Armadillos are often used in the study of leprosy, since they are among the few known species that can contract the disease systemically.
Picture from Armadillos.info
It's the armadillos unusually low body temperature that makes them susceptible to the leprosy causing bacterium. Humans can acquire a leprosy infection from armadillos by handling them or consuming armadillo meat. It is believed that armadillos originally contracted the disease from humans sometime in the late 15th Century.