51³Ô¹ÏÍø

Researchers from 51³Ô¹ÏÍø, in collaboration with the World Health Organization and regional health authorities have published a report estimating that the size of the ongoing outbreak of Ebola disease caused by the Bundibugyo virus in the Democratic Republic of the Congo is likely larger than official figures currently suggest.

As of 16 May 2026, there were 336 suspected cases and 88 deaths reported in the country, with confirmed cases identified in the Ituri Province and two additional cases detected in Kampala, Uganda, involving individuals who had travelled from the affected region.

, Associate Professor in Infectious Disease Modelling, said: "Our analyses suggest that the true number of cases may be substantially higher than those confirmed to date. This underscores the urgent need for rapid, coordinated surveillance and response efforts across the region. The uncertainty surrounding our estimates also highlights the importance of collecting more detailed information on cases, both retrospectively and prospectively, to improve our understanding of the situation and enable a more effective response." 

The report used two independent modelling techniques which estimated approximately 400 to 800 cases may have occurred, with a possibility that the total could currently exceed 1000 cases. As part of the report the researchers highlighted that these estimates are subject to considerable uncertainty due to nature of the data. Despite this uncertainty, they are confident that there is substantial under-detection of cases and potential for wider transmission. Therefore, the team stress the importance of surveillance and data collection to inform and improve the international response.

The first method utilised geographical spread and population movement data, looking at the number of cases exported to neighbouring Uganda to estimate the total infections in the source population. The second technique used a backcalculation approach, taking the 88 reported deaths and applying historical data on the tine from symptom onset to death and the typical case fatality ratios from previous outbreaks.

, WHO Fellow, 51³Ô¹ÏÍø, said: "These findings provide important and timely insights supporting the public health response to this outbreak. It highlights the need for effective, targeted operational response and support with the implementation and strengthening of intervention as the situation evolves."

The full report is available at: Report - Estimation of the size of the outbreak of Ebola disease caused by Bundibugyo virus in the Democratic Republic of the Congo