Pre-erythrocytic stages of the Plasmodium life cycle analyzed by comparative proteomics in the study of Lasonder et al. . Mosquito stages are shown on a pale pink background; stages in the vertebrate host on a pale blue background. (a) Oocyst derived sporozoites (ODS) are generated within the oocyst embedded in the mosquito midgut. (b) ODS egress from the oocyst and invade salivary glands. (c) Salivary gland sporozoites (SGS) are transmitted to the vertebrate host and invade hepatocytes. Other stages included for reference include gametocyte maturation, gamete fertilization and zygote formation, which precede invasion of the mosquito midgut by the ookinete; and the liver and blood stages. The stage-specific proteins characterized by Lasonder et al.  (in red ovals) are depicted at the point of the cycle where they are predicted to function. Modified from Vickerman and Cox .