The Bundibugyo Ebola virus
Not all Ebola outbreaks are alike. The one affecting the DRC since 2026 is caused by the Bundibugyo species, rarer than the Zaire species — a difference that changes everything when it comes to available vaccines and treatments.
Treatments & vaccines: a key difference by species
The only licensed Ebola treatments and vaccine target the Zaire species — not the Bundibugyo species behind this outbreak.
| What the species changes | Bundibugyo the species behind this outbreak | Zaire the most studied species |
|---|---|---|
| Known outbreaks | 3 — 2007, 2012, 2026 | most documented outbreaks |
| Historical fatality rate | 25 to 50% | up to 90% |
| Licensed vaccine | none | Ervebo (rVSV-ZEBOV) |
| Licensed treatments | none | Inmazeb, Ebanga (monoclonal antibodies) |
During this outbreak, several candidates are being evaluated in clinical trials against the Bundibugyo species — including the broad-spectrum antibody MBP134, the antiviral remdesivir, and obeldesivir for post-exposure prophylaxis — under WHO coordination. In the absence of a licensed targeted treatment, intensive supportive care (rehydration, oxygenation, monitoring) remains the cornerstone of care and significantly improves the chances of survival.
Transmission
- Direct contact with the blood, secretions or organs of an infected animal or person, alive or deceased
- High-risk funeral rites and transmission in healthcare settings without adequate protection
- No airborne transmission
Incubation period
An infected person is not contagious until symptoms appear. That is what makes contact tracing effective: people are isolated before transmission becomes possible.
Course of the disease
Fever, intense fatigue, muscle pain, headache, sore throat — non-specific signs easily mistaken for malaria or typhoid.
Vomiting, diarrhea, skin rash, kidney and liver damage, and sometimes bleeding. Diagnosis confirmed by RT-PCR blood test.
Reducing the risk of transmission
Human-to-human transmission happens through direct contact with body fluids. The measures that limit the risk are therefore concrete and well established:
- Avoid unprotected direct contact with a sick person, their body fluids and their personal belongings;
- Entrust the bodies of the deceased to safe burial teams: traditional funeral rites are one of the main drivers of transmission;
- Report any suspicious fever to a health centre immediately rather than treating it at home;
- Wash hands frequently, and follow protective measures in healthcare facilities.
A rarely encountered species
The Orthoebolavirus genus contains six species, four of which are pathogenic to humans. The vast majority of documented outbreaks — including the 2014-2016 West Africa epidemic and the 2018-2020 North Kivu outbreak — were caused by the Zaire species, by far the most studied.
The Bundibugyo species is named after the Ugandan district where it was first identified in 2007. Before this outbreak it had been involved in only two others: Uganda in 2007, then the DRC's Orientale province in 2012. That thin track record is why no licensed vaccine exists against it, and why the response relies on supportive care and on products still under clinical evaluation.