KENEMA, Sierra Leone — So many patients, nurses and health workers have died in the government hospital that many people in this city, a center of the world’s worst Ebola epidemic, see it as a death trap. Now, the wards are empty in the principal institution fighting the disease. Ebola stalks the city, claiming lives every day, but patients have fled the hospital’s long, narrow buildings, which sit silent and echoing in the fading light. Few people are taking any chances by coming here. “Don’t touch the walls!” a Western medical technician yelled out. “Totally infected.” Some Ebola patients still...