#Bundibugyo Virus Disease #Outbreak, #DRC - Situation #Report No. 15, Data as of 23 August '26 (WHO, summary): 5,584 cases & 2,680 deaths in DRC

 

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Event description

Democratic Republic of the Congo

    More than three months into the response, the Bundibugyo virus disease  (BVD) outbreak in the Democratic Republic of the Congo remains characterized by  sustained transmission, high mortality and continued geographic expansion. 

    The epidemiological picture is increasingly heterogeneous, with  persistent transmission in established hotspots in Ituri, intensifying transmission  in parts of Nord-Kivu and Haut-Uélé, and continued geographic expansion  through the emergence of cases in previously unaffected health zones. 

    Since External Situation Report #14, a total of 563 new confirmed cases and 302 confirmed deaths have been reported, bringing the cumulative total to  5 584 confirmed cases, including 2 680 deaths. 

    The number of affected health zones has increased from 55 to 57 across  six provinces, with Viadana in Bas-Uélé and Mutwanga in Nord-Kivu being  the most recently affected health zones.

Figure 1. Daily growth trend in confirmed Bundibugyo virus disease cases in the  Democratic Republic of the Congo, by date of report, data as of 23 August 2026

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    During the most recent 21 days (3 – 23 August 2026), 1 782 confirmed  cases were reported nationally. Compared with the preceding 21-day period (13  July – 2 August 2026), reported cases declined slightly by 57 (−3.1%). Given  the small magnitude of this decline and the potential influence of reporting  delays and retrospective data reconciliation, this should be interpreted cautiously  because it does not yet provide clear evidence of declining transmission. 

    The national trend also masks a continued redistribution of reported incidence, with cases declining by 13.4% in Ituri but increasing by 32.5% in  Nord-Kivu and 122.2% in Haut-Uélé. Consequently, Ituri’s contribution to newly  reported cases declined from 84.0% to 75.1%, while the contribution of Nord-Kivu  increased from 12.9% to 17.6% and that of Haut-Uélé more than doubled  from 2.9% to 6.7%.

    During the same period, 973 confirmed deaths were reported nationally, a  slight decrease of 16 deaths (−1.6%) compared with the preceding 21 days. A  marked geographic redistribution of mortality was nevertheless observed. While  deaths declined by 8.8% in Ituri, they increased by 15.1% in Nord-Kivu and  85.2% in Haut-Uélé. Consequently, Ituri’s contribution to newly reported deaths  declined from approximately 78.3% to 72.6%, while Nord-Kivu’s contribution  increased from 18.7% to 21.9% and Haut-Uélé’s nearly doubled from 2.7% to  5.1%. Transmission therefore remains dominated by Ituri but is increasingly  distributed across other active foci, indicating that the outbreak is becoming progressively less concentrated in its original epicentre.

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    At health-zone level, the changing geographic pattern is more pronounced, with substantial variation in reported incidence across established  and emerging transmission foci. In Ituri, reported cases declined markedly in  Mongbwalu from 223 to 50 (−173; −77.6%), Lita from 96 to 56 (−40; −41.7%),  and Nizi from 292 to 210 (−82; −28.1%), while Bunia declined slightly from 411  to 384 (−27; −6.6%) and Rwampara from 271 to 258 (−13; −4.8%). In contrast,  cases increased in Bambu from 33 to 63 (+30; +90.9%), Mangala from  55 to 92 (+37; +67.3%), and Nia-Nia from 69 to 89 (+20; +29.0%).

    Outside Ituri, reported cases increased substantially in Katwa from 115  to 162 (+47; +40.9%) and Beni from 34 to 53 (+19; +55.9%) in Nord-Kivu, and  in Isiro from 19 to 49 (+30; +157.9%) and Wamba from 9 to 47 (+38; +422.2%)  in HautUélé. These patterns indicate that the declining contribution of  Ituri is being driven primarily by substantial reductions in several established  hotspots, particularly Mongbwalu and Nizi, rather than by a uniform decline across  the province.

    At the same time, increasing incidence in selected health zones within  Ituri and the continued growth of foci in NordKivu and Haut-Uélé indicate an  increasingly heterogeneous and geographically dispersed transmission pattern. 

    Reported deaths at health-zone level show a broadly similar geographic redistribution  but also highlight important discordance with trends  in reported cases. In Nord-Kivu, deaths in Katwa increased from 71 to 112 (+41;  +57.7%), alongside the increase in reported cases, while deaths in Beni increased  from 29 to 35 (+6; +20.7%). In Haut-Uélé, deaths increased in Isiro  from 11 to 18 (+7; +63.6%) and Wamba from two to 17 (+15; +750.0%),  consistent with increasing reported incidence in both health zones. In Ituri, deaths  declined substantially alongside cases in several established hotspots,  including Mongbwalu from 82 to 20 (−62; −75.6%), Nizi from 146 to 58 (−88;  −60.3%), Lita from 62 to 25 (−37; −59.7%), and Rwampara from 173 to 72  (−101; −58.4%).

    However, the pattern was not consistent across all health zones. Most  notably, Bunia recorded a 29.8% increase in deaths, from 104 to 135 (+31),  despite a 6.6% decline in reported cases. Deaths also increased in Bambu from 5  to 13 (+8; +160.0%), alongside the increase in cases, while Mangala showed  little change in deaths, from 37 to 40 (+3; +8.1%), despite a 67.3% increase in  reported cases. These discordant trends warrant cautious interpretation of  apparent declines in reported incidence. Where fatal infections are more  consistently ascertained than non-fatal cases, a reduction in reported cases  without a corresponding reduction in deaths may reflect differences in case  ascertainment,  reporting delays, or the lag between case detection and death  rather than a true decline in transmission. Interpretation of recent health-zone  mortality patterns in Ituri is further limited by 250 cumulative deaths that had not  yet been assigned to a health zone as of 23 August 2026.

