Leishmaniasis is caused by a protozoa parasite, one of more than 20 Leishmania species, transmitted to humans by the bite of infected female phlebotomine sandflies. More than 90 species of mosquitoes have been identified as carriers of the Leishmania parasite. There are 3 main types of the disease: visceral (often called kala-azar, the most severe form of the disease), cutaneous (the most common), and mucocutaneous. Leishmaniasis is caused by the protozoa parasite Leishmania, which is transmitted by the bite of infected mosquitoes. The disease affects the world's poorest people and is associated with malnutrition, displacement, poor housing conditions, weak immune systems, and lack of resources. Leishmaniasis is related to environmental changes such as deforestation, construction of dams and irrigation systems, and urbanization. An estimated 700,000 to 1 million new infections and 20,000 to 30,000 deaths occur each year. Only a small proportion of people infected with Leishmania parasites will eventually develop the disease.