Jeremy Writebol in Wichita, Kansas, said Wednesday he's been able to talk with Nancy Writebol as she fights the illness.
He says his mother is able to move around the home where she's in isolation and has been able to get plenty of fluids.
Jeremey Writebol says he's concerned about his father, David Writebol, who was exposed before his wife learned of her condition. Jeremy Writebol said his father is feeling fine and is checking his temperature every six hours to monitor his condition.
The Writebols' Charlotte church is planning a prayer service Wednesday night for her and Kent Brantly, another medical missionary fighting the disease.