Species breadth is a preparedness metric: lessons from the 2026 Bundibugyo virus disease outbreak.

Recent outbreaks of non-Zaire orthoebolaviruses have exposed a persistent weakness in outbreak preparedness: diagnostic, vaccine, therapeutic, regulatory, and research systems remain disproportionately optimized for Ebola virus (EBOV). The 2026 Bundibugyo virus disease outbreak in the Democratic Republic of the Congo and Uganda illustrates the consequences of this species restriction. Initial testing with an EBOV-focused assay was negative, whereas broader molecular testing and genomic sequencing subsequently confirmed Bundibugyo virus, highlighting a gap between clinical suspicion and species coverage. This Commentary proposes an auditable species-breadth profile across four preparedness domains: diagnostics, vaccines, therapeutics, and evidence generation. For a minimum audit covering EBOV, Sudan virus, and Bundibugyo virus, each domain can be scored from 0/3 to 3/3 using predefined criteria for deployable detection, countermeasure availability, access pathways, and the capacity to initiate rigorous research during an outbreak. Species-breadth assessments should be integrated with specimen referral, genomic sequencing, cross-border surveillance, responder protection, community engagement, and contingency financing. Preparedness should, therefore, be judged not only by the availability of tools for one Ebola virus species, but by the ability of surveillance, diagnostics, countermeasures, and research systems to respond rapidly to whichever pathogenic orthoebolavirus emerges next.