A Bundibugyo ebolavirus (BDBV) outbreak that prompted a global health emergency declaration last month has reached 695 confirmed cases and 138 confirmed deaths across the Democratic Republic of the Congo and Uganda, according to the World Health Organization’s Disease Outbreak News report DON607, published 13 June 2026.
The DRC accounts for 676 of those confirmed cases — concentrated in three eastern provinces — while Uganda has recorded 19 confirmed cases and 2 confirmed deaths, with evidence of limited local transmission beyond the initial imported cases.
Three Provinces, One Epicenter
Ituri Province remains the outbreak’s core, with 629 confirmed cases spanning 19 health zones, tracing back to an initial cluster in Mongbwalu Health Zone detected in early May. North Kivu Province has recorded 44 confirmed cases across nine health zones, and South Kivu has reported 3 confirmed cases from a single health zone. The spread across provincial boundaries — and into Uganda’s capital, Kampala, and the neighboring district of Wakiso — signals sustained cross-border movement of the virus.
The WHO was alerted to an outbreak of unknown high-mortality illness in Mongbwalu on 5 May 2026. Laboratory confirmation of Bundibugyo virus disease in eight samples followed on 15 May, and the DRC Ministry of Public Health officially declared the country’s 17th Ebola disease outbreak that same day. The WHO Director-General determined the situation constituted a Public Health Emergency of International Concern (PHEIC) on 17 May 2026.
Between 8 June and the DON607 reporting date of 13 June, an additional 161 confirmed cases and 45 confirmed deaths were recorded in the DRC — a five-day increment WHO attributes partly to the scale-up of testing capacity and clearance of a backlog of previously collected samples, as well as ongoing transmission. As of 10 June, 262 individuals were hospitalized in isolation across affected areas. The confirmed case fatality rate among laboratory-confirmed cases stands at approximately 19.9 percent (138 deaths among 695 confirmed cases).
“Contact tracing coverage is running at approximately 45 percent — well below the 90 percent threshold considered necessary to stay ahead of an outbreak of this nature.” — WHO situation monitoring, as reported by outbreak trackers citing DON series data
No Licensed Countermeasures for This Strain
A critical gap shaping the response is the absence of any regulatory-approved vaccine or specific antiviral treatment for Bundibugyo ebolavirus. The vaccines licensed to date — including rVSV-ZEBOV (Ervebo) and the two-dose Ad26.ZEBOV/MVA-BN-Filo regimen — target only the Zaire ebolavirus strain and offer no established cross-protection against BDBV.
On 28 May 2026, WHO convened expert and advisory groups to assess candidate medical countermeasures. The groups identified the single-dose rVSV-BDBV vaccine candidate, under development by the International AIDS Vaccine Initiative (IAVI), as the most promising vaccine option — but estimated it will require seven to nine months before it is ready for clinical trial assessment. For post-exposure prophylaxis, the oral antiviral obeldesivir was designated a priority investigational candidate, though experts noted its effectiveness depends on robust contact tracing, which remains operationally constrained in parts of eastern DRC. WHO’s advisory groups recommended that all identified candidate products be deployed exclusively within clinical trials to generate rigorous safety and efficacy data.
Response measures currently in place include deployment of rapid response teams, establishment of safe and optimized treatment centers, reinforced surveillance and laboratory capacity, infection prevention and control assessments, and community engagement programs, implemented by national authorities in collaboration with WHO and partners.
What remains unknown: whether the diagnostic backlog clearance in DRC accounts for most of the recent confirmed-case acceleration or whether underlying transmission has itself increased; whether any of the individuals reported to have recovered carry meaningful protective immunity; and when clinical trials for investigational countermeasures could begin enrolling in affected areas.