Atomic force microscopy was used to image the membrane cytoskeleton network of normal and P. falciparum-infected ghosts. The membrane cytoskeleton network was examined in air-dried ghost preparations from normal and infected cells. We found that the spectrin network was changed in infected ghosts. The thickness of the normal red cell membrane was about 15.05 +/- 2.27 nm, while the thickness of the P. falciparum-infected membrane was found to be 22.97 +/- 3.84 nm. The ghost containing ring stage parasites exhibited areas of particle-like protrusions ranging in size from 0.2 to 0.7 mu m. The surface of the P. falciparum parasite was also imaged in air-dried samples, showing the existence of a large protrusion extending from the parasite surface. (C) 1997 Academic Press.