History · Ebola
Ebola: from the first outbreaks to the 2026 Bundibugyo epidemic
Ebola is not one virus appearing in one place. It is a group of related viruses that have caused repeated outbreaks in central and western Africa since 1976, with very different consequences depending on the species involved, the strength of the health system and how quickly cases are identified.
The 2026 outbreak matters because it is caused by Bundibugyo virus, a less familiar member of the Ebola-virus family, and because it has moved across borders from the Democratic Republic of the Congo.
Chapter 1
1976: the disease is recognised
Ebola disease was first recognised in 1976 during two outbreaks occurring at roughly the same time: one in what is now the Democratic Republic of the Congo and another in what is now South Sudan.12
The Congolese outbreak centred around Yambuku, near the Ebola River from which the disease took its name. Transmission was amplified by contaminated needles and close contact in healthcare settings. The Sudan outbreak spread through communities and hospitals as well.1
Those events established a pattern that has repeated ever since: an animal-to-human spillover begins an outbreak, then human transmission accelerates through close contact, healthcare exposure and unsafe burial practices.
Chapter 2
Different viruses, different outbreaks
The term "Ebola" covers several related viruses.
Zaire ebolavirus has caused many of the largest and deadliest outbreaks, including the 2014–16 West African epidemic. Sudan virus has caused repeated outbreaks in Uganda and surrounding areas. Bundibugyo virus was first identified in 2007 and has generally produced a lower case-fatality rate than Zaire ebolavirus, though it can still cause severe and fatal disease.1
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That distinction became particularly important once vaccines and treatments were developed. Countermeasures effective against one Ebola virus are not automatically effective against another.
The successful rVSV-ZEBOV vaccine transformed responses to Zaire ebolavirus. But the 2026 epidemic is caused by Bundibugyo virus, for which the same licensed vaccine cannot simply be assumed to provide protection.
Chapter 3
2014–16: Ebola becomes a global crisis
The West African epidemic beginning in 2014 changed the world's understanding of the scale an Ebola outbreak could reach.
More than 28,600 cases were reported across Guinea, Liberia and Sierra Leone, with cases also exported elsewhere.1 The epidemic overwhelmed health systems and demonstrated how difficult Ebola becomes to control once transmission is established in densely connected urban areas rather than remaining concentrated in smaller rural outbreaks.
It also accelerated work on vaccines, rapid diagnostics, clinical treatment and emergency-response systems.
The lesson was that containment depends on speed: finding cases, isolating patients, tracing contacts and protecting healthcare workers before chains of transmission multiply.
Chapter 4
DRC becomes the centre of repeated outbreaks
The Democratic Republic of the Congo has experienced more Ebola outbreaks than any other country.
Some have remained relatively small. Others have become prolonged emergencies because they occurred amid conflict, displacement and mistrust of authorities.
The 2018–20 outbreak in eastern DRC became one of the largest ever recorded, with more than 3,400 cases. It also produced cross-border cases in Uganda.1
Repeated outbreaks have given Congolese health teams substantial experience with Ebola response. But experience does not remove the structural problems that make containment difficult: insecure territory, mobile populations, damaged health systems and misinformation.
Chapter 5
2026: Bundibugyo returns at scale
The current outbreak began in north-eastern DRC and was declared a Public Health Emergency of International Concern by WHO on 15 May 2026.3
It is the DRC's 17th recorded Ebola outbreak and is caused by Bundibugyo virus. The epidemic spread through Ituri and neighbouring areas and crossed into Uganda, while violence and population movement complicated surveillance and treatment.3
By early October the outbreak had grown into the largest recorded Bundibugyo-virus epidemic. WHO reported thousands of confirmed cases and deaths.
On 6 October, Kenya confirmed its first imported Ebola case: a man who had lived in DRC, travelled through Uganda and arrived in Nairobi before testing positive and dying.4
The Kenyan case did not mean sustained transmission was occurring in Kenya. Its importance was different: it demonstrated how easily a prolonged outbreak can generate cases far beyond its original centre.
Chapter 6
Why contact tracing matters
Ebola spreads through direct contact with the blood or bodily fluids of an infected person, or with contaminated materials. People are not generally considered infectious before symptoms begin.
That makes contact tracing unusually important. Health teams identify people who had relevant exposure, monitor them through the virus's incubation period and isolate anyone who develops symptoms.
This is why a single imported case can generate dozens of public-health actions without necessarily becoming a local outbreak.
Border screening can help, but it is imperfect. Travellers can be incubating disease without symptoms, and medication can sometimes mask fever. The defence therefore relies on several layers rather than one checkpoint.
Chapter 7
What the 2026 outbreak changes
The current epidemic reinforces three lessons from Ebola's history.
First, "Ebola" is not one interchangeable disease. The exact virus matters for vaccines, treatment and expected severity.
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Second, an outbreak can remain primarily regional while still creating international cases through normal travel.
Third, containment depends as much on functioning institutions as on medicine: laboratories, local trust, contact tracing, safe treatment and communication all have to work together.
The imported Kenyan case is therefore not a separate story from the DRC outbreak. It is evidence of what a long-running epidemic looks like once transmission, insecurity and cross-border movement overlap.