Visceral leishmaniasis. Third World doctor examining a teenage boy who is recovering from visceral leishmaniasis (kala-azar). The doctor is palpating his abdomen and examining his hand. 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, jaundice, a swollen abdomen and, without treatment, sometimes even death. Treatment with drugs is effective. Photographed in Sudan.