Which of the following is characteristic of a single-exposure, common-vehicle outbreak?

Question 1

Endemic means that a disease:

a. Occurs clearly in excess of normal expectancy

b. Is habitually present in human populations

c. Affects a large number of countries simultaneously

d. Exhibits a seasonal pattern

e. Is prevalent among animals

Question 2

The first table shows the total number of persons who eat each of two specified food items that were possibly ifeffective with group A streptococci. The second table shows the number of sick persons (with acute sore throat) who eat each of the various specified combinations of the food items.

Total number of persons who ate each   specified combination of food items

Ate   Tuna

Did   not Ate Tuna

Ate   egg salad



Did   not egg salad



Total   number of persons who ate each specified combination of food items & who   later became sick (with acute sore throats)

Ate   Tuna

Did   not Ate Tuna

Ate   egg salad



Did   not egg salad



What is the sore throat attack rate in persons who ate both egg salad & tuna

a. 60/75

b. 70/200

c. 60/133

d. 60/275

e. None of the above

Question 3

According to the results shown in the preceding tables, which of the following food items (or combination of food items) is most likely to be infective?

a. Tuna only

b. Egg salad only

c. Neither tuna nor egg salad

d. Both tuna & egg salad

e. Cannot be calculated from the data

Question 4

In the study of an outbreak of an infectious disease, plotting an epidemic curve is useful because:

a. It helps to determine what type of an outbreak (e.g. single-source, person-to-person) has occurred

b. It shows whether herd immunity has occurred

c. It helps to determine the median incubation period

d. A & c

e. A,b, & c

Question 5

Which of the following is characteristic of a single-exposure, common-vehicle outbreak?

a. Frequent secondary cases

b. Increasing severity with increasing age

c. Explosive

d. Cases include both people who have been exposed & those who were not exposed

e. All of the above