Plasmodium falciparum – schizonts, merozoites and haemozoin

Plasmodium falciparum – schizonts, merozoites and haemozoin
Author: Luhan Swart; Ralph Diedericks
Category: Infectious Disease
Published Date: 03/18/2014

An orphaned eleven year old HIV positive girl first presented with chronic diarrhoeal disease. Further examination revealed a mesenteric abscess, of which the infecting organism was identified as mycobacterium avium on culture. Six months later she represented with diarrhoeal disease and septic shock. Peripheral blood revealed a mild leukocytosis, a moderate thrombocytopenia (WCC = 12.84 x 109/l; Hb = 11.7 g/dl; Platelets = 48 x 109/l) and a high malaria parasitaemia of 4.7% consisting predominantly of early plasmodium falciparum trophozoites. The trophozoites consisted of one or two small delicate ring forms per normal sized red blood cell, some trophozoites had a double chromatin dot. There were very occasional late plasmodium falciparum schizonts present, each with at least 15 irregularly grouped small merozoites and a peripheral clump of dark brown pigment. Phagocytosed malaria pigment (haemozoin) was seen within both the neutrophils and monocytes. Apart from very severe cases, plasmodium falciparum schizonts can only rarely be seen in the peripheral blood. She initially received intravenous Artesunate and was then switched to oral therapy with Coartem. Four days post admission, it was noted that she developed a dactylitis affecting the fingers of both hands as well as an objective arthritis affecting her left ankle. The arthritis progressed to involve both knees and ankles and was thought to be a reactive polyarthritis secondary to the malaria. The polyarthritis responded well to ibuprofen. She continued to show good clinical progress and was discharged two weeks after admission. D: (To accompany photograph) Composite slide of Plasmodium falciparum on a MGG-stained thin film: (a) a delicate small ring form within a normal sized red cell and a late schizont; (b) and (c) late schizont; (d) ruptured schizont spilling merozoites; (e) neutrophil and (f) monocyte containing haemozoin pigment.