Question

A person suffering from a disease caused by Plasmodium, experiences recurring chills and fever at the time when

• A. The sporozoites released from RBCs are being rapidly killed and broken down inside spleen
• B. The parasite after its rapid multiplication inside RBCs ruptures them, releasing the stage to enter fresh RBCs
• C. The trophozoites reach maximum growth and give out certain toxins
• D. The microgametocytes and megagametocytes are being destroyed by the WBCs

Answer 1

The Correct Option is B

The question is based on the life cycle of Plasmodium, the parasite responsible for causing malaria. To determine why a person experiences recurring chills and fever during a Plasmodium infection, we need to understand the specific stages of the Plasmodium life cycle related to the symptoms experienced.

Plasmodium goes through several stages in its host (the human body), primarily inside red blood cells (RBCs). The key part of the life cycle causing the symptoms of malaria, particularly the cyclical fevers and chills, is as follows:

1. After the mosquito bite, sporozoites enter the bloodstream and travel to the liver, where they infect liver cells and multiply.
2. These eventually burst out of liver cells as merozoites, which then invade RBCs.
3. Inside RBCs, merozoites grow into trophozoites, multiply, and mature into schizonts. The schizonts then rupture the RBCs, releasing more merozoites into the bloodstream. This rupturing of RBCs is associated with the release of toxins and thus triggers the febrile (fever) response.

Thus, the correct answer is:

• The parasite after its rapid multiplication inside RBCs ruptures them, releasing the stage to enter fresh RBCs.

Explanation of Why Other Options are Incorrect:

• The sporozoites released from RBCs are being rapidly killed and broken down inside spleen: This is incorrect as sporozoites initially target liver cells, not RBCs, and are not directly associated with the cause of fever.
• The trophozoites reach maximum growth and give out certain toxins: While trophozoites do develop inside RBCs, the symptom of fever specifically occurs due to the rupture of RBCs.
• The microgametocytes and megagametocytes are being destroyed by the WBCs: Gametocytes are involved in the sexual stage of the parasite lifecycle and not directly linked to the fever episodes.

Therefore, the recurring chills and fever are primarily observed when the parasite replicates inside RBCs, leading to their rupture and subsequent release of merozoites.