There were four confirmed cases and one probable case, all of whom died, the WHO said in a statement. The outbreak was the third in Congo’s northwest Equateur province.

“Thanks to the robust response by the national authorities, this outbreak has been brought to an end swiftly with the limited transmission of the virus,” said Matshidiso Moeti, WHO regional director for Africa.

“Crucial lessons have been learned from past outbreaks and they have been applied to devise and deploy an ever more effective Ebola response,” she said.

Vaccination in particular has played a key role in containing recent outbreaks and was launched just four days after the latest outbreak was declared.

Ebola is endemic to Congo, where it was discovered near the Ebola river in 1976.

The virus causes hemorrhagic fever and is spread through contact with the body fluids of an infected person.