Life cycle of malarial parasite

When an infected mosquito bites, it injects Plasmodium sporozoites into the bloodstream. The sporozoites migrate through the blood to the liver, where they form cyst-like structures containing thousands of merozoites. [Note: Diagnosis depends on laboratory identification of the parasites in red blood cells of peripheral blood smears.]Upon release, each merozoite invades a red blood cell, becoming a trophozoite and using hemoglobin as a nutrient. The trophozoites multiply and become merozoites. Eventually, the infected cell ruptures, releasing heme and merozoites that can enter other erythrocytes. [Note: Alternatively, released merozoites can become gametocytes, which are picked up by mosquitoes from the blood they ingest. The cycle thus begins again, with the gametocytes becoming sporozoites in the insect.] The eff ectiveness of drug treatment is related to the particular species of infecting plasmodium and the stage of its life cycle that is targeted.