Emory University Hospital in Atlanta will receive another U.S. Ebola patient for treatment this week.
The hospital, which has already treated and discharged two other U.S. citizens who contracted the contagious disease in Liberia, said in a news release that the fourth American infected with the virus was expected to arrive in Atlanta on Tuesday. The hospital said the patient would be treated in its isolation unit.
Air Force spokesman Lt. Col. James Wilson said this patient would be flown into Dobbins Air Reserve Base outside Atlanta before being transported to Emory.
Watch WSB-TV's report:
Another U.S. patient, an American doctor, is being treated in Nebraska and appears to be tolerating experimental treatments, though his recovery remains uncertain.
The family of Dr. Rick Sacra said he was able to eat breakfast Monday for the first time since arriving Friday at the Nebraska Medical Center in Omaha.
Dr. Philip W. Smith, left, and Dr. Angela Hewlett speak during a news conference about the condition of Dr. Rick Sacra, Sunday, Sept. 7, 2014, in Omaha Neb. Sacra who became infected with Ebola arrived at the Nebraska Medical Center on Friday for treatment in the hospital's specialized 10-bed isolation unit. The 51-year-old Sacra is the third American aid worker to be sickened with the Ebola virus. (AP/The World-Herald, Sarah Hoffman)
The 51-year-old remains in stable condition, and his wife, Debbie, he was more alert and that they a good half-hour conversation by video conference Sunday.
Sacra is being treated with an experimental drug that is different than the one given to the two Americans treated for Ebola at Emory last month.
Sacra's doctors are not naming the drug, but they said they've been consulting with experts on Ebola at the U.S. Centers for Disease Control and Prevention.
At the same time, the World Health Organization announced Monday that a doctor working for the U.N. agency is among the latest to become infected with the virus while working at a treatment center in Sierra Leone. The doctor is stable and will be evacuated from the country for further treatment.
A health worker is sprayed with disinfectant after he worked with patients that contracted the Ebola virus, at a clinic in Monrovia, Liberia, Monday, Sept. 8, 2014. Border closures, flight bans and mass quarantines are creating a sense of siege in the West African countries affected by Ebola, officials at an emergency African Union meeting said Monday, as Senegal agreed to allow humanitarian aid pass through its closed borders. (AP/Abbas Dulleh)
This is the second time a WHO health care worker has been infected with the disease.
So far, more than 3,500 people have been infected with the Ebola virus in a now historic outbreak that began in Guinea and spread to several other West African countries in recent months. More than half of these infections have occurred in Liberia, and WHO said it expects new cases to increase exponentially in the coming weeks.
"As soon as a new Ebola treatment facility is opened, it immediately fills to overflowing with patients, pointing to a large but previously invisible caseload," WHO said in a statement about the situation in Liberia. "Many thousands of new cases are expected in Liberia over the coming three weeks."
President Barack Obama pledged more assistance from the U.S. to help contain the Ebola outbreak. The White House said the president made the pledge in a telephone conversation Monday with U.N. Secretary-General Ban Ki-moon.
The African Union also said Monday that it would be sending medical support to West Africa with $6.4 million in support from the European Union.
The Associated Press contributed to this report.