Visceral leishmaniasis. Light micrograph of a section through spleen tissue from a patient suffering from visceral leishmaniasis. The white blood cell (macrophage, large circle, centre) is infected with Leishmania donovani protozoa (amastigotes, small purple bodies). These single- celled organisms are the cause of leishmaniasis. They sequester themselves inside macrophages and other tissue of the lymph system in order to hide from the body's immune defences. Symptoms of visceral leishmaniasis include enlargement of the spleen and liver, emaciation, kidney damage and eventual death. The disease is treatable with drugs. Giemsa stain. Magnification unknown.