At first, Dr. Martin Salia thought he had malaria or typhoid. A surgeon working in Sierra Leone, he told his wife back in Maryland that he had a headache and fever. He had two negative tests for Ebola, his wife said. Then the third came back positive. Sierra Leone's chief medical officer, Dr. Brima Kargbo, Salia left Freetown Saturday on a flight to the United States for treatment. His wife, Isatu Salia, said in a telephone interview that when she spoke to her husband early Friday his voice sounded weak and shaky.