The Bundibugyo outbreak in Ituri Province, eastern DR Congo, has reached 246 suspected cases and 80 suspected deaths across the Bunia, Rwampara and Mongbwalu health zones, per the WHO PHEIC technical assessment1. Anne Cori, Neil Ferguson and seven Imperial College London colleagues published a Q&A on Sunday assessing the outbreak had "likely gone undetected and spread for several weeks or months" before WHO received its signal on Tuesday 5 May2. Provincial health authorities in Ituri told RFI Afrique that the first haemorrhagic-fever deaths in Djugu and Irumu territories were recorded in April3. April community deaths to the 5 May WHO signal is at least four weeks of undetected onward transmission.
The scale already makes this the largest documented Bundibugyo outbreak on record, surpassing the 2007 Uganda outbreak's 131 cases. Imperial's panel estimates the Bundibugyo case-fatality rate at 30 to 40 per cent, lower than Zaire ebolavirus's 50 per cent average but still in the highest tier of human-pathogen lethality. At a 35 per cent rate, 246 suspected cases imply roughly 80 to 90 deaths if the chain runs to clinical conclusion, a figure the 80-plus suspected deaths already approach. Mongbwalu sits inside Djugu territory and Rwampara inside Irumu; both host active armed groups that constrain medical-team deployment.
The surveillance gap converts the headline figure from a story about African detection speed into a story about regional surge capacity. The pre-outbreak Filovirus roadmap had named precisely this scenario, non-Zaire Ebola species and the detection apparatus around them. The ECDC's parallel posture review of European preparedness reached compatible conclusions on detection lag. Imperial's "weeks or months" assessment is the operational consequence: by the time INRB confirmed species on 14 May, secondary chains inside the Bundibugyo 8 to 10 day incubation window were already running in three health zones, and contact tracing was opening at scale rather than at index.
