The director of the U.S. Centers for Disease Control and Prevention said on Thursday he has activated the agency's emergency operation center at the highest response level to help respond to the worst Ebola outbreak in history. In testimony at a special congressional hearing on Ebola, CDC Director Dr Thomas Frieden said the CDC has more than 200 staff members in Atlanta working on the outbreak, and will soon have more than 50 disease experts in West Africa to try to contain the outbreak. Although...