Creutzfeldt Jakob Disease – CJD – is the collective name for a group of diseases which cause progressive dementia and a loss of control of movement and balance. The overall incidence of CJD is approximately one case per million per year. However, this has increased in recent years. This increase is most likely due to active surveillance which has been established in many countries as well as improvements in diagnosis.
There are four types of Creutzfeldt Jakob disease. Sporadic CJD, the most common, usually affects individuals between the age of 50 and 75 years and is characterised by a rapidly progressive dementia. Familial CJD is an inherited disease associated with a gene mutation. Iatrogenic CJD results from transmission of a causative agent via medical or surgical treatment using accidentally contaminated materials, e.g., surgical instruments. New variant CJD – VCJD – is a new disease which was first described in March 1996.
Experimental evidence now indicates the VCJD and BSE are caused by the same agent. Brain tissue from VCJD patients show similar features to animals experimentally infected with the BSE agent. The source of infection remains to be established. The most likely explanation is the ingestion by humans of BSE contaminated food during the height of the epidemic in the UK prior to the implementation of the ban on specified bovine offals in the human food chain.