Human infection (transmission) occurs when a female mosquito inoculates the sporozoites of Plasmodium from its salivary gland into the blood of man. The sporozoites invade the cells of the liver and reproduce through multiple fission or sporulation (asexual reproduction) called pre-erythrocytic, exoerythrocytic, or intrahepatic schizogony or merogony. Each sporozoite produces daughter merozoites. These merozoites are released into the bloodstream through the infected liver cell. Once the merozoites are in the blood, they quickly invade RBCs and become trophozoites.