What happened to leprosy?

Why don't we have the disease, leprosy anymore? through history it follows briefly, stalking stories in the shadows of a moonlit night like the very face of Death itself. but then, it suddenly just dies. you don't really hear about it anymore. so where's it go? i mean, i know there's got to be some small third world country or civilization of some sort untouched and seldom seen by society, but what's keeping the majority of us from getting it? i know it was caused before by being filthy or rather something of the sort, but not EXACTLY what causes it (so also, what causes leprosy?). all in all and out the door, i'm not entirely sure as to the cause of leprosy but this kid on my debate team literally hasn't showered in almost a year an his flesh isn't falling in heaping piles of rotting goop straight from the bone. yet. (and no i'm not trying to exploit this being, just make a point, or solve one-i'm not sure, so please keep a chill pill at hand and don't get defensive or offensive towards me for this if you find it rude) i think leprosy would be a wicked way to die and find myself very interested in the matter. yet i can't really study it as i'd like to (yes, i know it's highly contagious) and i'd like to know more about it if you will. thank you kindly