Which one of the following cannot be used for preparation of vaccination against plague ?

Options

A. Heat killed suspension of virulent bacteria
B. Formaline inactivated suspension of virulent bacteria
C. A virulent live bacteria
D. Synthetic capsular polysaccharide material.

Answer

**Step-by-Step Solution:**

1. **Identify the Cause of Plague**: Understand that plague is caused by the bacterium *Yersinia pestis*. This is the first step in determining how vaccines are prepared against this disease.

2. **Understand Vaccine Preparation Methods**: Vaccines can be prepared using various methods, including:
- Heat-killed suspension of virulent bacteria
- Formalin-inactivated suspension of virulent bacteria
- Avirulent live bacteria
- Synthetic capsular polysaccharide material

3. **Evaluate Each Option**:
- **Heat-killed suspension of virulent bacteria**: This method can be used to create a vaccine because it involves killing the bacteria while retaining the ability to provoke an immune response.
- **Formalin-inactivated suspension of virulent bacteria**: This method is also valid for vaccine preparation as it inactivates the bacteria while preserving its antigens.
- **Avirulent live bacteria**: This method can be used as well, as it involves using a strain of the bacteria that is not harmful but can still elicit an immune response.
- **Synthetic capsular polysaccharide material**: This method is typically used for other vaccines (like those for pneumonia) but is not suitable for plague vaccination.

4. **Determine the Correct Answer**: Since synthetic capsular polysaccharide material is not used for the preparation of a plague vaccine, the correct answer to the question is option D.

5. **Conclusion**: The option that cannot be used for the preparation of vaccination against plague is synthetic capsular polysaccharide material.

**Final Answer**: Option D - Synthetic capsular polysaccharide material.

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