For years, there has been cautious optimism among global health officials that Ebola was, finally, under control. Better surveillance, faster diagnostics, and safer health care practices were just a few of the lessons learned from past outbreaks in West Africa that had transformed the response to such public health emergencies.
An Ebola awareness banner is displayed in the city of Bunia in the Democratic Republic of the Congo on May 23, 2026.
But the current Ebola epidemic now spreading rapidly in the Democratic Republic of the Congo (DRC) in central Africa has exposed a dangerous gap in those defenses that has led to, as of May 25, more than 900 suspected cases and 220 suspected deaths. Neighboring Uganda had 5 confirmed cases and 1 death.
“These are countries that have extensive experience with Ebola—it’s the 17th outbreak in the DRC alone since 1976—and they know how to respond to it,” said Daniel Lucey, MD, MPH, a clinical professor of medicine and health policy at the Geisel School of Medicine at Dartmouth who cared for patients with Ebola in Liberia and Sierra Leone during the large 2014 outbreak. “But that’s a lot different than saying they have the resources to do so. And, in fact, through a confluence of factors, things are now looking much worse.”
To start, the outbreak is being driven by the Bundibugyo ebolavirus, a rare cause of Ebola disease for which no proven treatment or vaccine exists. Worsening matters, the outbreak is occurring in a remote area of the DRC, which is experiencing ongoing, intense conflict that has likely limited the ability for prompt action.
The World Health Organization (WHO) was first alerted to a “high-mortality outbreak of unknown illness” on May 5. Ten days later, laboratory analysis confirmed the Bundibugyo ebolavirus in 8 of 13 blood samples. Within 48 hours, WHO Director-General Tedros Adhanom Ghebreyesus declared a Public Health Emergency of International Concern. He did so in unprecedented fashion, without first seeking advice from the WHO’s emergency committee, which instead convened shortly after the announcement.
Although experts considered such global response to be both prudent and rapid, the scale of cases indicate that the virus had likely been circulating since at least early March—months before detection.
“The virus already has a head start, and now we’re playing catch up,” said Boghuma Titanji, MD, PhD, an infectious disease physician and assistant professor of medicine at Emory University.
Several Orthoebolaviruses can cause Ebola disease, which is characterized by hemorrhagic fever. Most common is the Zaire ebolavirus, which is also the deadliest. It was responsible for the 2014 outbreak in West Africa that caused more than 11 000 reported deaths. Left untreated, 9 of 10 cases are fatal.
This latest epidemic, however, is being driven by the Bundibugyo virus, which was first discovered in 2007 and has been responsible for only 2 other known outbreaks. Compared with the Zaire virus, it has a lower fatality rate of 30% to 50%. That, Lucey said is still “astronomically high” and “entirely depends” on the capacity of the community to contain its spread.
That capacity, Titanji said, has been gutted after last year’s sweeping aid cuts from the US and other Western nations.
“The DRC got 70% of its foreign aid from the US before USAID was dismantled,” said Titanji, who cited how USAID (US Agency for International Development) staff previously played a pivotal role in flagging outbreaks and lending expertise to unidentified diseases. “They’re doing the best they can, but the DRC government, which in previous times has been able to scale up its response with the support of the global community, is now having to fill a sudden gap that happened essentially within the past 12 months.”
Satish Pillai, PhD, an incident manager for the Ebola response team at the US Centers for Disease Control & Prevention (CDC) told reporters at a press briefing on May 18 that the agency sent necessary personnel to support containment efforts in the DRC and that the number of staffers in the CDC’s DRC country office—approximately 25—has remained stable, but experts say frontline health workers remain underresourced.
“Even diagnosis is more difficult,” Titanji said, noting that none of the licensed diagnostic tests that can be deployed on site and deliver rapid results exist for Bundibugyo virus. “For Zaire, we have test kits, which you can perform in a very remote area and are able to say, ‘Yes’ or ‘No’ if it’s Zaire Ebola.”
In this case, she said, specimens must be transferred to specialized testing centers in Kinshasa, the capital of DRC.
Just as troubling is treatment. As Lucey said, “there’s no vaccines, monoclonals, antivirals, nothing.”
Currently, 2 licensed Ebola vaccines exist, one of which is recommended for use in outbreak settings. But that single-dose shot, marketed as Ervebo, is specifically targeted to the Zaire strain and is unlikely to provide any cross protection for Bundibugyo virus, Titanji said. “The genomes of this particular virus differ by up to 30%, so it’s not expected to generate an immune response that is protective for a virus that is so different.”
Any vaccine that would target the Bundibugyo virus, Amesh Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security, is undoubtedly in “very early stages of animal testing.” He noted that researchers are actively testing experimental therapeutics, including monoclonal antibody MBP134 and remdesivir, on this particular virus.
