A grim medieval disease could be set for a comeback, with the ghastly, rash-causing ailment spotted in parts of the world.

Leprosy has been spotted in the United States as the grim ancient illness filters through Florida. Thankfully the bacterial infection is treatable in its early stages, but can still cause permanent disabilities of limbs or nerves, WHO confirmed.

Heightened cases of leprosy in Florida are inching towards endemic levels according to a recent study, which warned armadillos may be the infection-causing animal.

A report from August last year warned of an increasing number of leprosy infections. The disease can be treated if caught in its early stages but a stigma lasting around the illness means some may conceal their ailment, LiveScience reported.