RESUMEN
The significance of Hansen disease, or leprosy, is underscored by fact that detection of this disease has remained stable over the past 10 yr, even though disease prevalence is reduced. Due to the long incubation time of the organism, health experts predict that leprosy will be with us for decades to come. Despite the fact that Mycobacterium leprae, the causative agent of leprosy, cannot be cultured in the laboratory, researchers are using innovative and imaginative techniques to discern the interactions of M. leprae with host cells both in vitro and in vivo to identify the host and bacterial factors integral to establishment of disease. The studies described in this review present a new and evolving picture of the many interactions between M. leprae and the host. Specific attention will be given to interactions of M. leprae bacilli with host Schwann cells, macrophages, dendritic cells and endothelial cells. The findings described also have implications for the prevention and treatment of leprosy.