Ebola
Severe, often fatal viral haemorrhagic disease caused by orthoebolaviruses, spread through bodily fluids.
DR Congo's Bundibugyo Ebola epidemic had killed 3,799 of 7,890 confirmed patients by WHO's 23 September 2026 count, as new cases shifted to Butembo and a river boat carried the virus to Sud-Ubangi.
Last refreshed: 4 October 2026
Timeline for Ebola
Mentioned in: Ebola shifts south to DR Congo's Butembo
Pandemics and BiosecurityMentioned in: G20 talks take Ebola pledges to US$3bn
Pandemics and BiosecurityMentioned in: UDPS official beaten to death in Butembo
Pandemics and BiosecurityMentioned in: Madagascar logs half July's mpox cases
Pandemics and BiosecurityMentioned in: WHO: 2,000 Congolese workers get Ervebo
Pandemics and BiosecurityBackground
Ebola disease, which WHO describes as severe and often fatal, is caused by orthoebolaviruses. WHO lists three species behind human outbreaks: Zaire ebolavirus, Sudan virus and Bundibugyo ebolavirus. It spreads through direct contact, via broken skin or mucous membranes, with the blood or body fluids of a sick or dead person, and with surfaces they have contaminated. WHO puts the average case-fatality rate at around 50%.
The disease was first recorded in 1976, in simultaneous outbreaks at Yambuku in what is now DR Congo and Nzara in what is now South Sudan. Licensed vaccines and treatments exist only for the Zaire species, which caused repeated large outbreaks and gave companies a reason to finish them. Bundibugyo has caused only a handful of outbreaks since its discovery in Uganda in 2007.
Deaths at home drive spread, because relatives WHO wash and bury a body are exposed when it is most infectious. WHO declares an outbreak over only after 42 days without a new case, the wait it applied before ending Uganda's 2026 chain.
Bundibugyo still has no licensed vaccine
Ervebo, Merck's vaccine, is licensed only against Zaire ebolavirus. On 20 August 2026 a release of 70,000 Ervebo doses from the emergency stockpile reached DR Congo, and about 2,000 frontline workers had been vaccinated by 10 September. A randomised ring-vaccination trial of 20,000 doses against Bundibugyo had not started; WHO expects it in October or November. On 19 September MSF began BRAVO, a separate study vaccinating about 20,000 frontline workers in Ituri and North Kivu with Ervebo.
On 27 August CEPI gave Egypt's Minapharm up to $16.5m for an African safety trial of its Bundibugyo vaccine; of CEPI's five candidates against the species, it is the only one with an African maker. Moderna's candidate entered human testing in Canada on 3 August.