MONROVIA, LIBERIA - AUGUST 15:  A security guard walks atop the roof of an abandoned hotel on August 15, 2014 in Monrovia, Liberia. People in the area suspected of contracting the Ebola virus are being brought by health workers to a temporary isolation center - a closed primary school originally built by USAID, while larger facililities are being constructed to house the surging number of patients. The Ebola epidemic has killed more than 1,000 people in four West African countries.  (Photo by John Moore/Getty Images)