(Adds comments from Sacra's wife, Nebraska Medical Center doctor, background; changes dateline to add OMAHA, previous MONROVIA)
By Derick Snyder and Katie Schubert
OMAHA, Nebraska/MONROVIA, Sept 4 (Reuters) - A third U.S. health missionary infected with the deadly Ebola virus in Liberia left the West African country's capital on Thursday in a plane headed for the Nebraska Medical Center in Omaha, the Christian organization SIM USA said.
Dr. Rick Sacra, a 51-year-old Boston physician, is the latest worker for SIM USA to be infected with the virus that has killed more than 1,900 people.
A Reuters cameraman saw Sacra, wearing white protective clothing, step out of the car that brought him to the tarmac and walk onto the aircraft.
The plane was expected to arrive in Omaha on Friday morning, hospital officials and SIM USA said. Sacra will begin receiving treatment in the hospital's Biocontainment Patient Care Unit, SIM USA said in a statement.
Sacra is in "reasonably stable shape. He's had a number of complications of his disease," but apparently was able to get on the plane under his own power, Dr. Phil Smith, director of the biocontainment unit, told a news briefing in Omaha.
Smith said Sacra would be given supportive care by a team of 30 to 35 people.
But he said there were no more doses of Mapp Biopharmaceutical Inc's experimental drug, ZMapp, which was given to the other two U.S. health missionaries who had contracted Ebola. Doctors, however, said it was not clear whether the drug had contributed to their eventual recovery.
SIM USA President Bruce Johnson said Sacra had been receiving "excellent care" from the group's staff in Liberia but said the Nebraska facility would provide advanced monitoring equipment and more treatment options.
Liberian Information Minister Lewis Brown confirmed that the plane carrying Sacra was identical to the Gulfstream jet that ferried Nancy Writebol and Dr. Kent Brantly, who contracted the disease in July while working at SIM USA'S health center in Liberia, back to the United States.
The Nebraska facility is similar to the one at Emory University in Atlanta where Writebol and Brantly were treated.
The 10-bed unit is one of four that were commissioned by the U.S. Centers for Disease Control and Prevention in 2005. The other two facilities are in Maryland and Montana.
The Nebraska unit, the largest of the four, is isolated from the rest of the hospital and has its own ventilation system and security access, according to the Nebraska Medical Center website.
Sacra's wife, Debbie, speaking at a news conference at the University of Massachusetts Medical School, said SIM had sent an American physician to assist with her husband's treatment and to begin organizing his evacuation.
"Rick and I have a close and loving marriage and his trips to Liberia are a part of our lives, but that doesn't make them easy," she said in a statement on the university's website.
She urged people to find a way "to meet the needs of Liberia and its neighbors in this time of fear and suffering. As Rick wrote to his medical colleagues, this epidemic is a wildfire about to rage out of control."
Sacra volunteered to return to Liberia when Writebol and Brantly became infected.
Sacra had not been caring for Ebola patients but was delivering babies, and had been following protocols to prevent the spread of the disease, the group said. It was not known how he contracted the virus. (Additional reporting by Bate Felix and Emma Farge in Dakar, Michele Gershberg in New York and Julie Steenhuysen in ChicagoWriting by Bate Felix and Julie Steenhuysen; Editing by Dominic Evans and Jonathan Oatis)