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Ebola disease caused by Bundibugyo virus - Democratic Republic of the Congo
25 September 2026Situation at a glance
Since the last Disease Outbreak News was published on 11 September 2026, the Bundibugyo virus outbreak in the Democratic Republic of the Congo has expanded further, with two additional health zones affected. These include Bulu health zone in a new province, Sud Ubangi, located on the north-west part of the country and Dungu health zone in Haut-Uélé province, bordering South Sudan. This brings the total number of affected health zones to 63 across seven provinces out of 26 provinces of the country: Bas-Uélé, Haut-Uélé, Ituri, North Kivu, South Kivu, Sud Ubangi and Tshopo. This latest geographic expansion increases the risk of cross-border transmission. As of 23 September 2026, the Democratic Republic of the Congo has reported 7890 confirmed cases, including 3799 deaths, resulting in a crude case fatality ratio (CFR) of 48.1%. At the national level, the number of new cases reported each day remains high. However, the situation varies across the country, with some provinces and health zones experiencing much higher levels of transmission than others. The continuously high CFR, and especially the continuous high rate of deaths occurring in communities, highlights the seriousness of the disease and the persistent challenges in timely case detection and access to early and adequate patient care. These delays can contribute to preventable illness and deaths among people in affected and newly affected areas, while also allowing transmission to continue within households, communities, and healthcare settings.
Description of the situation
Since the previous Disease Outbreak News was published on 11 September 2026, an additional 1133 confirmed cases, including 532 confirmed deaths, have been reported in the Democratic Republic of the Congo. The seven-day moving average shows a resurgence in early September followed by a decline over the most recent reporting days. However, the aggregate national trend conceals substantial variation in transmission intensity across affected provinces and health zones.As of 23 September, the Democratic Republic of the Congo has reported a total of 7890 confirmed cases, including 3799 deaths (CFR 48.1%). A total of 1966 patients have recovered to date.
Confirmed cases have been reported from 63 health zones across seven provinces, with 48 health zones from six provinces reporting at least one case in the last 21 days. Ituri remains the most affected province, with 28 of its 36 health zones reporting cases, followed by North Kivu (16/34), Tshopo (7/23), Haut-Uélé (7/13), Bas-Uélé (3/11), South Kivu (1/34), and Sud Ubangi (1/16). No new cases have been reported from South Kivu province since 29 May 2026. Dungu Health Zone in Haut-Uélé province and Bulu in Sud Ubangi are the most recently affected areas. As of 23 September, 70 new confirmed cases had been reported in the preceding 24 hours from 26 health zones located in Ituri, North Kivu, Haut-Uélé, Bas Uélé and Tshopo provinces.
Figure 1. Distribution of cumulative confirmed cases of Bundibugyo virus disease in the Democratic Republic of the Congo, as of 23 September
Ituri continues to be the epicentre of the outbreak, accounting for 6032 confirmed cases since the start of the outbreak, including 868 new confirmed cases reported in the previous 21 days, as of 23 September. North Kivu is the second most affected province, with a cumulative number of 1480 confirmed cases, including 567 reported in the last 21 days, as of 23 September. North Kivu province continues to report the highest CFR (59.7%) observed in this outbreak; and investigations are ongoing to better understand the factors contributing to this elevated mortality rate.
In Ituri, case incidence continues to decline gradually from the peak observed in mid-August, although transmission remains at elevated levels. North Kivu, in contrast, has experienced a substantial increase in incidence, reaching its highest reported level in mid-September, followed by a decline in recent reporting days. Haut-Uélé continues to demonstrate sustained transmission, albeit at levels below the peak recorded in late August, while Tshopo is showing renewed transmission activity following a period of low incidence. In Bas-Uélé, transmission remains sporadic, whereas no recent evidence of transmission has been reported in Sud-Kivu. Sud Ubangi is the seventh province to report a confirmed case of BVD, with one case that was reported on 10 September (Figure 2).
The number of individuals requiring follow-up as contact has also risen considerably with the expansion of the outbreak. As of 23 September, 83.4% of identified contacts were successfully monitored during the previous 24 hours with 26 980 contacts seen out of 32 342 requiring follow up. The large volume of contacts under surveillance highlights the extent of potential exposure within affected communities and the substantial demands placed on response operations.
The response is being implemented in a challenging humanitarian environment, where conflict, insecurity, displacement, and limited access to basic services continue to affect outbreak control. These constraints continue to hamper surveillance, case finding, contact tracing, infection prevention and control, and timely access to appropriate care, thereby limiting the overall effectiveness of response activities.
