Medics are battling to contain the spread of the disease across West Africa which has already killed 670 people.
Dr. Kent Brantly is a medical director for American Christian charity Samaritan's Purse and became ill whilst working in a care centre in the Liberian capital of Monrovia.
He's currently being given 'intensive treatment' in isolation at a specialist hospital.
His wife Amber said in a statement: "We appreciate so much all the words of comfort and acts of kindness extended to our family.
"As people with a deep faith in Jesus, we sincerely thank the thousands of people worldwide who have lifted up Kent and this dreadful situation in prayer. We continue to lean on that faith and take great consolation in our God in these times.
"We have a strong family unit within a stronger faith community that has given us incredible support. Kent remains very physically weak but his spirit has been determined throughout this ordeal.
"This is a challenging time for our family."
Dr Brantly's colleague Nancy Writebol is also ill with the virus.
Samaritan's Purse President Franklin Graham said: "We are doing everything possible to help Dr. Brantly and Nancy.
"We ask everyone to please pray urgently for them and their families.
"Their heroic and sacrificial service—along with the entire team there—is a shining example of Christ's love in this crisis situation."
Dr Brantly's wife and two children had been staying with him in Liberia but flew home to America before he started showing symptoms of the virus.
Samaritan's Purse say it's removing all non-essential staff from Liberia but will keep medics in the country to treat patients.
Ebola has a fatality rate of up to 90% and the incubation period can be anything up to 21 days. There is no cure of vaccine.
It can cause massive internal bleeding and is spreading throughout Liberia, Sierra Leone, and Guinea infecting hundreds of people at an unprecedented rate.
Doctors are treating patients in layered protective suits that are decontaminated each time a person leaves the isolation unit.
Chief Executive of the Christian Medical Fellowship, Doctor Peter Saunders, told Premier's News Hour: "It's a fairly infectious disease.
"It's spread by a virus, you pick it up from contact from body fluids from an animal or person that's infected.
"People will generally within 20 days of contact get a flu like illness."
He added the risk to the UK is low: "It can only really be picked up by direct contact with an animal or someone who's infect so people in the UK are quite safe."
Meanwhile the UK Government is to hold an emergency meeting on the threat of the virus spreading to the UK.
Doctors, border officials and airport staff are being urged to be on alert to spot signs of the disease.
Foreign Secretary Philip Hammond will chair the Cobra meeting, he said: "As far as we're aware there are no British nationals so far affected by this outbreak and certainly no cases in the UK.
"However the Prime Minister does regard it as a very serious threat."
Hear more from the Chief Executive of the Christian Medical Fellowship Doctor Peter Saunders here or listen back to the full interview on News Hour catch up: