Two out of five samples from patients in the Democratic Republic of Congo (DRC) have tested positive for Ebola virus disease, sparking the DRC government to declare an outbreak, the World Health Organization confirmed Tuesday.

The five samples are all from the iIkoko Iponge health facility near Bikoro in Equateur Province, which is located in the northwestern part of the country along the shores of Lake Tumba. In the past five weeks, the area has reported 21 cases, including 17 deaths, suspected to be from a viral haemorrhagic fever. This is a generic term for illnesses involving fever and bleeding that are caused by a variety of viruses, including Ebola.

The WHO notes that Bikoro’s health facilities have “limited functionality” and largely rely on international aid and supplies. The DRC’s Ministry of Health tested the five patient samples at the Institut National de Recherche Biomédicale (INRB) in Kinshasa, the country’s capital.

After the DRC notified WHO of the outbreak, the international agency set up a dedicated team of staff to coordinate a response and released $1 million in emergency funding to support the response activities. WHO is preparing to deploy a multidisciplinary group of experts to Bikoro in the coming days. But a group of experts, including some from WHO and Doctors Without Boarders (Médecins Sans Frontières), already traveled to Bikoro today to help rapidly scale up response efforts.

“Our top priority is to get to Bikoro to work alongside the Government of the Democratic Republic of the Congo and partners to reduce the loss of life and suffering related to this new Ebola virus disease outbreak,” WHO Deputy Director-General of Emergency Preparedness and Response Dr. Peter Salama said in a press statement. “Working with partners and responding early and in a coordinated way will be vital to containing this deadly disease.”

This outbreak is the ninth for the DRC since the Ebola virus was discovered in samples from the country (then Zaire) in 1976. Ebola is endemic to the DRC and transmitted to people from wild animals, including primates and bats. Ebola virus disease causes fever, pain, diarrhea, vomiting, and unexplained hemorrhaging. It spreads from person to person through bodily fluids and leads to death in about 50 percent of cases.

The last outbreak, in 2017, was quashed quickly with rapid, coordinated responses, the WHO notes.