Question

Describe the asexual and sexual phases of life cycle of Plasmodium that causes malaria in humans

Answer 1

Life Cycle of Plasmodium

• Plasmodium requires two hosts to complete its life cycle.

• When female Anopheles mosquito bites a healthy human being, it releases Plasmodium, which lives in its body as sporozoite (infectious form).

• The parasites multiply (asexual reproduction) in the liver cells and finally burst the liver cells. Sporozoites are released in blood.

• Parasites enter RBCs and further multiply (asexual reproduction) here and finally burst RBCs also.

• Bursting of RBCs is accompanied by release of a toxic substance called haemozoin (associated with fever and chills).

• In the RBCs, only sporozoites change into gametocytes (sexual stage). Gametocytes multiply.

• When the diseased person is bitten by a female Anopheles mosquito, gametocytes are introduced into the mosquito.

• Gametocytes fertilise and develop inside the intestine of mosquito to form sporozoites.

• Sporozoites are stored in the salivary glands of mosquito and are released into the healthy person who is bitten by this mosquito.