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The Mysteries Surrounding Creutzfeldt-Jakob Disease Creutzfeldt-Jakob Disease
is a killer. What we know is that it wastes no time. Creutzfeldt-Jakob Disease
will kill a person within one year of contraction. It is yet unknown how
Creutzfeldt-Jakob Disease chooses its victims, but it does seem to have
accomplices, known as the spongiform encephalopathies, in the rest of the animal
kingdom. It is possible that it may be known what means Creutzfeldt-Jakob
Disease uses in order to annihilate its victims, but the theory surrounding that
is still controversial. By examining the facts and observing the evidence we
shall one day uncover the truth behind this malicious killer. Creutzfeldt-Jakob
Disease is a rare neuro-degenerative disease. Creutzfeldt-Jakob Disease is a
rare neuro-degenerative disease that leads to the loss of coordination, dementia
and death. Death usually occurs within a year of the onset of symptoms.
Creutzfeldt-Jakob Disease is a human disease and can be dormant for as long as
thirty years.
The average age of onset is sixty years, but there are recorded instances of
onset as easily as sixteen years and as old as 80 years. It is estimated that,
world-wide, between 0.5 and 1 case per million population occurs annually.
Increased incidence in some regions of the world has been attributed to the
possibility of a genetic predisposition. In the United States the incidence has
been reported as being 0.9 deaths per million population attributable to
Creutzfeldt-Jakob Disease. This is an inexact figure however, due to the fact
that Creutzfeldt-Jakob Disease is not a reportable disease in the United States
(Holman) and the Center for Disease Control does not actively monitor the
disease (Altman). To track the disease the Center for Disease Control has
initiated a four-state study of death certificates (Altman), but since death
certificates are not always accurate Davanpour) the survey may not provide an
accurate assessment. This leaves the true prevalence in the United States and
other countries remaining a mystery. Compounding the uncertainty, autopsies are
rarely performed on atypical dementia patients (Harrison) because medical
professionals fear infection (Altman).
The officially reported rate of Creutzfeldt-Jakob Disease incidence is less
than one case per million people per year (World). An informal survey of
neuropathologists, however, registered a theoretical range of 2 - 21% of all
dementia as actually Creutzfeldt-Jakob Disease (Harrison) and hundreds of
thousands of Americans suffer from severe dementia every year (Brayne; United).
Two other studies average about a 3% Creutzfeldt-Jakob Disease rate among
dementia patients (Mahendra; Wade). A preliminary 1989 University of
Pennsylvania study showed that 5% of patients diagnosed with dementia were
actually dying from Creutzfeldt-Jakob Disease (Boller). It would seem that
Creutzfeldt-Jakob Disease is seriously underdiagnosed. The most common
misdiagnosis of Creutzfeldt-Jakob Disease is Alzheimer's disease (Harrison).
Creutzfeldt-Jakob Disease was even described as “Alzheimer’s in fast forward (Wlalzek).”
The symptoms and pathology of both diseases overlap. There can be spongy changes
in the brain (a classic effect of Creutzfeldt-Jakob Disease) in Alzheimer's
disease, for example, and senile plaques deposited on the brain (a classic
effect of Alzheimer's disease) in Creutzfeldt-Jakob Disease (Brown).
The causes may overlap as well; epidemiological evidence suggests that people
eating meat more than four times a week for a prolonged period have a three
times higher chance of suffering dementia than long-time vegetarians (Giem),
although this result may be confounded by vascular factors (Van Duijn). Paul
Brown, medical director for the U.S. Public Health Service (Gruzen), said that
the brains of the young people who died from the new variant Creutzfeldt-Jakob
disease in Britain even look like the brains of Alzheimer's patients (Hager).
Stanley Prusiner, the scientist who coined the term prion, speculates that
Alzheimer's may in fact turn out to be a prion disease as well (Prusiner). In
younger victims the disease could look like multiple sclerosis or a severe viral
infection, according to Alzheimer's expert Gareth Roberts (Brain). Twenty
percent or more of people clinically diagnosed with Alzheimer's disease are
found at autopsy to not have had Alzheimer's at all (McKhann). At Yale, out of
46 patients clinically diagnosed with Alzheimer's, 6 were proven to have
actually had Creutzfeldt-Jakob Disease at autopsy (Manuelidis). In another
post-mortem study 3 out of 12 Alzheimer patients actually died from a spongiform
encephalopathy which is the class of diseases that Creutzfeldt-Jakob Disease
belongs to (Teixeira).
These spongiform encephalopathies appear to be diseases that enter the brain
and cause holes to appear which can then alter an animal’s functioning and
abilities. Eventually death occurs and the brains of these animals strongly
resemble sponges. At one point the causative agent was thought to be slow
viruses of the central nervous system, but no viruses were ever found and people
afflicted with spongiform encephalopathies never exhibited signs of
inflammation, indicating that the immune system was not involved in these
diseases (Quinion). Recently Professor Stanley Prusiner received the Nobel Prize
for his theory that Creutzfeldt-Jakob Disease and other spongiform
encephalopathy diseases were caused by proteinaceous infectious particles, or
prions. Prions are proteins without DNA that occur in the brains of all mammals
and are harmless until an altered form adopts the role of an infectious agent
(Altman). The normal function of prion proteins is not completely understood,
but recent research on mice that lack the gene which encodes the prion protein
suggest that it protects the brain against dementia and other degenerative
problems associated with old age (Gee). Sometimes rogue prions are produced by
genetic mutations. This explains why some cases of Creutzfeldt-Jakob Disease in
humans appear to be inherited.
If these rogue prions are transmitted from an infected animal to a new host
they will convert any normal prions that they encounter into copies of
themselves (Gee). The end result produces a brain full of vacuoles, especially
in the cortex and cerebellum, and covered in amyloid plaques (Altman).
Prusiner’s theory is still controversial as it has yet to be demonstrated
experimentally. However, it is of great importance because it is now established
that a type of Creutzfeldt-Jakob Disease called new-variant Creutzfeldt-Jakob
Disease, has, on occasion, been passed to humans through the consumption of beef
from cattle infected with Bovine Spongiform Encephalopathy, also commonly known
as Mad Cow’s Disease (Quinion). It is believed that the cattle themselves were
infected through farmers feeding them with protein from sheep infected with
scrapie, another spongiform encephalopathy (Quinion) suggesting that these
diseases can jump across species barriers.
Due to the fact that prions can be found in the brains of all mammals it is
probable that most mammalian species develop these spongiform encephalopathies.
Specific examples include Scrapie, the spongiform encephalopathy of sheep, TME
(transmissible mink encephalopathy) which affects mink, CWD (chronic wasting
disease) which affects muledeer and elk, and most commonly known is BSE (bovine
spongiform encephalopathy or mad cow disease). Creutzfeldt-Jakob Disease is not
the only known human spongiform encephalopathy. Also known to affect humans are
GSS (Gertmann-Straussler-Scheinker syndrome), FFI (Fatal Familial Insomnia),
Kuru, and Alpers Syndrome. The human diseases are characterized by loss of motor
control, dementia, paralysis wasting, and eventually death usually following
pneumonia. GSS occurs at approximately 2% of the rate of Creutzfeldt-Jakob
Disease (Chesebro). It usually occurs in the fourth or fifth generation, and was
once thought to be familial or genetic, but has been found to be sporadic as
well. GSS is characterized by cerebellar ataxia and motor problems. Dementia is
less common than with Creutzfeldt-Jakob Disease and the course of the disease
lasts several years until death occurs, whereas Creutzfeldt-Jakob Disease
patients seldom live more than a year.
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