COLUMBIA, S.C. (AP) — A hospital is Greenville is warning 11 brain surgery patients they might have been exposed to a rare brain disease that is always fatal.

The Greenville Hospital System said Tuesday a patient who had surgery in February was later diagnosed with Creutzfeldt-Jakob disease. Officials say 11 more patients came in contact with surgical instruments used on the sick patient.

The hospital says the instruments were sterilized, but the Centers for Disease Control and Prevention recommends additional sterilization if Creutzfeldt-Jakob disease is suspected. The disease can only be verified through an autopsy.

The CDC says the disease affects about 300 people in the United States annually, and there has never been a case involving transmission through surgical instruments.

Hospital officials say they are warning people out of an abundance of caution.