Which one of the sexually transmitted diseases is correctly matched with its pathogen ?

Options

A. Urethritis-Bacillus anthracis
B. Syphilis-Treponema pallidum
C. Gonorrhoea-Entamoeba histolytica
D. Soft sore- Bacillus brevis

Answer

To solve the question regarding which sexually transmitted disease (STD) is correctly matched with its pathogen, we will analyze each option provided.

### Step-by-Step Solution:

1. **Identify the First Option: Urethritis**
- Urethritis is described as inflammation of the urethra.
- It can be caused by various pathogens, including bacteria and viruses.
- Common bacterial causes include **Escherichia coli**, **Neisseria gonorrhoeae**, and **Chlamydia trachomatis**.
- However, the option states it is caused by **Bacillus anthracis**, which is incorrect. Bacillus anthracis is the causative agent of anthrax, not urethritis.
- **Conclusion**: This option is incorrect.

2. **Identify the Second Option: Syphilis**
- Syphilis is a well-known STD.
- It is caused by the bacterium **Treponema pallidum**, which is a spirochete.
- This matches correctly with the definition of syphilis.
- **Conclusion**: This option is correct.

3. **Identify the Third Option: Gonorrhea**
- Gonorrhea is another STD.
- It is caused by the bacterium **Neisseria gonorrhoeae**.
- The option states it is caused by **Entamoeba histolytica**, which is incorrect. Entamoeba histolytica is responsible for amoebic dysentery, not gonorrhea.
- **Conclusion**: This option is incorrect.

4. **Identify the Fourth Option: Soft Sore**
- Soft sore, also known as chancroid, is an STD.
- It is caused by the bacterium **Haemophilus ducreyi**.
- The option states it is caused by **Bacillus brevis**, which is incorrect. Bacillus brevis is not associated with soft sore.
- **Conclusion**: This option is incorrect.

### Final Answer:
The only correctly matched STD with its pathogen is **syphilis**, which is caused by **Treponema pallidum**. Therefore, the correct answer is **B**.