What types of Creutzfeldt-Jakob disease are there?
There are three types of Creutzfeldt-Jakob Disease: sporadic (or classical), hereditary (or familial) and acquired (or iatrogenic).
Sporadic or classical (sCJD) - Sporadic CJD accounts for the greatest number of human deaths from this group of diseases (approximately 85 per cent). CJD affects approximately one in every million people each year. So, in the Australian population of about 20 million, there are likely to be approximately 20 cases in one year. CJD most often affects people between the ages of 50 to 70 years.
Hereditary or familial - In hereditary CJD, the person has a family history of the disease and/or tests positive for a genetic mutation associated with CJD. About 5 to 10 percent of cases of CJD in the United States are hereditary.
Acquired or iatrogenic (aCJD) - Acquired CJD occurs when the patient is contaminated through medical procedures. Another type of acquired CJD called variant CJD refers to people who contract the disease when they eat beef tainted with BSE (bovine spongiform encephalopathy or mad cow disease).
A new variant of the disease (usually called just variant Creutzfeldt-Jakob Disease (vCJD) but sometimes new variant Creutzfeldt-Jakob Disease (nvCJD)) is distinguished from the classical type by its early onset (usually in the 20s) and a predominance of psychiatric and sensory symptoms. The prions in this form are thought to be transmitted by consuming the meat of bovines with so-called mad cow disease (Bovine Spongiform Encephalopathy), although there is no definite proof of this association as yet. However over 95% of identified cases of vCJD are in Britain, which suffered a mad cow disease epidemic in the mid-80s.