The main purpose of this protocol is to permit us to see patients who are referred to us for diagnosis and treatment of known or suspected leishmaniasis (from the Peace Corps, Smithsonian Institution, tourists, etc.). In the process of working up these patients, we sometimes encounter parasite isolates that are useful for research. We also can perform tests of cell-mediated immune function to evaluate how patients are responding to therapy. In addition, the protocol permits us to observe therapeutic responses to other drugs besides pentavalent antimony, if necessary.