Nancy Writebol fought for her life against Ebola hemorrhagic fever on Thursday.
While she did, the virus that befell the American missionary in Liberia as she worked to save its victims continued on a rampage through West Africa.
It is believed to have killed 729 people in Guinea, Liberia, Sierra Leone and Nigeria from March through July 27, the World Health Organization said Thursday.
It is the worst Ebola outbreak in history. There is no cure and no vaccine, but care from medical workers so far has helped sustain the lives of nearly half of those stricken.
Dr. Thomas Frieden, director of the Centers for Disease Control and Prevention, said Thursday that even in a best-case scenario, it could easily take three to six months to stem the epidemic in West Africa.
The outbreak also prompted the CDC to issue a warning against all "nonessential" travel to the countries coping with an outbreak, Frieden said.
As for Writebol, her family is praying that her life is spared, too.
U.S. government officials are in ongoing talks to bring Writebol and another Ebola-stricken American, fellow aid worker Dr. Kent Brantly, back from Liberia, an administration official and a State Department source said on Thursday.
Writebol's husband, David, who is with the same mission as his wife, is near her, said their son Jeremy, who spoke with CNN's Chris Cuomo from the United States.
But she is isolated from him, and he has to wear head-to-toe protective clothing similar to a hazmat suit so that he does not contract a disease that starts out with similar symptoms as a strong flu but can end in internal bleeding and death.