模型的关键步骤。根据大鼠小脑颗粒神经元的生存特性，按照抑制筛选的原理．对小脑颗粒神经元进行了体外分离和培养，经神经元特异性的烯醇化酶(NSE)免疫组织化学染色，表明体外培养的小脑颗粒神经元细胞纯度较高，可以用于细胞作用模型的建立。