Bundibugyo Ebola outbreak becomes largest on record with 5 794 cases and 2 786 deaths, DRC

The Bundibugyo Ebola outbreak in the Democratic Republic of the Congo had grown to 5 794 confirmed cases and 2 786 deaths as of August 26.

It is the largest Ebola outbreak recorded in the country, regardless of Ebola virus species, and sustained transmission now spans 60 health zones across six provinces, up from 54 health zones in the previous update. The crude case fatality ratio stood at 48.1%, while 1 293 patients had recovered.

The previous update, published on August 14, reflected data through August 12. Since then, the reported total has risen by 1 129 confirmed cases and 602 deaths.

When The Watchers last reported on the outbreak on July 14, the latest national figures stood at 1 926 confirmed cases and 702 deaths across five provinces. The total has since increased by 3 868 cases and 2 084 deaths, while the outbreak has spread into a sixth province.

Ituri remains the center of transmission, with 4 802 confirmed cases recorded since the outbreak began. North Kivu is the second-most affected province, with 775 cases and the outbreak’s highest provincial case fatality ratio at 68%; the reasons for the elevated ratio remain under investigation.

Of the 60 affected health zones, 28 are in Ituri, 15 in North Kivu, seven in Tshopo, six in Haut-Uélé, three in Bas-Uélé and one in South Kivu.

Six additional health zones reported confirmed cases between the August 14 and August 28 updates. They were Ganga and Viadana in Bas-Uélé; Biena, Manguredjipa and Mutwanga in North Kivu; and Tshopo health zone in Tshopo Province.

Bas-Uélé began reporting cases on August 12, becoming the sixth province affected during the current outbreak. During the 24 hours ending August 26, authorities reported 81 new confirmed cases across 19 health zones in Ituri, North Kivu, Haut-Uélé and Tshopo.

Response teams followed up 22 091 of the 26 850 contacts requiring monitoring on August 26, equivalent to 82.3%. The size of the contact list reflects the scale of potential exposure within affected communities.

Insecurity and displacement continue to restrict access to healthcare and make surveillance, case investigations and contact follow-up more difficult.

The International Health Regulations Emergency Committee met for a second time on August 18 and advised that the epidemic continued to meet the criteria for a Public Health Emergency of International Concern. The designation was first made on May 17.

The WHO Director-General accepted the Committee’s advice and determined that the outbreak did not meet the criteria for a pandemic emergency.

An assessment of the outbreak’s growth between May 17 and August 12 produced a case-based effective reproductive number, or Rt, of 1.24, corresponding to a doubling time of 52 days. Because low case detection probably means that this estimate understates transmission, mortality data were also examined.

The mortality-based analysis produced an estimated Rt of 1.55 and a doubling time of 21 days. Combining several analytical methods suggested that the epidemic’s actual size could be three to four times that captured through surveillance.

That figure is a model-based estimate, not a confirmed case count. The epidemic’s growth rate remained classified as very high as of August 12.

The August 14 risk reassessment rated the risk within the DRC as very high and the risk to countries sharing land borders with the DRC as high. Risk for the rest of the African Region and at the global level remained low.

The assessment considered continued transmission and geographic expansion, population mobility, conflict and insecurity, laboratory constraints and the absence of a licensed vaccine or specific antiviral treatment for Bundibugyo virus disease.

Vaccination of healthcare workers with Ervebo began in several DRC locations, including Kisangani in Tshopo Province, on August 27. Ervebo is licensed and WHO-prequalified for Ebola virus disease caused by Ebola virus, or EBOV, but whether it protects people against Bundibugyo virus has not been established.

The Technical Advisory Group on candidate vaccine prioritization recommended including Ervebo in a randomized clinical trial during the outbreak. Separately, the WHO-sponsored PARTNERS treatment trial in Ituri has enrolled more than 250 confirmed patients.

Between August 17 and 23, the Logistics Cluster dispatched approximately 40 metric tonnes and 211 m³ (7 451 feet³) of relief items from Bunia to 19 last-mile destinations. The operation served 16 government and humanitarian partners, while transport and storage services remained available to response organizations free of charge.

The epidemic is unfolding amid armed violence, population displacement and restricted access to healthcare in parts of eastern DRC. Approximately one million internally displaced people live in Ituri Province.

Overcrowding and limited water, sanitation and hygiene services in displacement sites, informal settlements and mining communities make early detection, infection prevention and clinical care more difficult.

Bundibugyo virus disease is caused by Bundibugyo virus, classified within the species Orthoebolavirus bundibugyoense. It spreads between people through direct contact with infected blood, bodily fluids or contaminated materials.

No vaccine or specific antiviral treatment is currently approved specifically for Bundibugyo virus disease. Controlling the outbreak depends on quickly identifying cases, isolating and caring for patients, tracing contacts, conducting safe burials and working with affected communities.

The current epidemic is the second documented Bundibugyo virus disease outbreak in the DRC, following the 2012 outbreak.

References:

¹ Ebola disease caused by Bundibugyo virus — Democratic Republic of the Congo — WHO — August 28, 2026

² Second meeting of the IHR Emergency Committee on the epidemic of Ebola Bundibugyo virus disease in the Democratic Republic of the Congo — WHO — August 28, 2026