Key features of placental malaria. Haematoxylin and eosin stained placental sections from the Mbarara trial are shown at 600X. A) Normal placental histology. B) Parasitized erythrocytes sequester in the intervillous space. C) Monocyte-macrophages accumulate and phagocytose parasitized erythrocytes and haemozoin. D) Monocyte macrophages become enmeshed in fibrin and degenerate. E) Residual haemozoin persists in fibrin following successful treatment.