Outbreak Investigation

Question 1

What are the steps in outbreak investigation?

Answer 1

Confirm
Describe
Determine Cause
Control

Question 2

Hospitals are seeing an increase of Salmonellosis cases in a certain county. Is this an outbreak?

Answer 2

Yes. An outbreak is an excess of cases in a geographic region.

Question 3

One case of rabies is reported in a dog in St Kitts. Is this an outbreak?

Answer 3

Yes. Since St Kitts is a rabies free country (haha), only one case is needed to be considered an outbreak.

Question 4

What are some variables in defining whether there is truly an outbreak?

Answer 4

What is the baseline for that disease?

Are we just testing more than before?

Was there a lab error?

Has there been an increase in population since the baseline was determined before?

Question 5

On the state/regional level, surveillance programs, pathologists, doctors, and the public are usually the ones detecting an outbreak. How is an outbreak detected in a farm setting?

Answer 5

Unusual morbidity, mortality, production, or reproductive losses.

Question 6

Give 2 MAIN reasons to investigate an outbreak

Answer 6

Identify the source

Prevent more outbreaks

Question 7

When describing an outbreak, you have to establish a case definition. What factors are included in a case definition?

Answer 7

Person
Place
Time
Clinical features

Question 8

If 11 out of 59 people eating at a restaurant at a certain time contract Salmonella from the food, what is the exposed population?

Answer 8

The 59 people eating at the restaurant

Question 9

Case identification for non-communicable diseases involves testing the entire exposed population to identify all potential cases. How is case identification performed for communicable diseases?

Answer 9

Investigate all contacts of the case

Question 10

What is the case fatality rate (CFR)?

Answer 10

Number of deaths among those who have the disease during a time interval

Question 11

Describing the clinical features of a disease to define a case definition includes what factors?

Answer 11

Clinical signs

Lab results

Pattern: attack rate and CFR

Question 12

What can we use for a spatio-temporal disease description?

Answer 12

Epidemic curve graphs

Spot maps (location)

Question 13

T/F: It is necessary to identify the responsible agent in order to perform a full outbreak investigation?

Answer 13

FALSE

Question 14

What are the possible hypotheses we can formulate to determine the cause of an outbreak?

Answer 14

Possible source

Likely agent

Best approach for control of the agent

Most likely method of transmission

Question 15

What are the 5 steps to describing an outbreak?

Answer 15

Establish a case definition

Case identification

Clinical observation

Spatio-temporal description

ID responsible agent (sometimes)