Nikhil Prasad Fact checked by:Thailand Medical News Team Aug 13, 2026 45 minutes ago
A major genetic investigation of the 2026 Bundibugyo Ebola outbreak in the Democratic Republic of the Congo (DRC) and Uganda has found that the virus appears to have emerged from a new animal-to-human spillover, rather than returning from viruses responsible for earlier outbreaks.
Genetic sequencing reveals that the 2026 Bundibugyo Ebola outbreak likely began with a new animal-to-human spillover
before spreading across borders.
Genetic Evidence Points to a New Spillover
Researchers generated 22 Bundibugyo virus (BDBV) genomes from infected people in the DRC and Uganda. Twenty-one high-quality genomes were used for detailed evolutionary analysis.
When scientists compared these genomes with viruses from the 2007–2008 Uganda outbreak and the 2012 DRC outbreak, the 2026 viruses formed their own strongly supported genetic cluster. This separation suggests that the current outbreak did not simply arise from an older Bundibugyo virus lineage that had remained circulating unnoticed.
Instead, the findings support a fresh zoonotic event, meaning the virus probably crossed from an animal reservoir into humans again before spreading between people.
Cross-Border Human Transmission Confirmed
Genetic analysis also demonstrated transmission between the DRC and Uganda. Epidemiological investigations indicated that the Ugandan cases included in the analysis belonged to a single transmission chain rather than representing several separate introductions.
Scientists identified 25 mutations within the 2026 virus cluster. Nine, or 36 percent, showed patterns consistent with ADAR-mediated RNA editing, a genetic signature associated with ebolavirus transmission in humans. Five mutations caused changes to the proteins produced by the virus.
Importantly, this Thailand
Medical News report highlights another concerning discovery: routine diagnostic testing did not always identify the infections. Samples tested negative using the GeneXpert Ebola assay, while broader tests targeting orthoebolaviruses detected the virus. One RT-PCR test also produced invalid results in five samples, yet genome sequencing successfully recovered Bundibugyo virus genetic material and confirmed infection.
Researchers Came from a Major International Network
The researchers were affiliated with Institut National de Recherche Biomédicale; Institute of Tropical Medicine Antwerp; KU Leuven; Uganda National Health Laboratory & Diagnostic Services; Laboratoire Provincial de Santé Publique, Ituri; Université de Kinshasa and Cliniques Universitaires de Kinshasa; TransVIHMI at Université de Montpellier, INSERM and IRD; Uganda Virus Research Institute; Institut National de Santé Publique; Uganda Ministry of Health; Makerere University; WHO offices in the DRC and Africa region; Uganda Peoples’ Defence Forces; Rodolphe Merieux INRB-Goma Laboratory; Ridgeback Biotherapeutics; University of Birmingham; University of California Los Angeles; University of Edinburgh; Redeemer’s Univer
sity; Université Libre de Bruxelles; University of Oxford; University of Manitoba; University of the Western Cape; and the Kinshasa School of Public Health.
Faster Local Testing Could Be Critical
The researchers warn that Bundibugyo virus remains particularly concerning because approved Bundibugyo-specific or pan-Ebola vaccines and treatments are unavailable. Population movement, insecurity in mining regions and weaknesses in healthcare systems could further complicate outbreak control.
Conclusions
The findings show how genomic sequencing can reveal where an outbreak came from, track transmission across borders and detect infections missed by some diagnostic tests. Expanding decentralized molecular testing and near-real-time sequencing could therefore allow health authorities to recognize future outbreaks earlier, follow viral evolution and respond before transmission becomes more difficult to contain.
The study findings were published in the peer reviewed journal: Nature Medicine.
https://www.nature.com/articles/s41591-026-04628-8
Read Also:
https://www.thailandmedical.news/articles/ebola
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