Ebola virus
Prepared By:
Dr. Amal Abu Alhommos
Clinical Pharmacist/Lecturer
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Background
Ebola previously known as Ebola hemorrhagic fever, is a rare and deadly disease caused by
infection with one of the Ebola virus strains. Ebola can cause disease in humans and
nonhuman primates (monkeys, gorillas, and chimpanzees).
The natural reservoir host of Ebola virus remains unknown. However, researchers believe that
the virus is animal-borne and that bats are the most likely reservoir. Four of the five virus
strains occur in an animal host native to Africa.
Ebola virus disease (EVD) first appeared in 1976 in 2 simultaneous outbreaks, one in Nzara,
Sudan, and the other in Yambuku, Democratic Republic of Congo. The latter occurred in a
village near the Ebola River, from which the disease takes its name.
The current outbreak in west Africa, (first cases notified in March 2014), is the largest and
most complex Ebola outbreak. It borders to Sierra Leone and Liberia, by air (1 traveller only)
to Nigeria, and by land (1 traveller) to Senegal.
The virus family Filoviridae includes 3 genera: Cuevavirus, Marburgvirus, and
Ebolavirus. There are 5 species that have been identified: Zaire, Bundibugyo, Sudan, Reston
and Taï Forest. The virus causing the 2014 west African outbreak belongs to the Zaire species.
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Transmission
Ebola is introduced into the human population through close contact with the blood,
secretions, organs or other bodily fluids of infected animals such as chimpanzees,
gorillas, fruit bats, monkeys, forest antelope and porcupines found ill or dead or in the
rainforest.
Ebola spreads through human-to-human transmission via direct contact (through
broken skin or mucous membranes) with the blood, secretions, organs or other bodily
fluids of infected people, and with surfaces and materials (e.g. bedding, clothing)
contaminated with these fluids.
Health-care workers have frequently been infected while treating patients with
suspected or confirmed EVD. This has occurred through close contact with patients
when infection control precautions are not strictly practiced.
People remain infectious as long as their blood and body fluids, including semen and
breast milk, contain the virus. Men who have recovered from the disease can still
transmit the virus through their semen for up to 7 weeks after recovery from illness.
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What are body fluids?
Body fluids include saliva, mucus, vomit, feces, sweat, tears, breast milk, urine,
and semen.
What does “direct contact” mean?
It means that body fluids (blood, saliva, mucus, vomit, urine, or feces) from an
infected person (alive or dead) have touched someone’s eyes, nose, or mouth
or an open cut, wound, or abrasion.
Can Ebola be spread by coughing or sneezing?
There is no evidence indicating that Ebola virus is spread by coughing or
sneezing. The virus is not transmitted through the air (like measles virus).
However, droplets (e.g., splashes or sprays) of respiratory or other secretions
from a person who is sick with Ebola could be infectious.
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How long does Ebola live outside the body?
Ebola is killed with hospital-grade disinfectants (such as household bleach).
Ebola on dry surfaces, such as doorknobs and countertops, can survive for
several hours; however, virus in body fluids (such as blood) can survive up to
several days at room temperature.
Are patients who recover from Ebola immune for life? Can they get it again the same or a different strain?
Recovery from Ebola depends on good supportive clinical care and a patient’s
immune response. Available evidence shows that people who recover from Ebola
infection develop antibodies that last for at least 10 years, possibly longer.
No evidence if people who recover are immune for life or if they can become
infected with a different species of Ebola.
If someone survives Ebola, can he or she still spread the virus?
Once someone recovers from Ebola, they can no longer spread the virus. However,
Ebola virus has been found in semen for up to 3 months.
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Can Ebola be spread through mosquitos?
There is no evidence that mosquitos or other insects can transmit Ebola virus.
Only mammals (for example, humans, bats, monkeys and apes) have shown the
ability to spread and become infected with Ebola virus.
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Diagnosis
 It can be difficult to distinguish EVD from other infectious diseases such as malaria, typhoid
fever and meningitis. Confirmation that symptoms are caused by Ebola virus infection are made
using the following investigations:
1. Antibody-capture enzyme-linked immunosorbent assay (ELISA)
2. Antigen-capture detection tests
3. Serum neutralization test
4. Reverse transcriptase polymerase chain reaction (RT-PCR) assay
5. Electron microscopy
6. Virus isolation by cell culture.
7. Samples from patients are an extreme biohazard risk; laboratory testing on non-inactivated
samples should be conducted under maximum biological containment conditions.
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Symptoms of Ebola
Fever
Severe headache
Muscle pain
Weakness
Diarrhea
Vomiting
Abdominal (stomach) pain
Unexplained hemorrhage (bleeding or bruising)
 Symptoms appear from 2 to 21 days after exposure to Ebola, but average is 8 to 10 days.
 Recovery from Ebola depends on good supportive clinical care and the patient’s immune
response. People who recover from Ebola infection develop antibodies that last for at least 10
years.
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Treatment and Vaccines
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.
No licensed vaccines are available yet, but 2 potential vaccines are undergoing human safety
testing.
