牛海绵状脑病的研究现状

本文着重介绍牛海绵状脑病（ＢＳＥ）的临床症状、组织病理学变化、诊断及临床前诊断的前景，评述ＢＳＥ的发病起源和流行过程，分析为什么仅在英国如此大规模的流行，以及荷兰等其他国家发生ＢＳＥ的危害性和预防、控制的措施。本文进一步讨论ＢＳＥ遗传因子方面的发现，和试验传播的结果，包括可能危及人类健康的问题。     

牛海绵状脑病

牛海绵状脑病，是一种由未被确定的病原因子引起的牛的新传染病。它以脑灰质发生海绵状变性为特征。本文从该病的病原学猜测、流行病学、临床症状、诊断及分子生物学等几个方面综述了近年来国外的研究进展情况。     

牛海绵状脑病近况简介

1986年英国首次诊断出牛海绵状脑病（BSE）后，便开始了对BSE进行广泛性的研究，1992年国际动物流行病学组织将BSE列为重点研究项目[1]。本文将近来报道的有关BSE的资料进行简介：1流行情况英国1985年4月出现可疑病例，1986年发生17例并确认本病，1987年约发生486例，至1988年11月共发生1544例，以后逐年增多，1992年及1993年病牛超过35000头。从80年代至1995年底估计BSE病例已超过13万头以上，并已有3万多头牛死于BSE。到1996年3月已证实有BSE的国家和地区有：大不列颠、北爱尔兰、爱尔兰共和国、瑞典、瑞士、法国、阿曼苏丹、福…     

牛海绵状脑病研究进展

1.概述 牛海绵状脑病（Bovine SpongiformEncenphalopathy,BSE）,俗称疯牛病（Mad Cow Disease）,是牛的一种进行性、非炎性、高致死性的变性性神经系统疾病。其中要临床特征为精神状态异常、姿势和运动异常、感觉异常;病理组织学变化以脑干灰质特定神经元核周体或神经纤维网出现海绵状空泡变性为特征。该病被OIE规定为B类传染病,我国将其规定为A类传染病。     

羊痒病、疯牛病、克-雅二氏病

1羊痒病和朊病毒1730年,欧洲的英格兰发现绵羊的一种怪病,它能引起绵羊(偶见于山羊)发生一种缓慢发展的致死性中枢神经系统疾病.以共济失调、麻痹、衰弱和严重的皮肤骚痒为主要临床症状,病畜死亡率达100%,人们称之为羊痒病.1755年,羊痒病广泛传播,19世纪初从英格兰传入英国,并造成严重流行.目前已遍布于欧洲、亚洲和美洲多数养羊业比较发达的国家.我国至今仍然没有发生羊痒病的报道.     

牛海绵状脑病的卫生检疫

牛海绵状脑病（Bovinespongiformencephalopathy，BSE）是由非常规的传染性因子引起、潜伏期很长、病势逐渐加重并以死亡为转归的牛的一种中枢神经系统疾病。其病理学特征为中枢神经系统的灰质形成海绵样空泡。据此将本病命名为牛的海绵状脑病。英国于1986年首先发现BSE，这种病的原始型是山羊和绵羊的痒病（ScraPie）。本病在美国、爱尔兰、瑞典、法国、瑞士、丹麦、阿曼苏丹、福克兰群岛都有发生。1992年5月，国际兽疫局（OIE）召开的第60次会议上，将BSE列为重点疫病，放在牛的卫生检疫上，对BSE进行充分了解和监视是十分必要目…     

Direct Costs of Bovine Spongiform Encephalopathy Control Measures in Germany

On 26 November 2000, the first autochthonous case of bovine spongiform encephalopathy (BSE) was detected in Germany. Since then, a total of 413 BSE cases have been confirmed, resulting in the culling and destruction of 17 313 heads of cattle. In view of the possible risks for human and animal health, Germany has adopted EU regulations along with some additional requirements concerning active surveillance and response measures after detecting a BSE‐positive animal. In this study, we used a stochastic model to estimate the costs incurred by the ensuing legislative amendments responding to BSE between November 2000 and December 2010. The total costs were estimated to range between 1847 and 2094 million Euros. They peaked in 2001 (about 394 million Euros) and declined since. About 54% of the costs (approximately 1000 million Euros) were incurred by the extension of the feed ban for animal protein to all farmed livestock. Active surveillance accounted for 21% (405 million Euros), the incineration of animal protein for 13% (249 million Euros) and the removal of specified risk material for 11% (225 million Euros). Only 1% of the costs was related to response measures after detecting a BSE‐positive animal, including indemnity payments for culled cattle and confiscated carcasses at the slaughterhouse.     

