The agency announced Wednesday that it would temporarily remove its volunteers from Liberia, Sierra Leone and Guinea. There are currently 340 members assigned to those three countries, with most of them working in education.
This has been the largest outbreak of the Ebola virus in history, and has spread quickly since the first cases were detected in Guinea in March. The virus is a hemorrhagic fever that spreads through direct contact with bodily fluids and kills up to 90% of infected patients. While initial symptoms can include fever, dizziness, chills, and vomiting, some infected patients suffer extreme internal and external bleeding.
There is no vaccine or cure for the virus.
As doctors struggle to treat the infected -- there have been more than 1,200 cases reported so far -- African leaders have also worked to stop the outbreak from spreading further. Liberian President Ellen Johnson Sirleaf announced Sunday that she had closed all but three border crossings, and Nigeria's largest airline has reportedly stopped all flights to Liberia and Sierra Leone after a man with Ebola was intercepted at the airport in Lagos.
Medial efforts to stop the outbreak from spreading have been stymied by skepticism from local communities. Many of the villages hit hardest by the virus are far from any major cities, and The New York Times reported that aid workers from Doctors Without Borders and the Red Cross had been blocked from entering villages to examine and treat the sick.
Sierra Leone's top expert on the Ebola virus, Dr. Sheik Umar Khan, died Tuesday afternoon after treating more than 100 patients for the sickness. And a doctor at a hospital in Monrovia, Liberia, has also died.
Two Americans, a doctor and another aid worker who were working with a religious relief group in Liberia, have contracted the disease. Their survival prospects remain unclear.