NEW YORK » Two American aid workers seriously ill with Ebola will be brought from West Africa to Atlanta for treatment in one of the most tightly sealed isolation units in the country, officials said Friday.

One is expected to arrive Saturday, and the other a few days later, according to Atlanta’s Emory University Hospital, where they will be treated. They are due to arrive in a private jet outfitted with a special, portable tent designed for transporting patients with highly infectious diseases.

It will be the first time anyone infected with the disease is brought into the country. U.S. officials are confident the patients can be treated without putting the public in any danger.

Ebola is spread through direct contact with blood or other bodily fluids from an infected person, not through the air.

The two Americans — Dr. Kent Brantly and Nancy Writebol — worked for U.S. missionary groups in Liberia at a hospital that treated Ebola patients. The State Department and the Centers for Disease Control and Prevention are assisting the groups in their transfer.

The government is working to ensure that any Ebola-related evacuations "are carried out safely, thereby protecting the patient and the American public," State Department spokeswoman Marie Harf said in a statement released Friday.

A Department of Defense spokesman said Dobbins Air Reserve Base in Marietta, Georgia, will be used for the transfer.

The aircraft is a Gulfstream jet fitted with what essentially is a specialized, collapsible clear tent designed to house a single patient and stop any infectious germs from escaping. It was built to transfer CDC employees exposed to contagious diseases for treatment. The CDC said the private jet can only accommodate one patient at a time.

Brantly and Writebol are in serious condition and were still in Liberia on Friday, according to the North Carolina-based charity Samaritan’s Purse, which is paying for their transfer and medical care.

An Emory emergency medical team in Liberia has evaluated the two aid workers, and deemed both stable enough for the trip to Atlanta, said Emory’s Dr. Bruce Ribner. Hospital spokesman Vincent Dollard said the first patient was scheduled to arrive Saturday.

Brantly, 33, works for Samaritan’s Purse while Writebol works for another U.S. mission group called SIM. Late last week, Samaritan’s Purse officials said Brantly had tested positive for the virus. Shortly after that announcement, Writebol’s infection was disclosed.

Liberia is one of the three West African countries involved in the Ebola outbreak, the largest since the virus was first identified in 1976.

The two-bed Emory isolation unit opened 12 years ago. It was designed to handle workers from the CDC if they became infected while working on a dangerous, infectious germ.

It is one of about four such units around the country for testing and treating people who may have been exposed to very dangerous viruses, said Dr. Eileen Farnon, a Temple University doctor who formerly worked at the Atlanta-based CDC and led teams investigating past Ebola outbreaks in Africa.

There is no specific treatment for disease, although Writebol has received an experimental treatment, according to the mission groups.

"If there’s any modern therapy that can be done," such as better monitoring of fluids, electrolytes and vital signs, workers will be able to do it better in this safe environment, said Dr. Philip Brachman, an Emory University public health specialist who for many years headed the CDC’s disease detectives program.

"That’s all we can do for such a patient. We can make them feel comfortable" and let the body try to beat back the virus, he said.

He was echoed by Emory’s Ribner, one of the doctors who will be seeing the Ebola patients. He stressed that safety precautions will be taken by staff in the unit.

"I have no concerns about even my personal health or the health of the other health care workers who will be working in that area," Ribner said.

The unit has its own laboratory equipment so samples don’t have to be sent to the main hospital lab. Located on the ground floor, it’s carefully separated from other patient areas, Farnon said.

Health experts say a specialized isolation unit is not even necessary for treating an Ebola patient. The virus does not spread through the air, so standard, rigorous infection control measures should work.

The current outbreak in Liberia, Guinea and Sierra Leone has sickened more than 1,300 people and killed more than 700 this year.

Medical Writer Marilynn Marchione in Milwaukee, National Security Writer Robert Burns in Washington and video journalist Johnny Clark and writer Ray Henry in Atlanta contributed to this report.