Figure 1

Histological types of oedema in severe malaria. Left column: Examples of the different histological types of oedema observed in the brain of fatal severe malaria in adults visualised with haematoxylin and eosin (A, C, E, G) or Luxol fast blue cresyl violet (LBCV, I). Right column: graphs indicating the incidence (% of cases) of the different histological types of oedema in cortex (yellow), diencephalon (orange) and brainstem (brown) of cerebral malaria (CM) and non-CM cases. No error bars are given as the bar chart represents the percentage of cases with or without a categorical histological feature. A. Rarefaction of the perivascular space characterized by separation of the compact parenchyma by fluid filled spaces (indicated by dashed line). B. There was no significant difference in the prevalence of perivascular rarefaction between CM and non-CM cases or between different brain regions. C-D. Perivascular pools of proteinaceous material indicated with a star (C). There was a greater prevalence in the brainstem compared with the diencephalon (P = .006) of CM cases (D). E-F. Vacuolar parenchymal oedema characterized by small isolated spaces (star) compare with compact parenchyma (diamond); (E). There was no difference between CM and non-CM cases or between different brain regions (F). G-H. Oedema between fibres of white matter tracts (star) compare with compact fibre tract (diamond); (G). There was a hierarchy of prevalence: brainstem > diencephalon > cortex. However, there was no difference between CM and non-CM cases (H). I-J. Decreased staining intensity of LBCV as a result of increased fluid-filled spaces between myelin fibres. Note myelin pallor in area indicated by dashed line radiating from the vessel in the bottom right corner (I). There was no significant difference between CM and non-CM cases or between different brain regions (J). Scale bar in A = 50 μm (for images A-G); scale bar in I = 100 μm.