Epidemiological Curve

Epidemiological curves or “epi curves” can shed light on whether

  • An outbreak is most likely due to a point source or person-to-person transmission
  • An outbreak is increasing or waning
  • The pathogen has a long or short incubation period

Create an epi curve

Create an epi curve using the Generate an Epi Curve [2 sheets] template.

The template consists of an Excel file with two worksheets. Entering information into the first worksheet (Case Data) will automatically construct an epi curve in the second worksheet (Epi Curve). The resulting histogram will illustrate the number of cases of respiratory disease over time.

Step 1: Click on the Case Data tab at the bottom of the workbook. Replace the generic dates (“Date 1”, etc.) with the range of illness onset dates for the cases. Enter the number of cases in the row and column that corresponds with the appropriate illness onset date and case classification category.

Categories include:

  • Confirmed cases (column B)
  • Probable cases (column C)
  • Suspect cases (column D)

Step 2: Click on the Epi Curve tab at the bottom of the workbook to see the graph automatically populated. Make changes by right clicking on the graph and selecting the appropriate option or by changing data in the Case Data worksheet.

See Quick Learn: Using an Epi Curve and Interpreting Epidemic Curves During Foodborne Outbreaks for information on interpreting an epi curve.