Smallpox, caused by the variola virus, was a highly contagious infectious disease that caused infected individuals to develop a fever and a progressive, disfiguring skin rash. Three of out 10 individuals infected with smallpox died. Many survivors have permanent scars, often on their faces, or were left blind. Through vaccination, the disease was eradicated in 1980. However, research for effective vaccines, drugs and diagnostics for smallpox continues in the event it is used as a bioterror weapon.