A disease spread indirectly through a vector is

Options

A. Sleeping sickness
B. Malaria
C. kala-azar
D. All the above

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a disease that is spread indirectly through a vector. A vector is an organism that transmits a pathogen from one host to another.

2. **Analyzing the Options**:
- **Option A: Sleeping Sickness**: This disease, also known as African trypanosomiasis, is caused by the protozoan Trypanosoma brucei and is transmitted by the tsetse fly. The tsetse fly acts as a vector, making this disease spread indirectly through a vector.

- **Option B: Malaria**: Malaria is caused by the Plasmodium species and is transmitted through the bite of infected female Anopheles mosquitoes. Here, the mosquito serves as the vector, indicating that malaria is also spread indirectly through a vector.

- **Option C: Kala Azar**: This disease is caused by the Leishmania species and is transmitted by the bite of infected sandflies. The sandfly acts as a vector, which means kala azar is also spread indirectly through a vector.

3. **Conclusion**: Since all three diseases (Sleeping Sickness, Malaria, and Kala Azar) are transmitted through vectors, the correct answer is:
- **Option D: All of the above**.

**Final Answer**: D. All of the above.

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