“During the 2014 outbreak, they were using drugs like remdesivir, which became famous from COVID-19,” said Adalja, an infectious disease physician. “We might soon see clinical trials launch once they get the infrastructure in place” that could, he added, lead to usage in this outbreak on an investigational new drug basis.
In a May 25 update, Ghebreyesus said the WHO is recommending 2 monoclonal antibodies to be prioritized in clinical trials and that a trial is being developed to test the antiviral obeldesivir as postexposure prophylaxis.
“We are facing an extremely serious and difficult outbreak,” Ghebreyesus said. “It will get worse before it gets better.”
On May 22, the WHO upgraded its risk assessment for the DRC from high to very high. As of press time, it continues to assess the risk in Uganda and other neighboring countries as high, but currently the global risk remains low. The outbreak does not yet meet the WHO’s criteria of a pandemic emergency.
Ebola, Adalja acknowledged, is a “deadly, scary disease,” but, he said, “it’s not actually that contagious.” In fact, it’s less infectious than measles, COVID-19, or even SARS. It’s not airborne, and it typically spreads through contact with bodily fluids, such as saliva, blood, vomit, or feces. People with Ebola infection are also not considered contagious until they’re symptomatic, which tends to occur between 2 and 21 days after exposure.
One reason it’s spreading so quickly then, Lucey said, is due to significant population movement in the area. Recent developments in decades-long conflict has left more than 100 000 people displaced, and the epicenter of the outbreak is a high-traffic mining zone. Lucey predicts cases will soon emerge in border nations such as Rwanda and South Sudan.
Beyond those regions, Adalja said, “I’m not very worried about international spread.” Similarly, Titanji noted that Ebola cases are often highly concentrated, geographically, because most “transmission happens when people are too sick to travel.”
Still, at least 1 US resident, a physician working with a Christian missionary group, contracted the disease while treating patients in the DRC. The critically ill patient was transported to Germany for specialty care. Although Pillai said the European destination was selected due to its “significantly shorter” flight time, Lucey found it surprising the patient wouldn’t be sent to the US, which now has several biocontainment facilities “well equipped” for managing Ebola. Another US physician, who has not yet shown symptoms, was transported to Prague and quarantined.
Around the same time, the US imposed an entry ban on foreign travelers who have been in the DRC, Uganda, or South Sudan in the past 21 days. The order, issued by the CDC, has resulted in at least 1 diverted flight.
“There’s not great evidence that any sort of unilateral travel ban does anything to slow an epidemic curve,” said Anand Parekh, MD, MPH, the chief health policy officer at the University of Michigan School of Public Health. On the contrary, he said, it may lead to increased stigmatization and panic and create additional logistical barriers to getting resources where they are most needed, further exacerbating an outbreak.
Adalja said such a ban may serve as an attempt to not “have a repeat of what happened” in 2014, when a person was diagnosed with Ebola in the US for the first time, after traveling from Liberia. He died less than 2 weeks later.
Experts note it’s impossible to forecast containment of the current outbreak. Lucey, like Ghebreyesus, warned it will “keep getting worse, quickly, before it gets better,” and Adalja said that, at minimum, it could be “months before every ember from this outbreak is gone.”
Titanji added that before making projections, public health officials first need to fully understand how widespread the outbreak is, which Adalja said that “we don’t have any handle on.”
Regardless of the pathogen and despite the challenges the current outbreak presents, Titanji said, “the principles of outbreak containment do not change.” Most urgent, Parekh said, is contact tracing, identifying cases, and instituting quarantines—no easy endeavor considering the DRC’s volatile circumstances. Equally imperative is ensuring health care workers have appropriate personal protective equipment (PPE) and communicating to the regional population how to prevent further transmission.
“We need to make sure that there’s education surrounding funerals and burial practices so they are conducted in a manner that maintains dignity but also mitigates spread,” he said. After death, the virus is present in high concentrations in bodily fluids, and rituals that involve washing or touching the body can amplify outbreaks.
Experts underscored the need for PPE for health care workers and volunteers—several have died amid the outbreak—and faster testing. “Without it, these cases can smolder in communities for weeks and weeks on end,” Titanji said of testing.
For now, with few medical countermeasures available for the Bundibugyo virus, frontline workers will have to rely on supportive care. Lucey anticipates that rehydration, one of the oldest outbreak-response tools available, will be essential for patients.
“What I found in West Africa is that if you can just rehydrate the patients and prevent them from going into shock, you can keep them alive day by day,” he said of the life-saving strategy he used as a treatment before the Zaire virus vaccine was introduced. “The best antiviral we have is our own immune system.”
Even so, Titanji hopes this outbreak will urge relevant stakeholders to move forward with the research and development of a Bundibugyo virus vaccine.
“This strain is new, relatively speaking, and has only caused 2 previous outbreaks, so you can see why there wasn’t a market incentive to invest in a vaccine,” she said. “But that delay proves costly when these pathogens inevitably show us what they’re capable of.”
