Q.What is Kala-azar?

About fifteen genera of protozoans parasitize the human body. Amoebiasis (amoebic dysentery), caused by Entamoeba histolytica living in the large intestine, has an infective trophozoite stage that penetrates the intestinal wall, secretes histolytic enzymes, and causes ulceration, bleeding and mucus-laden stools; house flies act as carriers from contaminated faeces/water to food. African sleeping sickness is caused by three Trypanosoma species, each with its own insect vector — T. gambiense (tsetse fly Glossina palpalis, Gambian sickness), T. rhodesiense (Glossina morsitans, Rhodesian sickness), and T. cruzi (the bug Triatoma megista, Chagas disease). Kala-azar (visceral leishmaniasis) is caused by Leishmania donovani, transmitted by the sandfly Phlebotomus, infecting endothelial cells, bone marrow, liver, lymph glands and the spleen's blood vessels, producing weight loss, anaemia, fever and spleen/liver enlargement. …