Congo had been due on Sunday to mark an end to the second-deadliest outbreak of the virus on record until a case was confirmed on Friday in the eastern city of Beni.
The outbreak has killed more than 2,200 people since August 2018 in an area of the country where militia violence hobbled efforts to contain it.
The latest victim was an 11-month-old girl, who was treated at the same health centre as the previous case, a 26-year-old electrician, said Boubacar Diallo, deputy incident manager for the WHO’s Ebola response.
It is not yet clear how the electrician contracted Ebola. He had no known contacts with other Ebola patients and was not a survivor of the virus who could have relapsed, the government said on Friday.
Flare-ups or one-off transmissions are common towards the end of Ebola outbreaks, and a new case does not necessarily mean that the virus will spread out of control again.
The WHO has identified 215 people who came into contact with the electrician, including 53 health workers at three facilities the man visited before he died, Diallo said.