Which of the following toxic substance is responsible for the chill and high fever recurring every three to four days in malaria?

Options

A. Haemotoxin
B. Haemoglobin
C. Haemozoin
D. Sporozoites

Explanation

To answer the question regarding which toxic substance is responsible for the chills and high fever recurring every three to four days in malaria, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Malaria**: Malaria is caused by parasites of the genus Plasmodium, which are transmitted to humans through the bites of infected female Anopheles mosquitoes.

2. **Identifying Symptoms**: The primary symptoms of malaria include chills, high fever, sweating, headaches, nausea, and vomiting. The fever typically occurs in cycles, often every 48 to 72 hours, depending on the type of Plasmodium.

3. **Examining the Options**:
- **Hemotoxin**: This is a toxic substance found in the venom of some animals, not related to malaria.
- **Hemoglobin**: This is a protein in red blood cells that carries oxygen; it is not a toxic substance and does not cause malaria symptoms.
- **Hemozoin**: This is a byproduct of the digestion of hemoglobin by the malaria parasite. The parasite breaks down hemoglobin and releases free heme, which is toxic to cells. The parasite then converts this toxic free heme into an insoluble crystalline form known as hemozoin.
- **Sporocytes**: These are the infectious form of the malarial parasite but are not responsible for the symptoms.

4. **Conclusion**: The substance responsible for the chills and high fever in malaria is **Hemozoin**, as it is the toxic byproduct produced by the malaria parasite during its lifecycle.

5. **Final Answer**: Therefore, the correct answer is **Hemozoin**.