Figure 1

The appearance of microvascular sequestration with the use of different imaging techniques. (A) Photomicrograph of a brain section from an adult Vietnamese patient who died with cerebral malaria, demonstrating blood vessels packed with parasitized erythrocytes (hematoxylin-eosin stain, magnification × 400, courtesy Gareth Turner). (B) An electron micrograph of a capillary demonstrating microvascular obstruction. Parasitized erythrocytes (P) obstruct the passage of an uninfected erythrocyte (U) (courtesy of Emsri Pongponratn). (C) Still from an orthogonal polarization spectral imaging video (Additional file 1) of a patient with severe falciparum malaria, showing the cobblestone pattern of the capillaries surrounding the rectal crypts. The polarization filter causes red structures to appear dark grey, hence erythrocytes are visible as grey spots; their movement can be measured by using image-analysis software. The presence of sequestration is suggested in vessels where there is no erythrocyte movement.