Update: A plane carrying the fourth U.S.  aid worker infected with Ebola virus landed around 9:30 a.m. Tuesday at Dobbins Air Reserve Base  in metro Atlanta.

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A third person with the Ebola virus will be admitted to Emory University Hospital on Tuesday, the hospital said in a statement released Monday.

The person, whom Emory would not identify, is being flown by air ambulance from West Africa, where this latest outbreak of Ebola has now claimed more than 1,800 lives. This outbreak of the virus is the largest in history, according to the U.S. Centers for Disease Control and Prevention.

The arrival of the new patient to Emory marks the fourth time during the current outbreak that an American with the virus will be treated in the United States. Last week Dr. Rick Sacra, an American aid worker who had been treating Ebola victims in Liberia when he contracted the virus, was flown to a University of Nebraska hospital.

The Nebraska hospital has a biocontainment isolation unit similar to the infectious disease isolation unit at Emory. In August, missionaries Dr. Ken Brantly and Nancy Writebol were flown by air ambulance from Liberia, where they had been trying to save patients infected with the highly lethal virus. Both were initially given doses of the experimental drug ZMapp before they were transported to Emory for further treatment.

The decision to give the two Americans an experimental drug unavailable to hundreds of Africans infected with Ebola was controversial. Not long after Writebol and Brantly were treated, Mapp Biopharmaceuticals Inc., which is developing the drug, announced it had run out of available doses. Since then the San Diego company has accelerated animal trials of the serum.

It is unclear whether the new patient arriving at Emory has been or will be given the drug.

Brantly and Writebol were released from Emory late last month after nearly three weeks in the unit.

In early August the World Health Organization declared the outbreak an international public health emergency. While stemming the rate of infection in West Africa has been difficult and some methods of containing the disease have been controversial — quarantining whole quadrants of cities — Ebola can only be transmitted through bodily fluids.

Television news reported late Monday that the plane carrying the latest patient will land at Dobbins Air Force Base at 8:30 a.m. Calls to Phoenix Air, the Cartersville-based air ambulance service that has transported several Ebola patients for treatment, were not immediately returned on Monday evening.