X and Y are type of diseases. X can spread from an infected person to a healthy person by actual contact between them and can spread from an infected person to healthy person with food, air or water. Y remains confined to the person who develops them and do not spread to others.
Which of the following is protozoan pathogen?

Options

A. Streptococcus pneumoniae
B. Variola virus
C. Varicella zoster virus
D. Plasmodium vivax

Answer

To determine which of the given pathogens is a protozoan pathogen, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Types of Diseases**:
- Disease X spreads from an infected person to a healthy person through direct contact or via food, air, or water. This indicates that X is an infectious disease.
- Disease Y remains confined to the individual who develops it and does not spread to others, indicating it is a non-infectious disease.

2. **Identify the Pathogens**:
- The question provides four options:
- Streptococcus pneumoniae
- Variola virus
- Varicella zoster virus
- Plasmodium vivax

3. **Classify Each Pathogen**:
- **Streptococcus pneumoniae**: This is a bacterium that causes pneumonia. Therefore, it is not a protozoan.
- **Variola virus**: This is a virus that causes smallpox. Therefore, it is not a protozoan.
- **Varicella zoster virus**: This is a virus that causes chickenpox and shingles. Therefore, it is not a protozoan.
- **Plasmodium vivax**: This is a protozoan that causes malaria. Therefore, it is a protozoan pathogen.

4. **Conclusion**:
- Among the options given, the only protozoan pathogen is **Plasmodium vivax**.

### Final Answer:
The protozoan pathogen among the options provided is **Plasmodium vivax**.

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