Open Outbreak

Ebola virus disease

Also known as: Ebola, ebolavirus, Zaire ebolavirus, Bundibugyo ebolavirus, Sudan ebolavirus, EVD, Ebola disease

Ebola virus disease is a rare but very serious viral illness. It belongs to a group of related viruses, and large outbreaks in people are known to be caused by Ebola virus, Sudan virus, and Bundibugyo virus. The virus is thought to come from animals, probably fruit bats, and then spread between people through direct contact with blood or other body fluids, or with contaminated surfaces. People do not spread Ebola before symptoms start. Symptoms often begin suddenly with fever, weakness, muscle pain, headache, and sore throat, then can progress to vomiting, diarrhoea, abdominal pain, and organ problems. Some patients bleed, but bleeding is not always present. WHO says the incubation period is 2 to 21 days. Across past outbreaks, case fatality has ranged from 25% to 90%, averaging around 50%. Early supportive care improves survival. Licensed vaccines and recommended antibody treatments exist for Ebola virus disease caused by Ebola virus, but not yet for Sudan or Bundibugyo virus disease.

Key facts

TransmissionDirect contact through broken skin or mucous membranes with blood or body fluids of a sick or dead person; contact with contaminated objects or surfaces; contact with infected animals. People are not infectious before symptoms begin.
Incubation2 to 21 days.
Case fatalityAround 50% on average across past outbreaks; reported range 25% to 90%. Recent outbreak figures vary by virus and setting, for example 48.3% among confirmed Bundibugyo cases reported by WHO in the Democratic Republic of the Congo as of 2026-09-07.
Reproduction numberunknown
VaccineApproved vaccines are available for Ebola virus disease caused by Ebola virus: Ervebo, and the Zabdeno/Mvabea regimen. No approved vaccine is listed by WHO for Sudan or Bundibugyo virus disease.
TreatmentEarly intensive supportive care improves survival. For Ebola virus disease caused by Ebola virus, WHO recommends the monoclonal antibodies ansuvimab (mAb114) or REGN-EB3 (Inmazeb). No approved therapeutics are listed by WHO for Sudan or Bundibugyo virus disease.
ReservoirThought to be fruit bats of the Pteropodidae family.
Endemic regionsSub-Saharan Africa, especially parts of Central and East Africa. WHO notes Ebola virus is enzootic in some animal populations in the Democratic Republic of the Congo, and outbreaks have also occurred in countries such as Uganda, Sudan/South Sudan, Guinea, Liberia, Sierra Leone, and neighbouring areas during spread events.

Transmission

Ebola spreads through direct contact with infected body fluids, not through casual contact at a distance. WHO says infection happens when blood or other body fluids from a sick person, or from someone who has died from Ebola, get into broken skin or the eyes, nose, or mouth of another person. Contaminated objects and surfaces can also spread infection. Health workers are at special risk if infection-control steps are not followed. Funeral and burial practices that involve touching the body can also pass the virus on. People do not transmit Ebola before symptoms begin. Outbreaks often start with a spillover from animals to humans; WHO says fruit bats are thought to be the natural hosts, and infection can follow close contact with infected wild animals found ill or dead. Reviews of past outbreaks describe the same pattern: a likely animal introduction followed by human-to-human spread through body fluids and contaminated materials.

Symptoms and severity

Symptoms usually begin suddenly after an incubation period of 2 to 21 days. WHO lists early symptoms as fever, fatigue, malaise, muscle pain, headache, and sore throat. These are often followed by vomiting, diarrhoea, abdominal pain, rash, and signs that the kidneys or liver are not working well. Bleeding can happen, including blood in vomit or stool, but WHO notes this is less common than many people think and may appear later. Ebola is severe because it can lead to shock, dehydration, and failure of several organs. WHO says the average case fatality rate across outbreaks is about 50%, with a very wide range of 25% to 90%. Severity varies by virus species, access to care, and how early treatment starts. In the current 2026 Bundibugyo outbreak in the Democratic Republic of the Congo, WHO reported a crude case fatality ratio of 48.3% among confirmed cases as of 2026-09-07.

Treatment and vaccines

The most important treatment is early supportive care. WHO says intensive rehydration and treatment of symptoms improve survival, and early care can be lifesaving. Supportive care means giving fluids, managing pain, treating other infections when present, and monitoring the patient closely. For Ebola virus disease caused by Ebola virus, WHO recommends two monoclonal antibody treatments: ansuvimab (mAb114) and REGN-EB3 (Inmazeb). Vaccines are also available, but only for that species. WHO lists two approved vaccine approaches for Ebola virus disease: Ervebo and the Zabdeno/Mvabea regimen. Ervebo is recommended for outbreak response. The situation is different for Sudan virus disease and Bundibugyo virus disease. WHO says there is no approved vaccine or treatment yet for those illnesses, although candidate products are being developed. This matters because not every “Ebola” outbreak can be controlled with the same vaccine or medicines.

Where it occurs

Ebola disease outbreaks have mainly occurred in sub-Saharan Africa. WHO says the disease was first recognized in 1976 in what are now South Sudan and the Democratic Republic of the Congo. Since then, outbreaks have appeared repeatedly in Central and East Africa, with the very large 2013-2016 West Africa epidemic showing that spread can extend across borders and into cities. The Democratic Republic of the Congo is a major focus in the WHO archive, with repeated Ebola virus disease outbreaks and WHO noting that Ebola virus is enzootic in some animal populations there. Uganda has had repeated Sudan virus outbreaks, and in 2026 WHO reported Bundibugyo virus spread linked to the Democratic Republic of the Congo and Uganda. Imported cases have also been recorded in Europe and North America during major outbreaks, but sustained transmission has mainly remained in African outbreak settings where exposure, healthcare access, and surveillance conditions allow chains of transmission to continue.

Recent history

This site’s archive lists 44 Ebola-related WHO notices or major epidemic records since 1996, showing that Ebola is not a one-off event. The recent pattern has included both small flare-ups and larger outbreaks. In 2022, WHO reported and then closed outbreaks in the Democratic Republic of the Congo, including a single confirmed case in North Kivu and an outbreak in Equateur. In 2025, WHO reported another Ebola virus disease outbreak in Kasai Province in the Democratic Republic of the Congo and declared it over on 2025-12-01, with 64 total cases and 45 deaths. In 2026, WHO’s Disease Outbreak News has focused on a large Bundibugyo virus outbreak centered in the Democratic Republic of the Congo with spread into Uganda and exported cases identified in Europe. By 2026-09-25, WHO described expansion to 63 health zones across seven provinces and assessed the risk in the Democratic Republic of the Congo as very high.

What to watch

The warning signs are mostly about change in spread, geography, and countermeasures. More concerning signals would include sustained human-to-human transmission in new districts or countries, especially across borders; infection in health workers or health facilities, which can amplify outbreaks; delays in finding cases and tracing contacts; and spread in crowded urban settings. Another important signal is the virus species involved. If an outbreak is caused by Sudan virus or Bundibugyo virus, WHO says there is no approved vaccine or treatment yet, so control depends more heavily on fast public-health work and supportive care. For Ebola virus outbreaks caused by Ebola virus, shortages of vaccine or monoclonal antibody supply would also matter. WHO has also pointed out that resurgence from viral persistence in survivors is possible, so unexplained new cases after an outbreak has ended deserve urgent investigation. Rising case fatality, wider geographic spread, or repeated exportations would make the situation more worrying.

Related outbreaks

Updated