scrapie

Scrapie is one of the transmitted spongiform encephalopathy (tse) diseases and it is most common in small ruminants such as ovine and caprine. scrapie agent is a misfolded prion protein (prpsc). pathological brain studies have shown neuron abnormalities and loss, neurogliosis, tissue vacuolization(spongiosis), and prpsc deposition؛ which explains the observed clinical signs. there are two groups of clinical signs recognized in affected animals: the neurological signs which are ataxia, pruritus in hairless areas, cachexia, and hyperesthesia—the behavioral changes such as restlessness, hyperexcitability to external stimuli, and resistance to handling. scrapie was first diagnosed in england about 270 years ago؛ then in 1946, it was found transmitable to caprine species as well. soon it spread out all over the world until 1998 they diagnosed scrapie with some different and new clinical signs and pathogenesis in norway؛ in 2003 it was known as a separate disease and named atypical scrapie. the previous form is named classical scrapie. every year scrapie harms millions of dollars because of carcass deletion. it can be transmitted to different species, even humans, in variable ways such as infected meat and body secretion. in this review article, we studied this disease in different aspects including etiology, genetic factors, pathogenesis, pathology, diagnosis, and control and prevention. we also checked the possibility of scrapie being the origin of many tse diseases.