Scrapie is a deadly, degenerative and transmissible disease that affects the central nervous system of sheep and goats.
Scrapie has been known since the 18th century. This disease has been present in sheep and goats for centuries and has been observed worldwide, but especially in Western Europe and North America. In French the disease is called Tremblante and in German Traberkrankheit.
The name Scrapie is derived from one of the symptoms. Due to severe itching, sick animals scrape their skin against fences or other fixed objects. Other symptoms are a dry coat and skin, and severe weight loss. Movement disorders can also occur. However, these are not as pronounced as with BSE in cattle; usually only one animal of the herd is affected.
Long incubation time
Scrapie has an incubation period of more than two years. As a result, the disease symptoms are only seen in adult animals. In non-susceptible animals, the pathogen has virtually no chance of causing disease symptoms during their relatively short lives.
There are classical forms and atypical forms of scrapie. Scrapie, like BSE, is a transmissible spongiform encephalopathy (TSE) or prion disease. Prion diseases are very unusual; unlike bacterial, viral or parasitic infections, prion diseases are caused by a protein that is normally present in the host. This protein is known as a prion protein or simply PrP.
Spreading the infection
Scrapie is an infectious disease. The nature of the agent (the prion) that causes Scrapie is not fully understood, and the mode of transmission is not entirely clear. It has been established that the Scrapie agent can survive several years in the environment, that it is relatively resistant to disinfectants and that host genetic (hereditary) factors mainly determine the susceptibility to the disease. In sheep, the assumption is that an important route of horizontal and vertical transmission is via the placental material (afterbirth) of infected ewes during lambing.
Stability of BSE infectivity towards heat treatment even after proteolytic removal of prion proteinVeterinary Research 52 (2021)1. - ISSN 0928-4249
Characterization of goat prions demonstrates geographical variation of scrapie strains in Europe and reveals the composite nature of prion strainsScientific Reports 10 (2020)1. - ISSN 2045-2322
Four types of scrapie in goats differentiated from each other and bovine spongiform encephalopathy by biochemical methodsVeterinary Research 50 (2019). - ISSN 0928-4249
Modelling of strategies for genetic control of scrapie in sheep : The importance of population structurePLoS ONE 13 (2018)3. - ISSN 1932-6203
Low fraction of the 222K PrP variant in the protease-resistant moiety of PrPres in heterozygous scrapie positive goatsJournal of General Virology 98 (2017)7. - ISSN 0022-1317 - p. 1963 - 1967.
Protecting effect of PrP codons M142 and K222 in goats orally challenged with bovine spongiform encephalopathy prionsVeterinary Research 48 (2017)1. - ISSN 0928-4249
Variation in the prion protein in Dutch goats for selective breeding to eradicate Scrapie
EU-approved rapid tests might underestimate bovine spongiform encephalopathy infection in goatsJournal of Veterinary Diagnostic Investigation 29 (2017)2. - ISSN 1040-6387 - p. 232 - 236.
Genetic, histochemical and biochemical studies on goat TSE cases from CyprusVeterinary Research 47 (2016). - ISSN 0928-4249 - 14 p.
Scrapie incidence and PRNP polymorphisms : Rare small ruminant breeds of Sicily with TSE protecting genetic reservoirsBMC Veterinary Research 12 (2016)1. - ISSN 1746-6148