A special plane transporting Writebol arrived in landed at Bangor International Airport in Bangor, Maine, just after 8 a.m. Maine is the closest airport to Africa and is often a stopping point for international flights.
IMAGES: Second Ebola patient arrives in Atlanta
The plane refueled and received a federal inspection before taking off for Atlanta around 8:45 a.m., where Writebol will be treated. For safety reasons, airport employees did not get on the plane while it was on the ground in Bangor.
The plane landed at 11:25 a.m. at Dobbins Air Force Base in Atlanta. Writebol was then transported to Emory University Hospital where she was wheeled in on a stretcher.
SIM USA officials said they are grateful for the government resources deployed to bring missionary Writebol back to the United States.
"Nancy has arrived safely. Let me just take a pause. Samaritan's Purse and SIM are so grateful," SIM President Bruce Johnson said while choking back tears.
RAW: SIM president speaks on Charlotte missionary with Ebola
At a press conference Tuesday afternoon, Johnson said Writebol is weak but was able to stand and walk from a stretcher onto the plane that brought her to Dobbins Air Force Base in Georgia.
"We've seen her arrive on a stretcher. It was a much different scene than Kent (Brantly). There is an age difference between Kent and Nancy," Johnson said.
RAW VIDEO: Ebola patient Nancy Writebol wheeled into Emory University Hospital
SIM officials said Writebol is exhibiting signs of an appetite and asked for soup and yogurt.
Her sons, Jeremy and Brian, arrived in Atlanta Tuesday to welcome her, while her husband David remains in Liberia where he plans to travel back to the United States in the next few days.
In a statement, David said, "We still have a long ways to go but we still have reason for hope."
"Nancy and I are profoundly grateful to the U.S. government and all that were marshaled on behalf of them to have Nancy back in the U.S. I am very happy," David Writebol said.
WATCH ENTIRE news conference with SIM on Nancy Writebol
Through SIM, David Writebol said a week ago they were thinking about a funeral but kept their faith and are hopeful for her recovery.
Writebol's son, Jeremy, said his mother "is still struggling" but that "there seems to be improvement."
Johnson said he does not know how Writebol contracted Ebola in Liberia. He said she did not have any direct contact with Ebola patients.
ABC News Chief Health & Medical Editor Dr. Richard Besser said the doctors at Emory will first assess Nancy's condition and prioritize her needs.
RAW INTERVIEW: ABC's Dr. Besser says Ebola being handled in special way in U.S.
"If she's at all dehydrated, they can give her fluid. If she needs a blood transfusion, they can do that. It's the supportive care that they can give that she would not have been able to get in Liberia that hopefully can make a difference here," Besser said.
The two Americans infected with Ebola are getting an experimental drug so novel it has never been tested for safety in humans.
Ebola has killed at least 887 people in four West African countries.
WSB-TV has learned DeKalb County police were on high alert Tuesday because of threats directed at Writebol's ride to the hospital. READ MORE.
Back in Charlotte
Eight of Writebol's fellow missionaries are also settling in, under observation by doctors in case they exhibit any signs of Ebola.
“We would keep those in an isolated area, isolated room, the staff caring for them would be dedicated to those folks,” said Novant Health’s Kip Clark.
Novant Hospital officials spent Tuesday afternoon on the phone with the Centers for Disease Control and state health officials and said they are preparing special equipment and pressurized rooms in case of an outbreak in Charlotte.
Channel 9 reached out to a SIM spokesperson to check on the latest health conditions of the six children and two adults who are staying in south Charlotte, but didn't hear back.
Read more on missionaries being monitored in Charlotte here.
Two other hospitals are isolating and testing patients for possible Ebola infections.
Those cautious measures are being taken as the largest Ebola outbreak in history rages on in West Africa.
Hospitals in Columbus, Ohio, and New York are waiting for test results after patients showed possible symptoms of the deadly Ebola virus.
A 46-year-old Columbus woman who recently traveled to one of the Ebola hot zones is being held in isolation.
The Columbus Health Department said she was hospitalized several days ago, but is doing well as she waits for her test results.
Mount Sinai in New York City is also still waiting on test results for a patient who showed up with possible symptoms yesterday.
It usually takes 24 to 48 hours for results.
Last week, the CDC sent a health alert to hospital across the country urging them to ask patients about their travel history to help identify potential cases.
What is Ebola?
Ebola hemorrhagic fever is a severe, often fatal disease in humans and nonhuman primates (such as monkeys, gorillas, and chimpanzees), according to the Centers for Disease Control.
Infection often spreads between humans because of direct contact with blood or other secretions of an infected person or exposure to objects that have been contaminated.
During outbreaks, Ebola can spread quickly within heath care settings, according to the CDC.
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