Which of the following is a protozoan disease?

Options

A. Tetanus
B. Measles
C. Filariasis
D. Sleeping sickness

Explanation

To determine which of the following is a protozoan disease, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Identify the Diseases**: We have four diseases to evaluate: Tetanus, Measles, Filariasis, and Sleeping Sickness.

2. **Analyze Tetanus**:
- Tetanus is caused by a bacterium known as *Clostridium tetani*.
- Since it is caused by bacteria, it is not a protozoan disease.

3. **Analyze Measles**:
- Measles is caused by a virus called the Morbillivirus.
- As it is a viral disease, it is also not a protozoan disease.

4. **Analyze Filariasis**:
- Filariasis is caused by nematodes (roundworms).
- Therefore, it is classified as a helminthic disease, not a protozoan disease.

5. **Analyze Sleeping Sickness**:
- Sleeping Sickness is caused by a protozoan known as *Trypanosoma brucei*.
- This disease is transmitted through the bite of the tsetse fly and affects the human blood.

6. **Conclusion**:
- Among the options provided, Sleeping Sickness is the only disease caused by protozoa. Therefore, the correct answer is Sleeping Sickness.

### Final Answer:
Sleeping Sickness is a protozoan disease.