ATLANTA (AP) — An American woman treated for the Ebola virus at Emory University Hospital says the 21 nurses involved “went far beyond the line of duty.”

Nancy Writebol spoke Friday to nursing students on the school’s campus just outside Atlanta, telling them to be compassionate and brave.

Writebol challenged students to “be the best of the best.”

Writebol was the second American to receive treatment at Emory after contracting the Ebola virus in Liberia during the summer of 2014. She has since returned to volunteer work in Liberia with the charity SIM, based in North Carolina.

Writebol spoke for 20 minutes, telling students about her experiences at a Liberian hospital and then as a patient at Emory. She thanked the hospital’s staff for welcoming her and other patients during a time of intense fear of Ebola.