Minister of Health Dr. Oly Ilunga said Thursday in Kinshasa. Two of those cases are confirmed to be Ebola.

Lab results are pending on the other nine cases which are suspected to be Ebola.

Ebola virus disease, which most commonly affects people and nonhuman primates such as monkeys, gorillas and chimpanzees, is caused by one of five Ebola viruses.

On average, about 50% of people who become ill with Ebola die.

The new outbreak was announced Tuesday. Sickness is occurring in the Bikoro health zone, 400 kilometers (about 250 miles) from Mbandaka, the capital of Equator province.

The risk to public health is assessed as high at the local level, moderate at the regional level and low at the global level, according to the WHO.

The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission.

The affected area in Bikoro is remote, with limited communication and poor transportation infrastructure, the WHO said. Bikoro has a population of about 163,000 spread over an area of approximately 1,075 square kilometers (415 square miles).

On Tuesday, Ilunga requested support to strengthen the response to this outbreak. The ministry and the WHO have developed a plan to respond to the outbreak over the next three months.

 The full extent of the outbreak is not known, according to the WHO, and the location poses significant logistical challenges.

Three health care professionals are among the confirmed cases, Ilunga said: “As health professionals are the first actors in the government’s response to Ebola, this situation is of concern to us and requires a response that is all the more immediate and energetic.”

Ebola is endemic to the Democratic Republic of Congo, and this is the nation’s ninth outbreak of Ebola virus disease since the discovery of the virus in the country in 1976. The last outbreak occurred there in 2017 in the northern Bas Uele province. That outbreak was quickly contained due to joint efforts by the government, the WHO and other partners.

West Africa experienced the largest recorded outbreak of Ebola over a two-year period beginning in March 2014; a total of 28,616 confirmed, probable and suspected cases were reported in Guinea, Liberia and Sierra Leone, with 11,310 deaths, according to the WHO.