Previous studies have examined prevalence of leprosy-causing bacteria, Mycobacterium leprae and Mycobacterium lepromatosis, in rural Mexican long-nosed armadillo (Dasypus mexicanus) populations of the southeastern USA. However, few prevalence studies have been conducted in Alabama nor in urbanized, human-dominated areas where potential zoonotic transmission may be a public health concern. This study evaluated the prevalence of leprosy-causing bacteria in armadillos from rural, suburban, and urban zones in Lee and Mobile County, Alabama, USA. This study detected the first evidence of M. leprae-infection in a wild juvenile armadillo, from an individual sampled in a suburban zone of Mobile County, indicating potential vertical or environmental transmission. Additionally, 15/83 adult armadillos were infected in the Mobile County population, giving a total population prevalence of 16/93 (17%). Of the adults, more females were infected with M. leprae (11/36), especially lactating females, compared to males (4/47), despite more adult males being sampled overall. In Lee County, 64 adults were sampled and only one, a male, was M. leprae-positive, resulting in a total population prevalence of 1/94 (1%). The significantly lower occurrence than in Mobile County may be a result of environmental conditions, as the counties predominantly exist in two different ecoregions, the Piedmont and Southeastern Plains. Therefore, this study presents findings that may support an ecological-constraints hypothesis, previously applied to the northward expansion of M. leprae. Although no significant difference in prevalence was observed among the residential zones in this study, future research should investigate the prevalence of leprosy-causing bacteria in armadillos across different ecoregions and land use types to elucidate transmission dynamics and zoonotic risk, and inform public health strategies and wildlife management efforts in the southeastern USA.
Sciandra et al. (2026) studied this question.