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Ebola Outbreak FAQs

Last reviewed: July 2026

What is Ebola?

Ebola is a potentially severe illness, killing an average of half of those it infects. Initial infections in humans occur after close contact with wild animals. The virus is thought to reside in bats and can spread to non-human primates. Humans can be infected after contact with infected animals, through contact with an infected person’s body fluids, or via contaminated objects.

The disease can then spread within a community by human-to-human transmission. It is caused by several types of orthoebolaviruses (formerly ebolavirus), which infect internal organs, causing bloody diarrhoea and vomiting. The cause of death among Ebola patients is usually blood loss or organ failure. There are several treatments and vaccines available for some types of Ebola.

What viruses cause Ebola?

Ebola is caused by a group of viruses known as orthoebolaviruses (formerly ebolavirus). There are six identified types of orthoebolaviruses, four of which are known to cause illness in humans. Each is named after the region where it was first detected:

  • Ebola virus (Orthoebolavirus zairense): First identified in 1976 in Congo (DRC), formerly Zaire. It has caused multiple outbreaks in both Central and West Africa. It emerged in West Africa in 2014, causing a large outbreak that affected Guinea, Liberia, and Sierra Leone, which took over two years to control.
  • Sudan virus (Orthoebolavirus sudanense): First identified in 1976 in southern Sudan, now known as South Sudan. This virus has caused several outbreaks in southern Sudan, now South Sudan, and Uganda.
  • Bundibugyo virus (Orthoebolavirus bundibugyoense): First identified in 2007 in the western region of Uganda. It has led to two outbreaks: one in Uganda and one in Congo (DRC).
  • Taï Forest virus (Orthoebolavirus taiense): This virus has only caused one known human infection in 1994 in Cote d'Ivoire.

Two additional orthoebolaviruses have been identified but are not known to cause illness in humans:

  • Reston virus (Orthoebolavirus restonense): First identified in 1989, this virus is found in monkeys and pigs from the Philippines. While some people in contact with these animals developed antibodies, none exhibited symptoms, suggesting possible asymptomatic infections.
  • Bombali virus (Orthoebolavirus bombaliense): First identified in 2018, this virus has been found in bats in Sierra Leone, including near households. No human infections have been reported, and its pathogenicity in humans remains unclear.

How do people become infected?

People are infected following contact with infected blood or bodily fluids through broken skin or mucous membranes.

  • From animals to people

    How Ebola gets from animals or the environment and then into humans is unclear. The virus probably "resides" in bats. It may infect an intermediate species, such as monkeys or gorillas (non-human primates), that eat infected or partially-eaten fruit dropped by infected bats. Infection may happen during butchering, handling or cooking bushmeat (meat of wild animals). These include chimpanzees, gorillas, fruit bats, monkeys, forest antelopes and porcupines. Humans can also get infected by consuming undercooked meat of a dead "intermediate" animal.

  • From person to person

    The virus spreads to those in direct contact with the blood or body fluids of an infected person (either dead or alive). This can happen when caring for a sick person or through certain funeral practices such as communal washing of the body. This is why the virus often spreads within families, friends and to healthcare providers.
    People infected with Ebola are contagious once they develop symptoms and are infectious as long as body fluids contain the virus, which can be many months. Generally, the more severe the symptoms are, the more infectious the person is. The dead body of an Ebola victim is highly contagious.
    Even after the virus is undetectable in the blood and the person has recovered it can linger in some body fluids, such as semen, breast milk, and other “immune privileged” sites such as inside the eye and the central nervous system. Transmission has occurred through sexual contact months after men had cleared the virus from their blood.

    Ebola does not spread through the air the way colds and flu viruses do.

  • From objects or environment to people

    Infection can occur if a person is exposed to a contaminated environment or items such as soiled clothing, bed linen, gloves, protective equipment and medical waste (for example - needles, syringes).

How soon after exposure to the virus does a person show symptoms?

Symptoms develop between 2 and 21 days after exposure, generally at around 8-10 days.

What illness does it cause (symptoms)?

The early symptoms of Ebola infection are usually sudden and non-specific, including fever, severe headache, muscle pain, weakness, fatigue and a sore throat.

Vomiting, diarrhoea, rash and abdominal pain usually appear as the disease progresses. Some people may develop redness of the eyes and hiccups. The disease can progress to cause organ failure and bleeding, both internally and externally, which may lead to death. The average fatality rate is around 50%. However, in past outbreaks, fatality rates have varied from 25% to 90%.

How long are infected people contagious?

People infected with Ebola are contagious once they develop symptoms and are infectious as long as body fluids contain the virus, which can be many months. Generally, the more severe the symptoms are, the more infectious the person is. The dead body of an Ebola victim is highly contagious.

Even after the virus is undetectable in the blood it can linger in some body fluids, such as semen, breast milk, and other “immune privileged” sites such as inside the eye and the central nervous system.

How is Ebola diagnosed?

