leprosarium: A hospital or colony specifically for the treatment of lepers. Also known as a lazar house, after Lazarus, the patron saint of lepers. In many places, lepers were consigned to almost absolute quarantine, and if they ventured out into other areas were forced to wear noise-making apparatus to warn people of their coming.
In the early 1980s, an effective treatment for leprosy was discovered, and it was also discovered that leprosy isn't very communicable. About 95% of the population is naturally immune to it, according to American Leprosy Missions.
Perhaps the most famous leprosarium was that of Father Damien on the Hawai'ian island of Moloka'i. You can find out more than you'd ever want to know about him from EWTN, the Eternal Word Television Network.
Hopefully, a century or so from now, people will talk about leprosy and leprosariums they way they talk about the Whig party now, as something from the past that is never likely to return.