Ebola outbreak may have spread undetected for months in Congo

The first official cases were not detected until mid-May, but health workers now fear Ebola had been moving through eastern Congo since January, giving the virus months to spread in a region already strained by insecurity, displacement and weak surveillance.

The International Rescue Committee warned that the outbreak in Ituri Province may have circulated undetected for up to three months before confirmation, with only about 20% of contacts being traced. That gap matters because the outbreak involves the rare Bundibugyo strain of Ebola, for which the World Health Organization says there is no licensed vaccine or specific treatment.

WHO first alerted health authorities on May 5 to a high-mortality outbreak of unknown illness in Ituri, then confirmed Bundibugyo virus disease in laboratory samples on May 15, finding the virus in eight of 13 samples. Two days later, on May 17, WHO declared the outbreak a Public Health Emergency of International Concern. The agency and the Centers for Disease Control and Prevention have both said the response is unfolding in a difficult humanitarian and security environment, with conflict, population displacement, mining-related movement and frequent cross-border travel all complicating containment.

The outbreak has already been described by aid groups as one of the largest Ebola outbreaks on record, and the IRC warned it could become the deadliest if the response remains underfunded and delayed. Public health workers are trying to isolate cases and trace contacts in remote areas where fear, mobility and broken trust can outrun the system built to stop the virus.

The danger is not confined to Congo. WHO says the outbreak in the Democratic Republic of the Congo and Uganda was confirmed in May, and the CDC says no Ebola cases from this outbreak have been confirmed in the United States. The agency still says the risk to the American public and travelers remains low, even as enhanced screening and travel restrictions have been put in place for people coming from affected countries.

The crisis has also spilled into politics in Kenya, where U.S. plans to monitor exposed Americans at a newly built 50-bed facility at Laikipia Air Base sparked backlash from Kenyan doctors, rights activists and legal groups. The plan called for asymptomatic Americans exposed abroad to be monitored there, with patients who developed symptoms or tested positive moved onward for care in Europe. A Kenyan court temporarily suspended the facility and later extended the block, ordering the government to disclose its agreement with Washington. On June 1, protesters in Nanyuki demonstrated against the plan, and Reuters reported that the clashes killed two people.

For communities in Congo and across the region, the lesson is stark: when Ebola slips past detection for months, the cost is measured not just in cases, but in the breakdown of trust, movement of families, and the strain placed on health systems that were already too fragile to absorb another crisis.