New CDC modeling says the Ebola outbreak in the Democratic Republic of Congo and Uganda could produce more than 20,000 cases within three months unless isolation and other measures increase.
Jason Asher of the CDC's Center for Forecasting and Outbreak Analytics said, "If only 20% of cases enter isolation within two days of symptom onset, more than 20,000 cases are projected."
Asher added that higher isolation rates change the outlook: "If 70% of cases started isolating within that two-day period, there's a 94% probability of limiting the outbreak to fewer than 10,000 cases" in the next three months.
Dr. Satish Pillai, the CDC Ebola response incident manager, said the domestic risk to the general U.S. population "remains low" and that "there's no reason anyone in the U.S. should change their behavior, or even worry about traveling internationally other than to the Democratic Republic of Congo or Uganda."
The World Health Organization reports 397 confirmed cases and 65 deaths in the outbreak.
The outbreak is caused by the Bundibugyo type of Ebola, which currently has no available vaccines or treatments, and early response efforts were hampered because standard Ebola tests did not pick up the Bundibugyo strain.
Officials say the outbreak's epicenter in Ituri province is a conflict zone, and the World Health Organization declared the situation an international health emergency in May.
Jennifer Nuzzo, director of the Pandemic Center at Brown University School of Public Health, said the CDC analysis "affirms what we have worried about since the beginning: This outbreak is following a dangerous trajectory and will get a lot worse unless we do more to stop it at its source." Jeremy Konyndyk, president of Refugees International, said he was "very, very worried" and warned the response capacity is weaker now than it would have been previously.
On a call with reporters, Asher stressed the modeling "is not a forecast; it is a planning tool," and the CDC built its scenarios using data through May 24, when about 50 deaths had been reported.
An American surgeon who contracted Ebola in Congo, Dr. Peter Stafford, was evacuated to Germany for treatment; his wife and four children, who were exposed, were also flown to Germany, and another doctor, Patrick LaRochelle, was taken to the Czech Republic for monitoring.
The CDC's analyses emphasize that large-scale, sustained public health interventions similar to those deployed in the 2014 West Africa outbreak are needed and that isolating people after exposure is key; Pillai said, "We've responded to Ebola outbreaks before. We know how to end this. Our goal is control, containment and ending the outbreaks in DRC and Uganda. And we are working every day towards that goal."
Emmanuel de Merode, director of Virunga National Park, said a team of more than 800 park rangers is on the front lines setting up checkpoints to screen visitors for Ebola and trying to protect primates in an area that borders Uganda.
De Merode said the park is footing the bill to construct five screening posts on roads leaving the Ebola-affected area, with some to be completed by the end of next week and others later this month, and that each post costs $44,000.
He described the screening posts as complex facilities that include at least six buildings, a diagnosis room, reliable internet, an analysis room, computer equipment and a robust isolation center, and said each will channel large crowds through controlled passageways and accommodate 30 staff, with about two-thirds of those serving as security and eight paramedics being recruited for each site.
De Merode said preparedness in the region is "catastrophic" because of a dramatic drop in international support, noting U.S. aid of $1.4 billion in 2024 and just over $400 million in 2025; he said many health workers have contracted the disease and died, and that in one province of 11 million people there were only two body bags, prompting the park to purchase 100 within 48 hours and arrange for another 1,000 to arrive soon.
He said the park has assigned five vehicles to local health services and that there is a shortage of infrared thermometers for diagnosis.
De Merode described an upsurge in militia attacks on park staff in recent weeks, saying two staff were killed 10 days ago, five were injured last Thursday — three critically and one who lost an eye — and that another attack this morning killed two people among staff; he said the past few weeks are "certainly the worst we've experienced in the past 30 years."
Virunga is home to several hundred mountain gorillas, about a third of the global population, and de Merode said the park has about 200 rangers in the south around the mountain gorilla population, has closed tourism and is taking strong measures to prevent contact because gorillas are thought to be highly susceptible to Ebola; by some estimates 98% of gorillas who get Ebola die and the virus has already reduced the global gorilla population by approximately one-third, he said, adding there has been one Ebola case in Goma, about 20 kilometers away.
De Merode said the last Ebola epidemic lasted 18 months, that there are signs this one could be significantly worse and that it could become an international problem if the international response does not materialize; he said Virunga was effective at managing gorilla risk in the 2018-2020 outbreak and that he is reasonably confident the park can do so again. On June 3, de Merode discussed these efforts and conditions in eastern DRC.