1) A commensal bacterium

1. A) does not receive any benefit from its host.
2. B) is beneficial to its host.
3. C) may also be an opportunistic pathogen.
4. D) isn't capable of causing disease in its host.
5. E) always causes disease in its host.

Answer: C

2) Which of the following statements is TRUE?

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

Answer: E

3) A nosocomial infection is

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

Answer: B

4) The major significance of Robert Koch's work is that

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

Answer: D

5) Which of the following is NOT a verified exception in the use of Koch's postulates?

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

Answer: E

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

1. A) botulism
2. B) tuberculosis
3. C) measles
4. D) the common cold
5. E) diphtheria

Answer: A

7) Biological transmission differs from mechanical transmission in that biological transmission

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

Answer: C

8) Which of the following definitions is INCORRECT?

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

Answer: B

9) Focal infections initially start out as

1. A) sepsis.
2. B) bacteremia.
3. C) local infections.
4. D) septicemia.
5. E) systemic infections.

Answer: C

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

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

Answer: C

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

1. A) bacteremia
2. B) focal infection
3. C) local infection
4. D) septicemia
5. E) systemic infection

Answer: D

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

1. A) antibiotic resistance
2. B) lapse in aseptic techniques
3. C) gram-negative cell walls
4. D) lack of handwashing
5. E) lack of insect control

Answer: C

13) Transient microbiota differ from normal microbiota in that transient microbiota

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

Answer: D

14) Which of the following statements about nosocomial infections is FALSE?

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

Answer: E

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

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

Answer: C

16) Which of the following is NOT a reservoir of infection?

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

Answer: E

17) Which of the following is NOT a communicable disease?

1. A) malaria
2. B) AIDS
3. C) tuberculosis
4. D) tetanus
5. E) typhoid fever

Answer: D

18) Which of the following is a fomite?

1. A) water
2. B) droplets from a sneeze
3. C) pus
4. D) insects
5. E) a hypodermic needle

Answer: E

19) Which of the following statements about biological transmission is FALSE?

1. A) The pathogen reproduces in the vector.
2. B) The pathogen may enter the host in the vector's feces.
3. C) Houseflies are an important vector.
4. D) The pathogen may be injected by the bite of the vector.
5. E) The pathogen may require the vector as a host.

Answer: C

20) Which of the following definitions is INCORRECT?

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

Answer: E

21) Symptoms of disease differ from signs of disease in that symptoms

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

Answer: A

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

1. A) ecology.
2. B) epidemiology.
3. C) communicable disease.
4. D) morbidity and mortality.
5. E) public health.

Answer: B

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

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

Answer: D

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

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

Answer: E

25) Which of the following pairs is mismatched?

1. A) malaria — vector
2. B) salmonellosis — vehicle transmission
3. C) syphilis — direct contact
4. D) influenza — droplet infection
5. E) None of the pairs is mismatched.

Answer: E

26) Which of the following can contribute to postoperative infections?

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

Answer: E

In Figure 14.2, when is the prevalence the highest?

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

Answer: C

28) A cold transmitted by a facial tissue is an example of

1. A) direct contact.
2. B) droplet transmission.
3. C) fomite.
4. D) vector.
5. E) vehicle transmission.

Answer: E

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

1. A) analytical
2. B) case control
3. C) descriptive
4. D) experimental
5. E) prodromal

Answer: C

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

1. A) subacute.
2. B) subclinical.
3. C) latent.
4. D) zoonotic.
5. E) acute.

Answer: C

32) A needlestick is an example of

1. A) direct contact.
2. B) droplet transmission.
3. C) indirect contact transmission by fomite.
4. D) direct biological transmission by vector.
5. E) vehicle transmission.

Answer: C

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

1. A) lifestyle
2. B) genetic background
3. C) climate
4. D) occupation
5. E) All of these are predisposing factors of disease.

Answer: E

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

1. A) urinary tract infections
2. B) pneumonia
3. C) salmonellosis
4. D) tetanus
5. E) anthrax

Answer: A

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

1. A) prodromal
2. B) decline
3. C) convalescence
4. D) incubation
5. E) both incubation and convalescence

Answer: E

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.

36) Situation 14.1 is an example of

1. A) human reservoirs.
2. B) a zoonosis.
3. C) a nonliving reservoir.
4. D) a vector.
5. E) a focal infection.

Answer: B

37) The etiologic agent of the disease in Situation 14.1 is

1. A) sheep.
2. B) soil.
3. C) Coxiella burnetii.
4. D) pneumonia.
5. E) wind.

Answer: C

38) The method of transmission of the disease in Situation 14.1 was

1. A) direct contact.
2. B) droplet.
3. C) indirect contact.
4. D) vector-borne.
5. E) vehicle.

Answer: E

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

1. A) acid production by bacteria
2. B) bacteriocin production
3. C) bacteria occupying host receptors
4. D) bacteria causing disease
5. E) bacteria producing vitamin K

Answer: D

40) The yeast Candida albicans does not normally cause disease because of

1. A) symbiotic bacteria.
2. B) antagonistic bacteria.
3. C) parasitic bacteria.
4. D) commensal bacteria.
5. E) other fungi.

Answer: B

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

1. A) incubation.
2. B) illness.
3. C) decline.
4. D) convalescence.

Answer: B

42) Which one of the following is NOT a zoonosis?

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

Answer: E

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

1. A) communicable disease.
2. B) latent infection.
3. C) nosocomial infection.
4. D) sporadic disease.
5. E) None of the answers is correct.

Answer: C

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

1. A) endemic level.
2. B) epidemic level.
3. C) sporadic infection.
4. D) communicable disease.
5. E) pandemic.

Answer: B

45) Which of the following statements is FALSE?

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

Answer: C

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

Answer: TRUE

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

Answer: TRUE

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

Answer: FALSE

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

Answer: FALSE

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

Answer: FALSE

6) Compromised hosts are always suffering from suppressed immune systems.

Answer: FALSE

7) A host is not considered diseased until an infection changes one's state of health.

Answer: TRUE

8) Reservoirs of infections are always animate objects.

Answer: FALSE

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

Answer: FALSE

10) Both normal and transient flora can become opportunistic pathogens.

Answer: TRUE