An epi curve can be used to infer which aspects of an outbreak?

• A. The exact pathogen name
• B. The geographic origin of the outbreak
• C. The exposure period and overall outbreak pattern
• D. The final case fatality rate

Answer: (C)

An epi curve plots cases by date of onset, letting you see how an outbreak unfolds over time. From this, you can infer the exposure period and the overall outbreak pattern. A sharp, single peak after a brief window points to a point-source exposure with a short incubation period; a longer, gradual rise and fall suggests a common source over an extended period; multiple waves indicate ongoing person-to-person or propagated spread. This timing information helps you estimate when people were exposed and how the outbreak evolves, which is crucial for guiding interventions. The curve alone can’t reveal the exact pathogen name (that requires lab testing), geographic origin (needs location data and investigation), or the final case fatality rate (which needs outcomes data and the total number of cases).