Smallpox

Smallpox is a whole-body disease caused by a virus. The patient starts experiencing general symptoms 12 days after being infected, including high fever. Later, the fever decreases and a skin rash appears. 

Eventually, the fever rises again and more severe symptoms begin in the lungs, heart, circulatory system and brain, resulting in the death of up to 50% of those infected. Those who survive are permanently scarred.

Smallpox was eradicated in 1979 thanks to worldwide vaccination efforts.