L32

Question 1

What is the epidemiological triad?

Answer 1

Host, agent, environment

United by a vector

Question 2

What is the example for direct transmission?

Answer 2

Person to person

Question 3

What are the 2 examples of indirect transmission?

Answer 3

Common vehicle (air, water, food)
Vector (insect, animal)

Question 4

Define outbreak. What is the rate equation?

Answer 4

Increased event incidence vs expected rates
= new cases/population at risk
Depends on type of outbreak & setting

Question 5

How many infected people determine a foodborne disease outbreak?

Answer 5

2+ related illness following consumption of common food item

Question 6

What are the 3 aspects of a case definition?

Answer 6

1. Time & place
2. Restrictions: person details like age, gender, ethnicity
3. Clinical criteria: symptoms & clinical tests

Question 7

What are limits that challenge the development of case definition?

Answer 7

New definition of the disease
Emerging clinical picture
Lab tests are limited or not definitive

Question 8

Define sensitivity, include the equation.

Answer 8

Correctly identify new infection

= a/a+c

Question 9

Define specificity, include the equation.

Answer 9

True negatives - people who don’t have infection

= d/b+d

Question 10

Why do you want lower false positives?

Answer 10

Increases positive predictive value (PPV)

Question 11

What is the x axis for the epidemic curve? Y axis?

Answer 11

X = time (period, used in rate calculation)
Y = # cases

Question 12

What are the options for the shape of the epidemic curve?

Answer 12

Single exposure
Multiple exposure
Continuous exposure
Person to person transmission

Question 13

What are 2 things your disease hypothesis should contain?

Answer 13

Source of infection

Mode of transmission

Question 14

What are 2 tools for depict the data about your hypothesis? What about studies you could do?

Answer 14

1. Epidemic curve
2. Line listing = descriptive
   Studies:
   Case control = most common
   - CALCULATE OR!
   Cohort