Naturally acquired leprosy in the nine-banded armadillo: a decade of experience 1975-1985.

A decade has passed since our first report of naturally acquired leprosy in the nine-banded armadillo. Our studies and those of others during this period confirm the identification of the etiologic agent as Mycobacterium leprae. Confirmation is based on the results of histopathologic examination and microbiologic evaluations that included attempts to culture the organism, flourescent antibody studies, mycolic acid analysis, and DNA determinations demonstrating complete relatedness between the natural agent and M. leprae. Surveys involving large numbers of animals demonstrate a significant prevalence of the disease in armadillos captured in Louisiana and Texas. The discovery of naturally acquired leprosy in a chimpanzee in 1977 and a sooty mangabey monkey in 1979 reinforce the concept of leprosy as a zoonosis. Extensive contact with armadillos has been implicated by other observers in seven patients with leprosy in Texas. We believe the prevalence of leprosy in wild armadillos requires that they be considered a source of infection in patients from geographic areas where leprosy and armadillos co-exist.