Leishmania

Leishmania are dimorphic intracellular protozoan parasites of vertebrates that are transmitted by phlebotomine sand flies. Multiple Leishmania spp. cause diverse human disease, which includes cutaneous lesions, destructive mucosal lesions, and severe visceral disease. The parasite’s complex life cycle includes cellular and biochemical changes that are required for transition from the sand fly to vertebrate host. Leishmania have novel mechanisms of RNA processing and uncommon mechanisms of gene regulation. Cellular immune mechanisms are protective, but the parasite subverts immune function to promote intracellular survival. Treatment of leishmaniasis is challenging, so prevention is critical. Development of an effective vaccine may be possible.