FREETOWN, Sierra Leone -- An official in Sierra Leone says one of the country's top doctors has contracted the Ebola virus.

Dr. Victor Willoughby is the 12th Sierra Leonean physician to become infected -- 10 of whom have died.

Government Chief Medical Officer Dr. Brima Kargbo confirmed Sunday that Willoughby had tested positive for Ebola.

Nearly 1,800 people have died from Ebola this year in Sierra Leone amid the regional epidemic. Doctors and nurses have been especially vulnerable because the disease is spread through direct contact with the bodily fluids of the sick.

Junior doctors in Sierra Leone last week launched a strike to demand better medical treatment for health workers who contract the disease. Kargbo said Sunday that skeleton crews have returned to aid the senior doctors.