Thursday’s milestone was overshadowed, though, by the enormous health challenges still facing Congo: the world’s largest measles epidemic, the rising threat of COVID-19 and another new Ebola outbreak in the north.

“We are extremely proud to have been able to be victorious over an epidemic that lasted such a long time,” said Dr. Jean-Jacques Muyembe, who coordinated the national Ebola response and whose team also developed a new treatment for the once incurable hemorrhagic disease.

The announcement initially was set for April but another case emerged just three days before the Ebola-free declaration was expected. That restarted the 42-day waiting period required before such a proclamation can be made.

The epidemic, which began in August 2018, presented an unprecedented challenge for the World Health Organization, Congo’s Health Ministry and international aid groups because it was the first Ebola epidemic in a conflict zone.

Armed groups posed such a risk that vaccinations sometimes could only be carried out by small teams arriving by helicopter.

Only a few years earlier, West Africa’s Ebola epidemic killed more than 11,000, as at that time there was no licensed vaccine or treatment.

The COVID-19 outbreak in the region has been minimal so far, but the challenges of Ebola underscore how fraught it could be to test and treat those in areas under the control of armed rebels.

 “Ebola has changed our culture,” said Esaie Ngalya, whose grandmother died from the virus. “Now I go to see my uncle but we don’t shake hands. In our culture that is considered disrespectful but now we have no choice because health comes first.