The Ebola outbreak in the Democratic Republic of the Congo has spread to a sixth province and is now the second-largest on record, with the World Health Organization warning it is on track to eclipse the deadliest outbreak in history — the 2014–2016 West African crisis that killed more than 11,000 people across Guinea, Liberia and Sierra Leone. As of late this week, DRC authorities had recorded more than 4,449 confirmed cases and over 2,100 deaths across six of the country's 26 provinces, with the vast majority — more than 3,400 cases — concentrated in Ituri, a remote northeastern province near the borders with Uganda, South Sudan and Rwanda. A death recorded in Bas-Uele province this week marked the outbreak's spread to a previously unaffected area, after the deceased had travelled from Haut-Uele province.

The scale and speed of the crisis are alarming health authorities. At the equivalent point in the 2014–2016 outbreak, only 755 cases had been recorded; the current outbreak has reached its death toll nearly three times faster. WHO Director-General Tedros Adhanom Ghebreyesus said this week that "at its current pace, it's on track to eclipse" that earlier crisis, while his colleague Dr Abdirahman Mahamud, head of the WHO's emergency response division, projected the outbreak's peak is still six months away under a moderate scenario — with a worst case of nine to twelve months. Uganda has separately reported 20 imported cases, all in the capital, Kampala, with no community transmission detected.

The outbreak is compounded by a cluster of structural crises. Health workers at the Nizi treatment centre in Ituri went on strike this week, having gone three months without pay, temporarily shutting the facility. Rebel group activity in the region restricts access, while widespread misinformation — including claims that Ebola is not real — is keeping patients away from clinics. Between 60% and 70% of new cases are being recorded outside the pool of contacts already being monitored, meaning authorities are unable to keep pace with the virus. "We are chasing the virus; the virus is ahead of us," said Dr Mohamed Yakub Janabi, the WHO's regional director for Africa.

A critical complication is that the outbreak involves the rare Bundibugyo strain of the Ebola family of viruses, for which there is currently no licensed vaccine or approved treatment. Unlike the better-known Ebola virus, the Bundibugyo strain has historically carried case fatality rates of 30–50%. Genomic sequencing of samples published this week in the journal Nature Medicine confirmed the virus is genetically distinct from previous Bundibugyo outbreaks in 2007 and 2012, suggesting it originated in a new spillover from an infected animal to a human rather than from earlier outbreaks. Officials at Africa CDC have also raised concerns the virus may be mutating.

Efforts to close the medical gap are accelerating. Two vaccines specifically designed against the Bundibugyo strain have entered Phase I human safety trials, and Tedros announced this week that WHO is recommending a Phase III efficacy trial of Ervebo — the only existing licensed Ebola vaccine, currently approved only for a different strain — after animal studies showed it may offer some cross-protection against Bundibugyo. Clinical trials of two potential treatments are also underway in Ituri, with a WHO-sponsored partners trial having reached 100 patients, a milestone officials described as evidence that research can be mobilised rapidly even in difficult conditions. Mahamud expressed cautious optimism, saying that if response measures were implemented simultaneously across all five active transmission zones, "we are expecting a turnaround in three months."