7th Pandemic of cholera was caused by –
**Core Concept**
The 7th pandemic of cholera was a significant global outbreak of the disease, which has had multiple pandemics throughout history. Cholera is caused by the bacterium Vibrio cholerae, typically spread through contaminated water or food.
**Why the Correct Answer is Right**
The 7th pandemic of cholera was caused by Vibrio cholerae O139, a new serogroup of the bacterium. This pandemic occurred in the early 1990s and was first identified in India. The O139 serogroup was distinct from the classical O1 serogroup, which had caused previous pandemics. The emergence of the O139 serogroup led to a significant increase in cholera cases worldwide.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not correct because Vibrio cholerae O1 is associated with the 6th pandemic, not the 7th.
**Option B:** This option is not correct because Vibrio cholerae O139 is the correct cause of the 7th pandemic, not Vibrio cholerae O139's biotype.
**Option C:** This option is not correct because Vibrio cholerae is a bacterium, not a virus, and Vibrio cholerae O139 is a specific serogroup, not a different bacterium.
**Clinical Pearl / High-Yield Fact**
The emergence of new serogroups of Vibrio cholerae, such as O139, highlights the ongoing threat of cholera as a global health issue and the need for continued vaccination efforts and public health measures to prevent outbreaks.
**Correct Answer: C. Vibrio cholerae O139**