A Charlotte-based missionary group says that the third American serving in Liberia who tested positive for Ebola will return to the United States for treatment.
Rick Sacra, an American doctor was treating obstetrics patients at SIM USA's hospital in Monrovia, the group announced Tuesday.
On Thursday, SIM officials said Sacra is being flown to The Nebraska Medical Center in Omaha, Nebraska, for treatment.
"Rick was receiving excellent care from our SIM/ELWA staff in Liberia at our Ebola 2 Care Center," said Bruce Johnson, president SIM USA. "They all love and admire him deeply. However, The Nebraska Medical Center provides advanced monitoring equipment and wider availability of treatment options."
While in Monrovia, Sacra was not treating Ebola patients, which are located in an isolation unit separate from the main hospital on the mission organization's campus.
It is not yet known how he contracted the virus specifically.
SIM President Bruce Johnson says Sacra decided to return to Liberia after the other two people became ill. Johnson says he returned to Liberia about a month ago after Dr. Kent Brantly and Charlotte missionary Nancy Writebol became ill with Ebola.
Johnson says the 51-year-old Sacra lives in the Boston area.
He says it's not known whether Sacra will return to the U.S. for treatment.
A Liberian doctor on the missionary's treatment team said it was too soon to tell whether he would be evacuated. The doctor would speak only on condition of anonymity because he was not authorized to discuss the matter with reporters.
The announcement came as Dr. Tom Frieden, the director of the Centers for Disease Control and Prevention, said in a news conference Tuesday that the window to tamp down the Ebola outbreak is closing.
"We need a global coordinated unified approach," Frieden said. "This is not just a problem for West Africa, not just a problem for Africa, it's a problem for the world, and the world needs to respond."
The first human trial of an experimental Ebola vaccine will begin this week, as the deadly outbreak continues to spread.
According to the World Health Organization, there are more than 3,000 cases of Ebola. More than 1,500 people have died from the virus in West Africa.
"My heart was deeply saddened, but my faith was not shaken, when I learned another of our missionary doctors contracted Ebola," Bruce Johnson, president of SIM USA, said Tuesday.
"As a global mission, we are surrounding our missionary with prayer, as well as our Liberian SIM/ELWA colleagues, who continue fighting the Ebola epidemic in Liberia. We have gifted Liberian doctors, medical staff and support staff who are carrying on the fight."
Dr. Sacra isolated himself when signs of the virus began to show. He has since been transferred to the ELWA Ebola isolation unit.
He is reportedly doing well and is in good spirits.
Missionary Nancy Writebol and Dr. Kent Brantly, from Samaritan's Purse, underwent treatment at an isolation unit at Emory University Hospital in Atlanta last month after contracting the virus while serving in Liberia in late July.
Last month, they both tested clear of the virus and was discharged from the hospital.
Writebol left the hospital on Aug. 19 and went with her husband, David, to an undisclosed location to rest and spend time with one another.
Brantly was discharged two days later and spoke in a press conference that morning.
On August 11, three missionaries who were serving in Liberia arrived in Charlotte by private charter. Among the three was David Writebol.
David was cleared from quarantine less then a week later and went to Atlanta to be with his wife.
The other two missionaries were SIM USA doctors who were treating Ebola patients at SIM's ELWA medical facilities in Monrovia.
The missionaries were kept in quarantine on the SIM campus in southwest Charlotte.
The remaining missionaries were in considered in good health and were released from the SIM campus to be reunited with family and friends in late August.
Copyright 2014 WBTV. CNN contributed to this report. All rights reserved.