Plum J
Department of Clinical Chemistry, Microbiology and Immunology, University of Ghent.
Verh K Acad Geneeskd Belg. 1997;59(5):435-49.
Prion diseases are transmissible neurodegenerative disorders of humans and animals. The prion protein (PrPc) gene is expressed to some extent in many cell types but principally in neurons. Normal PrPc may contribute in the protection of neurons and are protease sensitive. Abnormal prions consist of a post-translationally modified form of PrP, PrPsc, which is partly protease resistant. PrPsc is a protein with high resistance to inactivation by irradiation, heat and harsh chemical treatments. It is currently proposed that PrPsc is an infectious protein that propagates by inducing the normal PrPc to become the abnormal PrPsc. PrPsc cause transmissible spongiform encephalopathies (TSE), an unusual group of degenerative brain diseases that can be transmitted by inoculation or ingestion of diseased brain or other tissues. The human diseases occur in an inherited, acquired and sporadic forms. Transmission of prion diseases between species is limited by a species barrier, determined in part by the degree of sequence homology between the host PrP and inoculated PrPsc. The epidemic of bovine spongiform encephalopathy (BSE) in the United Kingdom is a new disease that has affected over 160,000 cattle and has presumably arisen from dietary exposure to PrPsc from sheep with scrapie. Until shown otherwise we must assume that oral consumption of infectious BSE protein is a new factor for Creutzfeldt-Jakob (CJD) disease in man. This disease is a new variant of CJD (nvCJD) and has a different clinical picture. Early diagnostic markers to facilitate the diagnosis and screen blood and organ donors are not available. The control of the disease relies on the measures to eradicate the spread of BSE by banning the use of ruminant tissues in ruminant feed and slaughter and rendering procedures to ensure inactivation of prions of all infected animals. The control of nvCJD is based on reduction of exposure to BSE by banning a variety of tissues for consumption. A surveillance worldwide is increased for both BSE and nv-CJD and the WHO update regularly recommendations to limit the risk of transmitting the disease. The extent and size of the nvCJD will depend on different factors among others the dose of infectious material, the route of infection, the genetic susceptibility of the person. Therefore is not possible to predict how important the disease will be.
朊病毒病是人和动物的可传播性神经退行性疾病。朊病毒蛋白（PrPc）基因在许多细胞类型中都有一定程度的表达，但主要在神经元中表达。正常的PrPc可能有助于保护神经元，且对蛋白酶敏感。异常朊病毒由翻译后修饰形式的PrP即PrPsc组成，PrPsc对蛋白酶部分抗性。PrPsc是一种对辐射、加热和苛刻化学处理具有高度抗性的蛋白质。目前认为PrPsc是一种传染性蛋白质，它通过诱导正常的PrPc转变为异常的PrPsc来传播。PrPsc会导致可传播性海绵状脑病（TSE），这是一组不寻常的退行性脑部疾病，可通过接种或摄入患病大脑或其他组织进行传播。人类疾病有遗传、获得性和散发性三种形式。朊病毒病在物种间的传播受到物种屏障的限制，部分由宿主PrP与接种的PrPsc之间的序列同源程度决定。英国的牛海绵状脑病（BSE）疫情是一种新出现的疾病，已感染超过16万头牛，据推测是由于食用了患有羊瘙痒病的绵羊的PrPsc而引起的。在有其他证据之前，我们必须假定口服感染性BSE蛋白是人类克雅氏病（CJD）的一个新因素。这种疾病是CJD的一种新变体（nvCJD），具有不同的临床表现。目前尚无有助于诊断以及筛查血液和器官捐献者的早期诊断标志物。疾病的控制依赖于通过禁止在反刍动物饲料中使用反刍动物组织以及采取屠宰和无害化处理程序以确保所有感染动物的朊病毒失活等措施来根除BSE的传播。nvCJD的控制基于通过禁止食用多种组织来减少接触BSE。全球范围内对BSE和nv - CJD的监测都在加强，世界卫生组织定期更新建议以限制疾病传播风险。nvCJD的范围和规模将取决于多种因素，包括感染性物质的剂量、感染途径、个体的遗传易感性等。因此，无法预测这种疾病的严重性。
