(CNN) -

Another American doctor infected with the deadly Ebola virus has arrived home for treatment in the United States.

A plane carrying Dr. Rick Sacra landed Friday morning in Omaha, Nebraska, and he was then was taken to Omaha's Nebraska Medical Center, center spokeswoman Jenny Nowatzke said.

His doctors in Nebraska said they are treating him with "aggressive supportive care," including fluids and electrolytes, and they are continuing to examine him to make sure nothing else is wrong. The doctors said they are exploring "experimental options," calling on experts throughout the world to see what experimental therapeutics might work best and what treatment is "most promising."

Sacra, the third American with Ebola to return to the United States for treatment, was stationed in Liberia when he was exposed to the virus.

His wife, Debbie Sacra, said he was "clearly sick" but was in "good spirits" and was able to walk onto the plane in Liberia before the flight to Nebraska. "We are really encouraged by that news and are looking forward to reuniting with him," she said.

When Sacra's temperature went up, he sent the president of SIM, the aid organization he works for, an email that read:

"To all of you at SIM, and to my colleagues here in Liberia at ELWA Hospital, I apologize," read a tearful Bruce Johnson, president of SIM USA. He went on to explain that Sacra is a humble man and would be embarrassed by the global media attention. He said Sacra was concerned that the attention on his case would disrupt broader patient care at ELWA Hospital in Liberia.

The email went on to say: "Regarding evacuation: I know and accept that there is no easy solution for an evacuation, so I don't expect one. Jesus is right here with me in Liberia!"

As soon as the physician was symptomatic, he was admitted locally to an Ebola case management center near a 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," Johnson said. "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."

She will be traveling to Nebraska this weekend, Johnson said.

"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."

Rick 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, Johnson said. Brantly and Writebol were flown to Atlanta last month for treatment at Emory University Hospital and have since been released.

Sacra started to show symptoms of hemorrhagic fever on August 29. Health care workers did an Ebola test on him Monday, which came back positive for the deadly virus.

Sacra was following all protocols and taking necessary precautions against Ebola, Johnson said. It is unclear how he became infected, but SIM is working with the Centers for Disease Control and Prevention to determine the point of contact.

Doctors in Nebraska said they know they are in for a "long haul" with Sacra's treatment. They are hopeful but believe he could be under treatment for at least two to three weeks.

If he does recover fully, SIM leaders said that Sacra has said he intends to go back to Liberia to continue to help build and strengthen the country's medical infrastructure.