LSAT 154, Section 3, RC Passage 3, Cholera

RC Passage 3 Explanation

Paragraph Summaries

1. Scientists wonder what happens to V. cholerae during the times between epidemics, and how it could arise in places where it was thought to be eradicated.
2. Against biologists’ skepticism, Colwell used a new antibody test and proved that V. cholerae could survive in seawater, and couldn’t always be cultured, and thus, doesn’t require a human host.
3. Colwell’s research shows bacteria like V. cholerae enter unculturable dormant states when the environment doesn’t favour reproduction. She hypothesizes changes in seawater temperature or salinity awakens the bacteria from dormancy.

Analysis

This is a pretty straightforward sciences passage talking about cholera. We start with question in paragraph 1, which the rest of the passage sought to answer.

In paragraph 1, we wonder how cholera outbreaks arise when there hasn’t been a recent epidemic. The underlying assumption is that the bacterium requires a human host to survive.

Paragraph 2 talks about the outbreaks in Chesapeake Bay and New Orleans, and how Colwell realized that people mistakenly believed V. cholerae wasn’t present in the water just because it couldn’t be detected by culture methods. She develops a new antibody test and proves that V. cholerae was in the water.

The final paragraph answers passage 1’s question, which is what happens to V. cholerae in between epidemics. Colwell’s studies found the bacterium goes dormant, and thus unculturable, when the environment isn’t favourable. Though no one knows for sure what causes the bacterium to awaken, Colwell believes it can be due to seawater temperatures or salinity.