Infectous stage of plasmodium is -

Life cycle of Plasmodium vivax. (1) Sporozoites present in the salivary gland of female Anopheles mosquito are injected into skin capillaries when the mosquito bites humans. (2) They enter liver cells to initiate exoerythrocytic schizogony. Some sporozoites become dormant hypnozoites (2a,b) which are reactivated after varying intervals to produce relapses. Most sporozoites complete the pre-erythrocytic schizogony (2c). to form merozoites which infect red blood cells, to initiate the cycle of erythrocytic schizogony (3) which is repeated every 48 hours. Some merozoites initiategametogony, forming male and female gametocytes (4) which are ingested by mosquito in its blood meal. Male gametocyte undergoes exflagellation.(5) one male gamete feilises female gamete to form zygote. It develops into the motile ookinete, which penetrates the stomach wall and becomes the oocyst inside which sporozoites develop. (6) Sporozoites released by rupture of mature oocyst (7) enter the haemocoele (8) and reach the salivary glands of the mosquito