Despite the absence of antecedent established coma, cerebral pathology in this case is very similar to that observed in fatal falciparum infections, confirming that it was important to exclude this co-infection. Although there was obvious accumulation/sequestration of infected erythrocytes in capillaries and venules, there were also some differences between these appearances and those seen with fatal falciparum infections. For example, there was no platelet clumping, no notable thrombi, and uninfected erythrocytes were also interspersed with infected cells. Neither was up-regulation of ICAM-1 expression detected in endothelial cells, suggesting that the mechanism of sequestration/accumulation of infected erythrocytes in knowlesi infections needs further investigation. In falciparum cerebral malaria, display of ICAM-1 by up regulated endothelial cells mediates adhesion to parasitized red cells [19] .