A health worker in Liberia sprays an Ebola-infected man with disinfectant chemicals CREDIT: AP Photo/Abbas Dulleh State-imposed policies that require health workers returning to the U.S. from Ebola-sticken countries to isolate themselves are having a “chilling effect” on humanitarian efforts in Western Africa, according to Doctors Without Borders, one of the major organizations that’s coordinating the effort to treat Ebola patients abroad.