Ebola Virus Disease (EVD)
This topic covers all about Ebola virus disease, symptoms, treatments, prevention, FAQs etc
Key facts on Ebola Virus Disease
- Ebola virus disease (EVD), formerly known as Ebola haemorrhagic fever, is a severe, often fatal illness in humans.
- EVD outbreaks have a case fatality rate of up to 90%.
- EVD outbreaks occur primarily in remote villages in Central and West Africa, near tropical rainforests.
- The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission.
- Fruit bats of the Pteropodidae family are considered to be the natural host of the Ebola virus.
- Severely ill patients require intensive supportive care. No licensed specific treatment or vaccine is available for use in people or animals.
Source: World Health Organisation (WHO)
Ebola Virus Fact Sheet
- Ebola Virus Disease (formerly known as Ebola Hemorrhagic Fever) is a Severe, often fatal illness, with a death of up to 90%. The illness affects humans and non-human primates (monkeys, gorillas and chimpanzees).
- Genus Ebola Virus is 1 of 3 members of the Filoviridae family (filovirus), along with genus Marburgvirus and genus Cuevavirus. Genus Ebola Virus comprises 5 distinct species:
- Bundibugyoebolavirus (BDBV)
- Zaire ebolavirus(EBOV)
- Reston ebolavirus (RESTV)
- Sudan ebolavirus (SUDV)
- Tai Forest ebolavirus (TAFV)
- As on 18th May 2014, the Ministry of Health (MOH) of Guinea has reported a cumulative total of 253 clinical cases of Ebola Virus Disease (EVD), including 176 deaths.
- Latest figures on number of cases/deaths and countries affected can be obtained from WHO website http://www.afro.who.int/en/clusters-a-programmes/dpc/epidemic-a-pandemic-alert-and-response/outbreak-news/4140-ebola-virus-disease-west-africa-situation-as-of-18-may-2014.html
- Ebola is introduced into the human population through close contact with the blood, secretions, organs or other bodily fluids of infected animals, chimpanzee, gorilla, fruit bats, monkeys, forest antelopes and porcupines.
- Human-to human transmission, with infection resulting from direct contact (through broken skin or mucous membranes) with the blood, secretions, organs or other bodily fluids of infected people, and indirect contact with environments contaminated with such fluids, Health-care workers have frequently been infected while treating patients with suspected or confirmed EVD.
- The virus can be transmitted through semen of affected person upto 7 weeks after recovery from illness.
- 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 are infectious as long as their blood and secretions contain the virus. Ebola virus was isolated from semen 61 days after onset of illness in a man who was infected in a laboratory.
Signs and symptoms
Case Definition EBVD
EVD is a severe acute viral illness often characterized by the sudden onset of
- Intense weakness,
- Muscle pain,
- Sore throat.
- Impaired kidney and liver function, and
In some cases, both internal and external bleeding.
- Laboratory findings include low white blood cell and platelet counts and elevated liver enzymes.
- Incubation period: 2 to 21 days.
Suspected (clinical) case:
- Any person ill or deceased who has or had fever with acute clinical symptoms and signs of hemorrhage, such as bleeding of the gums, nose-bleeds, conjunctival injection, red spots on the body, bloody stools and/or melena (black liquid stools), or vomiting blood(haematemesis) with the history of travel to the affected area. Documented prior contact with an EBVD case is not required.
Probable case (with or without bleeding):
- Any person (living or dead) having had contact with a clinical case of EHF and with a history of acute fever.
- Any person (living or dead) with a history of acute fever and three or more of the following Symptoms: headache/ vomiting/nausea/ loss of appetite/ diarrhea/ intense fatigue/ abdominal pain/ general muscular or articular pain/ difficulty in swallowing/ difficulty in breathing/hiccoughs
Any unexplained death.
- The distinction between a suspected case and a probable case in practice relativelyunimportant as far as outbreak control is concerned.
