Visceral leishmaniasis. View of a 4 year old girl with visceral leishmaniasis (kala-azar). A doctor is palpating her swollen abdomen. Kala-azar is a tropical disease caused by Leishmania sp., a parasitic protozoan. Leishmaniasis is transmitted by bites from infected sand-flies. This is the more serious form which can cause fever, and, without treatment, sometimes even death. Treatment with drugs is effective. Photographed in Sudan.