Epidemiology Flashcards
The total population disease burden at a specific point in time is referred to as the:
a. ratio.
b. mortality.
c. incidence.
d. prevalence.
e. attributable fraction.
D
Herd immunity is least affected by:
a. antigenic portion of the agent.
b. antigenic stability of the agent.
c. serologic epidemiology.
d. random distribution of immune individuals within the herd.
e. movements of individuals within the population.
C
Which of the following characteristics of a biological agent is most likely to be seen in a disease which occurs in epidemic proportions?
a. High infectivity.
b. High pathogenicity.
c. High virulence.
d. Low antigenicity.
e. Viability.
A
Brucellosis, a bacterial zoonosis, and Q Fever, a rickettsial zoonosis, have one important epidemiological characteristic in common:
a. both have a high mortality rate in animals.
b. both are transmitted by swine.
c. they can be prevented by vaccination.
d. both cause pulmonary disease in man.
e. the reproductive and accessory reproductive organs serve as the principle source of environmental contamination.
E
Which one of the following frustrations would you most likely expect in preparing to carry out cohort studies on animal disease?
a. Costly and time consuming, and plagued by the continual changing of the cohort.
b. Difficult time in selecting a comparison group or control population upon which to test your hypothesis.
c. Cohort populations are unchanging, and that no new individuals are introduced into the study population.
d. Data collected retrospectively is often incomplete, and plagued by high degrees of institutional bias.
e. Unable to get accurate estimates of incidence or prevalence of the disease using the cohort study technique.
A
A measure of the spread of an infectious disease among susceptibles following exposure to a primary case is known as the:
a. period prevalence rate.
b. secondary attack rate.
c. proportional attack rate.
d. morbidity rate.
e. prevalence rate.
B
The time necessary after acquisition of infection for an agent to multiply sufficiently to be transmitted by an arthropod is the:
a. extrinsic incubation period.
b. infectivity period.
c. vector circadian period.
d. pre-latent period.
e. latent period.
A
The term “3 host tick” refers to:
a. ticks can carry infection to only three species of animals.
b. ticks can carry three different diseases at one time.
c. the tick goes through feeding of blood meals on three different hosts to complete its life cycle.
d. the adult tick can live three years on one host.
e. the larval stage must feed on three different hosts to complete cycle
C
Using the following 2X2 display, which relationship correctly depicts the specificity of a diagnostic test?
] Disease ] No Disease ]
] ] ]
Positive ] A ] B ] A + B
] ] ]
Negative ] C ] D ] C + D
] ] ]
] A + C ] B + D ]
] ] ]
a. A/(C+D)
b. D/(A+B)
c. A/(A+C)
d. D/(B+D)
e. A/(C+D)
D
A disease which tends to be localized in space and time is called:
a. outbreak.
b. sporadic.
c. enzootic.
d. pandemic.
e. epizootic.
A
What study plan would be best to determine the effectiveness of a new vaccine in preventing disease in humans?
a. Case-control study.
b. Cohort study.
c. Prevalence study.
d. Morbidity study.
e. Retrospective study.
B
A certain causal factor is thought to be associated with an extremely rare disease. What study plan would yield the best data with limited financial and human resources.
a. Prevalence study.
b. Case-control study.
c. Prevalence study.
d. Morbidity study.
e. Case evaluation study.
B
Which of the following factors is least likely to influence the rate of spread of a disease?
a. Infectivity of the agent.
b. Number of susceptible hosts.
c. Number of sources.
d. Virulence of the agent.
e. Percentage of immunes.
D
When considering instituting a vaccine program against a particular disease, which of the following factors should be of least concern?
a. local prevalence of disease.
b. viability of disease agent.
c. immunogenicity of vaccine.
d. antigenic stability of the agent.
e. exposure potential of the herd.
B
One of your clients has a feedlot containing 15,000 cattle, 10,000 of which are susceptible. In a current outbreak of disease, 3,000 became sick and 300 died. The case fatality rate was:
a. 10%
b. 25%
c. 2%
d. 30%
e. 3%
A
An organism which is highly immunogenic can still produce a second infection in the same individual if it has high:
a. pathogenicity.
b. virulence.
c. antigenicity.
d. mutability.
e. antigenic portion.
D
The essential difference between infection and disease is:
a. immune status.
b. pathogenicity.
c. virulence.
d. portal of entry.
e. shedding of organism.
B
You are studying a group of 25 cattle, 20 angus and 5 Holsteins. Using a table of random numbers you select a sample of 5 cattle from the population. They turn out to be 5 Holsteins. This is a:
a. representative sample.
b. random sample.
c. stratified random sample.
d. invalid sample.
e. personally biased sample.
B