Molecular tools have helped overcome challenges posed by the slow growth of M. leprae in vivo and its inability to grow in vitro. Other than humans, armadillos are the only animal known to be susceptible to leprosy. Because of this, colonies of armadillos have been important in research to model the disease. Since 1978, NIAID has supported contracts for the propagation of M. leprae in armadillos to derive sizable quantities of the bacterium, its DNA, and antigens as resources for researchers working throughout the world. The armadillo facility is located at the National Hansen’s Disease Program Laboratories (NHDP), Baton Rouge, Louisiana, and the M. leprae research reagents are being developed at Colorado State University, Fort Collins.
As part of these NIAID-funded contracts, investigators at NHDP are developing the armadillo as a research animal model for human leprosy and investigators at Colorado State University are developing improved skin test antigens to detect leprosy. Trials to determine the safety of new skin test antigens were conducted in volunteers in the United States and at the Anandaban Hospital in Nepal to determine the utility of a skin test for epidemiologic surveillance and diagnosis in leprosy-endemic regions.