Deck 2: The Dynamics of Disease Transmission

Question 1

What is the name of the occurrence of a clearly higher than expected number of cases of a disease within a limited geographical region?

A) Pandemic
B) Epidemic
C) Endemic
D) Zoonosis
E) Attack rate

Answer 1

B
The definition of epidemic is precisely the occurrence of a clearly higher than habitual number of cases of a disease within a certain geographic region.Pandemic refers to a worldwide epidemic.Endemic refers to the habitual occurrence.Zoonosis describes a disease that is transmitted from animals to humans.

Question 2

The population of Oriol City in June 2018 was 612,437.According to the Oriol City's health department,there were 329 new cases of Raven's disease during 2018.Counting those new cases,by December 31 it was estimated that there were 6580 persons with Raven's disease in Oriol City.What was the incidence rate of Raven's disease in 2018?

A) 26 per 100,000 population
B) 33 per 100,000 population
C) 54 per 100,000 population
D) 1074 per 100,000 population
E) 5000 per 100,000 population

Answer 2

C
The numerator to calculate the incidence rate is the total number of new cases (329),and the denominator is the total number of people who were at risk of developing the condition (in this case we use the population at the middle of that period,612,437).We express the incidence rate per 100,000 to avoid the decimals: 329/612,437 = 0.000537 × 100,000 = 53.7.

Question 3

There was a food poisoning outbreak on April 1,2018,at the City Z Food Safety Conference.There were 1,000 people registered for the conference with luncheon,100 volunteers to host attendees,and 50 people who served the luncheon during the conference.Except for 50 people who served the food,all of the participants and volunteers ate the food from the luncheon at the conference on April 1,2018.After an initial outbreak of food poisoning is reported,an epidemiologist sends surveys to all people at risk to investigate the cause.However,only 900 people among those at risk answer the survey.After analysis of 900 survey results,the epidemiologist concludes that the most suspected foods in the outbreak are pepperoni pizza and meatball spaghetti.What is the most suspected food for food poisoning after cross-tabulation? Use the following table to answer the question. Summary of Survey Responses

A) Pepperoni pizza only
B) Meatball spaghetti only
C) Both pepperoni pizza and meatball spaghetti
D) Neither pepperoni pizza nor meatball spaghetti
E) We cannot determine the cause of food based on this information

Answer 3

A
Pepperoni pizza only attack rate is 41.09% (113 divided by 275),and meatball spaghetti only is 16.53% (62 divided by 375).The attack rate of both pepperoni pizza and meatball spaghetti is 38.00% (57 divided by 150).Some may choose both of them which are the most suspected food.If both the foods were the most suspected food,we should have a higher attack rate in meatball spaghetti only group as well.

Question 4

During the conquest of Mexico,outbreaks played an important role that favored the Spaniards.There were several outbreaks of smallpox that killed thousands of natives.Smallpox was introduced into America by the Europeans.Why were the natives particularly afflicted by smallpox outbreaks?

A) Among natives, the proportion of susceptibles was higher.
B) Among Spaniards, the proportion of immunes was extremely low.
C) Spaniards had the cure for smallpox.
D) Natives had a gene that made them more prone to die from smallpox.
E) Spaniards were protected from smallpox because they had armors.

Question 5

Which term most accurately describes the following definition? "The occurrence in a community or region of cases of an illness,specific health-related behavior,or other health-related events clearly in excess of normal expectancy." [Porta M,ed.A Dictionary of Epidemiology.New York: Oxford University Press; 2014.]

A) Endemic
B) Epidemic
C) Pandemic
D) Attack rate
E) Incubation period

Question 6

Malaria is a parasitic disease transmitted by the Anopheles mosquito bite.This mode of transmission is called

A) direct.
B) single exposure.
C) multiple exposure.
D) mosquitosis.
E) vector.

Question 7

There was a food poisoning outbreak on April 1,2018,at the City Z Food Safety Conference.There were 1,000 people registered for the conference with luncheon,100 volunteers to host attendees,and 50 people who served the luncheon during the conference.Except for 50 people who served the food,all of the participants and volunteers ate the food from the luncheon at the conference on April 1,2018.Based only on the information given in this question,how many people are at risk in this food poisoning outbreak?

A) 1,000
B) 1,100
C) 1,150
D) 150
E) 50

Question 8

There was a food poisoning outbreak on April 1,2018,at the City Z Food Safety Conference.There were 1,000 people registered for the conference with luncheon,100 volunteers to host attendees,and 50 people who served the luncheon during the conference.Except for 50 people who served the food,all of the participants and volunteers ate the food from the luncheon at the conference on April 1,2018.After an initial outbreak of food poisoning is reported,an epidemiologist sends surveys to all people at risk to investigate the cause.However,only 900 people among those at risk answer the survey.After analysis of 900 survey results,the epidemiologist concludes that the most suspected foods in the outbreak are pepperoni pizza and meatball spaghetti.What is the overall attack rate for those who ate meatball spaghetti? Use the following table to answer the question. Summary of Survey Responses

A) 41%
B) 38%
C) 27%
D) 40%
E) 23%

Question 9

What is the most accurate definition of the incubation period (of an infectious disease)?

A) The time of onset of clinical illness or the onset of recognizable symptoms
B) The interval from receipt of infection to the time of onset of clinical illness (the onset of recognizable symptoms)
C) The time of invasion by an infectious agent
D) The time between initiation of infection and first shedding or excretion of the agent
E) The period between exposure and the onset of infectiousness

Question 10

An outbreak of measles occurred in City A.There were 1,000 confirmed cases among children younger than 10 years old.Unfortunately,50 children died of measles.Fifty represent 5% of the total number of cases.What concept is being illustrated in this example?

A) Attack rate
B) Secondary attack rate
C) Case-fatality rate
D) Incubation period
E) Subclinical disease

Question 11

The population of Oriol City in June 2018 was 612,437.According to the Oriol City's health department,there were 329 new cases of Raven's disease during 2018.Counting those new cases,by December 31 it was estimated that there were 6580 persons with Raven's disease in Oriol City.What was the prevalence of Raven's disease in 2018?

A) 26 per 100,000 population
B) 33 per 100,000 population
C) 54 per 100,000 population
D) 1074 per 100,000 population
E) 5000 per 100,000 population