Five people have recovered from a rare Ebola outbreak in the Democratic Republic of Congo, offering a rare sign of hope as the virus triggers health alerts across Africa, Europe and South America.

The recoveries come as global health authorities race to contain an outbreak caused by the Bundibugyo strain of Ebola, a less common variant for which there is currently no approved vaccine or licensed treatment.

Four nurses who contracted the virus while treating patients in eastern Congo have now been discharged from a hospital in Bunia after recovering from the disease. A laboratory worker had earlier recovered, bringing the total number of survivors to five.

The development marks an important milestone in an outbreak that has rapidly become one of Africa’s most closely watched health emergencies.

While the recoveries show that patients can survive the disease with early medical intervention, the outbreak is also exposing how quickly health threats in Africa can become global concerns.