Periodic appearance of malaria symptoms occur due to periodic

Options

A. Entry of merozoites into erythrocytes
B. Attack of liver cells by merozoites
C. Formation of signet ring
D. Release of pyrogen in blood.

Answer

**Step-by-Step Solution:**

1. **Understanding Malaria and its Causative Agent**:
- Malaria is caused by the protozoan parasite *Plasmodium vivax*. It is important to know that this parasite is transmitted through the bite of an infected female Anopheles mosquito.

2. **Infection Process**:
- When an infected mosquito bites a human, it injects sporozoites (the infective stage of *Plasmodium vivax*) into the bloodstream. These sporozoites travel to the liver.

3. **Multiplication in the Liver**:
- Inside the liver, the sporozoites multiply and develop into merozoites. This stage does not cause symptoms.

4. **Entry into Red Blood Cells (RBCs)**:
- The merozoites then enter the red blood cells (RBCs). Inside the RBCs, they continue to multiply and eventually lead to the breakdown of hemoglobin.

5. **Formation of Hemozoin**:
- The breakdown of hemoglobin produces a toxic substance called hemozoin. This process occurs every 48 to 72 hours, leading to the periodic release of hemozoin into the bloodstream.

6. **Role of Hemozoin as a Pyrogen**:
- Hemozoin acts as a pyrogen, which means it can induce fever. The release of hemozoin into the bloodstream is what causes the periodic appearance of malaria symptoms, particularly fever.

7. **Conclusion**:
- Therefore, the periodic appearance of malaria symptoms occurs due to the periodic release of hemozoin, which is a breakdown product of hemoglobin in the RBCs.

**Final Answer**: The periodic appearance of malaria symptoms occurs due to the periodic release of hemozoin.

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