Key info
Date:
20 May 2026
Authors:
Ruth McCabe1, Lennox Ebbarnezh2, Solome Okware3, Richard Fotsing4, Etien Koua5, Paul Mbaka6, Adelard Lofungola7, Dav M Ebengo8,9, Placide K Mbala9,10, Tania T Bishola8,9,11, Christian M. Ibolobolo9, Herman M. Matondo8,9, Jean-Clement M Sibo8,9, Sabine L van Elsland1, Martina McMenamin2, Neil M Ferguson1, Olivier le Polain de Waroux2*, Anne Cori1*
Affiliations:
1 51³Ô¹ÏÍø; 2 WHO Health Emergencies Programme, Geneva, Switzerland; 3 WHO Country Office for Uganda; 4 WHO Country Office for the DRC; 5 WHO Regional Office for Africa; 6 Uganda Ministry of Health; 7 Insitut National de Santé Publique (INSP) DRC; 8 One Health Institute for Africa (INOHA), University of Kinshasa, DRC; 9 Modeling and Epidemic Intelligence Unit, Dept of Epidemiology and Global Health, Institut National de Recherche Biomédicale, Kinshasa, DRC; 10 Dept of Medical Biology, Microbiology Service, University Clinics of Kinshasa, University of Kinshasa, DRC; 11 Dept of Biology, Faculty of Science and Technology, University of Kinshasa, DRC; *Contributed equally
Correspondence:
Dr Anne Cori
a.cori@imperial.ac.uk
Summary
As of 20 May 2026, a total of 516 suspected cases of Bundibugyo virus disease (BVD) - a form of Ebola virus disease caused by Bundibugyo virus - had been reported in the Democratic Republic of the Congo including 131 deaths. Eight cases were laboratory-confirmed in the Ituri Province from 13 samples, and two cases were confirmed in Kampala, Uganda, among individuals travelling from Ituri Province, Democratic Republic of the Congo. Together, this suggests that the epidemic is larger than currently ascertained; however, the true magnitude remains uncertain.
To estimate the size of the epidemic in the Democratic Republic of the Congo, we applied two independent approaches. The first approach uses population movement data in conjunction with evidence of the two exported cases detected in Uganda. The second approach relies on reported suspected deaths (assumed to be more completely captured than cases) combined with estimates of the case fatality ratio and time from symptom onset to death derived from previous Bundibugyo virus outbreaks, as well as assumptions about how fast the epidemic has been growing.
Both methods yield broadly consistent results, suggesting that as of 20 May 2026, approximately 400 to 900 cases of BVD may have occurred in the Democratic Republic of the Congo. However, there is considerable uncertainty around these estimates, with values of over 1000 not being able to be excluded given current data. Despite this uncertainty, the convergence of findings from two independent methods strengthens confidence in the conclusion of substantial under-detection and the potential for wider transmission.
These estimates rely on a number of key assumptions: that transmission is largely concentrated in Ituri and Nord Kivu provinces, estimates of the scale and patterns of population movement from these areas to Uganda, and values of epidemiological parameters derived from past Bundibugyo virus outbreaks, including the case fatality ratio (CFR) and time between symptom onset and death. Each of these assumptions is subject to uncertainty and may influence the resulting estimates.
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