An Ebola outbreak caused by the Bundibugyo virus has spread across the Democratic Republic of the Congo and into Uganda, reaching 378 confirmed cases and 63 confirmed deaths as of June 2, 2026 — already the largest outbreak on record for this Ebola species, according to a modeling report published by the U.S. Centers for Disease Control and Prevention.
The CDC’s Morbidity and Mortality Weekly Report states it plainly: “As of June 2, 2026, a total of 378 confirmed cases (363 in DRC and 15 in Uganda) and 63 confirmed deaths (62 in DRC and one in Uganda) have been recorded.” The vast majority of illness and death remains in the DRC, where this is the country’s 17th declared Ebola outbreak. Those figures put the case-fatality rate among confirmed cases at roughly 17 percent, though both the numerator and the denominator are likely to shift as suspected cases are confirmed or discarded. (Working from its own confirmed denominator, the World Health Organization has separately reported a case-fatality rate of 14 percent.)
The trajectory has been steep. In its Disease Outbreak News of May 29, WHO counted 134 confirmed cases and 18 confirmed deaths across both countries, including nine confirmed cases in Uganda. As of an earlier cutoff of May 27, the DRC alone had logged 906 suspected cases and 223 suspected deaths still under investigation. WHO described an outbreak that “continues to evolve rapidly, with increasing case numbers, geographic spread, and ongoing cross-border transmission,” and assessed the risk as very high nationally in the DRC, high regionally, and low globally.
The case for speed
What makes the CDC analysis sobering is not the current count but the math behind it. The report estimates a median reproduction number of 2.51, with an interquartile interval of 2.27 to 2.82 — each case, on average, seeding more than two others. The authors then modeled the next three months under different assumptions about how quickly patients are isolated after symptoms begin.
The fork in the road is patient isolation. In scenarios where only 20 percent of patients enter isolation, a majority of simulations — 65 percent — projected the outbreak exceeding 20,000 cases within three months. Push isolation to 70 percent, and 94 percent of simulations projected fewer than 10,000 cases over the same period — roughly a one-in-17 chance (about 6 percent) of still reaching 10,000 or more.
The report warns that if large-scale and sustained public health interventions are not rapidly implemented to reduce transmission, the outbreak could become as large as the 2014–2016 West Africa Ebola epidemic.
In a June 5 briefing, the CDC’s Dr. Pillai cautioned that real-world isolation appeared to sit “in one of the lower end” of the modeled scenarios — the dangerous end. He also stressed that “the numbers are not completely known” and will change as diagnostics are reviewed.
A central complication: there is no licensed countermeasure. Both the CDC and WHO state that no approved vaccine or specific treatment currently exists for Bundibugyo virus. That leaves classic public-health tools at the front line. The MMWR names “rapid identification of cases, contact tracing, isolation and treatment of persons with BVD, community engagement, and use of safe and dignified burial” as the measures “necessary to control the outbreak.”
For the United States, the CDC assessed the overall risk to the general public as low, with a low likelihood of importation and a low risk of sustained transmission if a case were imported. One exposure has already crossed borders: WHO reported that a U.S. physician tested positive on May 17 after treating patients in the DRC and is receiving care in Germany.
The figures here are surveillance counts subject to revision, and the projections are modeled scenarios, not forecasts of what will happen.