Ebola has returned to Africa.

The Democratic Republic of Congo declared an outbreak in Bikoro, located in Equateur Province, after lab results confirmed two cases of the hemorrhagic fever earlier in the week. By Thursday (May 10), a total of 11 cases had been confirmed along with one fatality, CNN reports.

The initial confirmed cases were centered in the northwestern region of the country, and were two of five samples tested by the Institut National de Recherche Biomédicale.

Three health workers were among those infected, raising more concern that the virus could continue to  spread, if not contained.

"One of the defining features of this epidemic is the fact that three health professionals have been affected," Health Minister Oly Ilunga said in a statement. "This situation worries us and requires an immediate and energetic response."

According to the World Health Organization, there have been 27 reported cases over the past five weeks, including 17 deaths. The virus has a 50 percent survival rate.

This is the ninth outbreak of Ebola in the Congo since the disease was first discovered in 1976.

“Our country is facing a new epidemic of the Ebola virus which constitutes an international health emergency,” the ministry said. “We have the human resources well trained in this matter who have always been able to quickly control previous epidemics.”

Dr. Peter Salama, WHO Deputy Director-General, Emergency Preparedness and Response, said that the organization is “working with partners and responding early and in a coordinated way will be vital to containing this deadly disease.”

Nigeria and Kenya began screening travelers as a result of the outbreak.

Ebola In Africa

The fist case of the virus  was discovered near the Ebola River in the Democratic Republic of Congo, nearly 40 years ago. Since then, the virus has infected patients in several countries in West Africa as well as the United States, the U.K., and Spain.

The deadliest Ebola outbreak, which was in 2014 and centered around Libera, Guinea and Sierra Leone, killed more than 10,000 people and lasted for months. During this time, there were 11 reported cases of the disease in the U.S., but only four were confirmed.

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Ebola is spread through person-to-person contact with the blood, or other bodily fluids, of an infected person. The virus can also be spread through sexual contact.

The origins of Ebola are unknown, but have been liked to primates and fruit bats, according to the Center for Disease Control.