Figure 2: Number of confirmed Bundibugyo virus disease cases in the Democratic Republic of the Congo, by date of notification, as of 23 September 2026
Figure 3: Number of deaths among confirmed Bundibugyo virus disease cases in the Democratic Republic of the Congo by date of notification, as of 23 September 2026.
Epidemiology
Bundibugyo virus disease (BVD) is a severe Ebola disease caused by the Bundibugyo virus, one of the Orthoebolavirus species. It is a zoonotic disease, with fruit bats suspected to be the natural reservoir.Human infection is thought to occur through close contact with the blood or secretions of infected wildlife, such as bats or non-human primates, and it subsequently spreads from person-to-person through direct contact with the blood, secretions, organs, or other bodily fluids of infected individuals or contaminated surfaces and materials. Transmission is particularly amplified in health-care settings when IPC measures are inadequate and during unsafe burial practices involving direct contact with deceased individuals.
The incubation period for BVD ranges from two to 21 days, and infected individuals are not infectious until symptom onset. Early symptoms such as fever, fatigue, muscle pain, headache, and sore throat are non-specific, which complicates clinical diagnosis and can delay detection. These symptoms then progress to gastrointestinal symptoms, organ dysfunction, and, in some cases, haemorrhagic manifestations.
The historical CFR from the past two BVD outbreaks, reported in Uganda and in the Democratic Republic of the Congo in 2007 and 2012, were 30% and 50%, respectively.
Differentiating BVD from other endemic febrile illnesses such as malaria is challenging without laboratory confirmation using polymerase chain reaction (PCR) or antigen- or antibody-based assays. Outbreak control relies on rapid case identification, isolation and care, contact tracing, safe burials and strong community engagement, as no approved vaccines or specific treatments currently exist for BVD.
Since first detected in May 2026, this BVD outbreak has rapidly evolved into a large and geographically expanding epidemic in the Democratic Republic of the Congo, with sustained transmission, high mortality and an increasing risk of further international spread. The current outbreak is the second documented Bundibugyo virus disease outbreak in the country, after the 2012 outbreak, and the largest Ebola disease outbreak ever recorded in the Democratic Republic of the Congo irrespective of Ebola virus species. The population at greatest risk of exposure is concentrated in communities living in and moving through the health areas with active transmission.
Public health response
For detailed information about the ongoing public health response actions by the Ministry of Health, WHO and partners please refer to the latest situation reports published by the WHO Regional Office for Africa: Ongoing outbreak in the Democratic Republic of the Congo | WHO | Regional Office for AfricaHealth authorities in the Democratic Republic of the Congo, in collaboration with WHO and partners, are continuing to implement and coordinate extensive public health measures, including disease surveillance, laboratory testing, infection prevention and control, clinical care, community engagement, research, logistics and support for response interventions and essential health services, engaging donors and mobilizing additional resources to address critical funding gaps and sustain response operations across affected and at-risk areas. A substantial scale-up is ongoing across all response pillars to get ahead of the outbreak.
WHO risk assessment
On 14 August 2026, WHO reassessed the risk of the outbreak of BVD, incorporating newly available information on the evolving situation. The risk for countries sharing land borders with the Democratic Republic of the Congo was separated from the risk for other countries in the African Region.The risk in the Democratic Republic of the Congo was assessed as very high, the risk for countries sharing land borders with the Democratic Republic of the Congo was assessed as high, and the risks for the rest of the African region and at the global level was again assessed as low.
For further information, please see WHO Rapid Risk Assessment-Ebola disease caused by Bundibugyo virus, Democratic Republic of the Congo v4
WHO advice
Based on the currently available information, WHO advises against any restriction of travel to, or trade with, affected countries. WHO continues to closely monitor and, where necessary, verify travel and trade measures in relation to this event.The updated Temporary Recommendations issued to States Parties on 24 August 2026 underscore the importance of coordinated outbreak control, strengthened cross‑border collaboration, and sustained surveillance and preparedness to prevent further regional spread and ensure an effective public health response. Rapid recognition of cases, testing and optimized supportive care can reduce mortality, and improve community perceptions and acceptance of health care within the response.
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Ebola disease caused by Bundibugyo virus - Democratic Republic of the Congo
Since the last Disease Outbreak News was published on 11 September 2026, the Bundibugyo virus outbreak in the Democratic Republic of the Congo has expanded further, with two additional health zones affected. These include Bulu health zone in a new province, Sud Ubangi, located on the north-west...
