ATLANTA (CNN) -

Both Americans who were treated for the Ebola virus have been discharged from the hospital.

"Today is a miraculous day," Dr. Kent Brantly, a 2003 Abilene Christian University grad, said at a news conference in Atlanta with staff of Emory University Hospital. "I am thrilled to be alive, to be well and to be reunited with my family." The hospital announced he was being discharged Thursday.

The other patient, Nancy Writebol, was released Tuesday, and is choosing not to make public comments, the hospital said.

"We are tremendously pleased with Dr. Brantly and Mrs. Writebol's recovery," said Dr. Bruce Ribner, director of Emory's Infectious Disease Unit.

They pose no public health risk, Ribner said.

"What we learned in caring for them will help advance the world's understanding of how to treat Ebola infections and help, hopefully, to improve survival" in other parts of the world, Ribner said at a news conference.

"There may be some recovery time because this is a fairly devastating disease," but in general patients without organ damage are expected to "make a complete recovery," he said.

Both patients were evacuated from Liberia earlier this month in a plane specially equipped with an isolation tent and accompanied by medical staff outfitted in head-to-foot protective clothing. The plane was able to take only one patient at a time and made two trips. They were taken to an isolation unit at Emory.

Joy and relief

Brantly was in Liberia for faith-based charity Samaritan's Purse, and its president, Franklin Graham expressed joy over the doctor's release.

"Today I join all of our Samaritan's Purse team around the world in giving thanks to God as we celebrate Dr. Kent Brantly's recovery from Ebola," he said.

Writebol's husband David, who was with her in Africa, visited her at Emory on Sunday, he said in a statement. She is recovering, he said.

He stood outside the isolation room, as they looked at each other through the glass.

"We both placed our hands on opposite sides of the glass, moved with tears to look at each other again," he said.

Experimental medication

For Brantly to leave isolation, two blood tests done in a two-day period had to come back negative.

The Ebola virus spreads via direct contact with bodily fluids, like blood, sweat and feces. Brantly's will no longer be infectious.

There is a slight possibility that the virus could linger for up to three months in his semen, according to the World Health Organization.

The virus has no known cure, and left untreated, infections can be deadly in up to 90% of cases. Nearly half the patients receiving medical care in the current outbreak in Liberia, Sierra Leone, Nigeria and Guinea are surviving.

Treatment consists of giving fluids, monitoring vital signs and responding to acute medical crises. Symptoms include fever, aches, diarrhea and bleeding.

Brantly and Writebol also received an experimental drug called ZMapp, which was also given to three healthcare workers in Liberia, who appear to be recovering.

Fears of U.S. outbreak

Brantly and Writebol were the first known people infected with Ebola to enter the United States.

Their arrival triggered a surge of angst on social media from people afraid the patients could spread the virus.

But experts have said that additional infected people could cross U.S. borders by happenstance, given the proliferation of international air travel and the enormity of the current outbreak.