- A person without any symptoms having had physical contact with a case or the body fluids of a case within the last three weeks. The notion of physical contact may be proven or highly suspected such as having shared the same room/bed, cared for patient, touched body fluids, or closely participated in a burial (e.g. physical contact with the corpse).
- Suspected or probable case with laboratory confirmation (positive IgM antibody, positive PCR or Viral isolation).
- Other diseases that should be ruled out before a diagnosis of EVD can be made include: malaria, typhoid fever, shigellosis, cholera, leptospirosis, plague, rickettsiosis, relapsing fever, meningitis, hepatitis and other viral haemorrhagic fevers.
- Ebola virus infections can be diagnosed definitively in a laboratory through several types of tests:
- antibody-capture enzyme-linked immunosorbent assay (ELISA)
- antigen detection tests
- serum neutralization test
- reverse transcriptase polymerase chain reaction (RT-PCR) assay
- electron microscopy
- Virus isolation by cell culture.
- Samples from patients are an extreme biohazard risk; testing should be conducted under maximum biological containment conditions.
Prevention and control
Risk of infection with Ebola virus and how to avoid it
- Casual contact in public places with people that do not appear to be sick do not transmit Ebola. One cannot contract Ebola virus by handling money, groceries or swimming in a pool. Mosquitoes do not transmit the Ebola virus.
- Ebola virus is easily killed by soap, bleach, sunlight, or drying. Ebola virus survives only a short time on surfaces that have dried in the sun.
- Reducing the risk of Ebola infection in people
- In the absence of effective treatment and a human vaccine, raising awareness of the risk factors for Ebola infection and the protective measures individuals can take is the only way to reduce human infection and death.
- 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 in the community arising from direct or close contact with infected patients,particularly with their body fluids. Close physical contact with Ebola patients should be avoided. Gloves and appropriate personal protective equipment should be worn when taking care of ill patients at home and should be disposed after use as per biosafety guidelines. Regular hand washing is required after visiting patients in hospital, as well as after taking care of patients at home.
- Dead patients to be handled for cremation/burial under biosafety precautions.
Controlling infection in health-care settings
- Human-to-human transmission of the Ebola virus is primarily associated with direct or indirect contact with blood and body fluids. Transmission to health-care workers has been reported when appropriate infection control measures have not been observed.
- It is not always possible to identify patients with EBV early because initial symptoms may be non-specific. For this reason, it is important that health-care workers apply standard precautions consistently with all patients – regardless of their diagnosis – in all work practices at all times. These include basic hand hygiene, respiratory hygiene, use of personal protective equipment (according to the risk of splashes or other contact with infected materials), safe injection practices and safe handling after death of infected patient.
- Health-care workers caring for patients with suspected or confirmed Ebola virus should apply, in addition to standard precautions,other infection control measures to avoid any exposure to the patient’s blood and body fluids and direct unprotected contact with the possibly contaminated environment. 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 suspected human and animal Ebola cases for diagnosis should be handled by trained staff and processed in suitably equipped laboratories.
Guidelines for health care providers
Health care workers if handle the patients without observing recommended universal precautions are at high risk of acquiring the infection. Therefore health workers while taking care of these patients should observe the following:
- In addition to standard universal precautions, health workers should strictly apply recommended infection control measures to avoid exposure to infected blood, fluids, or contaminated environments or objects – such as a patient’s soiled linen or used needles.
- They should use personal protection equipment such as individual gowns (impermeable), gloves, masks and goggles or face shields and shoe cover.
- They should not reuse protective equipment or clothing unless they have been properly disinfected with 1% bleach or phenolic products.
- They should change gloves between caring for each patient suspected of having Ebola and strictly follow hospital waste management guidelines.
- Invasive procedures that can expose medical doctors, nurses and others to infection should be carried out under strict, safe conditions. For aerosol generating procedures PPE should include respiratory protection N95 masks or higher and the procedure should be performed in airborne isolation room.
- Infected patients should be kept separate from other patients and healthy people, as much as possible.
