We all worry about getting sick. But consider a name synonymous with terror throughout the centuries, an illness that doesn't just kill you, but transforms you into a deformed, rotting outcast of society. Are you thinking about . . . Leprosy?

A faint tingling in your hands might be the first symptom of infected granulomas eating into the sensory nerves. The germ has a cozy relationship with your immune system, and your body barely notices as it spreads. Your numbed fingers are subject to repeated injury and infection as your skin become heavily infiltrated with the infectious bacteria -- Mycobacterium leprae -- a close cousin of tuberculosis. Over decades of suffering, patches of lifeless flesh begin creeping over your extremeties, turning into ulcerating infections that shrink your arms into nubs. The nose thickens and spreads into a lion-like face. Once the symptoms become noticeable, it's time to move.

A leper colony is like a real-life zombie movie of the undead. These camps were not established to cure victims -- who were generally thought to be cursed anyway -- but to keep them out of sight of the shuddering unafflicted. Lepers cannot touch money out of fear of contagion, and these tiny societies existed by the hundreds in the middle ages. Amazingly, a few such colonies can still be found countries like Japan and Nigeria.

Today's laboratories are still unable to culture the organism, and the mode of transmission remains a mystery. But thankfully, the prevalence of the illness has been reduced by modern treatment -- turning Leprosy into a disease that exists today mostly in people's nightmares and the occational queasy high-school joke. But don't sleep too comfortably. As recently as 2008, it was discovered that a natural reservoir of Leprosy -- also known as "Hanson's Disease" -- still exists among the wild nine-banded armadillo.