ebola the deadly african virus davood yadegarinia professor of infectious diseases and tropical...
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EbolaThe Deadly
African Virus
Davood YadegariniaProfessor of Infectious Diseases and Tropical Medicine
Research Center, Shahid Beheshti University of Medical Sciences
Definition
Ebola virus disease (formerly known as Ebola hemorrhagic fever) is:
A disease caused by the Ebola virus
Is severe- fatality rate 90%
Affects human and non human primates
Scientific ClassificationOrder: Mononegavirales
Family: Filoviridae
Genus: Ebola like viruses
Species: Ebola
Subtypes -5 types– Ebola-Zaire, Ebola-Sudan,Ebola-Ivory Coast
• disease in humans
– Ebola-Reston • disease in nonhuman primates
Ebola Taxonomy
Sudan(SUDV)
Group : Group V (-)sense RNA
Order : MononegaviralesFamily : Filoviridae
Genus : Ebolavirus
Bundibugyo(BDBV)
Tai forest(TAFV)
Formerly Cote d-Ivoire
Species
Zaire ebola(EBOV)
The most dangerous
Reston(RESTV)
Non-humans
Ebola Taxonomy
Ebola hemorrhagic feverFatality 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
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.
MASS GRAVES FOR EBOLA VICTIMS
Filoviridae or “Filoviruses”
• Most mysterious virus group
• Pathogenesis poorly understood
• Ebola
– natural history/reservoirs unknown ,
researchers believe the most likely natural
hosts are fruit bats
– exist throughout the world
– endemic to Africa
– filamentous ssRNA- (antisense) viruses
Image courtesy of the Centers for Disease Control
Natural Reservoir
Suspected to be a zoonotic (animal-borne)
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
History of Ebola virus
• Ebola first appeared in 1976 in two simultaneous outbreaks.
- Near the Ebola River in the Democratic Republic of Congo
- A remote area of Sudan.
STROKES YEAR REGIONS AFFECTED
DISCRIPTION
FIRST 1976 Democratic republic of congo (ZAIRE) &
sudan
First outbreak of Ebola. Hemorrhagic fever
SECOND 1989 Reston ,Virginia
mysterious outbreak. (initially diagnosed as Simian hemorrhagic fever virus (SHFV)) among a shipment of crab-eating macaque monkeys imported from the Philippines. named Reston ebolavirus (REBOV)
THIRD 2014 WEST AFRICA -affecting Guinea,
Sierra Leone, Liberia and Nigeria.
largest outbreak to the date
Case counts as of October 20, 2014
Total Case Count Laboratory Confirmed Cases
Total Deaths
9216
4218**
4555**
**Numbers are lower than actual laboratory confirmed cases and deaths because stratified data are temporarily unavailable for Liberia.
Cases by Country Total Case Count Laboratory Confirmed Cases
Total Deaths
Guinea 1519 1217 862
Liberia 4249 2484
Sierra Leone 3410 2977 1200
Total Case Count 9178 4194* 4546
Case counts as of October 20, 2014
*Numbers remain unchanged or are lower than actual cases because stratified data are temporarily unavailable for Liberia.
Countries with Widespread Transmission
Countries with Travel-associated Cases
Case by country Total case count Laboratory confirmed cases
Total death
Senegal 1 1 0
Spain 1 1 0
Case by country Total case count Laboratory confirmed cases
Total death
Nigeria 20 19 8
United states 3 3 1
Countries with Localized Transmission
Transmission
Environment to Human :
Fruit bats-natural reservoir
Gorilla, chimpanzee, monkey, porcupine, duiker
Human to human :
1.Direct contact
2.Contaminated medical equipment
3.Traditional burial rituals
4.Medical workers
5.Survivors(via semen for 2 months)
• Ebola is introduced into the human population through close contact with the blood, secretions, organs or other bodily fluids of infected animals.
•In Africa, infection has occurred through the handling of infected chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines found ill or dead or in the rainforest.
how do people become infected with the virus?
• Ebola is extremely infectious but not extremely contagious. It is infectious, because a very small amount can cause illness. Laboratory experiments on nonhuman primates suggest that even a single virus may be enough to trigger a fatal infection.
• Instead, Ebola could be considered moderately contagious, because the virus is not transmitted through the air. The most contagious diseases, such as measles or influenza, virus particles are airborne.
Transmission(cont)
CS250586A
You can’t get E bola through air
Facts about
EbolaYou can’t get E bola
through waterYou can’t get Ebola
through food
You can only get Ebola from:Touching the blood or body fluids of a person who is sick with or has died from Ebola.Touching contaminated objects, like needles.Touching infected animals, their blood or other body luids, or their meat.
Ebola poses no signiicant risk to the United States.
