Deck 14: Principles of Disease and Epidemiology

Question 1

One effect of washing regularly with antibacterial agents is the removal of normal microbiota. This can result in

A) no bacterial growth because washing removes their food source.
B) normal microbiota returning immediately.
C) fewer diseases.
D) increased susceptibility to disease.
E) body odor.

Answer 1

D

Question 2

Which one of the following does NOT contribute to the incidence of nosocomial infections?

A) lack of handwashing
B) lapse in aseptic techniques
C) antibiotic resistance
D) gram-negative cell walls
E) lack of insect control

Answer 2

D

Question 3

Focal infections initially start out as

A) local infections.
B) bacteremia.
C) systemic infections.
D) sepsis.
E) septicemia.

Answer 3

A

Question 4

Which of the following is NOT a reservoir of infection?

A) a sick animal
B) a hospital
C) a sick person
D) a healthy person
E) None of the answers is correct; all of these can be reservoirs of infection.

Question 5

Which of the following definitions is INCORRECT?

A) inapparent: infection characteristic of a carrier state
B) primary infection: an initial illness
C) chronic: a disease that develops slowly and lasts for months
D) acute: a short-lasting primary infection
E) secondary infection: a long-lasting illness

Question 6

Which of the following statements is TRUE?

A) At least one member must benefit in a symbiotic relationship.
B) Members of a symbiotic relationship cannot live without each other.
C) Symbiosis always refers to different organisms living together and benefiting from each other.
D) A parasite is not in symbiosis with its host.
E) Both members are harmed in a symbiotic relationship.

Question 7

A nosocomial infection is

A) always caused by pathogenic bacteria.
B) always caused by medical personnel.
C) only a result of surgery.
D) always present, but is inapparent at the time of hospitalization.
E) acquired during the course of hospitalization.

Question 8

A commensal bacterium

A) always causes disease in its host.
B) is beneficial to its host.
C) does not receive any benefit from its host.
D) isnʹt capable of causing disease in its host.
E) may also be an opportunistic pathogen.

Question 9

Which of the following statements about nosocomial infections is FALSE?

A) They may be caused by drug-resistant bacteria.
B) They may be caused by normal microbiota.
C) They may be caused by opportunists.
D) They occur in compromised patients.
E) The patient was infected before hospitalization.

Question 10

The rise in herd immunity amongst a population can be directly attributed to

A) vaccinations.
B) improved handwashing.
C) increased use of antibiotics.
D) antibiotic-resistant microorganisms.
E) None of the answers is correct.

Question 11

Transient microbiota differ from normal microbiota in that transient microbiota

A) are always acquired by direct contact.
B) never cause disease.
C) are found in a certain location on the host.
D) are present for a relatively short time.
E) cause diseases.

Question 12

Which of the following diseases is NOT spread by droplet infection?

A) botulism
B) measles
C) tuberculosis
D) the common cold
E) diphtheria

Question 13

Which of the following is a fomite?

A) a hypodermic needle
B) insects
C) water
D) pus
E) droplets from a sneeze

Question 14

Which of the following statements about biological transmission is FALSE?

A) The pathogen may enter the host in the vectorʹs feces.
B) Houseflies are an important vector.
C) The pathogen may be injected by the bite of the vector.
D) The pathogen may require the vector as a host.
E) The pathogen reproduces in the vector.

Question 15

Biological transmission differs from mechanical transmission in that biological transmission

A) requires direct contact.
B) occurs when a pathogen is carried on the feet of an insect.
C) works only with noncommunicable diseases.
D) involves reproduction of a pathogen in an arthropod vector prior to transmission.
E) involves fomites.

Question 16

Which of the following is NOT a communicable disease?

A) malaria
B) AIDS
C) tetanus
D) typhoid fever
E) tuberculosis

Question 17

Which of the following is NOT a verified exception in the use of Kochʹs postulates?

A) Some diseases are noncommunicable.
B) Some diseases are not caused by microbes.
C) Some diseases have poorly defined etiologies.
D) Some pathogens can cause several disease conditions.
E) Some human diseases have no other known animal host.

