The visceral lesions in simian malaria with special reference to the splenic reaction

A histopathological study of twelve cases of fatal monkey malaria due to infection with P. knowlesi has shown (1) the presence of a vascular mechanism that localizes the parasites in large numbers in the spleen; (2) the presence of a lymphoid reaction in the spleen; and (3) the activation of the reticulo-endothelial system as shown by histiocytic differentiation and active phagocytosis.