History

Discovery of the Virus

Ebola Virus Disease was first identified in 1976 following two nearly simultaneous outbreaks: one caused by the Ebola virus (EBOV) in the Democratic Republic of the Congo (DRC), and the other caused by Sudan virus (SUDV) in Sudan (now South Sudan).

Photo of the team of scientists who studied the 1976 Ebola epidemic in Yambuku (© Dr Joel Breman)

Early Human Transmission

Between the 1980s and 2000s, several epidemics affected Central Africa (Gabon, DRC, Republic of Congo), with a case-fatality rate of around 80%.

Photo of Red Cross members disinfecting a body bag during the 1995 Ebola epidemic in Kikwit, Zaire (Photo credit: US CDC)

West Africa Outbreak

The largest Ebola outbreak to date primarily affected Guinea, Liberia, and Sierra Leone, resulting in more than 28,000 cases and 11,000 deaths. This unprecedented epidemic is attracting worldwide attention and mobilizing major emergency efforts.

Photo credit: World Health Organization

First Ebola Vaccine

The WHO announced the demonstrated efficacy of the rVSV-ZEBOV (Ervebo®) vaccine, developed in Canada and produced by Merck*. Its effectiveness was confirmed during the 2015. “Ebola Ça Suffit!” ring vaccination trial in Guinea. Since then, WHO has recommended its use during EVD outbreaks, using a ring vaccination strategy: vaccinating contacts of confirmed cases, and the contacts of those contacts, to contain transmission and protect affected communities.¹

Photo credit: World Bank / Vincent Tremeau

Effective Therapeutic Treatment Identified

During the 10th outbreak in the DRC (with more than 3,470 cases and 2,287 deaths), monoclonal antibody treatments were evaluated in the PALM001 trial*. The trial identified two effective treatments for EVD: REGN-EB3 (Inmazeb®) developed by Regeneron Pharmaceuticals and MAb114 (Ebanga®) developed by INRB and Ridgeback Biotherapeutics²

Most Recent Outbreak in Guinea

In 2021, a new epidemic broke out in Guinea, with 23 confirmed cases and 12 deaths, reinforcing the focus on prevention and treatment strategies. The rapid deployment of the rVSV-ZEBOV vaccine and the monitoring of contacts for 21 days (maximum incubation period of the virus) enabled better control of this epidemic.

Most Recent Outbreak in the DRC

The most recent EVD outbreak to date was declared on September 4, 2025, in the Bulape health zone in Kasai Province. The outbreak began in August, when a severely ill pregnant woman presented to the local hospital for a cesarean delivery, resulting in transmission to more than ten individuals.³

Photo of the Bambalaie Ebola Treatment Center, 35 km from Bulape, set up by ALIMA in the Democratic Republic of Congo in 2025. Installation in and near the Bambalaie hospital. Democratic Republic of Congo.

Preparation and Implementation of the EBO-PEP Trial in Case of Outbreak

In the Democratic Republic of Congo, photo of the ALIMA-supported MSF Ebola Treatment Center in Bulape. Democratic Republic of Congo, 2025. ⁴

Henao-Restrepo AM, Camacho A, Longini IM, et al. Efficacy and effectiveness of an rVSV-vectored vaccine in preventing Ebola virus disease: final results from the Guinea ring-vaccination trial. Lancet. 2016;389(10068):505–18. DOI:10.1016/S0140-6736(16)32621-6. Photo credit: David Lindsay / Frederick National Laboratory for Cancer Research)
Mulangu S, Dodd LE, Davey RT Jr, et al. A Randomized, Controlled Trial of Ebola Virus Disease Therapeutics. N Engl J Med. 2019;381(24):2293-2303. DOI: 10.1056/NEJMoa1910993. Photo credit: David Lindsay / Frederick National Laboratory for Cancer Research)
Tsanni A. Agencies mobilize to stem Ebola epidemic in DRC [Internet]. Nature; 2025 [cited 2025 Nov 27]. Available from: https://www.nature.com/articles/d44148-025-00308-w.
Photo credit: ALIMA