American missionary Nancy Writebol is en route from Liberia to Atlanta, where she will be treated for the deadly virus Ebola.

Writebol’s air ambulance left Liberia at 9:12 p.m. Monday, Atlanta time, the Associated Press reported. Her flight is expected to touch down at Dobbins Air Force Base sometime this morning. The exact time is unknown, because it’s not known whether the flight was to make any stops en route.

Return to ajc.com and MyAjc.com for real-time updates, including photos and video, of her arrival and transfer to Emory University Hospital.

Writebol will be the second Ebola patient under Emory’s care. Dr. Kent Brantly arrived there Saturday. Both patients caught the virus while caring for West Africans struck down by the worst outbreak the world has yet seen.

Ebola, known as a hemorrhagic fever, can kill up to 90 percent of its victims, depending on the strain. The current outbreak in four West African nations has killed between 50 and 60 percent of those who contracted the virus.

The Emory patients will be held in strict seclusion in a specially constructed isolation unit.They will be closely monitored and given fluids and other supportive care to keep their blood pressure and other vital signs stable. Otherwise, there is little doctors can do but wait for the body to fight off the virus.

However, a few days ago, Brantly and Writebol both received doses of an experimental drug not tested in humans. It appears to have been successful; Brantly was able to walk from an ambulance into the Emory hospital when he arrived. Writebol reportedly has also been able to leave her bed for short times and to have regained some appetite.

Many people reacted with shock and anger to the news that officials were deliberately bringing people infected with Ebola to the United States.

Doctors from the Centers for Disease Control and other world health organizations have repeatedly assured the public that Ebola, while very deadly, is not highly contagious. Like HIV, it is transmitted only through direct contact with an infected person’s bodily fluids — not through air or water.

Monday, officials at Mt. Sinai Hospital in New York announced that they had isolated a man who walked into the emergency room with symptoms consistent with Ebola. The man reportedly had traveled recently to West Africa, but it has not been confirmed yet whether he is infected with Ebola.

It is not known how long Brantly and Writebol will remain at Emory.

Brantly works for Samaritan’s Purse, a nondenominational Christian charity run by Franklin Graham, the son of evangelist Billy Graham. Writebol works for another missionary group, SIM. Both charities are based in North Carolina, where Writebol lives. Brantly lives in Texas.