Which of the following diseases is caused by a protozoan

Options

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

Answer

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

### Step-by-Step Solution:

1. **Identify the Diseases**: The question lists four diseases:
- Blastomycosis
- Syphilis
- Influenza
- Babesiosis

2. **Research Each Disease**:
- **Blastomycosis**: This disease is caused by a fungus known as *Blastomyces*. Therefore, it is not caused by a protozoan.
- **Syphilis**: This disease is caused by a bacterium called *Treponema pallidum*. Hence, it is also not caused by a protozoan.
- **Influenza**: This disease is caused by a virus known as *Haemophilus influenzae*. Thus, it is not caused by a protozoan.
- **Babesiosis**: This disease is caused by a protozoan called *Babesia*. Therefore, this disease is indeed caused by a protozoan.

3. **Conclusion**: Based on the analysis, the only disease caused by a protozoan is **Babesiosis**.

### Final Answer:
The disease caused by a protozoan is **Babesiosis**.

---