A review of Bundibugyo virus and the 2026 outbreak: lessons for epidemic preparedness

The ongoing 2026 outbreak of Ebola virus disease caused by Bundibugyo virus (BDBV) in the Democratic Republic of the Congo and Uganda has renewed attention to one of the least studied human-pathogenic orthoebolaviruses. Since its discovery in western Uganda in 2007, only two recognised outbreaks of BDBV had been reported, limiting opportunities to define the epidemiology, pathogenesis, diagnosis, clinical spectrum, and optimal management of BDBV or to develop species-specific countermeasures. The current outbreak, declared a Public Health Emergency of International Concern by WHO on May 17, 2026, has also exposed the gap between scientific innovation and operational readiness. Although pan-filovirus diagnostics, investigational vaccines, therapeutics, and adaptive clinical trial platforms are now available, their deployment has been constrained by delayed diagnosis, limited access to species-inclusive diagnostics, insecurity due to conflict, population displacement, and fragile health systems. In this Review, we synthesise evidence on BDBV from its discovery to the current 2026 outbreak, highlighting advances in epidemiology, clinical management, diagnostics, vaccines, therapeutics, and preparedness. More broadly, the outbreak shows that scientific innovation alone is insufficient; its public health impact depends on integrated, species-inclusive systems capable of rapidly detecting, evaluating, and responding to outbreaks caused by any human-pathogenic Orthoebolavirus spp.