#Bundibugyo Virus Disease #Outbreak, #DRC, #Uganda - Weekly #Report 18, Data as of 13 Sept. '26 (WHO, summary): 7,258 cases and 3,510 deaths in DRC

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Event description

Democratic Republic of the Congo

    The Bundibugyo virus disease (BVD) outbreak in the Democratic Republic  of the Congo has expanded to a seventh province, with the first confirmed  case reported in Bulu Health Zone, Sud-Ubangi, a province bordering the  Central African Republic and the Republic of the Congo. 

    This latest geographic expansion heightens concern about further spread  towards international borders, while transmission within the country remains  increasingly heterogeneous across affected provinces and health zones. 

    Since External Situation Report #17, a further 572 confirmed cases and 284 confirmed deaths have been reported, bringing the cumulative total to  7258 confirmed cases, including 3510 deaths [case fatality ratio (CFR) 48.4%], as of 13 September 2026. 

    Ituri remains the principal focus but its relative contribution continues to  decline, accounting for 78.0% of cumulative confirmed cases, while transmission  continues to increase in Nord-Kivu and persists in Haut-Uélé. 

    The outbreak now affects 62 health zones across seven provinces, with  Bulu Health Zone in Sud-Ubangi being the latest affected.

    At the national level, daily incidence remains high and fluctuating, with  the seven-day moving average declining from its mid-August peak, followed by a modest rebound in early September. This national pattern masks increasingly divergent provincial trajectories. 

    Ituri continues to decline from its mid-August peak but remains at a high  level, while Nord-Kivu is experiencing a sharp and sustained increase, reaching its  highest incidence since the start of the outbreak and increasingly driving the  national trajectory. 

    Transmission in Haut-Uélé remains sustained but has declined from its  August peak. 

    Tshopo shows a recent increase from a low baseline, while Bas-Uélé  continues to report sporadic transmission, and no recent transmission is evident in  Sud-Kivu. 

    Overall, the epidemic is becoming more geographically heterogeneous,  with declining transmission in Ituri and Haut-Uélé occurring alongside rapid  intensification in Nord-Kivu, renewed activity in Tshopo and continued geographic  expansion to new areas.

Figure 1. Daily national trend in confirmed Bundibugyo virus disease cases, with  seven-day moving average, by date of report, Democratic Republic of the Congo, as of 13 September 2026

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    During the most recent 21 days (24 August – 13 September 2026), 1674  confirmed cases were reported nationally. 

    Compared with 1782 cases during the preceding 21-day period (3 – 23 August 2026), this represents a decrease of 108 cases (−6.1%). Reported  cases declined by 25.0% in Ituri, from 1338 to 1004, and by 16.7% in Haut-Uélé,  from 120 to 100. 

    In contrast, cases increased sharply by 76.1% in Nord-Kivu, from 314 to  553, while Tshopo increased from 8 to 13 cases and Bas-Uélé from 2 to 3  cases. One case was also reported in the newly affected province of Sud-Ubangi  during the latest period. Consequently, Ituri’s contribution to newly reported cases  fell markedly from 75.1% to 60.0%, while Nord-Kivu’s contribution nearly  doubled from 17.6% to 33.0%; Haut-Uélé’s contribution declined slightly from  6.7% to 6.0%. 

    Overall, the modest 6.1% national decline masks a pronounced geographic redistribution of transmission, with the substantial decline in Ituri  increasingly offset by rapidly intensifying transmission in Nord-Kivu and continued geographic expansion.

    During the same period, 830 confirmed deaths were reported nationally,  compared with 973 deaths during the preceding 21 days, representing a decrease of 143 deaths (−14.7%). The national decline was driven largely by  Ituri, where reported deaths decreased from 706 to 495 (−29.9%), while deaths  also declined in Haut-Uélé, from 50 to 31 (−38.0%). 

    In contrast, deaths increased substantially in Nord-Kivu, from 213 to 299  (+40.4%). Consequently, Ituri’s contribution to newly reported deaths fell  markedly from 72.6% to 59.6%, while Nord-Kivu’s contribution increased from  21.9% to 36.0%; Haut-Uélé’s contribution declined from 5.1% to 3.7%. Tshopo  and Bas-Uélé each reported two deaths during the latest period, while one death  was reported in Sud-Ubangi. 

    Overall, the national reductions in both cases (−6.1%) and deaths (−14.7%) were driven predominantly by declining transmission and mortality in  Ituri and mask sharply divergent provincial trajectories. In particular, the  simultaneous increases in cases (+76.1%) and deaths (+40.4%) in Nord-Kivu  indicate substantial intensification of the outbreak there, with the province now  accounting for one-third of newly reported cases and more than one-third of  newly reported deaths nationally.