Who is most at risk?During an outbreak, those at higher risk of infection are:health workers;
family members or others in close contact with infected people;
mourners who have direct contact with the bodies of the deceased as part of burial ceremonies; and
hunters in the rain forest who come into contact with dead animals found lying in the forest.
More research is needed to understand if some groups, such as immuno-compromisaed people are more susceptible than others to contracting the virus.
the patients will have Diarrhea.
Pharyngitis with the inflammation of the throat and eye.
causes severe damage to the skin.
attacks every tissue and organ of the body except the skeletal muscles and bones.
can attack the connective tissues that are rapidly multiplying in collagen.
causes small blood clots to form in the bloodstream of the patient and forms red
spot on the skin
Spontaneous bleeding then occurs from body orifices and gaps in the skin
EFFECT OF EBOLA
EHF & EVD
EHF ( Ebola Hemorrhagic Fever ) :
Internal and External Bleeding occurs Genital swelling Increased feeling of pain in the skin Rash over the entire body that often contains blood Roof of mouth looks red
EVD ( Ebola Virus Disease) : Bleeding dose not occur
Ebola hemorrhagic feverTarget 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
Signs and Symptoms
Early symptoms :
Influenza(fatigue,fever,headache,joint & abdominal pain)
Vomiting,diarrhea
Loss of appetite
Sore throat,chest pain,hiccups,shortness of breath, trouble
swallowing
Weakness
Maculopular rash(50% cases)
Myalgia(muscular pain or tenderness),back pain
Mucosal redness of the oral cavity
Acute symptoms :
Bleeding from puncture sites and mucous
membrane(eg.nose,gums and gastrointestinal tract)
Internal and subcutaneous bleeding
anuria(absence of urine formation)
raddening of eyes,bloody vomit
Impaired blood clotting
Multiple organ dysfunction
syndrome which leads to death
Signs and Symptoms
Diagnosis
• Diagnosing Ebola in an person who has been infected for only a few days is difficult, because the early symptoms, such as fever, are nonspecific to Ebola infection and are seen often in patients with more commonly occurring diseases, such as malaria and typhoid fever.
• However, if a person has the early symptoms of Ebola and has had contact with the blood or body fluids of a person sick with Ebola, contact with objects that have been contaminated with the blood or body fluids of a person sick with Ebola, or contact with infected animals, they should be isolated and public health professionals notified. Samples from the patient can then be collected and tested to confirm infection.
Laboratory tests used in diagnosis include:
Timeline of Infection Diagnostic tests available
Within a few days after symptoms begin
Antigen-capture ELISA testing
IgM ELISA
PCR
Virus isolation
Later in disease course or after recovery
IgM and IgG antibodies
Retrospectively in deceased patients Immunohistochemistry testing
PCR
Virus isolation
Treatment No specific vaccine or medicine (e.g., antiviral drug) has been proven to
be effective against Ebola.
Symptoms of Ebola are treated as they appear.
The following basic interventions, when used early, can significantly improve the chances of survival:
1-Providing intravenous fluids (IV)and balancing electrolytes (body salts)
2-Maintaining oxygen status and blood pressure
3-Treating other infections if they occur
Treatment
Some experimental treatments developed for Ebola have been tested and proven effective in animals but have not yet been tested in randomized trials in humans.
Recovery from Ebola depends on the patient’s immune response. People who recover from Ebola infection develop antibodies that last for at least 10 years, possibly longer.
Prevention There is no FDA-approved vaccine available for Ebola.
If you travel to or are in an area affected by an Ebola outbreak, make sure to do the following:
1-Practice careful hygiene. Avoid contact with blood and body
fluids.
2-Do not handle items that may have come in contact with an
infected person’s blood or body fluids.
3-Avoid funeral or burial rituals that require handling the
body of someone who has died from Ebola.
Prevention
4-Avoid contact with bats and nonhuman primates or
blood, fluids, and raw meat prepared from these
animals.
5-Avoid hospitals where Ebola patients are being
treated. The U.S. embassy or consulate is often able
to provide advice on facilities.
6-After you return, monitor your health for 21 days
and seek medical care immediately if you develop
symptoms of Ebola
Ebola hemorrhagic feverPrevention
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
Prevention Healthcare workers who may be exposed to people with Ebola should
follow these steps:
1-Wear protective clothing, including masks, gloves, gowns,
and eye protection.
2-Practice proper infection control and sterilization measures.
3-Isolate patients with Ebola from other patients.
4-Avoid direct contact with the bodies of people who have
died from Ebola.
Prevention
• 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
PRECAUTIONS
Use Standard PrecautionsRoutine Hand washingHandle and Dispose of Shar Instruments SafelyCook meat thoroughlyEnvironment Cleaning
ISOLATION PROCEDURES
Select Site for the Isolation Area
Isolation area must consist of :
1)An isolated toilet 2)Adequate ventilation 3)Screened windows
Plan How to Arrange the Isolation Area