Epi Tools Everyone Can Use
Emily Mosites, MPH
Alice Green, DVM
Katie Garman, MPH
Objectives
• Review concepts from regional outbreak
training
– Line list
– Resources for outbreaks
• Demonstrate use of statistical software to
develop
– Epi-curve
– Symptom profile
– 2x2 tables (OR, RR)
• Data management/ analysis tips
Regional Outbreak Training
Objectives
• Provide Regional Health Departments with
tools to investigate clusters and outbreaks
• Today: foodborne diseases
– Concepts are generalizable
• Promote collaboration and understanding
between epidemiologists/CEDS staff,
environmentalists, and laboratorians
– “Epi-Ready” model
The “Stool”
Foodborne illness
investigations
Epi
Tools
Foodborne illness
investigations
Tools
• Many tools you can use
• Today’s focus
– Excel
– SAS
– EpiInfo
Compile a Line list: Excel
Data Entry Tips
• Blank does not equal “No”
• Single-word variable name
• Use 1= yes & 0= no OR 1=yes & 3=no
– Proper alignment to calculate RR
Analysis in Excel
Why Excel?
If you don’t want to start having dreams
in SAS code
If you have never heard of EpiInfo
If you find yourself doing analysis in the
middle of the woods with only
Microsoft ® Office™
USE EXCEL!!!
Overview
• Summarizing Data with PivotTables
• RR, OR, and Chi Squares Test Page
• Incubation period and EpiCurve
We will send you an excel workbook with
these formulas and explanations!
Why use SAS in an
outbreak investigation?
• It’s powerful
•Fisher’s exact
•Easy to screen large numbers of variables
• It’s subsidized by CDC
• It’s fun!!
• Embrace your dorkiness
Fisher’s Exact Test
Meal Date (exposure)
Illness Onset Date
End Illness Date
• Why use Epi-Info (Version 3.5.1)
– Easy
• Point and click
• Rapid questionnaire development
• Simple commands
– Accessible
• available anywhere at anytime at www.cdc.gov
– FREE
www.cdc.gov/epiinfo
Click on analyze data
Click on Read
(Import)
Select the
correct data
format
Find your file
Make sure all of
your records have
been imported
Start looking at your data
Type “=1” to select those
who were sick
Select your
variable
Select
List
Select your variable
Sick = 1 is selected
To unselect click on cancel select
Create symptom profile
using frequency command
Frequencies
Select
your
variables
Stratify
by sick
Symptom Profile
Develop an epi curve using
the graph command
Select Bar
Graph
Choose onset date
Calculating relative risk or
odds ratio using the tables
command
Remember…
• In order to calculate
RR
– 1= yes
– 3= no
BBQ
No
BBQ
0
well
15
1
ill
20
20
5
RR= 15/(15+20) = 0.53
20/(20+5)
BBQ
No
BBQ
1
ill
20
3
well
15
5
20
RR= 20/(20+15) = 2.85
5/(5+20)
Add
exposure
variable
Add outcome variable
BBQ Chicken
Sweet Tea
Resources for Outbreaks
http://health.state.tn.us/ceds/resources.htm
Modifiable gastrointestinal
outbreak questionnaires
Sample databases
Thank you!
• Connie Robinson and staff
• Rand Carpenter
• John Dunn
Questions
• Emily: Emily.Mosites@tn.gov
• Alice: Alice.Green@tn.gov
• Katie: Katie.Garman@tn.gov
615-741-7247