For those like me who had to look this up...
What is Creutzfeldt-Jakob Disease?
Creutzfeldt-Jakob disease (CJD) is a rare, degenerative, invariably fatal brain disorder. Typically, onset of symptoms occurs at about age 60.. There are three major categories of CJD: sporadic CJD, hereditary CJD, and acquired CJD. There is currently no single diagnostic test for CJD. The first concern is to rule out treatable forms of dementia such as encephalitis or chronic meningitis. The only way to confirm a diagnosis of CJD is by brain biopsy or autopsy. In a brain biopsy, a neurosurgeon removes a small piece of tissue from the patient's brain so that is can be examined by a neurologist. Because a correct diagnosis of CJD does not help the patient, a brain biopsy is discouraged unless it is need to rule out a treatable disorder. While CJD can be transmitted to other people, the risk of this happening is extremely small.
And from the FaD site....
Creutzfeldt-Jakob disease (CJD) is a rare but fatal neurodegenerative disease for which there is no effective treatment. New variant CJD is associated with eating beef from cattle infected with bovine spongiform encephalopathy (BSE). The number of cases and reported deaths in the UK is still fortunately less than 200 but has grown significantly since 1990. The 2003 annual report of the CJD Surveillance Unit in the UK suggests that the number of cases has passed its peak although there are still concerns that the number of cases may reach epidemic proportions. Our understanding of the disease is still incomplete and the incubation period is largely a matter for speculation.