Over the span of a few days, public health officials went from announcing a new Ebola outbreak in the Democratic Republic of Congo on May 15 and Uganda to declaring it an international public health emergency two days later.

By that time, the toll was notable. More than 200 people had been infected, and more than 80had died before the disease was identified as a rare strain of Ebola, the viral hemorrhagic fever that sparked a global outbreak in 2014.

There are two critical questions about timing: When did this outbreak actually start? And why did public health officials detect it so late?

And there’s another key question to consider: Has the U.S., which has traditionally been a key player in emerging outbreaks, been hampered in its response by its withdrawal from the World Health Organization?

When did it start?

The early data on the outbreak —- 246 suspected cases and 65 suspected deaths in the initial report — raised the eyebrows of some infectious disease experts.

“My immediate impression was that this is an extraordinarily large number of deaths and suspected cases that was being reported in what was supposed to be a new outbreak,” says Boghuma Titanji, an infectious disease physician at Emory University. “My immediate instinct was that this has been ongoing for a couple of weeks and has taken some time to identify. That sent off alarm bells in my mind.”

Since then, the toll has risen to at least 88 deaths and more than 330 suspected infections. Health officials now believe that the first known case was a health worker in Bunia, DRC, who began experiencing fever, hemorrhaging, vomiting and intense malaise on April 24. That person later died, according to WHO. But it would take another three weeks before health officials officially said Ebola was spreading.

That delay has allowed the virus to spread, says Jeremy Konyndyk, president of Refugees International and former director of the United States Agency for International Development’s Office of U.S. Foreign Disaster Assistance during the Obama administration. “This outbreak has a lot of momentum.”

Why did it take so long to detect?

The species of Ebola that’s spreading is partly to blame for the delay. It’s called Bundibugyo, and it’s relatively rare, with a genetic sequence that’s about 30% different than Ebola virus species that typically cause outbreaks, says Titanji. That also means there are no approved vaccines or treatments.

“Some of the initial testing that was done didn’t pick up this Bundibugyo virus,” she says, since those tests were designed for more common versions of Ebola. As a result, samples had to be sent to more specialized testing centers. That can take time, especially in this region of DRC, where ongoing conflict and difficult travel conditions can delay shipments.

What’s been the U.S. role?

At least one American who worked in the DRC for a nongovernmental organization has been sickened in this outbreak, the U.S. Centers for Disease Control and Prevention confirmed in a press call May 18. Six additional Americans are considered high-risk exposures.

The CDC is working with the State Department to move these individuals to Germany for monitoring and treatment. “Given the previous experience with caring for Ebola patients, coupled with the flight times being significantly shorter, this allows us to get these persons to points of care quickly,” said CDC Ebola response incident manager Satish Pillai in the call.

Pillai also said the agency was surging technical and field experts requested by the DRC, beyond the 25 or so staff members in the CDC DRC Country Office. “Anything that the country office and the Ministry [of Health] is requesting for support, we will be providing,” he said.

But cuts made by the Trump Administration to U.S. domestic and international health agencies raises questions about whether the U.S. is continuing to support disease surveillance across DRC.

“The U.S. invested in disease surveillance capacity in Congo because it is such a hotbed of known novel outbreak risks,” says Konyndyk. “That disease detection surveillance architecture has been badly weakened.” 

The U.S. CDC and the United States Agency for International Development both played key roles in surveillance. USAID had staff all across the country who could gather disease intel. And CDC staff, both in DRC and the U.S., helped transport samples and analyze them.

CDC has been battered by funding and staffing cuts over the past year and a half. And USAID’s DRC mission was shuttered last year, limiting the U.S. response, says Konyndyk.

In a statement to NPR, the State Department said “It is false to claim that the USAID reform has negatively impacted our ability to respond to Ebola,” adding that funding and support to combat Ebola would continue.

Other moves by the Trump administration are having an impact, say the disease doctors. A shrinking budget at the World Health Organization – most notably because of the administration’s withdrawal from the U.S. body – have reduced the size of WHO’s international emergency division, says Konyndyk. [does WHO confirm this?]

At a May 17 press conference, CDC’s Pillai did not respond to a question about whether funding cuts to CDC contributed to the delay. He did say that CDC only learned about the outbreak on May 14th, the day before it was announced.

That relatively late-in-the-game notification struck Demetre Daskalakis, a former high-ranking official at CDC. “We used to be like the first or second call for many of these things,” he says. “Though I’m not on the ground at the DRC to tell you what happened, it does seem weird that we accrued a couple 100 cases of this before CDC got any inkling of information.”

On the press call, Pillai said the difficult conditions of the outbreak’s epicenter likely account for the delay. Cases are concentrated in the Ituri province of northeastern DRC, a mining area experiencing ongoing conflict.

In the past, humanitarian programs operating in such areas have acted as informal disease surveillance networks.

Aid workers, providing medical care or food in conflict regions, can often flag unusual outbreaks of diseases in areas outside of the government’s reach, says Konyndyk.

U.S. funding for such programs “has been almost wiped out,” he says. “Total humanitarian funding in Congo was over $900 million in the last year of the Biden administration, that dropped by close to 80% down to 179 million during the first year of the Trump administration.”

It’s difficult to say for certain whether aid cuts caused the delayed reporting, says Konyndyk. But “at every level, international response capacity has been badly undermined by the U.S, and also wider global funding cuts.”

What the future holds

Overall, the delayed detection of this outbreak will make it harder to get under control., say the infectious disease specialists interviewed by NPR.

Right now, international health agencies — including the U.S. CDC — are scrambling to send staff and supplies. They’re focused on identifying cases, caring for patients and isolating their contacts to limit the spread.

“I’m very worried,” says Konyndyk. “The whole international response architecture is much weaker than it was a few years ago.”