Question

Which one of the following life cycle stages of malarial parasite is responsible for relapse of malarial symptoms?
 A. Merozoite
 B. Sporozoite
 C. Hypnozoite
 D. Gametocyte.

Answer 1

Hint: Malaria is caused by Plasmodium vivax, transmitted from the bite of female Anopheles mosquitoes. Plasmodium vivax is a protozoan parasite causing malaria. The life cycle of Plasmodium vivax involves two hosts, i.e. mosquitoes and humans.

Complete answer:
When infected female anopheles mosquitoes bite, the first form entering the human body is known as a sporozoite. Sporozoite attacks hepatocytes. Hypnozoite is the stage where a parasite undergoes a dormant stage in the hepatic cell known as hepatic dormancy. When patients recover from malaria, they may show symptoms even after several months or even after a year. It occurs because hypnozoite reactivates.

Sporozoites mature and convert into merozoites. Merozoites infect mature RBCs. When the parasite enters the RBC, it is called trophozoite. Further, gametocytes are transferred into the mosquito's body. It further differentiates into macrogamete or microgamete. On the fusion of macrogamete and microgamete, the zygote develops which attaches to the gut lining of mosquitoes. On maturation of the oocyte, Sporozoite is released in salivary glands of mosquitoes. Therefore, Hypnozoite is responsible for relapse of malarial symptoms. Malaria can be transmitted through other sources such as blood transfusion, organ transplantation, infected needles, etc.

So, the correct answer is option C.

Note: If a person with sickle cell anaemia suffers from malaria, it shows lethal effect. Fever, chills, headache, nausea, vomiting are basic symptoms of malaria. Liver cells are also known as hepatocytes or hepatic cells. Some of the symptoms of malaria are headache, fever, muscle aches, etc.