2. Introduction
Ebola virus causes Ebola virus disease
(EVD)/ Ebola hemorrhagic fever(EHF) an acute,
severe, often fatal illness, with a death rate of up to
90%
Illness affects humans and nonhuman primates
(monkeys,gorillas,chimpanzees)
Ebola viruses found in several African countries
Ebola first appeared in 1976 in 2 simultaneous
outbreaks, in nzara, sudan and in yambuku near the
ebola river, democratic republic of Congo
3. Since then, outbreaks have appeared sporadically in
Africa
The recent ebola outbreak in west Africa 2014 is the
largest,Cases and deaths surpassed all previous
combined
On August 8,2014 the WHO Director-General declared
this outbreak a Public Health Emergency of
International Concern
4. Ebola virus disease(EVD)
Acute febrile illness characterized by multisystem
involvement
Begins with abrupt onset headache, myalgias and
fever
Proceeds to prostration, rash,shock and often to
bleeding manifestations
Epidemics usually begin with a single case acquired
from an unknown reservoir in nature
Spread mainly through close contact with sick persons
or their body fluids
5. Virology
Ebola bolongs to virus family Filoviridae ( 3 genera-
Cuevavirus, Marburgvirus, Ebolavirus)
Genus ebolavirus comprises 5 distinct species-
1)Bundibugyo ebolavirus (BDBV),2)Zaire
ebolavirus (EBOV) ,3)Sudan ebolavirus
(SUDV),4)Reston ebolavirus (RESTV),5)Taï forest
ebolavirus (TAFV)
2014 west African outbreak due to Zaire species
Reston ebolavirus has caused disease in nonhuman
primates but not in humans
6. The viruses destroyed by heat 60°C, 30 min and by
acidity
It may persist for weeks in blood at room temperature
Ebola virus are biosafety level 4 pathogens because of
high associated mortality rate and aerosol infectivity
7. Molecular structure
• Filamentous, enveloped RNA virus ,Approx. 19 kb in length
or 60-80 nm in diameter
• Single-stranded, linear, non-segmented ,Negative-sense
RNA (encoded in a 3’ to 5’ direction)
• Appears to have “spikes” due to glycoprotein on Outside
membrane
8.
9. Ebola outbreaks
2014 west africa outbreak till
Feb 2015, WHO and respective
governments have reported a
total of 23,406 suspected cases
and 9,467 deaths
WHO believes that this
substantially understates the
magnitude of the outbreak
13. Reservior
Natural hosts: In Africa, fruit bats (Pteropodidae
family) three species tested positive for Ebola, but had
no symptoms of the virus, are considered possible
natural hosts for ebola.
Hammer-headed bats (Hypsignathus
monstrosus),Franquet's epauletted fruit bats
(Epomops franqueti) and little collared fruitbats (
Myonycteris torquata )
Animals monkeys, apes, or pigs may become
infected when they eat fruit partially eaten by bats
carrying the virus
14. Transmission
From animals
Ebola is introduced into the human population through close
contact with the blood, secretions, organs or other bodily
fluids of infected animals
Animals such as chimpanzees, gorillas, fruit bats, monkeys,
forest antelope and porcupines found ill or dead or in the
rainforest.
Undercooked meat. “bushmeat”
16. There is no evidence that mosquitos or other insects
can transmit Ebola virus
Human-to-human transmission:
Direct contact through broken skin or mucous membranes
(eyes, nose,mouth) with the blood, secretions, organs or
other bodily fluids (including but not limited to feces, saliva,
sweat, urine, vomit, breast milk, and semen) of infected
people.
17. Contact with objects contaminated (bedding, clothing,
needles, syringes etc.) with such fluids
Burial ceremonies in which mourners have direct contact
with the body of the deceased person.
Men who have recovered from the disease can still transmit
the virus through their semen for up to 7 weeks after
recovery from illness.
18. Health-care workers:
This has occurred when infection control precautions are not
strictly practiced while treating patients with suspected or
confirmed EVD
19. Pathogenesis
Acute infection associated with high levels of
circulating virus and viral antigen
Ebola replicate well in virtually all cell types
Viral replication is associated with cellular necrosis
Virus interacts with the cellular cytokine system
releases high proinflammatory cytokines contribute to
severity of illness
20. The glycoprotein spike mediate attachment to cells and
fusion.
The glycoprotein's high sugar content may contribute to
ineffective neutralizing antibodies.
A smaller circulating glycoprotein may suppress the
immune response to the virion surface protein or block
antiviral effector mechanisms.
Glycoprotein expression inhibits V integrin expression,
an effect that leads to detachment and subsequent death
of endothelial cells
21. Pathogenesis
GP
Secreted
GP
Full length
transmem
brane GP
Binds to
endothelial
cells,
monocytes,
macrophages
Multiplica
tion
Dimeric
protein
Inhibition of
Neutrophils
activation
Release of
cytokines
Inflammatory dysregulation,
Immune suppression,
Loss of vascular integrity.
22.
23. Virions are abundant in fibroblasts, interstitium lesser
extent the appendages of the subcutaneous tissues.
Viruse escape through small breaks in the skin or
possibly through sweat glands may occur
Recovery is apparently mediated by the cellular
immune response
Convalescent-phase plasma has little in vitro virus-
neutralizing capacity and is not protective
24. Clinical features
Incubation period: 2-21 days. A person infected with
Ebola virus is not contagious until symptoms appear.
