Ebola virus disease, or Ebola for short, is a contagious illness that is native to Africa. It belongs to a family of viruses known as Filoviridae. These diseases cause hemorrhagic fever — a serious condition that can lead to severe bleeding, organ failure, and death.
Humans contract Ebola from infected animals. After the initial transmission, the virus can be passed on through contact with body fluids.
Since Ebola was discovered in 1976, several outbreaks have occurred, primarily in Africa. The most severe happened between 2014 and 2016. In August 2018, the Democratic Republic of Congo’s Ministry of Health reported an Ebola outbreak in North Kivu province, which has become the second-deadliest ever.
On average, only about one-half of the people who contract Ebola will survive. (1)
There’s no cure for Ebola, but certain supportive care measures may improve survival. Also, newer therapies are coming down the pike to prevent and treat this serious disease.
Ebola Strains
Researchers have identified the following five strains of the Ebola virus:
- Tai Forest (formerly called Ivory Coast)
- Sudan
- Zaire
- Bundibugyo
- Reston
The virus that caused the 2014–2016 outbreak in Africa belonged to the Zaire species.
Reston is the only strain that doesn’t cause severe disease in humans.
Another type of Ebola virus, called Bombali, was recently discovered in bats, but it’s not known if it causes disease in other animals or people.
Signs and Symptoms
Symptoms of Ebola usually crop up between 5 and 10 days after you’ve had the infection. (3) But they can begin anywhere from 2 to 21 days after contact with the virus.
Early symptoms might include:
- Fever
- Severe headache
- Chills
- Joint and muscle aches
- Weakness or fatigue
These first signs may be vague and hard to recognize as Ebola.
As time goes on, symptoms may become more severe and include:
- Nausea, vomiting, diarrhea, or stomach pain
- Red eyes
- Chest pain
- Cough or sore throat
- A raised rash
- Severe weight loss
- Bruising
- Bleeding (usually from the eyes)
- Internal bleeding (3)
How Does Ebola Spread?
Scientists don’t know exactly where the Ebola virus comes from, but they believe fruit bats are the most likely hosts.
Bats carrying the virus may transfer it to other animals (such as apes and monkeys). Human beings can contract Ebola through close contact with an infected animal.
When humans pick up Ebola, they can spread the virus through their bodily fluids and secretions, such as blood, vomit, and feces, and any materials contaminated with those fluids.
You may contract Ebola through sexual contact or needle-sharing, as well. Some research has found men who have recovered from Ebola may spread the virus through their semen for several months following their recovery.
Healthcare workers who treat Ebola can be infected if they come in close contact with patients.
People with Ebola remain contagious for as long as their blood and body fluids contain the virus. In some cases, contact with a deceased body of someone who had Ebola can transmit the virus. (1,4)
Ebola and Animals
Close contact with infected bats or other animals with the virus is one way to contract Ebola from animals. Another is handling or eating bushmeat — wild animals hunted for food — in areas where Ebola is common.
Some studies have shown that Ebola has been detected in dogs and cats that live in affected areas.
While there are no reports of dogs or cats spreading the virus to people or other animals, some unusual pets, such as exotic monkeys, apes, or pigs, may spread Ebola if they’re infected with it. (6)
There’s no evidence that the Ebola virus can be spread through insect bites. (3)
Risk Factors
You may be more at risk for contracting Ebola if you:
- Travel to areas in Africa where outbreaks have occurred
- Treat or care for other people with the virus
- Conduct research on high-risk animals
- Prepare the bodies of people who have died from Ebola for burial (3)
Your risk of being infected with Ebola is very low, unless you travel to places where the virus is prevalent and have had close contact with other people or animals who have the virus.
Diagnosis
Diagnosing Ebola can be tricky. Some of the symptoms mimic those of other illnesses, such as malaria and typhoid fever. (7)
According to the Centers for Disease Control and Prevention (CDC), the criteria for determining if a person has Ebola early on, includes both of the following:
- A combination of symptoms suggestive of the virus
- A possible exposure to Ebola within 21 days of when symptoms started
If someone does show early signs of the virus and has a possible exposure, public health authorities should be notified. Additionally, the patient should be isolated and given a blood test.
Ebola can be detected in a person’s blood, but it may take up to three days after symptoms begin for the virus to reach measurable levels. A positive blood test indicates that Ebola was identified and confirmed. (8)
Some blood tests that are used to detect Ebola are:
- Enzyme-linked immunosorbent assay (ELISA)
- Reverse transcriptase polymerase chain reaction (PCR)
Treatment
There’s no proven treatment available to cure the Ebola virus, but researchers are investigating many options.
