Animal Prion Diseases
Prion diseases occur in many animal species, most notably in ruminants. While scrapie in sheep has been recognised for three centuries and goat scrapie has been recognised for decades, BSE in cattle is a relatively novel disease which was first diagnosed
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Animal Prion Diseases Otto Windl and Mike Dawson
Abstract Prion diseases occur in many animal species, most notably in ruminants. While scrapie in sheep has been recognised for three centuries and goat scrapie has been recognised for decades, BSE in cattle is a relatively novel disease which was first diagnosed in the UK in the mid 1980s. BSE was most likely caused through dietary exposure to animal feed contaminated with prions and disease was subsequently transmitted to people. The BSE epidemic is almost at an end, but the recent identification of so called atypical forms of BSE and scrapie pose many questions about the possible spectrum of prion diseases in animals and their transmissibility to other species, including humans. The pathogenesis of animal prion diseases has been studied both in natural infections and in experimental animal models. Detection of infectivity is greatly helped by suitable rodent models, in particular transgenic mice. Clinically infected animals show characteristic neuropathology in the brain and spinal cord which is accompanied by the accumulation of a conformationally altered, protease-resistant host protein. The post-mortem diagnosis is based on the detection of this protein, PrPSc , but despite recent impressive developments a routine ante-mortem diagnostic test has proved elusive. There is no treatment for prion diseases in animals, but disease outbreaks are controlled through a mixture of movement restrictions on holdings, culling of affected animals and herds and, for classical scrapie in sheep, selective breeding for genetic resistance. Prions are very stable and can remain in the environment for prolonged periods. This poses serious practical questions with regard to the decontamination of infected premises. The control of BSE specifically through restrictions in animal feeding practises has been successful, but the changing spectrum of these diseases plus the economic pressures to relax feed bans and reduce levels of surveillance will require constant vigilance to safeguard animal and public health. Keywords Animal prion disease · Bovine spongiform encephalopathy (BSE) · Scrapie · Rodent models O. Windl () · M. Dawson Animal Health and Veterinary Laboratories Agency, New Haw, KT15 3NB, United Kingdom e-mail: [email protected] M. Dawson e-mail: [email protected]
J. R. Harris (ed.), Protein Aggregation and Fibrillogenesis in Cerebral 497 and Systemic Amyloid Disease, Subcellular Biochemistry 65, DOI 10.1007/978-94-007-5416-4_18, © Springer Science+Business Media Dordrecht 2012
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O. Windl and M. Dawson
Introduction
The scientific and political profile of prion diseases, or transmissible spongiform encephalopathies (TSE)s, animal and human, increased significantly in the last two decades of the twentieth century. Before 1986, interest was mainly restricted to very rare and exotic diseases in humans and to scrapie, a transmissible, fatal, neurodegenerative disease of unknown aetiology affecting sheep and occasionally goats. Classical scrapie in
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