The American doctor who contracted Ebola while treating victims of the deadly virus in Liberia has asked for prayers that he and an infected colleague from the U.S. will survive. "I’m praying fervently that God will help me survive this disease. Please continue to pray along with me, and pray for my friend Nancy who is also very sick," Kent Brantly relayed through visiting friends. The director of the 33-year-old's hospital in Texas says Brantly is "terrified" and has a grave prognosis. The outbreak of Ebola has spread to at least three countries in West Africa and killed more than 670 people.