GROUP – 2 PRESENTATION
TOPIC:
PRESENTER:
MEMBERS OF GROUP 2
NO
NAME
NO
NAME
1
Mustapha Alpha – 5697
11
Umaru Barrie -
2
John Joe Sandy – 5478
12
Oredola Williams – 5613
3
Musa L. Kamara – 5557
13
Adetunji Wilson-Taylor -
4
Ahmad T. Garber – 5611
14
Yusuf Marah – 5432
5
John M. Koroma – 5722
15
Amara Conteh – 5839
6
Sukainatu Deen -
7
David F. Godwin – 5426
8
Prince Benjamin – 5721
9
Emmanuel Ucheya – 5470
10
Sylnata Johnson -
ORDER OF PRESENTATION
1. Brief overview of Prion Diseases
2. Creutzfeldt-Jakob Disease (CJD)
PRION DISEASES
Are also called TRANSMISSIBLE SPONGIFORM
ENCEPHALOPATHIES (TSE).
They are rare progressive, fatal, and
untreatable neurodegenerative disorders that
affect both humans & animals.
They result from protein changes into an
abnormal form called prion.
Prions are much smaller than viruses and
differ from viruses, bacteria, and all living cells
because they do not contain any genetic
material.
PRION DISEASES Cont.
In prion diseases, a normal protein called cellular
prion protein (PrPC) changes shape (misfolds) and
becomes abnormal.
This abnormal substance is now called scrapie
prion protein (PrPSc), or prion.
PrPC
misfolding
Irreversible
PrPSc
(Prion)
Scrapie refers to the prion disease first observed
in sheep.
Mutations in the gene for the prion
protein can cause a misfolding of the
dominantly alpha helical regions into
beta pleated sheets.
PRION DISEASES Cont.
 The newly formed prions
resist breakdown by enzymes
in the brain. Thus, they slowly
accumulate.
 The body defense system
remove these PrPSc aggregates
leaving behind holes
 When samples of brain tissue are viewed through
a microscope, they somewhat resemble Swiss
cheese or a sponge (hence, the term spongiform).
 This causes degeneration of the brain cells leading
to mental changes and ultimately, death.
Types of Prion Diseases
 Creutzfeldt-Jakob
disease (CJD),
 Gerstmann-SträusslerScheinker syndrome (GSS),
 Fatal Familial Insomia (FFI),
 Kuru in humans as a result ritualistic cannibalism
in Papua New Guinea – relatives prepared and
consumed the tissues (including brain) of deceased
family members.
Types of Prion Diseases
 Bovine Spongiform
 Scrapie in sheep.
encephalopathy (BSE mad cow disease)
 Chronic Wasting Disease (CWD) in elk and deer,
 Alpers’ Syndrome in infants is also thought to be
a transmissible spongiform encephalopathy
caused by a prion. (Nwanebu F. C. et al. 2008)
Prion Characteristics
 No antibiotics can cure disease caused by prions.
 They are not typical of a prokaryotic organism or a
eukaryotic organism.
 All that is present in this pathogen is the protein
PrPSc, the mutation of PrPC
 PrPSc is resistant to any form of digestion.
 Prions are non-immunogens and do not induce an
immune response.
 Prions are not easy to decompose biologically
 They are resistant to high temperatures &
disinfectants
Creutzfeldt-Jakob disease
(CJD)
Creutzfeldt-Jakob disease (CJD)
Bovine Spongiform Encephalopathy (BSE) was first
described in the UK in 1985 as a prion-based disease that
affected cattle.
In 1996, similar condition was detected in a human being.
It was then referred to as “Human form of mad-cowdisease”
The BSE was later named Creutzfeldt-Jakob disease
(CJD)
The disease was named after a German
neurologist Hans Gerhard Creutzfeldt and Alfons
Maria Jakob.
CJD is characterized by progressive deterioration of mental
function, leading to dementia, involuntary jerking of muscles
(myoclonus), and staggering when walking (ataxia).
The disease usually occurs spontaneously but may result from
eating contaminated beef or from inheriting an abnormal gene.
CLASSES OF CJD
Sporadic CJD
Variant CJD
(vCJD)
Acquired CJD
Kuru
Familial CJD
Iatrogenic
CJD
A. SPORADIC CJD
–
–
–
–
Is the most common form accounting for 85% of cases of CJD.
affects about 1 in a million people each year globally.
It usually affects people over 40 years old.
No cause is known.
B. FAMILIAL CJD
– Accounts for about 15% of the cases of CJD.
– Familial CJD is often inherited and usually starts at an earlier
age.
– Results from a mutation in the gene for prion protein, which
causes normal PrPC to change shape (misfold) and become
disease-causing prion .
– Lasts longer than sporadic CJD.
C. ACQUIRED CJD
– CJD can be acquired by eating beef or beef products from cattle
who have bovine spongiform encephalopathy (mad cow disease).
– The most common types are: kuru, variant & iatrogenic CJD.
– Variant CJD usually begins around age 30 or younger, (in contrast
to sporadic CJD, which usually begins after 40 yrs of age).
i. Variant CJD (vCJD) - caused by the consumption of food
contaminated with prions especially from infected cow/sheep.
ii. Iatrogenic CJD - from contamination with tissue from an infected
person, usually from:
 Infected blood transfusion,
 use of human-derived pituitary growth hormones,
 gonadotropin hormone therapy,
 corneal and/or meningeal transplants, or
 Surgical instruments.
iii. Kuru - from cannibalism of deceased family members (Papua
New Guinea).
