Leishmaniasis is a parasitic disease caused by the Leishmania parasite, which is transmitted to humans through the bite of infected sandflies. The disease manifests in three main forms: cutaneous, mucocutaneous, and visceral leishmaniasis. Cutaneous leishmaniasis affects the skin, mucocutaneous leishmaniasis affects the skin and mucous membranes, and visceral leishmaniasis affects internal organs such as the spleen, liver, and bone marrow.