The first case of Ebola in more than 50 days has been detected in eastern Democratic Republic of Congo, the government says, in a major setback to hopes that the second worst outbreak in history might be over.
The central African country planned to declare an end to the outbreak on Sunday.
It has killed more than 2200 since August 2018 in an area of the country where rebel attacks hobbled efforts to contain it.
Until Friday, no new cases had been recorded since February 17.
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.
It can stay in semen for more than 550 days, researchers have said.
Ebola causes fever, bleeding, vomiting and diarrhoea and spreads among humans through bodily fluids.
The head of the World Health Organisation Tedros Adhanom Ghebreyesus confirmed the case on Twitter on Friday and said WHO had been expecting more cases to emerge, and was prepared to respond.
"Unfortunately, this means the government of (DR Congo) will not be able to declare an end to the ...outbreak ...as hoped," he said.