O Levels Biology (5090)•5090/11/O/N/23

Explanation
Cholera Causative Agent and Transmission
Steps:
- Identify the pathogen: Cholera is caused by Vibrio cholerae, a bacterium.
- Recall transmission: It spreads through fecal-oral route, primarily via water contaminated with infected feces.
- Eliminate viral options: Cholera is bacterial, not viral.
- Confirm medium: Not blood; it's waterborne, especially in areas with poor sanitation.
Why B is correct:
- Vibrio cholerae is a bacterium that produces toxins in the intestines, leading to severe diarrhea; per WHO definitions, it's transmitted orally through contaminated water sources like drinking or bathing water.
Why the others are wrong:
- A: Cholera isn't bloodborne; blood transmission applies to diseases like HIV or hepatitis.
- C: Cholera is caused by bacteria, not viruses; viruses cause diseases like norovirus gastroenteritis.
- D: Incorrect pathogen; no virus causes cholera, though some viruses spread via water.
Final answer: B
Topic: Disease
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