A new case of Ebola has been confirmed in northwestern Democratic Republic of Congo, the National Institute of Biomedical Research said Saturday, four months after the end of the country's last outbreak.

The case, a 31-year-old male, was detected in the city of Mbandaka, capital of Congo's Equateur province, the institute said. A health ministry spokesperson confirmed the discovery.

The patient began showing symptoms on April 5 but did not seek treatment for more than a week. He was admitted to an Ebola treatment center on April 21 and died later that day, the World Health Organization (WHO) said in a statement.

“Time is not on our side,” said Dr. Matshidiso Moeti, the WHO's Regional Director for Africa.”The disease has had a two-week head start and we are now playing catch-up."

Mbandaka, a crowded trading hub on the banks of the Congo River, has contended with two previous outbreaks -- in 2018 and in 2020. It is a city where people live in close proximity, with road, water and air links to the capital Kinshasa.

The WHO said that efforts to contain the disease are already underway in Mbandaka, and that a vaccination campaign will begin in the coming days.

Congo has seen 13 previous outbreaks of Ebola, including one in 2018-2020 in the east that killed nearly 2,300 people, the second highest toll recorded in the history of the hemorrhagic fever.

The last outbreak, also in the east, infected 11 people between October and December and killed six of them.