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 recent years, the United
States has reported fewer than 300 cases of CJD a year.
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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.
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Select the graph for larger image
Annual Death Rate and Age-Adjusted Dealth Rate
* Deaths during 1979-1998 are based on
ICD-9 codes, deaths beginning in 1999 are based on ICD-10
codes plus available computerized literal death certificate
data; 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. |
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Date:April 13 , 2007
Content source: National Center for Infectious Diseases
About vCJD
Variant CJD was first described in 1996 in the United Kingdom. It
has different clinical and pathologic characteristics from
classic CJD. Each disease also has a particular genetic profile
of the prion protein gene. (See
table below). The median age at death for vCJD patients is 28
years, compared with 68 years for patients with classic CJD. The
median duration of illness for vCJD is 14 months, compared to 5
months for classic CJD.
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. |
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Evidence for Relationship with BSE
(Mad Cow Disease) Since 1996, evidence has been increasing for a
causal relationship between ongoing outbreaks in Europe of a disease
in cattle, called bovine spongiform encephalopathy (BSE, or 'mad
cow' disease), and vCJD. There is now strong scientific evidence
that the agent responsible for the outbreak of prion disease in
cows, BSE, is the same agent responsible for the outbreak of vCJD in
humans. Both disorders are invariably fatal brain diseases with
unusually long incubation periods measured in years, and are caused
by an unconventional transmissible agent. However, this evidence
also suggests that the risk is low for having vCJD, even after
consumption of contaminated product. In 1996, because of the
emergence of vCJD in the United Kingdom, CDC enhanced its
surveillance for CJD in the United States.
There has been one confirmed case
of Variant Creutzfeldt Jakob Disease (vCJD) in the United States in
a Patient from the Middle East
The Virginia Department of Health
and the Centers for Disease Control and Prevention announce the
recent confirmation of a vCJD case in a U.S. resident. This is the
third vCJD case identified in a U.S. resident. This latest U.S. case
occurred in a young adult who was born and raised in Saudi Arabia
and has lived in the United States since late 2005. The patient
occasionally stayed in the United States for up to 3 months at a
time since 2001 and there was a shorter visit in 1989. In late
November 2006, the Clinical Prion Research Team at the University of
California San Francisco Memory and Aging C Center confirmed the
vCJD clinical diagnosis by pathologic study of adenoid and brain
biopsy tissues. The two previously reported vCJD case-patients in
U.S. residents were each born and raised in the United Kingdom
(U.K.), where they were believed to have been infected by the agent
responsible for their disease. There is strong scientific evidence
that the agent causing vCJD is the same agent that causes bovine
spongiform encephalopathy (BSE, commonly known as mad cow disease).
Variant CJD is a rare,
degenerative, fatal brain disorder that emerged in the United
Kingdom in the mid-1990s. Although experience with this new disease
is limited, evidence to date indicates that there has never been a
case transmitted from person-to-person except through blood
transfusion. Instead, the disease is thought to result primarily
from consumption of cattle products contaminated with the BSE agent.
Although no cases of BSE in cattle have been reported in Saudi
Arabia, potentially contaminated cattle products from the
United Kingdom may have been exported to Saudi Arabia for many years
during the large U.K. BSE outbreak. |
As of November 2006, 200 vCJD
patients were reported world-wide, including 164 patients
identified in the United Kingdom, 21 in France, 4 in the Republic of
Ireland, 3 in the United States (including the present
case-patient), 2 in the Netherlands and 1 each in Canada, Italy,
Japan, Portugal, Saudi Arabia and Spain. Of the 200 reported vCJD
patients, all except 10 of them (including the present case-patient)
had resided either in the United Kingdom (170 cases) for over 6
months during the 1980-1996 period of the large UK BSE outbreak or
alternatively in France (20 cases).
As reported in 2005 (1),
the U.S. National Prion Disease Pathology Surveillance Center at
Case Western Reserve University confirmed the diagnosis in the one
previously identified case of vCJD in a Saudi resident. He was
hospitalized in Saudi Arabia and his brain biopsy specimen was
shipped to the United States for analysis. This earlier vCJD
case-patient was believed to have contracted his fatal disease in
Saudi Arabia (1).
1)
Belay ED, Sejvar JJ, Shieh W-J, Wiersma ST, Zou W-Q, Gambetti
P, Hunter S, Maddox RA, Crockett L, Zaki SR, Schonberger LB.
Variant Creutzfeldt-Jakob disease death, United States. Emerg
Infect Dis 2005, 11 (9):1351-1354.
Date: November 29, 2006
Content source: National Center for Infectious Diseases
The current case-patient has no history of receipt
of blood, a past neurosurgical procedure, or residing in or visiting
countries of Europe. Based on the patient's history, the occurrence
of a previously reported Saudi case of vCJD attributed to
likely consumption of BSE-contaminated cattle products in Saudi
Arabia, and the expected greater than 7 year incubation period for
food-related vCJD, this U.S. case-patient was most likely
infected from contaminated cattle products consumed as a child when
living in Saudi Arabia (1).
The current patient has no history of donating blood and the public
health investigation has identified no risk of transmission to U.S.
residents from this patient.
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