- Dedicated medical equipment should be used (preferably disposable whenever possible).
- All non-dedicated, non-disposable medical equipment used for patient care should be cleaned and disinfected as per manufacturer’s instructions and hospital policies.
- Use of injections and sharps should be limited.
- If the use of sharp objects cannot be avoided, ensure that the following precautions are observed:
- Never replace the cap on a used needle.
- Never direct the point of a used needle towards any part of the body.
- Do not remove used needles from disposable syringes by hand, and do not bend, break or otherwise manipulate used needles by hand.
- Never re-use syringes or needles.
- Dispose of syringes, needles, scalpel blades and other sharp objects in appropriate, puncture-resistant containers.
- Ensure that containers for sharps objects are placed as close as possible to the immediate area where the objects are being used (‘point of use’) to limit the distance between use and disposal, and ensure the containers remain upright at all times.
- Ensure that the containers are securely sealed with a lid and replaced when ¾ full.
FAQs on Ebola Virus Disease
What is Ebola Virus Disease (EBVD)?
Ebola Virus Disease is caused by Ebola virus.
Where does EBVD usually occur?
Confirmed cases of Ebola Virus Disease have been reported from Democratic Republic of Congo (Zaire), Gabon, Sudan, Ivory Coast, Uganda, Liberia, Guinea, Sierra Leone, Nigeria. No case has been reported from India.
What is the incubation period?
Incubation period of EBVD is 2-21 days.
Can a person transmit the disease during incubation period?
What are the symptoms of EBVD?
It presents as fever, headache, joint and muscle aches, weakness, diarrhea, vomiting, stomach pain, lack of appetite, and abnormal bleeding. Symptoms may appear with in 2 to 21 days (commonly between 8-10 days) after exposure to ebolavirus.
What is the source of infection?
In Africa, fruit bats are considered to be the natural hosts of the Ebola virus. It is transmitted to humans through the close contact with the blood secretions, organs or other body fluids of infected animals like chimpanzees, gorillas, monkeys, fruit bats etc
How is human to human transmission of Ebola Virus occurring?
Ebola virus is transmitted through direct contact with the blood or bodily fluids of an infected symptomatic person or though exposure to objects (such as needles) that have been contaminated with infected secretions. It is not transmitted through air.
Who is most at risk?
During an outbreak, those at higher risk of infection are:
- health care workers (if they handle the patients without observing recommended universal precautions)
- contacts and family members of the patients coming in contact with blood or other secretions and body fluids of the patient.
- mourners who have direct contact with the bodies of the Ebola virus infected people as part of cremation/burial ceremonies;
Can a person get Ebola virus disease from contaminated food or water?
No. Ebola is not a food-borne illness. It is not a water-borne illness.
Can the Ebola virus disease be transmitted by a person who is infected but doesn’t have any symptoms?
No. Individuals who are not symptomatic are not contagious. In order for the virus to be transmitted, an individual would have to have direct contact with an individual who is experiencing symptoms.
When should someone seek medical care?
If a person has been in an area known to have Ebola virus disease (West African Countries - Liberia, Guinea, Sierra Leone & Nigeria as on 5th August 2014) or in contact with a person known or suspected to have Ebola and they begin to have symptoms within 21 days of contact, they should seek medical care immediately by reporting to nearest hospital.
What is the treatment?
There is currently no specific treatment for this disease. However, by intensive supportive care the mortality can be reduced as well as the spread of the disease can be prevented by instituting specific infection control practices.
Is there Vaccine available for EBVD?
There is no vaccine against EBVD anywhere in the world as of now.
Can Ebola be prevented?
Yes, Ebola can be prevented by observing the following:
- Close contact taking care of the patients should follow standard infection control practices.
- Any person coming from Ebola affected Areas (as mentioned in Q. No11) or coming in contact with suspected or confirmed EBVD and develops symptoms within 21 days should immediately report to health care facility.
- EBVD patient after cure should continue to follow infection control practices for a period of about two months.