A person suffering from severe chills and recurring high fever for 3-4 days was diagnosed with malaria . The causative agent is responsible for the secretion of a toxic substance, which ruptures RBCs . This substance is called

Options

A. Sporozoites
B. haematopoetin
C. haem- protease
D. haemozoin

Answer

To solve the question regarding the toxic substance secreted by the causative agent of malaria that ruptures red blood cells (RBCs), we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Disease**:
- Malaria is caused by the Plasmodium parasite, which is transmitted through the bite of infected female Anopheles mosquitoes.

2. **Identifying the Causative Agent**:
- The Plasmodium species responsible for malaria include Plasmodium vivax and Plasmodium falciparum. These parasites enter the human bloodstream and migrate to the liver.

3. **Life Cycle of the Parasite**:
- In the liver, the parasites mature and reproduce, eventually releasing merozoites back into the bloodstream.

4. **Impact on Red Blood Cells**:
- Merozoites invade red blood cells (RBCs) through a process called phagocytosis. Inside the RBCs, they digest hemoglobin, which is the protein responsible for carrying oxygen.

5. **Toxic Substance Formation**:
- During the digestion of hemoglobin, the heme groups are released. These heme groups are toxic to the parasites but can be utilized as an energy source.

6. **Conversion to Hemozoin**:
- The parasites convert the toxic heme into a less harmful form called hemozoin. While hemozoin is harmless to the parasites, it is toxic to humans and contributes to the symptoms of malaria, including fever and chills.

7. **Conclusion**:
- The toxic substance responsible for the rupture of RBCs and the symptoms of malaria is called **hemozoin**.

### Final Answer:
The toxic substance secreted by the causative agent of malaria that ruptures RBCs is called **hemozoin**.

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