The brain above illustrates the degenerative changes and atrophy caused by Creutzfeld-jakob Disease, a form of transmissible spongiform encephalopathy. When ‘mad cow disease’ is transmitted to humans it is classified as a varient of CJD. Typically CJD is transmitted through exposure to infected tissue usually through medical procedures, however there can be a other causes - such as hereditary CJD. A person is infected with a type of protein known as a ‘prion’, these occur normally within humans but the infectious form is folded in an abnormal way, which then alters normal, healthy prions in the cells of the host. It is thought that the neuronal loss and damage is caused by a build up of these proteins in the brain.
CJD is marked by a quick onset of neurological symptoms and a rapidly progressing dementia and decline of neurological functioning. Initially, individuals experience problems with muscular coordination; personality changes, including impaired memory, judgment, and thinking; and impaired vision. People with the disease also may experience insomnia, depression, or unusual sensations. As the illness progresses, mental impairment becomes severe. Individuals often develop involuntary muscle jerks called myoclonus, and they may go blind. They eventually lose the ability to move and speak and enter a coma. CJD is fatal, and there are no treatments for the condition.