system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do they find who is patient zero?
gpt
Epidemiologists study these things. They carefully take a patient's history, their location, the people they've interacted with, etc. After they've done gathering pertinent data, an analysis is done to highlight common denominators. It's like detective work trying to narrow down things to get to a point.