Which of the following diseases is caused by a protozoan

Options

A. Syphilis
B. influenza
C. Babesiosis
D. Blastomycosis

Explanation

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

### Step-by-Step Solution:

1. **Identify the Diseases and Their Causes**:
- **Syphilis**: This is a sexually transmitted disease caused by *Treponema pallidum*, which is a bacterium.
- **Influenza**: Commonly known as the flu, this disease is caused by various strains of the influenza virus, making it a viral disease.
- **Babesiosis**: This disease is caused by the protozoan parasite *Babesia*, which infects red blood cells (RBCs).
- **Blastomycosis**: This disease is caused by *Blastomyces dermatitidis*, which is a fungus.

2. **Evaluate Each Option**:
- **Syphilis**: Not caused by a protozoan; it is bacterial.
- **Influenza**: Not caused by a protozoan; it is viral.
- **Babesiosis**: Caused by a protozoan; this is the correct answer.
- **Blastomycosis**: Not caused by a protozoan; it is fungal.

3. **Conclusion**:
- The only disease listed that is caused by a protozoan is **Babesiosis**.

### Final Answer:
The disease caused by a protozoan is **Babesiosis** (Option C).

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