The World Health Organization (WHO) yesterday confirmed an Ebola hemorrhagic fever outbreak in Guinea, signaling the first appearance of the disease in a West African country and the involvement of the most lethal strain of the virus, Al-Jazeera reported.

Based on information from Guinea’s health ministry, the WHO said the “rapidly evolving outbreak” started in a forested area in the southeastern part of the country, with 49 cases and 29 deaths reported from four districts. In its Twitter account today, the WHO sharply upped the case count to 86 suspected cases—13 of them lab-confirmed—and 59 deaths.

health officials are investigating reports of suspected cases in bordering areas of Liberia and Sierra Leone, the WHO said.