Leprosy in Florida: a rising concern

Leprosy has shown an increase in incidence in Southeastern U.S. states such as Florida, where it is now considered endemic. Leprosy is caused by the bacteria Mycobacterium leprae (and rarely by M. lepromatosis) leading to a constellation of dermatologic and neurologic symptoms depending on the immune response of the host. We investigated the extent of reported cases of leprosy in Florida, evaluating the literature in regard to possible modes of transmission, particularly among individuals who do not have any known history of exposure to an individual with leprosy or known contact with armadillos. Several cases evidenced exposure to armadillo, and individuals without known exposure to another human with leprosy, or recent travel to endemic areas of the world, exposure to contaminated soil while gardening is proposed as a mechanism of infection. The role of the armadillo in soil contamination is plausible. Main hypotheses for routes of transmission include human-to-human transmission via prolonged respiratory exposure, and exposure to nine-banded armadillos (Dasypus novemcinctus) either directly or via contaminated soil (e.g. while gardening without gloves). Physicians should consider leprosy in the differential diagnoses of patients with dermatologic or neurologic symptoms in potentially new endemic areas, especially those whose condition continues to decline despite usual antibiotic therapy. Skin lesions should be tested for sensation (tactile, pain, and thermal), and neurologic symptoms (numbness) as well as exploration of nerve thickening should be included.