Early Stage (non-specific) : Fever,generalised body
weakness headaches,arthralgia,myalgia,back pain,mucosal
redness of the oral cavity,dysphagia,conjunctivitis,rash all
over body except in face
If the patients don’t recover gradually at this point,
there is a high probability that the disease will
progress to the second phase, resulting in
complications which eventually lead to death
(Mupapa et al., 1999).
25. Advanced Stage (specific) : Vominting, diarrhoea,
impaired renal function, anuria, impaired liver function,
tachypnea, internal and external bleeding,
neuropsychiatric manifestations
Patients who progressed to phase two almost always
die. (Ndambi et al., 1999)
26.
27. Additional findings include edema of the face, neck,
and/or scrotum; hepatomegaly; flushing; conjunctival
injection; and pharyngitis
Late hepatitis, uveitis, and orchitis have been reported,
with isolation of virus from semen or detection of
PCR products in vaginal secretions for several weeks
28. Around 10–12 days after the onset of disease, the
sustained fever may break, with improvement and
eventual recovery of the patient.
Recrudescence of fever may be associated with
secondary bacterial infections or possibly with
localized virus persistence.
Some people who have recovered from Ebola have
developed long-term complications, such as joint and
muscle pain and vision problems
29. Lab findings
Initially Leukopenia later neutrophilia.
Platelet counts fall below 50,000/L.
Laboratory evidence of DIC
Elevated liver enzymes.
The serum amylase elevation may be associated with
abdominal pain, suggesting pancreatitis.
Proteinuria is usual;
Decreased kidney function is proportional to shock.
30. Diagnosis
Clinical diagnosis: Difficult because early symptoms
are nonspecific to virus.
Laboratory tests used in diagnosis include:-
1.Within a few days after symptoms begin: Antigen-
capture enzyme-linked immunosorbent assay (ELISA)
testing, IgM ELISA, Polymerase chain reaction
(PCR),Virus isolation
2.Later in disease course or after recovery: IgM and
IgG antibodies
3.Retrospectively in deceased patients: Immuno-
histochemistry testing, PCR, Virus isolation
31. Differential diagnosis
More common febrile diseases Malaria, Typhoid
fever, Shigellosis, Cholera, leptospirosis, Plague,
Rickettsiosis Relapsing fever, Meningitis, Hepatitis
and other viral haemorrhagic fever
32. Treatment
No specific antiviral therapy (e.g., antiviral drug) or
vaccine is available for Ebola
Symptoms of Ebola and complications are treated as
they appear
The following basic interventions, when used early,
can significantly improve the chances of survival- 1)
Providing intravenous fluids and balancing
electrolytes (body salts), 2) Maintaining oxygen status
and blood pressure, 3) Treating other infections if they
occur
33. Extensive viral involvement in fatal cases—
supportive treatment may not be as useful as was once
hoped.
Vigorous treatment of shock should take into account
the likelihood of vascular leak in the pulmonary and
systemic circulation and of myocardial functional
compromise
Experimental: drug favipiravir (Avigan) &
vaccines cAd3-EBOZ and VSV-ZEBOV
34. Prevention and control
Reducing the risk of wildlife-to-human
transmission:
• Avoid Contact with infected fruit bats or monkeys/apes
• Animals should be handled with gloves and other
appropriate protective clothing
• Avoid consumption of their raw meat
• Animal products (blood and meat) should be thoroughly
cooked before consumption
35. Reducing the risk of human-to-human transmission:
• Avoid Direct/close contact with infected patients & their bodily
fluids
• Not handle items (e.g. clothes, bedding, needles, and medical
equipment) that may have come in contact with an infected
person’s blood or body fluids
• Avoid funeral or burial rituals that require handling the body
of someone who has died from Ebola
• Gloves and appropriate personal protective equipment should
be worn when taking care of ill patients at home.
• Regular hand washing with soap and water or an alcohol-based
hand sanitizer is required after visiting patients in hospital, as
well as after taking care of patients at home.
36. Controlling infection in health-care setting
Apply standard precautions consistently with all
patients regardless of their diagnosis in all work practices
at all times
Basic hand hygiene, respiratory hygiene, the use of
personal protective equipment (according to the risk of
splashes or other contact with infected materials), safe
injection practices and safe burial practices
Samples taken from humans and animals for
investigation of Ebola infection should be handled by
trained staff and processed in suitably equipped
laboratories
37. While caring for patients with suspected or confirmed
ebola virus :In addition to standard precautions,
Avoid any exposure to the patient’s blood and body fluids
Avoid Direct unprotected contact with the possibly
contaminated environment
When in close contact (within 1 metre) Of patients with
EBV:
Wear face protection (a face shield or a medical mask and
goggles)
A clean, non-sterile long-sleeved gown
Gloves (sterile gloves for some procedures)
38.
39. Good outbreak control relies on applying a package of
interventions,
Case management
Surveillance and contact tracing, a good laboratory service
Safe burials and social mobilisation
Community engagement is key to successfully controlling
outbreaks
40. Educating the communities affected: Raising
awareness of risk factors for Ebola infection and
protective measures that individuals can take is an
effective way to reduce human transmission
• About the nature of the disease
• About outbreak containment measures
• Prompt and safe burial of the dead
41. Outbreak containment measures including-
Prompt and safe burial of the dead
Identifying people who may have been in contact with
someone infected with Ebola
Monitoring the health of contacts for 21 days
The importance of separating the healthy from the sick
to prevent further spread
The importance of good hygiene and maintaining a
clean environment
