There was nothing of the sort in Biakato, despite the surging cases. In 2013, four Doctors Without Borders workers were abducted in an A.D.F. raid on a village in North Kivu Province. One escaped after 13 months; the other three have never been found.

The World Health Organization, which is leading the effort to get help to Biakato, has its own painful history in the town. During the last outbreak in this area, in 2019, armed men attacked its guesthouse in Biakato, killing three Ebola responders. Officials blamed the violence on the Mai-Mai, a term for local militias.

That leaves health officials walking a tightrope. Proceed too slowly, and Biakato could become a deep reservoir of Ebola, spreading infection across the region. Move too quickly, and they risk an attack, like a killing or a kidnapping of aid workers, that could collapse the entire effort.

Mistrust among local residents is also a problem. After decades of war, and numerous failed military operations, faith in the government has collapsed, officials said. The same Congolese soldiers who are supposed to protect the community also prey on it, seeking bribes or profiting from gold. When Ebola came along, locals saw the disease as yet another plot to suppress them.

“They don’t trust outsiders,” said Julien Harneis, the United Nations Ebola coordinator in Congo. “Experience has taught them not to.”

As infections began to rise in September, a W.H.O. team returned to Biakato to see how they might help. The omens were ominous, at first. The health workers woke one morning to find a headless sheep dumped outside their hotel — a sign they were not welcome, said Dr. Steve Ahuka, the head of Congo’s Ebola response.

But within weeks, Ebola had become so overwhelming that Biakato’s distrustful leaders were pleading for help.

On Oct. 12, Dr. Ahuka and Catherine Smallwood, a senior W.H.O. official, returned to Biakato to a very different reception. Local leaders formed a circle around Ms. Smallwood and, after apologizing for the 2019 killings, implored her to send help.

“They asked me to put the past in the past,” she recalled. “It was an extremely touching moment.”