Over the weekend, 30 suspected Ebola patients fled from a Liberian quarantine center during looting, which spread fear in the capital of Monrovia. On Tuesday, Liberian officials confirmed that they were able to track down all of the suspected patients when the final missing 17 turned themselves in at another treatment center.

The death toll of the Ebola outbreak in Africa has climbed to 1,229, and the total number of infections has reached 2,240, according to the latest data provided by the United Nation’s World Health Organization (WHO). This is already the worst Ebola outbreak in history, though there have been confirmed cases only in Guinea, Liberia, Nigeria and Sierra Leone.

But the WHO said on Tuesday that there are “encouraging signs.” In Nigeria, the situation looks “reassuring” as there’s already been a case of a full recovery.

“Evidence suggests that early detection and supportive therapy increase the prospects of survival,” the organization wrote in an email to reporters.

The 12 cases reported in Nigeria are all part of a single “single chain of transmission,” the WHO added, and no other infections have been reported outside the initial contagion.

The outbreak originated in Guinea, where where the situation “is less alarming” as public awareness of the outbreak increases. Local leaders are helping to open up villages to outside health workers, which has resulted in a “surge” of reported cases.

Despite this promising developments, however, cautions remain.

“The outbreak is not under control,” the WHO’s statement concluded. “As recent experience shows, progress is fragile, with a real risk that the outbreak could experience another flare-up.”

Additional reporting by the Associated Press.