BIO 261 Exam 4 – Powell Practice
Questions and All Correct Answers.
After reading the Microbiology Now which organism is an important risk for HAIs and how was
it spread in the study discussed in the article? What characteristics make this organism a
potential problem? - Answer
Why does epidemiologist acquire population-based data about infectious diseases? - Answer
Distinguish between an endemic disease, an epidemic disease, and a pandemic disease.; -
Answer Endemics are constantly present in a population, usually at low incidences.
Individuals that are infected with a pathogen that causes endemic disease are called reservoirs.
Epidemics occur when people a large number of people in a population at the same time
contract a disease.
Pandemics are widespread, usually worldwide.
Which is more severe, a disease with a high mortality or one with a high morbidity?; - Answer
Mortality is the incidence of death in a population, while morbidity is the incidence of disease,
including both fatal and nonfatal diseases. A disease with high mortality is more severe
What are the stages of a disease? What is an index case?; - Answer 1) Infection (organism
invades and colonizes the host)
2) Incubation period (the time between infection and onset of symptoms)
3) Acute period (disease is at its height)
4) Decline period (disease symptoms are subsiding)
5) Convalescent period (patient regains strength and returns to normal)
An index case is the first person recorded to have a disease
Pathogen must replicate and grow inside a host
2) A well-adapted pathogen will live in balance with its host (chronic infection- when the host
and pathogen survive)
3) New pathogens can emerge for which the host has no resistance (acute infection- pathogen
can be a selective force)
How does herd immunity prevent a nonimmune individual from acquiring a disease? Give an
example.; - Answer One that has contracted a disease will not be able to get the immune
sick thus those immune people wont be able to get the nonimmune sick
, What are the major means of human infectious disease transmission and give examples of
each.; - Answer 1) direct host-to-host (no intermediate needed; i.e. STDs, flu, common cold)
2) indirect host-to-host (pathogen goes to something else/an intermediate before the next host,
a living agent is a vector and a nonliving agent is a fomite; i.e. west nile virus, malaria, the
plague, H. pylori)
What is a zoonotic disease? What is a disease reservoir?; - Answer A zoonotic disease is any
disease that normally infects animals but is occasionally transmitted to humans (i.e. rabies)
Reservoirs are sites in which infectious agents remain viable and from which individuals can
become infected (i.e. soil for Clostridium)
What is the difference between a disease vehicle and a disease vector?; - Answer Disease
vehicles include air, water, food, and bodily fluids
Disease vectors include living agents like arthropods that transmit diseases from one host to
another
Why will a disease such as human rabies likely never be eliminated?; - Answer Because
rabies shows up in animals. Humans are accidental hosts, and all animals cannot be vaccinated.
Distinguish between common-source and host-to-host epidemics. Cite at least one example of
each. Describe how common-source epidemics can be recognized using epidemiological
surveillance data.; - Answer Common-source means the people who were infected with the
disease contracted it from the same source. Usually happens from contamination of food or
water (i.e. cholera); these epidemics can be recognized by the rapid increase in disease
incidence and then you can study where those who were infected have been
Host-to-host is when the disease shows a slow, progressive rise and a gradual decline (i.e.
influenza, Covid, chicken pox)
Distinguish between direct and indirect transmission of disease. Cite at least one example of
each.; - Answer Indirect transmission includes an agent that carries the pathogen from one
host to another; an example is malaria, where mosquitoes are used. Direct transmission is when
the disease is passed from host to host; an example is any STD.
Compare public measures for controlling infectious diseases caused by insect vectors and
human carriers.; - Answer If the reservoir is an animal, it can be immunized or destroyed.
Human reservoirs can be more difficult, but they can be quarantined, immunized, and treated.
This is how smallpox was eradicated
Describe some of the public health activities of the U.S. Centers for Disease Control and
Prevention.; - Answer
Questions and All Correct Answers.
After reading the Microbiology Now which organism is an important risk for HAIs and how was
it spread in the study discussed in the article? What characteristics make this organism a
potential problem? - Answer
Why does epidemiologist acquire population-based data about infectious diseases? - Answer
Distinguish between an endemic disease, an epidemic disease, and a pandemic disease.; -
Answer Endemics are constantly present in a population, usually at low incidences.
Individuals that are infected with a pathogen that causes endemic disease are called reservoirs.
Epidemics occur when people a large number of people in a population at the same time
contract a disease.
Pandemics are widespread, usually worldwide.
Which is more severe, a disease with a high mortality or one with a high morbidity?; - Answer
Mortality is the incidence of death in a population, while morbidity is the incidence of disease,
including both fatal and nonfatal diseases. A disease with high mortality is more severe
What are the stages of a disease? What is an index case?; - Answer 1) Infection (organism
invades and colonizes the host)
2) Incubation period (the time between infection and onset of symptoms)
3) Acute period (disease is at its height)
4) Decline period (disease symptoms are subsiding)
5) Convalescent period (patient regains strength and returns to normal)
An index case is the first person recorded to have a disease
Pathogen must replicate and grow inside a host
2) A well-adapted pathogen will live in balance with its host (chronic infection- when the host
and pathogen survive)
3) New pathogens can emerge for which the host has no resistance (acute infection- pathogen
can be a selective force)
How does herd immunity prevent a nonimmune individual from acquiring a disease? Give an
example.; - Answer One that has contracted a disease will not be able to get the immune
sick thus those immune people wont be able to get the nonimmune sick
, What are the major means of human infectious disease transmission and give examples of
each.; - Answer 1) direct host-to-host (no intermediate needed; i.e. STDs, flu, common cold)
2) indirect host-to-host (pathogen goes to something else/an intermediate before the next host,
a living agent is a vector and a nonliving agent is a fomite; i.e. west nile virus, malaria, the
plague, H. pylori)
What is a zoonotic disease? What is a disease reservoir?; - Answer A zoonotic disease is any
disease that normally infects animals but is occasionally transmitted to humans (i.e. rabies)
Reservoirs are sites in which infectious agents remain viable and from which individuals can
become infected (i.e. soil for Clostridium)
What is the difference between a disease vehicle and a disease vector?; - Answer Disease
vehicles include air, water, food, and bodily fluids
Disease vectors include living agents like arthropods that transmit diseases from one host to
another
Why will a disease such as human rabies likely never be eliminated?; - Answer Because
rabies shows up in animals. Humans are accidental hosts, and all animals cannot be vaccinated.
Distinguish between common-source and host-to-host epidemics. Cite at least one example of
each. Describe how common-source epidemics can be recognized using epidemiological
surveillance data.; - Answer Common-source means the people who were infected with the
disease contracted it from the same source. Usually happens from contamination of food or
water (i.e. cholera); these epidemics can be recognized by the rapid increase in disease
incidence and then you can study where those who were infected have been
Host-to-host is when the disease shows a slow, progressive rise and a gradual decline (i.e.
influenza, Covid, chicken pox)
Distinguish between direct and indirect transmission of disease. Cite at least one example of
each.; - Answer Indirect transmission includes an agent that carries the pathogen from one
host to another; an example is malaria, where mosquitoes are used. Direct transmission is when
the disease is passed from host to host; an example is any STD.
Compare public measures for controlling infectious diseases caused by insect vectors and
human carriers.; - Answer If the reservoir is an animal, it can be immunized or destroyed.
Human reservoirs can be more difficult, but they can be quarantined, immunized, and treated.
This is how smallpox was eradicated
Describe some of the public health activities of the U.S. Centers for Disease Control and
Prevention.; - Answer
