About CJD

This tissue slide shows sponge-like lesions in the brain tissue of a classic CJD patient. This lesion is typical of many prion diseases. Larger Picture
(Image courtesy Ermias Belay)

Classic CJD is a human prion disease. It is a neurodegenerative disorder with characteristic clinical and diagnostic features. This disease is rapidly progressive and always fatal. Infection with this disease leads to death usually within 1 year of onset of illness.
Important Note: Classic CJD is not related to "mad cow" disease. Classic CJD also is distinct from "variant CJD", another prion disease that is related to BSE.

For information about these diseases, see:

"Mad cow" disease (bovine spongiform encephalopathy or BSE)
Variant Creutzfeldt-Jakob Disease (vCJD)

Occurrence and Transmission

Classic CJD has been recognized since the early 1920s. The most common form of classic CJD is believed to occur sporadically, caused by the spontaneous transformation of normal prion proteins into abnormal prions. This sporadic disease occurs worldwide, including the United States, at a rate of approximately one case per 1 million population per year, although rates of up to two cases per million are not unusual. The risk of CJD increases with age, and in persons aged over 50 years of age, the annual rate is approximately 3.4 cases per million. In the most recent five year period, the United States has reported between 279 and 352 cases a year.
Whereas the majority of cases of CJD (about 85%) occur as sporadic disease, a smaller proportion of patients (5-15%) develop CJD because of inherited mutations of the prion protein gene. These inherited forms include Gerstmann-Straussler-Scheinker syndrome and fatal familial insomnia.

This graph demonstrates the annual deaths related to Creutzfeldt-Jakob disease in the United States from 1979 - 2009.

Select the graph for larger image.

Annual Death Rate and Age-Adjusted Death Rate

* Deaths obtained from the multiple cause-of-death data for 1979-1998 are based on ICD-9 codes, and those beginning in 1999 are based on ICD-10 codes with available computerized literal death certificate data. Death information was also obtained from other surveillance mechanisms; includes familial prion disease. Rates are adjusted to the US standard 2000 projected population.

Clinical and Pathologic Characteristics of Classic CJD

Classic CJD characteristics, as compared to variant CJD, are presented in the table below.

**Clinical and Pathologic Characteristics Distinguishing Classic CJD from Variant CJD**
Characteristic	Classic CJD	Variant CJD
Median age at death	68 years	28 years
Median duration of illness	4-5 months	13-14 months
Clinical signs and symptoms	Dementia; early neurologic signs	Prominent psychiatric/behavioral symptoms; painful dyesthesiasis; delayed neurologic signs
Periodic sharp waves on electroencephalogram	Often present	Often absent
"Pulvinar sign" on MRI*	Not reported	Present in >75% of cases
Presence of "florid plaques" on neuropathology	Rare or absent	Present in large numbers
Immunohitochemical analysis of brain tissue	Variable accumulation	Marked accumulation of protease-resistance prion protein
Presence of agent in lymphoid tissue	Not readily detected	Readily detected
Increased glycoform ratio on immunoblot analysis of protease-resistance prion protein	Not reported	Marked accumulation of protease-resistance prion protein
Source: Adapted from Belay E., Schonberger L. Variant Creutzfeldt-Jakob Disease and Bovine Spongiform Encephalopathy. Clin Lab Med 2002;22:849-62.
*An abnormal signal in the posterior thalami on T2- and diffusion-weighted images and fluid-attenuated inversion recovery sequences on brain magnetic resonance imaging (MRI); in the appropriate clinical context, this signal is highly specific for vCJD.

Reference in this website to any specific commercial products, process, service, manufacturer, or company does not constitute its endorsement or recommendation by the U.S. Government or CDC. CDC is not responsible for the contents of any "off-site" web page referenced from this server.

Date: November 15, 2012
Content source: Centers for Disease Control and Prevention
National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)
Division of High-Consequence Pathogens and Pathology (DHCPP)