Overview of Outbreak Investigations

Question 1

Goals of an outbreak investigation:

Answer 1

-To identify the source of illness
-To guide public health intervention

Question 2

Ways to recognize an outbreak:

Answer 2

-Routine surveillance activities
-Reports from clinicians and laboratories
-Reports from affected individuals

Question 3

Why investigate an outbreak?

Answer 3

-Characterize a public health problem
-Identify preventable risk factors
-Provide new research insights into disease
-Train health department staff in methods of
public health investigations and emergency
response

Question 4

Steps of an outbreak
investigation

Answer 4

-1. Verify the diagnosis and confirm the
outbreak
-2. Define a case and conduct case finding
-3. Tabulate and orient data: time, place,
person
-4. Take immediate control measures
-5. Formulate and test hypothesis
-6. Plan and execute additional studies
-7. Implement and evaluate control
measures
-8. Communicate findings

Question 5

Verify the diagnosis and
confirm the outbreak

Answer 5

-Confirm laboratory testing
-Rule out misdiagnoses or laboratory
error

Question 6

Define a case and conduct
case finding
Develop a specific case definition using:

Answer 6

-Symptoms or laboratory results
-Time period
-Location

Question 7

Define a case and conduct
case finding
-Conduct surveillance using case definition:

Answer 7

*Existing surveillance
*Active surveillance (e.g. review medical records)
*Interview case-patients

Question 8

Tabulate and orient data

Answer 8

*Create line listing
*Person
-Who was infected?
-What do the cases have in common?
*Place
-Where were they infected?
-May be useful to draw a map
*Time
-When were they infected?
-Create an epidemic curve

Question 9

Formulate and test hypothesis

Answer 9

*Develop hypotheses
*Conduct an analytic study to test
hypotheses

Question 10

Plan and execute additional
studies

Answer 10

*Environmental sampling
-Collect appropriate samples
-Allow epidemiological data to guide testing
-If analytic study results are conclusive,
don’t wait for positive samples before
implementing prevention

Question 11

Implement and evaluate
control measures

Answer 11

-Eliminating or treating the
source
-Work with regulators, industry, and
health educators to institute measures
-Create mechanism to evaluate both
short- and long-term success

Question 12

Communicate findings

Answer 12

-Identify a single member of the
investigation team to interact with
media and communicate progress and
findings
-Summarize investigation