In their first interview, four nurses who treated Ebola patient Thomas Eric Duncan in Dallas talk about going to great lengths to try to keep him alive.

Duncan went to Texas Health Presbyterian Hospital September 25th with a fever and was send home. But three days later he was back with a temperature of 103 degrees, and was diagnosed with Ebola.

John Mulligan, a nurse at Texas Health Presbyterian Dallas, treated Ebola patient Thomas Eric Duncan during his final hours in intensive care. 60 Minutes

Nurse John Mulligan treated the Liberian man during his final hours in intensive care before he died on October 8.

"On the first day he didn't say much," Mulligan said. "You could look in his eyes and tell he just didn't feel good. And we offered him words of encouragement. We let him know that we're here, whatever you need -- let us know and we'll get it.

"And we held his hand and talked to him and comforted him because his family couldn't be there," mulligan continued. "I mean, you can't take that risk with this type of disease of exposing, you know, loved ones, as much as you want them there. It's just not a possibility."

A few days after Duncan died, nurse Nina Pham became ill, followed by nurse Amber Vinson. Both of them have now recovered from Ebola.

Watch Scott Pelley's entire interview with the nurses this Sunday on 60 Minutes.