One Health preparedness for Ebola disease caused by Bundibugyo virus: lessons from the 2026 outbreak centred in the Democratic Republic of the Congo

The 2026 outbreak of Bundibugyo virus disease (BVD), caused by Bundibugyo virus (BDBV), involved limited international exportation but remained centred in eastern Democratic Republic of the Congo (DRC). The outbreak tested whether earlier institutional mobilisation translated into timely field delivery. We conducted a structured narrative review of peer-reviewed research, official reports and operational guidance on epidemiology, diagnostics, medical countermeasures (MCMs), One Health surveillance, clinical care, infection prevention and control (IPC), community engagement and cross-border preparedness. Key institutional mechanisms for emergency decision-making, coordination and MCM prioritisation were activated earlier than during the 2013–2016 Ebola virus disease epidemic in West Africa, widening the window for action. Field delivery nevertheless remained uneven: the model-adjusted median onset-to-sampling delay was 4.8 days among 129 confirmed patients, while insecurity posed additional challenges for field response. Preparedness was further constrained by uncertainty about reservoir ecology, limited clinical validation of BDBV-specific diagnostics and the absence of MCMs with established efficacy in BVD. We therefore propose a One Health alert-to-action pathway linking human, animal, environmental and community signals to BDBV-inclusive confirmation, safe care, IPC, cross-border continuity, accountable governance and feedback-informed adaptation. Earlier activation is a preparedness gain, but protection depends on whether that advantage is carried through reliable, traceable and equitable operational hand-offs.