Missionary doctor, who survived Ebola, Kent Brantly, donated a unit of blood to treat the third American aid worker who was infected with the virus, as the fight to save his life is still on.

According to NBC News, Dr. Brantly flew to Nebraska last week to donate his blood to use to treat Dr. Rick Sacra where he is being treated at a Medical Center in Omaha.

Samaritan's Purse President and CEO Franklin Graham said.

Sacra's wife, Debbie Sacra, told a news conference. She spoke to Brantly's wife, Amber.

Sacra also has received an experimental drug, but his doctors say they have been asked not to say which drug.

Graham thinks it helped. Graham said.

Dr. Angela Hewlett, who is treating Sacra, told a news conference.

Brantly and fellow missionary Nancy Writebol were treated at Emory University Hospital in Atlanta. They both got an experiment therapy based on engineered antibodies called ZMapp, and Brantly also got a unit of blood from an Ebola survivor. Graham said.

Graham said Brantly made the flight to and from Omaha on a Samaritan's Purse plane. Graham said.

Brantly said through a Samaritan's Purse spokesman.