    Ten previously affected health zones reported no confirmed cases  during the most recent 21 days (3 – 23 August 2026): Adja, Boga,  Kambala and Mahagi in Ituri; Goma and Lubero in Nord-Kivu; Rungu in Haut-Uélé;  Lubunga and WanieRukula in Tshopo; and Miti-Murhesa in Sud-Kivu. During  the same period, six health zones were reported as affected for the first  time: Mutwanga in Nord-Kivu; Gombari in Haut-Uélé; Bafwasende and Tshopo in  Tshopo; and Buta and Viadana in Bas-Uélé.

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    Mortality remains high, with 302 confirmed deaths reported during the last seven days, including 171 (56.6%) in the community and 131 (43.4%) in  BVD treatment facilities. The persistently high proportion of community deaths  (defined as both deaths at home and at non-BVD health facilities) highlights  continued challenges with early detection, referral and timely access to treatment,  while mortality in BVD treatment facilities may reflect late  presentation, quality of care and patient vulnerabilities, including age, malnutrition  and comorbidities; further analysis to understand the risk factors 

is underway.

    Among 4807 confirmed cases and 1820 deaths with available age and  sex information, adults aged 20 – 59 years continue to account for the majority of confirmed cases, representing about two-thirds of cases overall and  58% in the most recent epidemiological week. However, mortality remains disproportionately concentrated among young children.

    In week 34, children aged <5 years accounted for 17% of reported cases but 29% of deaths, continuing the increased contribution of this age group to  mortality observed in recent weeks. Overall, the sex distribution of cases is  relatively balanced, although females account for slightly more cases, while  deaths are broadly similar between males and females. These findings continue to  indicate a high burden of transmission among working-age adults alongside  

disproportionate mortality among young children.

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    The current BVD outbreak continues to follow a markedly different  trajectory from previous major Ebola disease outbreaks. 

    

    During the first 102 days of reporting, the 7-day moving average of  daily cases remained substantially higher than levels observed during  comparable periods of the 2014 – 2016 West Africa and 2018 – 2020 Democratic  Republic of the Congo outbreaks, reaching more than 90 confirmed cases per day  at its recent peak. With 5514 confirmed cases, including 2642 deaths, reported as  of 22 August 2026, this is the largest BVD outbreak ever recorded and the  secondlargest Ebola disease outbreak on record. Notably, the number of deaths  has already surpassed the 2287 deaths reported during the entire 2018–2020  outbreak in eastern Democratic Republic of the Congo.

Figure 7. Comparison of three major Ebola disease outbreak trajectories during  the first 102 days of reporting using seven-day moving averages of the daily number of confirmed cases reported.

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    The security situation in eastern Democratic Republic of the Congo  remains volatile and continues to present operational challenges for the  outbreak response. Recent insecurity has included armed clashes, attacks  affecting civilians and health services, population displacement and constraints on  humanitarian access in parts of the affected area. In addition, the AFC/M23 group  recently announced restrictions on movement to and from Ebola-affected government-controlled areas as a measure to reduce the risk of disease  importation into areas under their control.

    While the operational implications of these measures are still being assessed, continued insecurity, displacement and  restrictions on population  movement underscore the complexity of maintaining coordinated outbreak  response activities across areas with different security and administrative  contexts.

Uganda and France

    Uganda has now recorded 38 consecutive days without a new confirmed BVD case  since the last patient was discharged on 16 July 2026. All  identified contacts completed follow-up, with no further cases detected. The  continued high level of transmission in neighbouring eastern Democratic Republic  of the Congo, however, means that the risk of cross-border reintroduction  remains. France has reported no new confirmed BVD cases for 50 consecutive  days since the imported case was discharged on 4 July 2026. The outbreak is thus  considered over by WHO’s norm of 42 days without any cases. 

Risk Assessment

    According to WHO’s latest Rapid Risk Assessment as of 20 August 2026, the risk of further spread remains very high within the Democratic  Republic of the Congo and high for neighbouring countries sharing land  borders with the country. 

    The assessment reflects sustained transmission, continued geographic expansion, high mortality, population mobility, insecurity and persistent  response challenges. The risk is considered low elsewhere in Africa and globally.  The second IHR Emergency Committee, convened on 18 August 2026, also  reviewed the evolving situation and emphasized that the outbreak remains far  from controlled, and continues to constitute a Public Health Emergency of  International Concern.

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Situation interpretation

    The BVD outbreak continues to evolve into a more complex and geographically dispersed phase , in which modest reductions in some  established hotspots are being offset by intensification and emergence of  transmission elsewhere. 

    The simultaneous persistence of high mortality, community deaths, health-worker infections, uneven contact followup, localized treatment  constraints and community resistance indicates that expansion of response  capacity alone is not yet translating consistently into transmission control. The  priority must remain faster, locally differentiated and community-centred  operations, concentrating resources on active and emerging transmission foci,  closing critical surveillance, IPC and treatment gaps, and ensuring rapid access to  affected communities. At the same time, sustained regional preparedness and  cross-border coordination are essential to contain further geographic spread.

Source: 

Link: https://www.afro.who.int/health-topics/ebola-disease

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