Briefly describe the life history of the malarial parasite.
Malarial parasite (Plasmodium) completes its life cycle in two hosts., i.e. female anopheles mosquito and humans. Sporozoites are the infective stage. The sporozoites enter the human body, reach the liver through blood and multiply within the liver cells. Such liver cells burst and release the parasites (Cryptomerozoites) into the blood. Then they attack RBCs, multiply and cause their rupture. The rupture of RBCs is associated with the release of a toxin called haemozoin, which is responsible for the high recurring fever and the chill/ shivering and causing malaria. Sexual stages (gametocytes) develop in the red blood cells. The parasite then enters the female Anopheles mosquito along with the blood when it bites the infected person. Further development occurs in the stomach wall of the mosquito. The gametes fuse to form a zygote. It takes the worm-like shape called ookinete as it pierces the wall of the stomach. The zygote undergoes further development in the body of the mosquito to form sporozoites. Sporozoites are transported to and stored in the salivary glands of mosquitoes and are transferred to a human body during the bite of the mosquito. Female mosquito sucks human blood because it requires blood proteins for the development of its eggs.
