CEREBRAL MALARIA IN THE RHESUS-MONKEY (MACACA-MULATTA) - LIGHT AND ELECTRON-MICROSCOPIC CHANGES IN BLOOD-CELLS AND CEREBROVASCULAR ENDOTHELIA

To assess the interaction between the cellular elements of the blood a nd neurovascular endothelia in cerebral malaria, brain tissue from adu lt rhesus moneys (Macaca mulatta) infected with a virulent (W1) strain of Plasmodium knowlesi were studied by light and electron microscopic al techniques. Light microscopical examination showed sequestration of macrophages and margination of erythrocytes containing late stages of the parasite in the capillaries and venules throughout, the brains of the infected monkeys. Brain microvascular lesions (associated with pa rasitised erythrocytes and macrophage attachment to vascular walls) se en with the electron microscope, were swelling of the endothelial cell s, formation of pseudopodia, increased numbers of pinocytotic vesicles and disorganisation of the mitochondria. Parasitised mature erythrocy tes and macrophages adhered to the vascular endothelial lining in equa l proportions. The endothelial ultrastructural alterations were simila r to those described in experimental rodent and in clinical human cere bral malaria.