Phylogenetic analysis of the 2025 Ebola outbreak in the Democratic Republic of the Congo.

On 4 September 2025, the Ministry of Public Health, Hygiene and Social Welfare officially declared the 16th Ebola disease outbreak in the Democratic Republic of the Congo (DRC). This outbreak ended on 1 December 2025 and occurred in Bulape Health Zone, Kasaï Province, an area with limited access to appropriate healthcare facilities and resources. Here, we describe the probable index patient and molecular investigations of samples obtained from six suspected patients from the initial outbreak phase. We identified Orthoebolavirus zairense (EBOV) in five samples from different patients. In addition, we performed whole-genome sequencing and generated four complete EBOV genomes. These genomes form a well-supported phylogenetic cluster with genomes from the 1976 Yambuku/Mayinga outbreak. This study suggests a likely new zoonotic spillover event from an as-yet unidentified natural reservoir. While the close relationship to 1976 EBOV Yambuku/Mayinga genomes is striking, this poses additional challenges on the comprehension of the animal reservoir species.