Protozoa causes

Options

A. malaria
B. Kala-azar
C. sleeping sickness
D. All of these

Answer

### Step-by-Step Solution

1. **Understanding Protozoa**: Protozoa are single-celled organisms that can cause various diseases in humans. They are classified as parasites when they live in or on a host and benefit at the host's expense.

2. **Identifying Protozoan Diseases**:
- **Malaria**: This disease is caused by the protozoan parasite *Plasmodium vivax*, which is transmitted to humans through the bite of infected female Anopheles mosquitoes. Symptoms include fever, chills, and flu-like illness.

- **Black Fever (Kala-azar)**: This disease is caused by the protozoan *Leishmania donovani*. It primarily affects internal organs such as the spleen, liver, and bone marrow, leading to symptoms like fever, weight loss, and anemia.

- **Sleeping Sickness**: Caused by the protozoan *Trypanosoma brucei*, this disease is transmitted by the bite of the tsetse fly. Symptoms include fever, headaches, joint pains, and neurological issues leading to sleep disturbances.

3. **Summarizing Protozoan Diseases**: The main protozoan diseases mentioned are Malaria, Black Fever, and Sleeping Sickness. Each of these diseases is caused by specific protozoan parasites and transmitted through different vectors.

4. **Conclusion**: Protozoa cause various diseases in humans, and understanding these diseases is crucial for prevention and treatment.