Question

Which of the following statements about malaria is/are true?

• A. There are two stages in the life cycle of the malarial parasite
• B. Asexual stage occurs in mosquitoes
• C. Asexual stage occurs in humans and sexual stage starts in humans and ends in mosquitoes
• D. Asexual stage occurs in mosquitoes and sexual stage occurs in humans

Answer 1

Answer: (A), (C)

Asexual stage occurs in humans and sexual stage starts in humans and ends in mosquitoes

The Plasmodium parasite has two stages of reproduction in its life cycle, the asexual stage that takes place in the humans and the sexual stage that starts in the humans and ends in mosquitoes. The human infection begins when mosquito injects sporozoites in the patient's bloodstream. The sporozoites enter the liver where they form schizonts. Each schizont forms hundreds of merozoites that are released into bloodstream and invade RBCs. This is the asexual stage. Some of the merozoite-infected blood cells leave the cycle of asexual replication. Instead of replicating, the merozoites in these cells develop into sexual forms of the parasite, called male and female gametocytes. When a mosquito bites an infected human, it ingests the gametocytes. In the mosquito midgut the gametocytes develop further into mature sexual forms called gametes. This is sexual stage of reproduction of the parasite inside the mosquito.