Bulape, Kasai Province, DRC — 1 December 2025 — The Democratic Republic of the Congo (DRC) officially declared the end of its 16th Ebola virus disease outbreak on 1 December 2025, marking the close of a three-month emergency response in the Bulape Health Zone of Kasai Province. The outbreak, caused by the Zaire ebolavirus species (Orthoebolavirus zairense), resulted in 64 cases — 53 confirmed and 11 probable — and 45 deaths, yielding a case fatality ratio of 70.3%.
The declaration followed 42 consecutive days without any new confirmed cases, equivalent to two full incubation periods of the virus, in line with WHO protocol for declaring the end of an Ebola outbreak.
How the Outbreak Began
The first known index case was a pregnant woman at 34 weeks of gestation who presented at Bulape General Reference Hospital on 20 August 2025 with symptoms of high fever, bloody diarrhoea, haemorrhage, vomiting, and extreme weakness. She died on 25 August from multiple organ failure. Two healthcare workers who had initially been in contact with this first case also developed similar symptoms and died.
On 1 September 2025, the DRC Ministry of Health alerted WHO to suspected cases. Laboratory testing at the National Public Health Laboratory (INRB) in Kinshasa confirmed Ebola virus (EBOV) through GeneXpert and polymerase chain reaction (PCR) assays on 3 September 2025. The outbreak was officially declared on 4 September.
A New Zoonotic Spillover
Whole genome sequencing conducted early in the outbreak revealed that this was a new zoonotic spillover event — not directly linked to the 2007 Luebo or 2008/2009 Mweka Ebola outbreaks that occurred in the same region. The findings, published on the virological.org discussion forum, confirmed that the virus had crossed from an unknown animal reservoir into the human population independently of previous chains of transmission.
This was the 16th EVD outbreak in the DRC since the virus was first identified in 1976. It followed almost three years without a confirmed EVD outbreak in the country; the last had been a single-case outbreak in Beni, North Kivu, declared over on 27 September 2022.
Response Measures
The Ministry of Health, with support from WHO and partners, implemented a comprehensive public health response:
- A crisis committee was activated at both local and provincial levels
- Active surveillance and risk communication activities were deployed
- All cases were isolated, with infection prevention and control (IPC) measures implemented
- Contact isolation and tracing were conducted continuously
- The approved Ervebo vaccine was deployed from a stockpile of 2,000 doses in Kinshasa for ring vaccination of contacts and frontline health workers
Risk Assessment
WHO assessed the overall public health risk posed by the outbreak as high at the national level, moderate at the regional level, and low at the global level. The high national risk was driven by the complex humanitarian context, limited resources, the remote and hard-to-reach nature of the affected area, and frequent population movements between Bulape and Tshikapa city.
The outbreak disproportionately affected adults, with approximately 80% of suspected cases aged 15 years and older. The high proportion of healthcare worker infections early in the outbreak underscored critical gaps in infection prevention and control capacity at the health facility level.
Broader Context
The Kasai outbreak highlighted the persistent threat of Ebola in the DRC, where the virus is endemic in animal reservoirs. It also demonstrated the importance of rapid laboratory confirmation, ring vaccination, and coordinated international response. The Ervebo vaccine, prequalified by WHO and recommended by the Strategic Advisory Group of Experts on Immunization (SAGE), has been a critical tool in outbreak response, with a global stockpile coordinated by the International Coordination Group (ICG) for vaccine procurement.
The outbreak's conclusion on 1 December 2025 represented a significant achievement for DRC's health authorities and international partners, given the operational challenges of responding in a remote, resource-limited setting amid concurrent disease outbreaks.
Sources
- World Health Organization, Disease Outbreak News: Ebola virus disease – Democratic Republic of the Congo (5 September 2025). Available at:
- World Health Organization, Disease Outbreak News: Ebola virus disease – Democratic Republic of the Congo (1 December 2025). Available at:
- WHO Regional Office for Africa: Democratic Republic of the Congo declares Ebola virus disease outbreak in Kasai Province. Available at:
- The 16th Ebola Virus Disease Outbreak in Bulape Health Zone, Kasai, DRC: A new spillover event from an unknown reservoir host. Virological.org. Available at:
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Institutional Research Desk · Foresight Institute of Research and Translation
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