Transmission of Mycobacterium ulcerans to the nine-banded armadillo

Animal models for Mycobacterium ulcerans infections (Buruli ulcer) include guinea pigs, rats, and mice, but each has limitations in replicating the sp ectrum of human disease. Here, 19 adult nine-banded armadillos were inocula ted intradermally with M. ulcerans. Injection sites were examined and skin samples obtained for histologic and microbiology studies. Necropsies were c onducted to assess systemic involvement. In group 1 (n = 4), 2 animals deve loped progressive skin ulcers with undermined borders at the injection site s within 6-10 weeks. Biopsies showed features similar to human disease incl uding extensive necrosis in the deep dermis and subcutaneous fat, mixed cel lular infiltrates, and acid-fast bacilli (AFB). In group 2 (n = 15), 5 anim als developed progressive skin ulcers, 3 had evanescent papulo-nodules, 3 d ied shortly after inoculation of unknown causes, and 4 showed no signs of i nfection. Lesion samples from 3 animals with progressive ulcers were cultur e positive for AFB. Our findings indicate that nine-banded armadillos are s usceptible to M, ulcerans and may develop cutaneous lesions that closely mi mic Buruli ulcer.