Venetians celebrate during the Festa del Redentore in Venice. The festival began in 1576 when the Republic's Senate voted to build a church on the Giudecca Island to Christ the Redeemer to thank God for the city's deliverance from the Plague. Marco Di Lauro/Getty Images hide caption

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Chlorine can stop the Ebola virus. So medical workers disinfect their hands often at the Doctors Without Borders treatment center in Kailahun, Sierra Leone. Carl De Souza/AFP/Getty Images hide caption

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Zimbabwe's First Lady Grace Mugabe, shown here in a 2013 photo, recently received a doctorate from the University of Zimbabwe — though it appears she was in the program no more than a few months. Alexander Joe/AFP/Getty Images hide caption

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President Obama meets with Emory University doctors and health care workers during his visit Tuesday to the Centers for Disease Control and Prevention in Atlanta. Mandel Ngan/AFP/Getty Images hide caption

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Dr. Kent Brantly was medical director at Monrovia's only Ebola treatment center when he fell ill with the disease in July. He survived after being evacuated and treated in the United States. Courtesy of Samaritan's Purse hide caption

itoggle caption Courtesy of Samaritan's Purse