3. •Ebola virus disease (EVD), formerly Ebola hemorrhagic fever(EHF)
• is a Zoonotic disease
•caused by Ebola virus.
•Ebola is single stranded monosagmented RNA virus.
•It causes severe hemorrhagic fever that resembles fulminant septic
shock.
•Acquired upon contact with blood or body fluid of an infected
person or animal.
Introduction
4. • Bats drop partially eaten fruits, which Monkeys, Antelopes, Man,
etc feed on and contact the disease.
• Contact with Blood or body fluid of infected animals/person.
• Burial ceremonies- Direct contact with the corpse of infected
person. Embalming
• Formites; Utensils used by infected person, can spread the
disease.
Transmission
5.
6. 1. Direct contact with contaminated human body fluids such as
blood, urine, vomitus, faeces and semen
2. Contact with contaminated medical products such as
syringe needles
3. Consumption of wild animal meat (“bush meat”)
Mode of infection
7. • Body entry; The Virus Enters the body through mucous
membranes, breaks in the skin, or parenterally.
• Glycoprotein synthesis(GP); After infection, the Virus
synthesize GP called Ebola virus GP, that binds the virus to
Macrophages/ neutrophils, Dendritic cells, and Endothelial
cells of blood vessels.
Pathogenesis
8. •Macrophage/ Nuetrophils inactivation; EV uses EV GP to
invade Macrophage/ Neutrophil, then inhibit early steps of
their activation.
•This inactivation allows the virus to evade immune
system, colonize the host cells, and begin to replicate in
large number.
•Virus replicates preferentially in monocytes/macrophages
and dendritic cells which facilitate dissemination of the
virus throughout the body via lymphatic system
9. • Other cells are secondarily infected and there is rapid
viral growth in hepatocytes,endothelial and epithelial
tissues
• Macrophages infected with Ebola virus produce different
cytokines and nitric oxide (NO) .
• Breakdown products of necrotic cells also stimulate the
release of the same cytokines
• These cytokines are responsible for the fever, malaise,
vasodilatation, increased vascular permeability,
hypotension, and shock of ebola virus disease
10.
11. • Virus-infected macrophages synthesize cell-surface
tissue factor (TF), triggering the extrinsic coagulation
pathway
Liver dysfunction and protein C synthesis inhibited
Small blood clots form in vessels
Consume all the available coagulation proteins and
platelets
Normal coagulation is disrupted, this leads to abnormal
bleeding
Disruption of normal blood flow to organs and multi
organ failure
•
•
•
•
•
12. •EV disable antigen-specific immune responses, by
damaging Dendritic cells, which are responsibility for the
initiation of adaptive immune responses.
•Infected Dendritic cells fail to undergo maturation, thus
unable to present antigens to lymphocytes, as such Ebola
pt, fail to develop antibodies to the virus.
•Failure of adaptive immunity and lymphocyte apoptosis,
explain how EV cause severe/fatal illness
15. Late symptom
•Ecchymosis /bruising,
•Oozing from venipuncture site.
•Bleeding nose, ear.
•Eye inflammation(conjunctivitis).
•Bleeding from mouth/rectum.
•Genital swelling(labia/scrotum).
•Roof of mouth looks red.
•Confusion, Seizures, coma.
•Death mostly due to Shock
16. •Avoid bush-meat.
•Regular washing of hands.
•Early detection/Contact tracing/Isolation.
•Screening travelers from affected countries
•Quarantine of suspected case
•Proper sterilization of equipments
•Proper burials of died.
•Public awareness.
Prevention
17. •Ebola has no cure.
•Supportive treatment only;
• Oxygen; Help breathing
•Antibiotics: Prevent bacterial infection.
•Analgesic; Fever and body ache.
•IVF; Maintain fluid and electrolyte balance.
•Transfusion; Bleeding
Treatment
18. •Baize S. et al. Emergence of Zaire Ebola Virus Disease in Guinea -
Prepminary Report. N Engl J Med. 2014 Apr 16. epub
•Feldmann H , Geisbert TW. Ebola Haemorrhagic Fever. Lancet.
2011 Mar 5;377(9768):849-62.
•Fowler RA, Fletcher T, Fischer WA, et al. Caring for Critically Ill
Patients with Ebola Virus Disease: Perspectives from West Africa.
Am J Respir Crit Care Med. 2014 Aug 25. Epub
•Kortepeter MG, Bausch DG, Bray M. Basic Cpnical and Laboratory
Features of Filoviral Hemorrhagic Fever. J Infect Dis. 2011 Nov;204
Suppl 3:S810-6
•WHO Ebola Response Team. Ebola Virus Disease in West Africa –
The First 9 Months of the Epidemic and Forward Projections. N Eng
J Med. 2014 Sept 23. Epub
•Ebola-Reston Virus Infection Among Quarantined Nonhuman
Primates -- Texas, 1996 Morbidity and Mortality Weekly Report,
Vol 45, No 15;314 ,April 19, 1996 / 45(15);314-316
References
