Creutzfeldt-Jakob disease, rare, degenerative disease of the nervous system. It was thought that the Creutzfeldt-Jakob disease was caused by a slow virus that incubated in the body for months or years before symptoms appeared. Nowadays it is suspected to be a prion disease. The disease generally afflicts individuals during middle age. Earliest symptoms are memory loss or peculiar behavior, followed by visual disturbances and loss of muscular coordination. Death usually occurs within a year. There is no treatment or cure for this disease. Creutzfeldt-Jakob disease was first described in separate accounts in the early 1920s by 2 German neuropsychiatrists, Hans G. Creutzfeldt and Alfons M. Jakob. In 1996 a variation of the disease was discovered which is probably a human variant of the mad cow disorder.