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    Additionally, during the most recent 21 days (24 August – 13 September  2026), 49 of the 62 affected health zones (79.0%) reported at least one new  confirmed case, while 13 (21.0%) reported no new cases. Health zones reporting  no cases were Adja, Ariwara, Aungba, Kambala and Mahagi in Ituri; Goma in  Nord-Kivu; Gombari in Haut-Uélé; Lubunga, Tshopo and Wanie-Rukula in Tshopo;  Miti-Murhesa in Sud-Kivu; and Buta and Viadana in Bas-Uélé.

    Provincial trends also mask important differences between health zones.  In Ituri, where cases declined by 25.0% overall, several health zones continued to  increase, notably Komanda (22 to 76; +245.5%), Mangala (92 to 116;  +26.1%), Lita (56 to 65; +16.1%) and Mongbwalu (50 to 61; +22.0%). 

    In  contrast, major transmission areas declined substantially, including Bunia (384 to 285; −25.8%), Nizi (210 to 120; −42.9%), Rwampara  (258 to 106; −58.9%) and Nia-Nia (89 to 46; −48.3%). 

    Nord-Kivu shows the opposite pattern, with broad-based intensification  rather than an increase confined to a few hotspots. Cases increased in Katwa (162  to 175; +8.0%), Beni (53 to 111; +109.4%), Butembo (51 to 101;  +98.0%) and Musienene (27 to 46; +70.4%), alongside transmission in newly or  recently affected health zones. Haut-Uélé declined overall, but this also concealed  a marked increase in Pawa, from eight to 38 cases (+375%), while Isiro and  Wamba declined.

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    Weekly confirmed deaths peaked at 364 during 10 – 16 August, before  declining to 302 and 270 over the following two weeks. Deaths subsequently  increased to 276 during 31 August – 6 September and further to 284 during 7 –  13 September. 

    

    The composition of mortality, however, shifted in the latest week.  Community deaths decreased from 207 to 193 (−6.8%), while deaths in  treatment facilities increased from 69 to 91 (+31.9%). Consequently, the  proportion of deaths occurring in the community declined from its peak of 75.0%  to 68.0%, although it remains substantially higher than in most earlier weeks.

    The persistence of high community mortality may reflect multiple barriers  along the pathway to care, including delayed detection and notification, delayed  referral or transfer to treatment facilities, limited recognition of illness or  perceived severity, geographic and transport barriers, care-seeking outside formal  health facilities, and community acceptance or trust. These factors may result in  patients reaching treatment facilities late or dying before referral can be  completed.

    The continued predominance of community deaths, despite expanding  treatment capacity, therefore suggests that increasing bed capacity alone may be  insufficient and reinforces the need to strengthen early case detection, rapid 

referral and community-level pathways to timely care.

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Risk Assessment

    The risk of further spread remains very high within the Democratic Republic of the Congo. This assessment reflects sustained transmission,  continued geographic expansion, high mortality, population mobility, insecurity  and persistent response challenges. 

    

    A two-week invasion-risk forecast has identified 20 currently unaffected  health zones at elevated risk of transmission. 

    

    In descending order of predicted risk, these are Rethy, Watsa, Nyarambé,  Biringi, Dungu, Makoro, Karisimbi, Angumu, Rutshuru, Nyiragongo, Niangara,  Linga, Kirotshe, Bafwagbogbo, Alimbongo, Jiba, Poko, Rwanguba, Kamango and  Kibirizi. 

    

    The highest predicted risks are concentrated in Ituri and Haut-Uélé,  reinforcing the need for riskbased preparedness and readiness measures. 

    The risk is considered high for neighbouring countries sharing land  borders with the Democratic Republic of the Congo and 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 outbreak remains uncontrolled and increasingly heterogeneous,  with declining transmission in Ituri masking rapid intensification in Nord-Kivu, and  continued geographic expansion, including to Sud-Ubangi. Response efforts should prioritize targeted interventions in emerging and persistent hotspots,  particularly strengthening early detection, contact tracing, rapid isolation and  referral, IPC and community engagement. Approaches contributing to declining  transmission in areas of Ituri should be identified, consolidated and rapidly  adapted and scaled up in areas where transmission is increasing. Preparedness  should also be reinforced in high-risk health zones and along domestic and cross- border corridors to limit further geographic spread.

Source: 

Link: https://www.afro.who.int/countries/democratic-republic-of-congo/publication/ebola-bundibugyo-virus-disease-outbreak-3

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