Electron microscope studies of motile stages of malaria parasites II. The fine structure of the sporozoite of Laverania (= Plasmodium) falcipara

Abstract

1. 1) Thin sections of the sporozoites of Laverania (= Plasmodium) falcipara were examined by electron microscopy. 2. 2) The sporozoite is covered by a thick pellicle which merges at the blunt anterior tip into a specialized formation consisting of concentric rings surrounding a shallow cup. 3. 3) Leading up to the anterior cup is a paired organelle, the lobes of which are sinuous and extend back towards the nucleus. 4. 4) Near the nucleus there is a well-marked pit or micropyle, through which it is suggested the “sporoplasm” emerges in the liver cell, to initiate pre-erythrocytic schizogony. 5. 5) Fourteen fibrils are distributed around two-thirds of the periphery, with an extra one placed by itself in the remaining third. They extend from the apical cup to at least the region of the nucleus. 6. 6) Mitochondria are numerous in the cytoplasm of the sporozoite.