Question 18

Which of the following definitions is INCORRECT?

A) pandemic: a disease that affects a large number of people in the world in a short time
B) epidemic: a disease that is endemic across the world
C) sporadic: a disease that affects a population occasionally
D) endemic: a disease that is constantly present in a population
E) incidence: number of new cases of a disease

Question 19

The major significance of Robert Kochʹs work is that

A) microorganisms can be cultured.
B) microorganisms cause disease.
C) microorganisms are present in a diseased animal.
D) diseases can be transmitted from one animal to another.
E) microorganisms are the result of disease.

Question 20

Koch observed Bacillus anthracis multiplying in the blood of cattle. What is this condition called?

A) bacteremia
B) systemic infection
C) focal infection
D) local infection
E) septicemia

Question 21

A needlestick is an example of

A) indirect contact transmission by fomite.
B) direct contact.
C) droplet transmission.
D) direct biological transmission by vector.
E) vehicle transmission.

Question 22

Which of the following pairs is mismatched?

A) influenza  droplet infection
B) syphilis  direct contact
C) salmonellosis  vehicle transmission
D) malaria  vector
E) None of the pairs is mismatched.

Question 23

Which of the following can contribute to postoperative infections?

A) errors in aseptic technique
B) using syringes more than once
C) antibiotic resistance
D) normal microbiota on the operating room staff
E) All of the answers are correct.

Question 24

In which of the following patterns of disease does the patient experience no signs or symptoms?

A) incubation
B) prodromal
C) convalescence
D) decline
E) both incubation and convalescence

Question 25

Figure 14.1 Figure 14.1 shows the incidence of influenza during a typical year. Which letter on the graph indicates the endemic level?

A) a
B) b
C) c
D) d
E) The answer cannot be determined based on the information provided.

Question 26

Figure 14.2 In Figure 14.2, when is the prevalence the highest?

A) February
B) January
C) July
D) March
E) The answer cannot be determined based on the information provided.

Question 27

The etiologic agent of the disease in Situation 14.1 is

A) sheep.
B) pneumonia.
C) Coxiella burnetii.
D) soil.
E) wind.

Question 28

A researcher has performed a prospective study on a disease. To which specific kind of epidemiological study is this referring?

A) analytical
B) prodromal
C) case control
D) experimental
E) descriptive

Question 29

Which of the following is NOT a predisposing factor of disease?

A) genetic background
B) occupation
C) lifestyle
D) climate
E) All of these are predisposing factors of disease.

Question 30

Situation 14.1
During a six-month period, 239 cases of pneumonia occurred in a town of 300 people. A clinical case was defined as fever ≥ 39°C lasting >2 days with three or more symptoms (i.e., chills, sweats, severe headache, cough, aching muscles/joints, fatigue, or feeling ill). A laboratory-confirmed case was defined as a positive result for antibodies against Coxiella burnetii. Before the outbreak, 2000 sheep were kept northwest of the town. Of the 20 sheep tested from the flock, 15 were positive for
C. burnetii antibodies. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years.
Situation 14.1 is an example of

A) a vector.
B) a nonliving reservoir.
C) a zoonosis.
D) a focal infection.
E) human reservoirs.

Question 31

The science that deals with when diseases occur and how they are transmitted is called

A) public health.
B) morbidity and mortality.
C) epidemiology.
D) communicable disease.
E) ecology.

Question 32

The yeast Candida albicans does not normally cause disease because of

A) antagonistic bacteria.
B) other fungi.
C) commensal bacteria.
D) symbiotic bacteria.
E) parasitic bacteria.

Question 33

Which of the following is NOT an example of microbial antagonism?

A) acid production by bacteria
B) bacteria causing disease
C) bacteriocin production
D) bacteria occupying host receptors
E) bacteria producing vitamin K

Question 34

The CDC is located in

A) Washington, DC.
B) Atlanta, GA.
C) Los Angeles, CA.
D) New York City, NY.
E) Chicago, IL.

Question 35

A disease in which the causative agent remains inactive for a time before producing symptoms is referred to as

A) subclinical.
B) latent.
C) acute.
D) subacute.
E) zoonotic.

