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

Published in the Scandinavian Journal of Laboratory Animal Science an international journal of laboratory animal science Introduction 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 the 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 & Lovik, 2000). In 1971, significant advancement in experimental leprosy research was made when ninebanded armadillos (Dasypus novemcinctus) were successfully infected with M.leprae and developed generalized 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. Armadillos are primitive, insectivorous to omnivorous, nocturnal mammals that construct and live in burrows; they are brown or grey in colour and have yellowish white-coloured hairs on the ventral side of the body arising from soft skin (Fitch et al., 1952). They have a hard, flexible carapace (shell) formed from ossified (fused) dermal plates on the dorsal side protecting most of their body from head to tail. This bony armour has nine movable rings between the shoulder and the hip shield which gives an armoured appearance hence the name “Armadillo” means “Little armoured one” in Spanish. The name Dasypus is derived from a Greek Word Nine-banded Armadillo Dasypus novemcinctus Animal Model for Leprosy (Hansen’s Disease)