A suspected diagnosis is made based on a person's possible exposure to the virus and their symptoms. The disease can be confirmed by a blood test. Tests require highly specialised equipment and secure handling. Only a few laboratories routinely have this capability. A number of tests, including rapid tests to detect some strains of Ebola are available.

How is it treated?

The management of Ebola-infected patients focuses on supportive therapy. This may include intravenous fluids, supplemental oxygen, blood transfusions, medications to support blood pressure and reduce gastrointestinal symptoms, and antibiotics for any secondary bacterial infections. Early supportive medical interventions improve the chance of survival.

There are currently two drugs approved for the treatment of Ebola caused by Orthoebolavirus zairense (Zaire strain), Inmazeb and Ebanga. Both of these treatments were evaluated in a clinical trial during the 2018-2020 Ebola outbreak in Congo (DRC). Neither of these has so far been evaluated for the treatment of Ebola caused by other strains.

There are no approved specific treatments for the Bundibugyo and Sudan strains of Ebola. Potential treatments for the Bundibugyo strain are under investigation. In early July 2026, researchers started multiple clinical trials aimed at improving treatment and prevention strategies for Bundibugyo virus disease. These trials include the evaluation of two treatment options, administered either individually or in combination.

Is there a vaccine?

There are currently two licensed vaccines against Ebola virus disease (previously Zaire) type of Ebola. They are both prequalified by the World Health Organization, and are not commercially available.

  • The Ervebo vaccine was licensed in 2019 and is recommended for use as part of an Ebola outbreak response. It is a single-dose vaccine approved for individuals 12 months of age and older and is the only Ebola vaccine available in the global stockpile.
  • The Zabdeno and Mvabea vaccine is part of a two-dose vaccine regimen, consisting of an initial dose of Zabdeno followed by Mvabea approximately 8 weeks later, that is approved for individuals 1 year and older. Due to the two-dose requirement, this vaccine regimen is generally not used during outbreak responses.

Animal studies suggest that the vaccines against the Zaire strain of Ebola do not protect against the other types of Ebola, and there are currently no approved vaccines for the Bundibugyo and Sudan strains of Ebola.

  • Bundibugyo: Vaccine candidates against the Bundibugyo strain are under investigation. Of the three vaccine candidates in development, one has entered trials with a small group of adults to evaluate safety and immune response. Trials have also been initiated to explore post-exposure prophylaxis for individuals exposed to confirmed Ebola cases.
  • Sudan: The first clinical trial to assess the efficacy of a candidate vaccine against the Sudan strain began in 2025.

What locations are at risk for Ebola?

Most Ebola-causing viruses are believed to reside in bats and non-human primates, such as monkeys and apes, in Africa. Countries that have experienced recurrent Ebola outbreaks include the Congo, Congo (DRC), Gabon, Guinea, South Sudan and Uganda. Other countries previously reporting outbreaks include Cote d'Ivoire, Liberia, Mali, Sierra Leone and South Africa.

Outside the African continent, imported infections have occurred in several countries during large outbreaks in Africa, including Italy, Spain, the U.K., and the U.S. Additionally, one type of orthoebolavirus, the Reston virus, has been found in monkeys and pigs from the Philippines, though it is not believed to cause symptomatic infections in humans.

See the U.S. Centers for Disease Control and Prevention Ebola Disease Outbreaks Map for more information on geographical distribution of Ebola.

Who is most at risk?

People who have direct unprotected contact with infected people and their contaminated items are at highest risk of infection. This typically includes:

  • Healthcare workers taking care of patients infected with Ebola.
  • Family members and other people who are in direct contact with sick people, or dead bodies at funerals.
  • People who have direct contact with infected animals.

How can I protect myself?

  • Do not participate in high-risk activities – such as funerals in outbreak areas (do not touch / wash dead bodies).
  • Avoid hospitals that are treating suspected Ebola cases.
  • Avoid direct contact with sick people and their bodily fluids. This includes items that may have been contaminated with fluids like bedding and clothing.
  • Pay strict attention to hygiene.

Are there any movement restrictions, border controls?

Several countries have imposed entry restrictions, mandatory quarantine or enhanced entry screening, while some land border crossings remain closed. Changes to entry requirements and border closures can occur at any time and with little warning. Please see Ebola screening, border closures, entry restrictions and quarantine measures for details.

If someone is suspected/confirmed to have Ebola, can International SOS evacuate them?

International SOS is highly experienced in evacuating patients with infectious diseases, having safely and successfully transported patients with infectious diseases requiring in-transport isolation in many regions of the world.

Considerations
International evacuation of patients exposed to, or with confirmed Ebola or another viral haemorrhagic fever is highly complex. Patients with confirmed Ebola would only be considered suitable for movement with the use of patient isolation transport units and the patient clinical picture being suitable for safe transport in these isolation units.

  • Generally, the more serious the condition of the patient, the more unlikely transport will be possible or realistic in patient isolation transport units.
  • Patients with exposure or suspected exposure without symptoms are transportable, provided relevant health authority support is in place.

Link to full EVD Transportation document