An American physician who contracted Ebola while working in a West African hospital has received a blood transfusion from another American missionary doctor who survived the disease, hospital officials confirmed Thursday. Asked about the ethics of giving someone a drug that has no track record in humans, Thomas Geisbert, an Ebola expert at UTMB, said the results of tests on animals were strong and the need great. It will be extremely difficult to figure out whether the drug Sacra received or the Zmapp used by earlier Ebola patients contributed to their recovery. For that, Geisbert said, much bigger trials will be needed. animals can begin widespread testing in people in the coming months.