EPIDEMIOLOGY
Countries that have confirmed human cases of vCJD
Countries that have BSE cases
EPIDEMIOLOGY
Although CJD is the most common human prion
disease, it is still rare.
It occurs worldwide at a rate of about 1 case per
million population per year.
In the United States, CJD deaths among persons
younger than 30 years of age are extremely rare
(fewer than five deaths per billion per year).
In more than 85% of cases, the duration of CJD is
less than 1 year (median: four months) after onset
of symptoms. (CDC, 2008)
By the end of 2000, nearly 90 people had died from
the disease in the UK.
Deaths from vCJD have also been reported in France
& Italy.
PATHOPHYSIOLOGY
Normal protein called cellular prion protein (PrPC)
changes into scrapie prion protein (PrPSc)/prions.
 PrPSc has the ability to convert other PrPC to
itself.
 A chain reaction follows, resulting in a cluster of
tangled, nonfunctional proteins called plaques,
which are aggregates of PrPSc in the brain.
 The body defences remove these PrPSc
aggregates leaving behind holes
 This causes degeneration of the brain cells
leading to mental changes and ultimately, death.
CLINICAL MANIFESTATION
 The symptoms of CJD are caused by the progressive death of the brain
cells.
 The first symptom is rapidly progressive dementia leading to memory
loss,
 This is followed by personality changes and hallucinations.
 Other frequently occurring features include:
 Changes in behavior,
 lack of coordination and the ability to walk straight (ataxia),
 memory loss and
 visual impairment.
 In later stages:
 Mental deterioration becomes very obvious, with unintentional
movements (myoclonus),
 Blindness,
 weakness of limbs, and
 infected persons may even go into a coma.
DIAGNOSIS
 CJD is suspected when there are rapidly progressing dementia
with myoclonus.
 Further investigation can then be performed to support the
diagnosis including.
1.
2.
3.
4.
5.
Electroencephalography - usually done to check for characteristic
abnormalities in the electrical activity of the brain. (However, these
changes occur late in the disease )
CSF analysis for 14-3-3 protein - these proteins are often (but not
always) present in people with CJD & they may be present in many
other disorders.
Magnetic Resonance Imaging (MRI) - It can detect characteristic
changes in the brain, including some that occur only in people with
variant CJD.
Blood test for PrPSc - Research have showed that PrPSc could be
detected in the blood of animals long before the symptoms
appeared.
Biopsy of brain tissue is the definitive diagnostic test for all other
forms of prion disease.
TREATMENT
Currently, CJD cannot be cured, and its progress
cannot be slowed.
However, certain drugs may be given to relieve
symptoms:
Valproate - an anticonvulsant agent,
Clonazepam and benzodiazepine - reduce muscle
jerks & anxiety.
General support and care for the person and family
members are important
PREVENTION
Don’t feed cattle with animal bi-products.
Watch to make sure you are feeding your
animals safe feeds.
All imported meat must be inspected.
Infected countries should not export cattle
or meat to uninfected areas.
Animals suspected of the disease should be
quarantined
Active National Disease Surveillance system.
1.
REFERENCES
Chakraborty C. et al. (April 2005). "Prion disease: a deadly disease for protein
misfolding". Current Pharmaceutical Biotechnology 6 (2): 167–77.
2. Obi RK, Nwanebu FC (2008). "Prions And Prion Diseases". African Journal of
Clinical and Experimental Microbiology 9 (1): 38–52.
3. Ironside, J. W. et al. (1996). "A new variant of Creutzfeldt–Jakob disease:
neuropathological and clinical features.". Cold Spring Harbor symposia on
quantitative biology 61: 523–30
4. Niimi Y, et al. (December 2008). "MM2-cortical-type sporadic Creutzfeldt–Jakob
disease with early stage cerebral cortical pathology presenting with a rapidly
progressive clinical course". Neuropathology 28 (6): 645–51.
5. WHO. (Feb 2012) "Fact sheets no 180: Variant Creutzfeldt-Jakob disease"
6. Lugaresi E. et al. Oct 16, 1986). "Fatal familial insomnia and dysautonomia with
selective degeneration of thalamic nuclei". The New England Journal of Medicine
315 (16): 997–1003.
7. Peden A. H. et al (2004) "Preclinical vCJD after blood transfusion in a PRNP codon
129 heterozygous patient". Lancet 364 (9433): 527–9.
8. Emerging Infectious Diseases: "Is Creutzfeldt-Jakob Disease Transmitted in
Blood?" (Ricketts et al) vol 3, Jun 1997
9. "CJD (Creutzfeldt–Jakob Disease, Classic)". Centers for Disease Control and
Prevention. 2008-02-26. Retrieved 2009-06-20.
10. Corinne Ida Lasmézas et al. (2013). "Unique drug screening approach for prion
diseases identifies tacrolimus and astemizole as antiprion agents". Proceedings of
the National Academy of Sciences 110 (17): 7044.
THANK YOU!!!