Background The armadillo was the first animal model of leprosy. Its role in the transmission of leprosy remains controversial. The sooty mangabey model of leprosy led to the discovery that rhesus monkeys were more susceptible to leprosy when coinfected with simian immunodeficiency virus (SIV), but that leprosy may play a protective role against acquired immunodeficiency syndrome (AIDS) mortality. Recently, molecular methods have been developed for leprosy and may help resolve the role of zoonoses in leprosy.
Observations The recent identification of a case of leprosy in a native-born American on the east coast of the USA and the identification of leprosy as an immunologic reconstitution inflammatory syndrome (IRIS) in human immunodeficiency virus (HIV)-positive cases raise the question of what role zoonoses may play in leprosy.
Conclusions Leprosy in armadillos and sooty mangabeys has been manipulated by human experimentation. In the case of the armadillo, further study, including molecular techniques, is required to elucidate the role of the armadillo as a zoonosis in human leprosy. Experimentation with the sooty mangabey led to the discovery of an interaction between SIV and leprosy in rhesus monkeys, and prompted the continued investigation of the relationship between HIV and leprosy.