KINSHASA — Health authorities in the Democratic Republic of Congo are investigating whether the Ebola virus responsible for a rapidly expanding outbreak may have undergone genetic changes, as confirmed infections have surpassed 4,000 and deaths have approached 1,900.
Jean Kaseya, director-general of the Africa Centres for Disease Control and Prevention (Africa CDC), said officials were concerned by the scale and severity of the outbreak and planned further studies with the World Health Organization to determine whether the virus had changed. The possibility remains under investigation and has not been established as a confirmed cause of the outbreak's rapid spread.
The outbreak is caused by Bundibugyo virus, a less common Ebola species. Congo declared the outbreak on May 15 after laboratory testing confirmed infections in Ituri province. The WHO subsequently classified the outbreak as a public health emergency of international concern.
Congo's latest reported figures cited by Reuters showed 4,053 confirmed infections and 1,850 deaths, making the outbreak the largest recorded caused by Bundibugyo virus and the second-largest Ebola outbreak overall, behind the 2014-2016 West Africa epidemic.
Officials have pointed to unusually extensive community transmission as one reason for examining whether additional factors may be contributing to the outbreak's trajectory. Africa CDC has said contact tracing is identifying far fewer contacts than expected, while many infections and deaths are occurring outside health facilities, making conventional containment measures more difficult.
The WHO has reported continued transmission and geographic expansion, particularly in Ituri and North Kivu, with cases also reported in South Kivu, Haut-Uele and Tshopo. Uganda has also experienced imported infections linked to the outbreak, prompting regional surveillance and response measures.
Genomic research on the 2026 outbreak has already produced virus sequences that allow scientists to monitor its evolution. Researchers note that Bundibugyo virus naturally accumulates genetic changes over time, but determining whether any mutations are altering transmission, severity or response to medical countermeasures requires further investigation. A recent scientific analysis found no new mutations in a key catalytic region of the virus targeted in research on remdesivir.
Health authorities are therefore treating mutation as a question requiring further study rather than as an established explanation for the outbreak. Meanwhile, officials are expanding active case searches and surveillance as they attempt to identify infections that have escaped existing contact-tracing networks.
