Transcript Ebola Virus - Pleasant Valley Community School

Scientific Name:
Ebola Virus
Filoviridae family
4 strains – Ebola-Zaire, EbolaSudan, Ebola-Cote d’Ivoire,
Ebola-Reston
Common name: Ebola
Causes Ebola hemorrhagic fever
Description
• RNA strand virus
– Coiled RNA in spike-covered envelope
from host cell
• Long rods (800-1000 nm)
• Replication = 8 hours
– Therefore, spreads rapidly
Natural Habitat = Africa
Sudan
• Zaire (Democratic
Republic of the Congo)
– Ebola-Zaire
• Sudan
– Ebola-Sudan
• Gabon
• Ivory Coast
Ivory Coast
– Ebola-Cote d’Ivoire
Uganda
Gabon
• Uganda
• Republic of the Congo
(not the DRC)
Congo
DRC
Natural Reservoir
Suspected to be a zoonotic (animalborne)
However, it is unknown what
organism carries it naturally
without being infected
Suspected vectors
• Bats
• Primates (in some cases, have
been confirmed)
• Basically any other animal native
to Africa, including mosquitoes,
ticks, birds, reptiles
No benefits
Uses: Possible terror weapon
(no uses)
Never normal flora in humans
(it really sucks)
Ebola hemorrhagic fever
Transmission
Ebola-Reston has shown to be airborne
The other three strains are transmitted by contact of any kind (fluids
or skin)
Target Groups
Anyone who comes in contact with an infected animal or person is at
high risk of contacting the disease.
However, some people seem to have natural defenses in their
immune system that allow their bodies to kill the virus. Scientists do
not know exactly how this occurs.
Ebola hemorrhagic fever
Target Organs and Damage Methods
Target mainly small capillary vessels. Attach to walls, cause
leakage of blood and serum into surrounding tissue.
When white blood cells attack the virus, they dissolve – this releases
a chemical into the blood stream that signals the release of other
chemicals (pro-inflammatory cytokines, pro-coagulants, and
anticoagulants)
These injure blood vessels even worse, resulting in permanent
bleeding.
Eventually, the entire body is leaking and dissolving
Ebola hemorrhagic fever
Incubation Period: Anywhere from 2-21 days
As it progresses:
Symptoms:
• Severe headache
• Weakness
• Muscle aches
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Severe vomiting
Abdominal pain
Diarrhea
Pharyngitis
Conjunctivitis
External bleeding
Extremely high body temperature
Prostration
Ebola hemorrhagic fever
Fatality Rates:
• Ebola-Sudan – 60%
• Ebola-Zaire – 77-88%
• Ebola-Reston – Found in
monkeys, has not shown to be
fatal in humans
• Ebola-Cote D’Ivoire – Only one
human case recorded, patient
survived
MASS GRAVES FOR
EBOLA VICTIMS
Not much is known about the
body’s response because of
the dangers of handling
samples from infected patients
and the short time span
available for investigation.
Ebola hemorrhagic fever
Diagnosis and Identification
Clinical Diagnosis:
-Difficult because early symptoms (red eye, skin rash) are
nonspecific to virus.
-Takes a combination of many symptoms characteristic of
Ebola.
Laboratory Testing/Diagnosis:
-Antigen-capture enzyme-linked immunosorbent assay (ELISA)
-IgM ELISA test
-Polymerase Chain Reaction (PCR) – a DNA test to match the
DNA from the sample to known Ebola DNA
-All done within a few days of onset of symptoms
Ebola hemorrhagic fever
Diagnosis Continued
Advanced Stage Testing:
-Test for IgM and IgG anitbodies
Retrospective Testing:
-Immunohistochemistry testing
-Virus isolation
-PCR
(Occur after death)
Culture
Only grows in cells
Ebola hemorrhagic fever
THERE IS NO CURE FOR EBOLA HF
Care of Infected Persons:
-Supportive therapy
-Balance fluids and electrolytes
-Maintain oxygen status, BP
-Treatment of complicating infections
Experimental Treatment:
-In the Kikwit outbreak in DRC, doctors transmitted blood from survivors to
sufferers, hoping to transmit whatever antibodies helped them survive.
It is unknown whether or not survivors gain immunity from infection. Doctors
believe it is possible, but because of the limited ability to test this theory, it
remains to be seen.
Ebola hemorrhagic fever
Prevention
Classified as Biosafety level 4
(greatest threat to humans)
Extensive precautions taken when
dealing with suspected cases to
limit transmission
• Several layers of protective
clothing covering entire body (up
to four)
• Complete equipment sterilization
• Quarantine of Ebola HF patients
Ebola hemorrhagic fever
Future outlook
A study released in December of 2003 showed that researchers
studying infected monkeys have found a way to increase survival
rates
100% of infected monkeys had been dying
These were injected with rNAPc2, a factor known to inhibit blood
coagulation, a characteristic of Ebola HF
33% of these monkeys survived and regained health. All untreated
monkeys died.
rNAPc2 is known to be relatively safe in humans – this method is being
studied further
Sources
“Ebola Hemorrhagic Fever.” Special Pathogens Branch:
Diseases. Nov. 26, 2003. Center for Disease Control
and Prevention. 3/19/04
<http://www.cdc.gov/ncidod/dvrd/spb/mnpages/dispages
/ebola.htm>
Murphy, Frederick A. “Ebola Virus.” Encarta. CD-ROM.
Microsoft, 2002
Russell, Brett. Ebola Information. 3/19/04
<http://www.brettrussell.com/personal/ebola.html>
Col. Weeks, Byron, M.D. “Ebola – A Serious Threat.”
NewsMax.com. Oct. 17, 2001. 3/19/04
<http://www.newsmax.com/archives/articles/2001/10/12/
82239.shtml>