Figure 1. Plasmodium life cycle progression in the mammalian host and major targets of antiparasite immune responses. The malaria parasite is transmitted during the probing phase of a female Anopheles mosquito that delivers around a dozen sporozoites into the skin. Sporozoites are highly motile and rapidly enter a nearby capillary from where they eventually reach the liver. Sporozoites actively enter a suitable hepatocyte and commence intracellular transformation and replication. During EEF development, an infected hepatocyte will produce tens of thousands of pathogenic merozoites that egress out of the liver. Merozoites actively penetrate erythrocytes where they develop into growth stages (trophozoites) and finally into 16–32 new merozoites that initiate another blood stage cycle. A subpopulation of asexual blood stages will transform into male (pink) and female (blue) sexual stages that are transmitted to the Anopheles mosquito. Antibody-mediated protection may occur neutralizing the extracellular invasion stages (sporozoites and merozoites). Cellular immunity largely acts against the intracellular EEFs.