Supportive Care
Typically, people with Ebola will be given supportive care, which includes:
- Receiving extra fluids and oxygen
- Maintaining blood pressure
- Replacing lost blood
- Treating other infections (3)
Supportive care that’s started early can significantly improve a person’s chances of survival. (8)
Experimental Therapies
Scientists are studying several novel treatments for Ebola, which include blood transfusions from survivors and mechanical filtering of blood from patients. (8)
Another experimental therapy, called ZMapp, combines three monoclonal antibodies that bind to the protein of the Ebola virus, inactivating it.
In the 2014 Ebola outbreak, two Americans were treated with drug ZMapp and both survived, although it’s not known what role the drug played in their survival or recovery. Also, some patients with Ebola who were given ZMapp have died.
Studies are currently underway to determine whether the medicine is an effective option for Ebola.
Ebola Vaccines
Scientists are working on developing a vaccine to protect against Ebola. One experimental vaccine, called rVSV-ZEBOV, showed promise in a clinical trial involving 11,841 people in Guinea during 2015.
Results showed that among the 5,837 participants who received the vaccine, zero cases of Ebola were recorded 10 days or more after vaccination. On the other hand, 23 cases of Ebola were recorded 10 days or more after vaccination among those who didn’t receive the vaccine. (1)
Another vaccine, called the recombinant adenovirus type-5 Ebola vaccine, was tested in a phase 2 clinical trial in Sierra Leone during 2015. Results showed that the vaccine stimulated an immune response within 28 days. This response decreased over six months after the injection was given. Research on this vaccine is still in the works.
Complications
Ebola can cause serious complications, such as:
- Organ failure
- Severe bleeding
- Jaundice
- Seizures
- Coma
- Delirium
In many cases, the virus is harmful enough to cause death.
Prevention
Measures that may prevent the spread of Ebola include the following:
- Avoid visiting areas with known outbreaks.
- Isolate infected patients from anyone who doesn’t have Ebola.
- Have healthcare workers wear protective gear, including gloves, masks, goggles, gowns, and other clothing, while caring for Ebola patients.
- Decontaminate or destroy any surfaces or materials a patient has had contact with, including syringes, needles, and other medical equipment.
- Clean healthcare workers with a disinfectant such as chlorine, which kills the Ebola virus.
- Wash hands frequently with soap and water or use an alcohol-based sanitizer.
- Avoid handling or eating bushmeat.
- Encourage Ebola survivors, who are believed to be immune to the strain of Ebola they had, to help care for people who are sick with Ebola or bury those who die.
- Monitor anyone who comes into contact with an Ebola patient.
How to Kill Ebola
The Ebola virus can survive for several hours on dry surfaces, like doorknobs and countertops. And it can live for up to several days at room temperature in body fluids.
The virus can be killed using a U.S. Environmental Protection Agency (EPA)–registered hospital disinfectant with a label for a “nonenveloped virus.”
Controlling Outbreaks
Since the first case of Ebola, various outbreaks have occurred. Once the virus spreads to people, it can quickly transmit throughout families, healthcare settings, and other public areas.
Spotting cases of Ebola early on may be the key to stopping outbreaks.
“Contact tracing” is one tactic that experts use to identify people who have been exposed to someone with Ebola. It involves tracking down everyone who has come in direct contact with the sick person.
These contacts are watched for signs of Ebola for 21 days from the last day they were around the infected patient. If a contact develops a fever or other classic symptoms of Ebola, they will be immediately isolated and tested for the virus.
The World Health Organization (WHO) considers an Ebola outbreak to be over after 42 days (or two incubation periods) have passed without any new infections.
What If You Have Ebola?
If you suspect you have Ebola, you should see a doctor immediately. If you’re traveling, the closest U.S. Embassy can help you locate a medical facility.
It’s important to tell your healthcare provider that you think you have Ebola before you visit the hospital. Workers will likely have to take special precautions.
At your visit, your doctor might ask you the following questions:
- What are your symptoms?
- When did your symptoms start?
- How severe are your symptoms?
- Have you recently traveled to Africa?
- Were you in close contact with anyone who had Ebola?
- If you were in Africa, did you hunt or eat monkeys?
- Did you visit any caves or underground mines in Africa?
- Do you work in a lab that uses monkeys from Africa or the Philippines? (3)
Outcome
According to the WHO, the average Ebola case death rate is around 50 percent. But fatality rates have ranged from 25 to 90 percent, depending on the outbreak. (1)
Scientists aren’t sure why some people are able to bounce back from Ebola, while others aren’t. Receiving prompt supportive treatment is one way to improve your chances of surviving the virus.
Recovery is typically very slow for people who do survive. It can take months to regain strength, and the virus can remain active in the body for a while. (3)
Studies show survivors of Ebola have antibodies that can be detected in their blood up to 10 years after they’ve recovered from the virus.
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