The World Health Organization (WHO) has reported a total of 906 suspected Ebola cases and 223 suspected deaths associated with the Bundibugyo strain in the Democratic Republic of Congo (DRC). The outbreak, which continues to expand, has prompted authorities to enhance surveillance and testing efforts in affected areas.
Among these figures, 125 cases have been confirmed, including 17 fatalities, primarily in the eastern provinces of Ituri, North Kivu, and South Kivu. Meanwhile, Uganda has reported seven confirmed cases, three of which were imported from the DRC, along with one death. Importantly, no community transmission has been detected in Uganda to date.
Health officials estimate that the outbreak likely began roughly two months ago. It was declared a public health emergency of international concern after spreading undetected in a densely populated region. Experts have emphasized the severity of the Bundibugyo strain, which lacks an approved vaccine and carries a high fatality rate estimated between 30 and 50 percent.
“This means that up to half of those infected may succumb to the disease,” stated Anais Legand of the WHO Health Emergencies Programme, noting that the current data remain preliminary and require further verification. She added that early treatment interventions could help reduce mortality rates.
The WHO is working to strengthen testing capacity and clear a backlog of suspected samples. Officials noted that the increase in reported cases may reflect improved surveillance efforts rather than an actual worsening of the outbreak. “It is still too early to determine if the peak of the outbreak has passed,” Legand said, as investigations continue.
In a significant development, global health authorities are accelerating the evaluation of potential vaccines, therapies, and diagnostic tools. These include experimental vaccine candidates and antibody-based treatments, although most remain in early stages and would need emergency authorization before deployment. Unlike the more common Zaire strain, no approved vaccines or treatments currently exist for the Bundibugyo variant.
The WHO has recommended prioritizing several experimental options for clinical trials. These include vaccine candidates based on rVSV and ChAdOx1 platforms, antibody therapies such as MBP134, and antiviral drugs including obeldesivir and remdesivir. Diagnostic companies like BioFire Defense and Altona Diagnostics are also scaling up testing capabilities to support outbreak response efforts in the DRC.
Among the vaccine candidates under review is rVSVΔG/BDBV-GP, which employs the same platform as Merck’s approved Ervebo vaccine for the Zaire strain and has demonstrated survival benefits in animal studies. The University of Texas Medical Branch is involved in its development, with production timelines estimated at six to nine months.
A second vaccine candidate, a single-dose rVSV Bundibugyo vaccine developed by the International AIDS Vaccine Initiative, has been identified by the WHO as the most promising preventive option. Its development may take seven to nine months before it is ready for clinical trials.
The third candidate, ChAdOx1 Bundibugyo, is being developed by Oxford University and the Serum Institute of India using the same platform as the Oxford/AstraZeneca COVID-19 vaccine. The Serum Institute has commenced production under an emergency framework in coordination with CEPI and Oxford, with doses potentially available within two to three months for early clinical evaluation, pending additional animal studies.
Experts suggest that a single-dose regimen could be suitable for contacts of confirmed cases, while a two-dose approach might be reserved for high-risk groups such as healthcare workers and frontline responders.
Regarding treatments, the WHO has prioritized Mapp Biopharmaceutical’s MBP134, a pan-ebolavirus monoclonal antibody therapy, for clinical trials in confirmed Bundibugyo cases. This drug has demonstrated safety in early trials and is supported by the U.S. Biomedical Advanced Research and Development Authority (BARDA). Regeneron’s antibody candidate maftivimab is also under consideration, with laboratory studies indicating activity against Bundibugyo Ebola. The company is preparing existing supplies for possible clinical trials and has donated limited quantities of its approved antibody combination Inmazeb for potential use.
Other investigational therapies include antibody treatments derived from Ebola survivors, such as BDBV289-N, which showed up to 100 percent protection in animal studies even when administered days after infection. In antiviral research, Gilead Sciences’ oral drug obeldesivir is being evaluated as a post-exposure treatment, with preclinical data indicating strong protection in animal models. Remdesivir has also demonstrated laboratory activity against Bundibugyo, with some studies suggesting it may be more effective against this strain than the Zaire variant.
The WHO has proposed assessing combination therapies involving monoclonal antibodies and remdesivir to enhance treatment efficacy.
Diagnostic limitations have been identified as a significant obstacle in managing the outbreak. To address this, diagnostic tools such as BioFire Defense’s FDA-cleared Global Fever Special Pathogens Panel and Germany’s Altona Diagnostics RealStar Filovirus RT-PCR kit are being deployed and scaled up to improve detection in affected regions. Both companies are increasing production and collaborating with public health authorities to meet the rising demand.
Expanding diagnostic capacity remains crucial for tracking transmission chains and accelerating containment efforts as the situation evolves. Health authorities continue to closely monitor the outbreak while racing to develop effective medical countermeasures against the virus.
