(CNN) -- Another American doctor infected with the deadly Ebola virus is coming home for treatment in the United States.
Dr. Rick Sacra was stationed in Liberia when he was exposed to the virus. He will be flown to Nebraska, according to the international Christian mission organization Serving In Mission.
He's expected to arrive at Nebraska Medical Center in Omaha on Friday.
His spouse, Debbie Sacra, said he is "clearly sick" but is in "good spirits" and was able to walk onto the plane. "We are really encouraged by that news and are looking forward to reuniting with him," she said.
Sacra was admitted to an Ebola case management center over the weekend near the hospital in Monrovia where he has served for 15 years.
"Rick was receiving excellent care from our SIM/ELWA staff in Liberia at our Ebola 2 Care Center," said Bruce Johnson, president of SIM USA. "They all love and admire him deeply. However, The Nebraska Medical Center provides advanced monitoring equipment and wider availability of treatment options."
Sacra, who is from Holden, Massachusetts, was not treating Ebola patients directly. Instead he was delivering babies at a general hospital in Monrovia, Johnson said.
"I am surrounded by friends and family and the body of Christ, who are a great encouragement and who are praying fervently for Rick's recovery along with me," Debbie Sacra said in a statement. "We are trusting in God to be with Rick and us through this difficult circumstance.
"Rick would want me to urge you to remember that there are many people in Liberia who are suffering in this epidemic and others who are not receiving standard health care because clinics and hospitals have been forced to close. West Africa is on the verge of a humanitarian crisis, and the world needs to respond compassionately and generously."
Sacra had been to Liberia with SIM before, and volunteered to go again after he heard fellow missionaries Nancy Writebol and Dr. Kent Brantly had contracted the virus, SIM President Bruce Johnson said. Both were also flown to Atlanta for treatment and have been released.
The doctor started to show symptoms of haemorrhagic fever on Friday evening. Health care workers did an Ebola test on Monday, which came back positive for the deadly virus.
Sacra was following all protocols and taking all necessary precautions against Ebola, Johnson said. It is unclear how he became infected, but SIM is working with the CDC to determine the point of contact.