The Ebola outbreak in the Democratic Republic of the Congo is worsening, with aid agencies warning that the virus is spreading into new areas and edging closer to neighbouring South Sudan.

The Democratic Republic of Congo said on Tuesday that the number of confirmed Bundibugyo Ebola cases had risen to 1,963, including 719 deaths, as of July 12, with the outbreak now affecting five provinces: Ituri, North Kivu, South Kivu, Tshopo and Haut-Uélé.

The International Rescue Committee says the outbreak has not yet reached its peak, with transmission accelerating in existing hotspots while new cases emerge farther from the epicenter in Bunia. The spread to Kisangani in Tshopo Province, more than 500 kilometres west of Bunia, has raised concerns that the virus could travel along the Congo River to other major population centers, including Kinshasa.

The confirmation of two Ebola cases in Wamba, Haut-Uélé Province, near the South Sudan border, has also heightened fears of cross‑border transmission.

"The risk to South Sudan is particularly alarming. If Ebola crosses the border, it could spread silently before being detected, making the response far more complex and putting countless lives at risk," said Bob Kitchen, Vice President of Emergencies at the International Rescue Committee. He further warned that weak surveillance systems, limited health infrastructure, ongoing conflict and a sparse humanitarian presence could delay detection and response.

The World Health Organization estimates there is a 70% likelihood that Ebola could spread into South Sudan.

While contact tracing has improved to 78.3%, it remains below the 90% to 95% threshold recommended by the WHO to effectively contain an Ebola outbreak.

Response efforts continue to face significant operational challenges, including insecurity, border and airport closures, and limited access to affected communities. The IRC warns these constraints could allow undetected chains of transmission to continue spreading as it works with health authorities to strengthen surveillance, infection prevention, community engagement and frontline health services in high‑risk areas.