Ebola Bundibugyo outbreak in DRC and Uganda exceeds 1,100 cases

Ebola Bundibugyo outbreak in DRC and Uganda exceeds 1,100 cases

A rapidly escalating outbreak of the Bundibugyo strain of Ebola is challenging health officials in the Democratic Republic of Congo (DRC) and Uganda, with total cases now exceeding 1,100. The World Health Organization (WHO) declared the situation a public health emergency of international concern on May 17, 2026, citing high population density, urban involvement, and significant population movement in the region.

Since the outbreak was declared in mid-May, the Congolese government has reported more than 1,100 cases and almost 300 deaths. This represents the largest outbreak of the Bundibugyo strain to date. In neighboring Uganda, officials have confirmed 20 cases and two deaths.

The outbreak is centered in the DRC's Ituri province.

Diagnostic and Clinical Hurdles

Medical responders say knowledge gaps are hampering the detection and care of sick patients. The Bundibugyo strain is distinct from the more common Ebola Zaire, meaning standard tests often fail to detect it. Many early samples had to be sent to distant reference laboratories for confirmation, causing critical delays.

To close this gap, Cepheid announced on June 12 that it donated an initial delivery of Xpert Hemorrhagic Fever panel tests. This multiplex assay can detect several species, including Bundibugyo. The company is working to leverage existing GeneXpert systems already deployed across Africa to expand testing into decentralized, hard-to-reach areas.

Clinicians also struggle with early diagnosis because the first signs—fever, fatigue, muscle pain, and headache—are non-specific and mimic other endemic diseases like malaria. Abdou Sebushishe, a senior adviser at the International Medical Corps in eastern Congo, noted that the early stage of the disease appears milder than Zaire, which he believes is one of the reasons more than 50% of patients are arriving at treatment centers in an advanced stage.

A disconnect in symptom perception has also fueled community resistance. While roughly 40% of Ebola patients typically experience bleeding, the WHO and Congo’s National Institute for Biomedical Research found that only 10% of 505 confirmed Bundibugyo cases exhibited this symptom. Dr. Emmanuel Musingusi Bulemu, a Congolese health official, explained that this has led some community members to believe responders are lying about the disease because they have not seen their relatives bleed.

Treatment and Vaccine Gap

Unlike the Zaire strain, there are currently no licensed vaccines or targeted treatments for the Bundibugyo virus. The Ervebo vaccine, used for Zaire, has shown mixed or no protection against Bundibugyo in non-human primate studies; officials warn that a failed vaccine trial could further erode community trust.

However, several candidates are in development:

• Remdesivir: A nucleoside analog that has shown inhibitory activity against BDBV viral RNA synthesis.
• Obeldesivir: An oral prodrug of Remdesivir that may serve as post-exposure prophylaxis to interrupt community spread.
• MPB 134: A monoclonal antibody cocktail that has shown protection in ferrets and non-human primates.

Clinical trial protocols for Remdesivir and MBP134 are being finalized and are expected to initiate in the near future.

Regional Risk Assessment

The risk for the rest of the African region and the global community remains low.

Peter Piot, a professor at the London School of Hygiene and Tropical Medicine and co-discoverer of Ebola Zaire, expressed concern over the speed of the spread.

"But I have never seen this many cases this quickly,"

he said, adding that without peace in the conflict-hit region, stopping the outbreak will be difficult.