Why are nine-banded armadillos used in leprosy research?

Nine-banded armadillos are utilized in leprosy research primarily because they are one of the few animals known to be naturally susceptible to the disease.12

This utility is critical because the Mycobacterium leprae bacillus—the organism responsible for leprosy—cannot be grown in laboratory tissue culture media. Consequently, researchers rely on limited animal models, such as armadillos and the footpads of mice, to cultivate the bacillus for experimental study and to investigate the mysteries surrounding the disease's transmission and epidemiology.12