Zoology - Human Health and Diseases Question with Solution | TestHub

When the female Anopheles mosquitoes bite humans for a blood meal, they inject the sporozoites of Plasmodium into the skin wound. Thus sporozoite stage is the infective stage of Plasmodium in humans. These sporozoites reach the blood stream and migrate to liver. They infect liver cells (hepatocytes) where they divide asexually to form many merozoites. These merozoites rupture the liver cells and escape into bloodstream. Each merozoite infects an erythrocyte where it develops into ring form followed by trophozoite which shows intracellular feeding followed by schizont which in turn produce many merozoites. These newly formed merozoites come out of the erythrocytes by rupturing them. The rupture of erythrocytes causes release of a toxic substance, haemozoin, which is responsible for the chill and high fever. Some of these merozoites escape the asexual amplification cycle and form microgametocytes and microgametocytes. Their further development requires cooler temperature found in mosquitoes. These gametocytes are stored in erythrocytes till they are transferred to female Anopheles mosquito.