Sheik Umar Khan, the doctor leading anti-Ebola efforts in Sierra Leone—one of three Western African countries that have been hit by an outbreak—has contracted the virus himself, Reuters reports:

Khan, a Sierra Leonean virologist credited with treating more than 100 Ebola victims, has been transferred to a treatment ward run by medical charity Medecins Sans Frontieres, according to the statement released late on Tuesday by the president’s office.

Health minister Miatta Kargbo called Khan a national hero and said she would “do anything and everything in my power to ensure he survives”.

“I am afraid for my life, I must say, because I cherish my life,” Khan said in an interview before he developed symptoms of infection. Three nurses at the facility where he worked have died in the last week.

