Kent Brantly, one of two Americans being treated for the deadly Ebola virus in Atlanta, said in a Friday statement that he is "growing stronger every day." In the message, released by international relief agency Samaritan's Purse, Brantly also thanked God for aiding his recovery.
Brantly's words come six days after he arrived in the United States from Liberia, where he was working as a doctor in a post-residency program.
"I am writing this update from my isolation room at Emory University Hospital, where the doctors and nurses are providing the very best care possible," Brantly's statement reads. "I am growing stronger every day, and I thank God for His mercy as I have wrestled with this terrible disease."
The Ebola virus has killed more than 900 people in West Africa. On Friday, the World Health Organization declared the outbreak an international health emergency.
For more about the Ebola outbreak, see TIME's video above.