INFECTIOUS DISEASE EPIDEMIOLOGY
EXAM QUESTIONS WITH VERIFIED
ANSWERS
What are some examples of INDIRECT routes of transmission? - ANSWER-1. food-
borne
2. water-borne
3. vector-borne
4. air-borne
5. ting-borne
What are some pathogens/diseases that cross the placenta? - ANSWER-Toxoplasma
gondii - toxoplasmosis
Treponema palidum - syphilis
Listeria monocytogenes - listeriosis
Cytomegalovirus - usually asymptomatic
Parvovirus - erythema infectiosum
Lentivirus (HIV) - AIDS
Rubivirus - German measles (rubella)
What are the two different types of vector transmission? - ANSWER-1. mechanical - on
the BODIES of insects
2. biological - insect bites
What are the dynamics of infectiousness AFTER infection? - ANSWER-1. latent period
2. infectious period
3. non-infectious period
What are the dynamics of disease AFTER infection? - ANSWER-1. incubation period
2. symptomatic period
3. non-diseased
What is the first case of an infectious disease that is identified? - ANSWER-index
What is the "primary" case of an infectious disease? - ANSWER-the case that brings
the infection into a population
What is the "attack rate"? - ANSWER-#ill/#exposed
What is the epidemiologic triad that contributes to disease? - ANSWER-1. agent of
infection (infectivity, pathogenicity, virulence, immunogenicity, survival)
2. host (age, sex, genotype, behavior, nutritional and health status)
3. environment (weather, housing, geography, air quality, food)
, How is infectivity defined and measured? - ANSWER-ability to infect
# infected / # susceptible
How pathogenicity defined and measured? - ANSWER-ability to cause disease
# with clinical disease / # infected
How is virulence defined and measured? - ANSWER-ability to cause death
# of deaths / # of people with the disease
What are the components of the "chain of infection"? - ANSWER-infectious agents
reservoir
portals of exit
means of transmission
portals of entry
susceptible host
What are the 5 classes of infectious agents? - ANSWER-1. bacteria
2. viruses
3. fungi
4. protoctists/protozoa
5. helminths
What is a reservoir? - ANSWER-a host that carries a pathogen without injury to itself
and serves as a source of infection for other host organisms
*asymptomatic infective carriers*
T or F: reservoirs are the same as vectors - ANSWER-FALSE
What is a vector? - ANSWER-a host that carries a pathogen without injury to itself and
spreads the pathogen to susceptible organisms
*asymptomatic carriers of pathogens*
What are some examples of arthropod vectors? - ANSWER-Mosquitoes - arbovirus,
plasmodium
Fleas - Yersinia
Ticks - Borrelia, R. prowazeki
Tsetse flies - trypanozoma
Simulium flies - onchocerca
What are the four steps of Koch's postulates? - ANSWER-1. the same organism is
present in EVERY case
2. organism is isolated or grown in pure culture
3. disease can be reproduced in healthy animal after infection with pure culture
4. IDENTICAL pathogen can be reisolated from the experimental animals
EXAM QUESTIONS WITH VERIFIED
ANSWERS
What are some examples of INDIRECT routes of transmission? - ANSWER-1. food-
borne
2. water-borne
3. vector-borne
4. air-borne
5. ting-borne
What are some pathogens/diseases that cross the placenta? - ANSWER-Toxoplasma
gondii - toxoplasmosis
Treponema palidum - syphilis
Listeria monocytogenes - listeriosis
Cytomegalovirus - usually asymptomatic
Parvovirus - erythema infectiosum
Lentivirus (HIV) - AIDS
Rubivirus - German measles (rubella)
What are the two different types of vector transmission? - ANSWER-1. mechanical - on
the BODIES of insects
2. biological - insect bites
What are the dynamics of infectiousness AFTER infection? - ANSWER-1. latent period
2. infectious period
3. non-infectious period
What are the dynamics of disease AFTER infection? - ANSWER-1. incubation period
2. symptomatic period
3. non-diseased
What is the first case of an infectious disease that is identified? - ANSWER-index
What is the "primary" case of an infectious disease? - ANSWER-the case that brings
the infection into a population
What is the "attack rate"? - ANSWER-#ill/#exposed
What is the epidemiologic triad that contributes to disease? - ANSWER-1. agent of
infection (infectivity, pathogenicity, virulence, immunogenicity, survival)
2. host (age, sex, genotype, behavior, nutritional and health status)
3. environment (weather, housing, geography, air quality, food)
, How is infectivity defined and measured? - ANSWER-ability to infect
# infected / # susceptible
How pathogenicity defined and measured? - ANSWER-ability to cause disease
# with clinical disease / # infected
How is virulence defined and measured? - ANSWER-ability to cause death
# of deaths / # of people with the disease
What are the components of the "chain of infection"? - ANSWER-infectious agents
reservoir
portals of exit
means of transmission
portals of entry
susceptible host
What are the 5 classes of infectious agents? - ANSWER-1. bacteria
2. viruses
3. fungi
4. protoctists/protozoa
5. helminths
What is a reservoir? - ANSWER-a host that carries a pathogen without injury to itself
and serves as a source of infection for other host organisms
*asymptomatic infective carriers*
T or F: reservoirs are the same as vectors - ANSWER-FALSE
What is a vector? - ANSWER-a host that carries a pathogen without injury to itself and
spreads the pathogen to susceptible organisms
*asymptomatic carriers of pathogens*
What are some examples of arthropod vectors? - ANSWER-Mosquitoes - arbovirus,
plasmodium
Fleas - Yersinia
Ticks - Borrelia, R. prowazeki
Tsetse flies - trypanozoma
Simulium flies - onchocerca
What are the four steps of Koch's postulates? - ANSWER-1. the same organism is
present in EVERY case
2. organism is isolated or grown in pure culture
3. disease can be reproduced in healthy animal after infection with pure culture
4. IDENTICAL pathogen can be reisolated from the experimental animals