Question 36

In which of the following diseases can gender be considered a viable predisposing factor?

A) pneumonia
B) salmonellosis
C) anthrax
D) urinary tract infections
E) tetanus

Question 37

Symptoms of disease differ from signs of disease in that symptoms

A) are changes felt by the patient.
B) are specific for a particular disease.
C) always occur as part of a syndrome.
D) are changes observed by the physician.
E) None of the answers is correct.

Question 38

A cold transmitted by a facial tissue is an example of

A) fomite.
B) droplet transmission.
C) vector.
D) vehicle transmission.
E) direct contact.

Question 39

Emergence of infectious diseases can be attributed to all of the following EXCEPT

A) antibiotic resistance.
B) climatic changes.
C) ease of travel.
D) new strains of previously known agents.
E) The emergence of infectious diseases can be attributed to all of these.

Question 40

The method of transmission of the disease in Situation 14.1 was

A) direct contact.
B) indirect contact.
C) vehicle.
D) vector-borne.
E) droplet.

Question 41

Figure 14.4
Salmonella Heidelberg gastroenteritis occurred on three cruises aboard the T.S.S. Festivale. Figure 14.4 shows on-board clinic visits for diarrheal illness between February 10 and March 3. Explain the incidence pattern
shown on the graph. What are probable modes of transmission? What changes would you recommend before the ship books more cruises after March 3?

Question 42

A researcher only needs to select a cohort group when implementing an analytical epidemiological study.

Question 43

Figure 14.3 The graph in Figure 14.3 shows the incidence of polio in the United States. The period between 1945 and 1955 indicates a(n)

A) epidemic level.
B) communicable disease.
C) sporadic infection.
D) endemic level.
E) pandemic.

Question 44

Dengue fever, a zoonotic disease, is endemic in northern Mexico, but not in the U.S. Provide two plausible explanations for this dichotomy, and explain.

Question 45

If a prodromal period exists for a certain disease, it should occur prior to

A) convalescence.
B) decline.
C) illness.
D) incubation.

Question 46

For a particular disease at a specific time period, morbidity rates should always be equal or greater than mortality rates.

Question 47

Both normal and transient flora can become opportunistic pathogens.

Question 48

Reservoirs of infections are always animate objects.

Question 49

Which one of the following is NOT a zoonosis?

A) Hantavirus pulmonary syndrome
B) tapeworm
C) rabies
D) cat-scratch disease
E) All of these are zoonoses.

Question 50

Urinary tract infections are the most common forms of nosocomial infections.

Question 51

Which of the following statements is FALSE?

A) S. aureus is differentiated from other mannitol+ cocci by the coagulase test.
B) The M in MRSA stands for mannitol.
C) Antimicrobial therapy for hemodialysis-associated infections increases antibiotic resistance.
D) The USA300 strain accounts for most community-acquired MRSA.
E) The USA100 strain accounts for most hospital-acquired MRSA.

Question 52

A host is not considered diseased until an infection changes oneʹs state of health.

Question 53

Refer to Situation 14.2 What is the normal habitat of this gram -negative, facultatively anaerobic,
non-endospore-forming, lactose-positive rod? Provide a plan for identifying the source of infection and preventing further infection.

Question 54

When studying the epidemiology of a particular disease, why are retrospective studies commonly undertaken before prospective studies?

Question 55

Diseases that are referred to as emerging infectious diseases have only been discovered in the past fifty years.

Question 56

Compromised hosts are always suffering from suppressed immune systems.

Question 57

Pseudomonas bacteria colonized the bile duct of a patient following his liver transplant surgery. This is an example of a

A) nosocomial infection.
B) communicable disease.
C) sporadic disease.
D) latent infection.
E) None of the answers is correct.

Question 58

MMWR is a publication by the CDC that reports on only emerging diseases.

Question 59

Testing the effectiveness of a new drug for anthrax would be best performed as an experimental study.

Question 60

Would you expect all EIDs to be on the notifiable infectious disease list? Explain.