(Adds detail of latest missionary to contract virus)
By Andrea Lorenz
CHARLOTTE, N.C., Sept 3 (Reuters) - Appearing healthy, a U.S. missionary infected with Ebola while working in Liberia shared publicly her battle with the deadly virus for the first time on Wednesday, as the Christian organization she worked with detailed its newest case.
Dr. Rick Sacra, a 51-year-old Boston physician, is the latest missionary worker for SIM USA to be infected with Ebola and is receiving care in Liberia, according to the organization.
Sacra volunteered to return to Liberia, where he had previously delivered medical care, after two other U.S. missionary workers became ill with the virus, Bruce Johnson, president of SIM USA, told reporters on Wednesday.
One of them was Nancy Writebol, 59, of Charlotte, who was released last month from an Atlanta hospital that also treated another missionary who contracted the often lethal virus.
Speaking at times through tears about her recovery, Writebol told reporters there were mornings when she woke up and thought with surprise, "I'm alive."
Still, "there were many times when I thought, 'I don't think I am going to make it any more," she said. "There were some very, very dark days."
Sacra had been delivering babies and working with patients who were not known to have the deadly virus, SIM USA said. It said it had not yet determined how he contracted the disease.
The doctor had been following protocols for containment of the disease, the organization said, and he is receiving care within an isolated Ebola unit on its campus in Monrovia.
Global health officials have warned that the most severe Ebola outbreak in history appears to be worsening.
The outbreak has infected more than 3,000 people and killed some 1,550 since it was first detected early this year in West Africa, according to the World Health Organization.
For Writebol, recovery involved a dramatic medical journey as well as scrutiny over treatment options.
After contracting the disease in Liberia in July, she was flown back to the United States to receive care in an isolation unit at Emory University Hospital in Atlanta.
She was one of a few patients to receive an experimental treatment, ZMapp, although doctors at Emory said they could not determine whether it made a difference in her recovery.
A mother of two, Writebol has been recuperating with her husband, fellow missionary David Writebol, who was also in Liberia but developed no symptoms.
She was treated at Emory with another U.S. missionary, Kent Brantly, a Texas doctor who also received ZMapp and was released last month.
Brantly, who worked with another missionary group called Samaritan's Purse, this week said he felt like he was going to die during the throes of the illness.
"I don't think there is anything special about me that made God save my life," he told NBC News in an interview, which aired on Tuesday. "I survived. That is not to say that for everybody else who died God was absent." (Writing by Letitia Stein; Editing by David Adams, Scott Malone and Susan Heavey)