KINSHASA, Democratic Republic of Congo — The Ebola outbreak tearing through the Democratic Republic of Congo has surpassed 10,000 confirmed cases, making it the second-largest Ebola epidemic ever recorded and the deadliest since the 2014-2016 West Africa crisis that killed more than 11,000 people.

Congolese health officials put the toll at more than 10,060 cases and at least 4,887 deaths as of October 27, according to figures reported by Al Jazeera. The outbreak, caused by the Bundibugyo strain of the Ebola virus, was declared on May 15 and has since been designated by the World Health Organization a public health emergency of international concern.

A Strain With No Vaccine

Unlike the more familiar Zaire strain of Ebola, which has an approved vaccine and antibody treatments, the Bundibugyo strain has neither. That gap has made the outbreak especially difficult to bring under control even as case counts have climbed across eight of the DRC's provinces, with Ituri province as the epicenter, according to the European Centre for Disease Prevention and Control.

The virus has already crossed Congo's borders. A smaller, linked outbreak in Uganda has officially ended after 20 cases and two deaths, but Kenya has confirmed nine cases, including two deaths, all traced to a single traveler. Nigeria logged its first case on October 20; that patient was medically evacuated to Switzerland for treatment.

RESPONSE INDICATORS REMAIN BELOW TARGET AS THE OUTBREAK CONTINUES TO EXPAND

That's the blunt assessment from the U.S. Centers for Disease Control and Prevention, which has tracked the outbreak's spread since the summer. The State Department says the U.S. has committed more than $887 million toward the broader African-led response as of late September.

International aid groups and Congolese health workers are contending with a familiar set of obstacles: active conflict zones that limit access, distrust of outside responders in some communities, and a virus that spreads easily among caregivers and burial workers handling the dead. Treatment centers across Ituri and neighboring provinces have reported being overwhelmed, with aid workers describing shortages of protective equipment and trained staff even as new case clusters emerge weekly.

What's next: WHO officials and Congolese health authorities are expected to reassess containment strategy in the coming weeks, with growing pressure on vaccine makers to fast-track a shot effective against the Bundibugyo strain specifically — a process that, even on an accelerated timeline, would likely take months.