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Prevention and Control
Risk reduction messaging should focus on several factors:
Reducing the risk of wildlife-to-human transmission from contact with infected fruit bats or
monkeys/apes and the consumption of their raw meat. Animals should be handled with gloves
and other appropriate protective clothing. Animal products (blood and meat) should be
thoroughly cooked before consumption.
Reducing the risk of human-to-human transmission from direct or close contact with people
with Ebola symptoms, particularly with their bodily fluids. Gloves and appropriate personal
protective equipment should be worn when taking care of ill patients at home. Regular hand
washing is required after visiting patients in hospital, as well as after taking care of patients at
home.
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.
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Controlling Infection In Health-Care Settings
 Health-care workers should always take standard precautions when caring for patients,
regardless of their presumed diagnosis. These include basic hand hygiene, respiratory
hygiene, use of personal protective equipment (to block splashes or other contact with
infected materials), safe injection practices and safe burial practices.
 Health-care workers caring for patients with suspected or confirmed Ebola virus should apply
extra infection control measures to prevent contact with the patient’s blood and body
fluids and contaminated surfaces or materials such as clothing and bedding. When in close
contact (within 1 metre) of patients with EBV, health-care workers should wear face
protection (a face shield or a medical mask and goggles), a clean, non-sterile long-sleeved
gown, and gloves (sterile gloves for some procedures).
 Laboratory workers are also at risk. Samples taken from humans and animals for investigation
of Ebola infection should be handled by trained staff and processed in suitably equipped
laboratories.
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Previous Ebola Virus Disease Outbreaks
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Personal Protective Equipment (PPE) Guidelines For Ebola Response
 “These guidelines hold an important role in clarifying effective personal
protective equipment options that protect the safety of healthcare workers and
patients from Ebola virus disease transmission,” says Edward Kelley, WHO
Director for Service Delivery and Safety.
 It was most important to have PPE that protects the mucosae – mouth, nose and
eyes – from contaminated droplets and fluids.
 Given that hands are known to transmit pathogens to other parts of the body, as
well as to other individuals, hand hygiene and gloves are essential, both to
protect the health worker and to prevent transmission to others. Face cover,
protective foot wear, gowns or coveralls, and head cover were also considered
essential to prevent transmission to healthcare workers.
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Healthcare workers who may be exposed to people with Ebola should
follow these steps:
Wear appropriate PPE.
Practice proper infection control and sterilization measures. For more
information.
Isolate patients with Ebola from other patients.
Avoid direct contact with the bodies of people who have died from Ebola.
Notify health officials if you have had direct contact with the blood or
body fluids, such as but not limited to, feces, saliva, urine, vomit, and
semen of a person who is sick with Ebola. The virus can enter the body
through broken skin or unprotected mucous membranes in, for example,
the eyes, nose, or mouth
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How Do I Know If I Have Seasonal Influenza Or Ebola?
 Seasonal influenza and Ebola virus infection can cause some similar symptoms.
 However, fall and winter is the time for flu. While the exact timing and
duration of flu seasons vary, outbreaks often begin in October and can last as
late as May. Most of the time flu activity peaks between December and
February.
 There are tests to detect seasonal influenza and Ebola infection and should ask
about recent travel or exposure history.
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How Do I Protect Myself Against Ebola?
 Wash hands frequently or use an alcohol-based hand sanitizer.
 Avoid contact with blood and body fluids of any person, particularly who is sick.
 Do not handle items that may have come in contact with an infected person’s
blood or body fluids.
 Do not touch the body of someone who has died from Ebola.
 Do not touch bats and nonhuman primates or their blood and fluids and do not
touch or eat raw meat prepared from these animals.
 Avoid facilities in West Africa where Ebola patients are being treated.
 Seek medical care immediately if you develop fever, headache, muscle pain,
diarrhea, vomiting, stomach pain, or unexplained bruising or bleeding.
 Limit your contact with other people until and when you go to the doctor. Do not
travel anywhere else besides a healthcare facility.
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Should People Traveling To Africa Be Worried About Outbreak?
 Avoid all nonessential travel to Guinea, Liberia, and Sierra Leone, Democratic
Republic of the Congo (DRC).
Ebola is a very low risk for most travelers : it is spread through direct contact
with the blood or other body fluids of a sick person, so travelers can protect
themselves by avoiding sick people and facilities in West Africa where patients
with Ebola are being treated.
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What is ZMapp?
 ZMapp, being developed by Mapp Biopharmaceutical Inc., is an experimental treatment,
for use with individuals infected with Ebola virus. It has not yet been tested in humans for
safety or effectiveness. The product is a combination of three different monoclonal
antibodies that bind to the protein of the Ebola virus. It is not vaccine.
It's important to note that the standard treatment for Ebola remains supportive therapy.
This includes the following measures:
Balancing the patients' fluids and electrolytes;
Maintaining their oxygen status and blood pressure; and
Treating them for any complicating infections.
In addition, the most effective way to stop the current Ebola outbreak in West Africa is
isolating and caring for those patients, and tracing contacts to stop chains of transmission.
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References
http://www.who.int/mediacentre/factsheets/fs103/en/
http://www.cdc.gov/vhf/ebola/hcp/index.html
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