Which of the following pathogen generlly enters the small intestine through food and water contaminted with them and migrate to other organs through blood:-

Options

A. Plasmodium
B. Salmonella typhi
C. Haemophilius influenza
D. Entamoeba histolytica

Answer

**Step-by-Step Solution:**

1. **Identify the Pathogens**: The question provides four options:
- a. Plasmodium
- b. Salmonella typhi
- c. Haemophilus influenzae
- d. Entamoeba histolytica

2. **Understand the Entry Route**: The question specifies that the pathogen enters the small intestine through food and water that are contaminated.

3. **Analyze Each Pathogen**:
- **Plasmodium**: This pathogen is responsible for malaria and is transmitted by mosquito bites, not through contaminated food or water.
- **Salmonella typhi**: This bacterium causes typhoid fever and is known to enter the small intestine through contaminated food and water. It can then migrate to other organs via the bloodstream.
- **Haemophilus influenzae**: This bacterium is primarily associated with respiratory infections and does not enter through the gastrointestinal tract.
- **Entamoeba histolytica**: This protozoan causes amoebic dysentery and can also enter through contaminated food and water, but it primarily affects the intestines.

4. **Determine the Correct Pathogen**: Based on the analysis, Salmonella typhi is the pathogen that specifically enters the small intestine through contaminated food and water and can migrate to other organs through the bloodstream.

5. **Conclusion**: The correct answer to the question is option **b. Salmonella typhi**, which causes typhoid fever.