Nine-banded Armadillo Dasypus novemcinctus Animal Model for Leprosy (Hansen’s Disease)

Leprosy (Hansen’s disease) is a chronic infectious disease of mankind caused by Mycobacterium leprae. Despite several serious scientific attempts, M.leprae has never been cultivated in artificial bacteriological media. When M.leprae was identified as the causative germ of leprosy, Hansen (who discovered the causative germ of leprosy in 1873) attempted to cultivate the germ in animal models, but he failed. Nearly 85 years after the discovery of M. leprae successful transmission and multiplication of M.leprae in the footpads of laboratory mice was achieved. The mouse footpad model, although widely used in experimental leprosy, has its own limitations (Sheppard, 1960; Rojas and Lovik, 2001). In 1971, significant advancement in experimental leprosy research was made when nine-banded armadillos (Dasypus novemcinctus) were successfully infected with M.leprae and developed generalised lepromatous leprosy over a period of 18 to 24 months post inoculation. Since then, the nine-banded armadillo has become a favoured animal model for experimental leprosy (Krichheimer et al., 1972; Job et al., 2003). They remain as the only immunologically intact species which regularly develops lepromatous leprosy.