疯牛病发生与防制新进展

疯牛病（Mad-cow disease)是牛海绵状脑病（Bovine Spongiform Encephalopathy,BSE)的俗称，是一种慢性、传染性、致死性的中枢神经系统疾病。该病自1985年4月首次在英国发现以来，至今已在许多国家都有发现。目前，世界上有100多个过国家面临着严重疯牛病的威胁。本文从病原、流行病学、发生与防制等方面对疯牛病进行了综述。     

疯牛病感染因子的检测

研究目的是对北京某公司研制的一种牛血源性生物制品进行疯牛病感染因子的检测。通过对供体牛及其产地牛进行疯牛病流行病学调查及免疫细胞化学、Western blot和组织病理学检测，确认这些供体牛没有感染疯牛病，以其血液作为原料研制的生物制品没有携带疯牛病病原的危险，本研究也为在我国进一步建立牛源性药品、生物制品中疯牛病感染因子的检测和评估提供了科学资料。     

Age-period-cohort analysis of the Bovine Spongiform Encephalopathy (BSE) epidemic in Switzerland

Cattle born after animal-feed control measures were implemented in 1990 have become BSE cases in Switzerland, indicating sub-optimal effectiveness of these measures. To evaluate these measures, the incidence of BSE cases in Switzerland recorded through clinical case reporting from January 1991 to June 2000 (categorized into age groups and birth cohorts of 6-month duration) was analyzed by Poisson log-linear regression using an age–period–cohort model. The incidence was maximum in the cattle cohort born from October 1989 to March 1990, and dropped to zero in the cohort born from April to September 1991. A second peak was observed in a cohort born from April to September 1994. The first drop of incidence is interpreted as a result of initial implementation of the feed ban in 1990. The second peak might be related to exposure of cattle to feed intended for pigs and poultry.     

牛朊蛋白基因多态性对疯牛病影响的研究进展

朊蛋白(prion protein,PRNP)是近年来已证明的人和部分哺乳动物传染性海绵状脑病(transmissible spongiform encephalopathy,TSE)的主要根源,该蛋白编码基因的多态性显著影响了人和动物对TSE的易感性或抗病性。牛传染性海绵状脑病俗称"疯牛病"。作者分析了疯牛病的起源、监测和预防措施;简要介绍了牛PRNP基因的结构与功能;系统分析了牛科动物PRNP基因非编码区多态性与抗病性作用;总结了牛科动物PRNP基因启动子区域内23 bp插入/缺失和第1内含子区域内12 bp插入/缺失对疯牛病易感性的影响,为牛的抗病分子育种提供指导。     

疯牛病的研究动态和我国防控体系建设

目前,欧洲、北美洲、亚洲都不同程度发生疯牛病疫情,文章重点介绍世界各国在疯牛病预防、监测、基础理论方面的研究动态,以及我国疯牛病防控体系现状。     

Sequence variations of the bovine prion protein gene (PRNP) in native Korean Hanwoo cattle

Bovine spongiform encephalopathy (BSE) is one of the fatal neurodegenerative diseases known as transmissible spongiform encephalopathies (TSEs) caused by infectious prion proteins. Genetic variations correlated with susceptibility or resistance to TSE in humans and sheep have not been reported for bovine strains including those from Holstein, Jersey, and Japanese Black cattle. Here, we investigated bovine prion protein gene (PRNP) variations in Hanwoo cattle [Bos (B.) taurus coreanae], a native breed in Korea. We identified mutations and polymorphisms in the coding region of PRNP, determined their frequency, and evaluated their significance. We identified four synonymous polymorphisms and two non-synonymous mutations in PRNP, but found no novel polymorphisms. The sequence and number of octapeptide repeats were completely conserved, and the haplotype frequency of the coding region was similar to that of other B. taurus strains. When we examined the 23-bp and 12-bp insertion/deletion (indel) polymorphisms in the non-coding region of PRNP, Hanwoo cattle had a lower deletion allele and 23-bp del/12-bp del haplotype frequency than healthy and BSE-affected animals of other strains. Thus, Hanwoo are seemingly less susceptible to BSE than other strains due to the 23-bp and 12-bp indel polymorphisms.     

Trends in genotype frequency resulting from breeding for resistance to classical scrapie in Belgium (2006~2011)

In sheep, susceptibility to scrapie is mainly determined by codons 136, 154, and 171 of the PRNP gene. Five haplotypes are usually present (ARR, ARQ, ARH, AHQ, and VRQ). The ARR haplotype confers the greatest resistance to classical scrapie while VRQ renders animals most susceptible. In 2004, the European Union implemented a breeding program that promotes selection of the ARR haplotype while reducing the incidence of VRQ. From 2006 to 2011 in Belgium, frequency for the ARR/ARR genotypes increased from 38.3% to 63.8% (n = 6,437), the ARQ haplotype diminished from 21.1% to 12.9%, and the VRQ haplotype decreased from 2.0% to 1.7%. The status of codon 141, a determinant for atypical scrapie, was also evaluated. Out of 27 different breeds (n = 5,163), nine were abundant. The ARR/ARR frequency increased in eight of these nine major breeds. The selection program has had a major impact on the ARR haplotype frequency in Belgium. However, the occurrence of atypical scrapie represents a critical point for this program that warrants the continuous monitoring of scrapie. Additionally, genotype frequencies among the breeds varied greatly. Texel, a breed that is common in Belgium, can still be selected for due to its average ARR frequency.