EBOLA VIRUS - Dr. S.Sivasankara Narayani

1. 17CY312 – MEDICAL
MICROBIOLOGY (UNIT –II)
Dr. S. SIVASANKARA NARAYANI
ASSISTANT PROFESSOR
DEPARTMENT OF MICROBIOLOGY
AYYA NADAR JANAKI AMMAL COLLEGE
SIVAKASI
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EBola

2. EBOLA
• The Ebola virus causes an acute, serious illness which is often fatal if untreated.
• EVD first appeared in 1976 in 2 simultaneous outbreaks, one in what is now Nzara, South Sudan, and the other in Yambuku, DRC.
• The latter occurred in a village near the Ebola River, from which the disease takes its name.
• The 2014–2016 outbreak in West Africa was the largest Ebola outbreak since the virus was first discovered in 1976.
• The outbreak started in Guinea and then moved across land borders to Sierra Leone and Liberia.
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3. CONT..
• The current 2018-2019 outbreak in eastern DRC is highly complex, with insecurity
adversely affecting public health response activities.
• The virus family Filoviridae includes three genera: Cuevavirus, Marburgvirus, and
Ebolavirus. Within the genus Ebolavirus, six species have been identified: Zaire,
Bundibugyo, Sudan, Taï Forest, Reston and Bombali.
• The virus causing the current outbreak in DRC and the 2014–2016 West African
outbreak belongs to the Zaire ebolavirus species.
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4. STRUCTURE
• 80 nm in diameter, 970 nm long.
• cylindrical/tubular,
• viral envelope,
• matrix,
• nucleocapsid components.
• The virus generally appears in a long, filamentous form, but it
can also be “U-shaped,” in the shape of a “6” (the “shepherd’s
crook” appearance), or even circular.
• glycoprotein (GP) projecting as 7-10 nm long spikes from its
lipid bilayer surface.
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This virus belongs to the Filovirus family, and
structurally it resembles a length of thread.

5. CONT…
• Glycoproteins are proteins that
contain carbohydrate chains (glycans)
covalently attached to their
polypeptide side chains, a process
known as glycosylation
• The glycoprotein GP is the sole
resident of the Ebolavirus surface and
is responsible for attaching to and
entering new host cells.
• The outer viral envelope of the virion
is derived by budding from domains
of host cell membrane into which the
GP spikes have been inserted during
their biosynthesis
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7. GENOME
• negative-sense, non-segmented single
stranded linear RNA genome about 18-19 kb
in size.
• The 3′ terminus is not polyadenylated and the
5′ end is not capped.
• It contains approximately 19,000 base pairs.
• It encodes seven structural proteins:
nucleoprotein (NP), polymerase cofactor
(VP35), (VP40), GP, transcription activator
(VP30), VP24, and RNA polymerase (L).
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11. TRANSMISSION
• It is thought that fruit bats of the
Pteropodidae family are natural Ebola
virus hosts.
• blood, secretions, organs or other bodily
fluids of infected animals such as fruit
bats, chimpanzees, gorillas, monkeys,
forest antelope or porcupines found ill or
dead or in the rainforest.
• Ebola then spreads through human-to-human
transmission via direct contact (through broken
skin or mucous membranes) with:
• Blood or body fluids of a person who is sick
with or has died from Ebola
• Objects that have been contaminated with
body fluids (like blood, feces, vomit) from a
person sick with Ebola or the body of a person
who died from Ebola
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12. CONT..
• Health-care workers have frequently been infected
while treating patients with suspected or confirmed
EVD. This occurs through close contact with patients
when infection control precautions are not strictly
practiced.
• Burial ceremonies that involve direct contact with the
body of the deceased can also contribute in the
transmission of Ebola.
• People remain infectious as long as their blood
contains the virus.
• Pregnant women who get acute Ebola and recover
from the disease may still carry the virus in
breastmilk, or in pregnancy related fluids and tissues.
This poses a risk of transmission to the baby they
carry, and to others. Women who become pregnant
after surviving Ebola disease are not at risk of
carrying the virus.
• If a breastfeeding woman who is recovering from
Ebola wishes to continue breastfeeding, she should
be supported to do so. Her breast milk needs to be
tested for Ebola before she can start.
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13. SYMPTOMS
• Fever
• Fatigue
• Muscle pain
• Headache
• Sore throat
• Vomiting
• Diarrhoea
• Rash
• Symptoms of impaired kidney and liver
function
• In some cases, both internal and external
bleeding (for example, oozing from the gums,
or blood in the stools).
• Laboratory findings include low white blood
cell and platelet counts and elevated liver
enzymes.
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14. DIAGNOSIS
• antibody-capture enzyme-linked immunosorbent assay (ELISA)
• antigen-capture detection tests
• serum neutralization test
• reverse transcriptase polymerase chain reaction (RT-PCR) assay
• electron microscopy
• ·virus isolation by cell culture.
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15. WHO - DIAGNOSIS
• Automated or semi-automated nucleic acid tests (NAT) for routine diagnostic
management.
• Rapid antigen detection tests for use in remote settings where NATs are not
readily available. These tests are recommended for screening purposes as part of
surveillance activities, however reactive tests should be confirmed with NATs.
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16. SAMPLE
• Whole blood collected in ethylenediaminetetraacetic acid (EDTA) from live
patients exhibiting symptoms.
• Oral fluid specimen stored in universal transport medium collected from
deceased patients or when blood collection is not possible.
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17. TREATMENT
• Supportive care - rehydration with oral or intravenous fluids - and treatment of specific symptoms improves survival.
• There is as yet no proven treatment available for EVD.
• However, a range of potential treatments including blood products, immune therapies and drug therapies are
currently being evaluated.
• Providing fluids and electrolytes (body salts) through infusion into the vein (intravenously).
• Offering oxygen therapy to maintain oxygen status.
• Using medication to support blood pressure, reduce vomiting and diarrhea and to manage fever and pain.
• Treating other infections, if they occur.
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18. DRUGS
• regeneron (REGN-EB3)
• mAb114
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19. VACCINES
• An experimental Ebola vaccine proved highly protective against EVD in a major
trial in Guinea in 2015.
• The vaccine, called rVSV-ZEBOV, was studied in a trial involving 11 841 people.
• Among the 5837 people who received the vaccine, no Ebola cases were recorded
10 days or more after vaccination.
• In comparison, there were 23 cases 10 days or more after vaccination among
those who did not receive the vaccine..
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20. CONT..
• The rVSV-ZEBOV vaccine is being used in the ongoing 2018-2019 Ebola outbreak
in DRC. Pregnant and breastfeeding women should have access to the vaccine
under the same conditions as for the general population
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21. PREVENTION AND CONTROL
• Reducing the risk of wildlife-to-human transmission
• Reducing the risk of human-to-human transmission
• Outbreak containment measures
• Reducing the risk of possible sexual transmission
• Reducing the risk of transmission from pregnancy related fluids and tissue
• Controlling infection in health-care settings
• Care for people who recovered from EVD
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22. CLARIFICATION
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sivasan91@gmail.com

23. QUESTIONS TO THINK
• Types of ebola virus
• Diagnostic methods of Ebola viral disease
• Structure of ebola virus
• mechanism of ebolavirus infection
• Name the genes involved in the ebola infection?
• Name the vaccine used for ebola virus disease
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