Deck 14: Host-Microbe Relationships and Disease Processes

Question 1

All of the following pertain to microbial virulence except

A) varies among different microbial species
B) varies within the same species of a pathogen
C) increases with animal passage
D) increases by attenuation

Answer 1

D

Question 2

All of the following refer to the normal microflora except

A) no microflora is found in the fetus
B) resident microorganisms normally do not cause disease
C) some microorganisms are resident while others are transient
D) resident microorganisms are found in nervous system and blood

Answer 2

D

Question 3

Which of the factors below is not considered to be an example of a virulence factor?

A) prodrome
B) leukostatin
C) streptokinase
D) adhesions

Answer 3

A

Question 4

Which of the following does not pertain to the commensal organism E. coli?

A) found in large numbers on human host
B) found in the human intestinal tract
C) synthesizes vitamin K
D) synthesizes blood clotting factors

Question 5

The microorganism Staphylococcus aureus causes which condition?

A) gas gangrene
B) botulism
C) scalded skin syndrome
D) scarlet fever

Question 6

Which of the following statements about the relationship between hosts and microbes is true?

A) an opportunistic pathogen has a relatively low infectious dose
B) infection always leads to symptoms
C) some organisms can be pathogens and commensals
D) endogenous infections are caused by microbes that are endemic to environment

Question 7

A healthcare worker fails to follow aseptic procedures while cleaning a wound,washes his hands properly afterwards and suffers no ill effects-this is an example of:

A) commensalism
B) infection
C) infestation
D) contamination

Question 8

Symbiosis is an association between

A) two or more species
B) one or two species
C) two or more hosts
D) no species but all hosts

Question 9

Factors that improve the chances of a pathogen's ability to invade a host and cause infection are known as:

A) contagious factors
B) non-communicable factors
C) viral factors
D) virulence factors

Question 10

What causes the cytopathic effect (CPE)?

A) bacteria
B) fungi
C) protozoa
D) viruses

Question 11

Which of the following must be true in order to satisfy Koch's postulates?

A) causative agent must be observed in a small percentage of cases of disease
B) must be isolated from hosts that are not inoculated with the pure culture
C) when pure cultures inoculated in healthy hosts, they do not show disease
D) causative agent must be isolated from diseased host and grown in pure culture

Question 12

A symbiotic relationship in which one species benefits from the association while the other species is not harmed but does not benefit from the relationship is called:

A) parasitism
B) mutualism
C) commensalism
D) contamination

Question 13

Which of the following statements about host-microbes is true?

A) a host is any organism that harbors no other organism
B) infestation refers to the presence of larger parasites
C) in mutualism neither of the two species benefits from the relationship
D) virulence is defined as the capacity to produce disease

Question 14

The rapid transfer of a microbial pathogen through animals of a susceptible species

A) does not change the pathogenicity
B) increases its fitness in broth culture
C) can increase the intensity of the disease produced by that pathogen
D) can decrease the intensity of the disease produced by that pathogen

Question 15

All of the following are true of the relationship between microorganisms and diseases except

A) sickle cell anemia patients are resistant to malaria
B) bacterial infections can lead to endocarditis
C) viral infections invariably lead to nutritional deficiency
D) infections in the brain can result in mental disease

Question 16

Streptococcus pyogenes is a causative agent of:

A) scarlet fever
B) bacillary dysentery
C) anthrax
D) diphtheria

Question 17

A viral infection that involves continued and prolonged production of viruses in a host is referred to as a/an

A) abortive infection
B) productive infection
C) latent infection
D) persistent infection

Question 18

Normal microflora

A) can be found in the stomach and are adapted to acidic conditions
B) may be permanent or transient
C) may be responsible for opportunistic infections in immuno-compromised individuals
D) two of the above

Question 19

Which of the following microbes easily satisfies Koch's postulates?

A) fastidious bacteria
B) sepsis, for which many microbes are regularly isolated
C) hepatitis C, for which there is no suitable animal model
D) plague, as it can be isolated from sick patients

Question 20

The spreading of exotoxins from the site of infection via the blood is called:

A) septicemia
B) toxemia
C) colonization
D) adherence

Question 21

Giardia intestinalis,a protozoan,produces the following virulence factor:

A) adhesive disc
B) aflatoxin
C) beta-hemolysin
D) coagulase

Question 22

All of the following are true of most diseases caused by a fungus except

A) fungal spores enter the body through a cut or a wound
B) fungi could release enzymes that attack host cells
C) fungi can digest and invade neighboring host cells
D) fungi can use its flagellum to expel tissue fluids

Question 23

Which of the following is the correct pairing of a disease with its classification?

A) sickle cell anemia - degenerative disease
B) anemia - mental disease
C) Creutzfeldt-Jakob - mental disease
D) emphysema - idiopathic

Question 24

Eradication of a given infectious disease

A) has never been achieved
B) only occurs with infectious agents that are adaptable
C) is made easier when there is a lack of medical care
D) is difficult due to political, economic and scientific barriers

Question 25

Attenuation

A) is the increase in the pathogenicity of a microbe
B) is the process that weakens the disease-producing ability of a pathogen
C) does not affect the capacity to produce disease
D) is the process that decreases the number of organisms that enter the body

Question 26

Diseases in which permanent damage occurs produce:

A) toxemia
B) septicemia
C) sequelae
D) syndromes

Question 27

The Escherichia coli strain O157:H7

A) suggests that E. coli is a commensal
B) causes the common form of traveler's diarrhea
C) has a natural reservoir in armadillos
D) causes hemolytic uremic syndrome

Question 28

An idiopathic disease

A) has unknown causes
B) has no infectious basis
C) involves abnormal cell growth
D) two of the above

Question 29

What is a disease referred to when symptoms develop rapidly and it runs its course quickly?

A) primary infection
B) acute infection
C) subacute infection
D) chronic infection

Question 30

Iatrogenic diseases

A) include nosocomial infections
B) have no known causes
C) can be caused by chemicals, physical agents or viruses
D) are present at birth

Question 31

The virus that causes chicken pox in childhood

A) is a noncommunicable infectious disease
B) has no convalescence stage
C) produces hemolysins that release iron
D) is the causative agent of shingles

Question 32

A symptom

A) is present during the convalescent stage
B) can be observed or felt only by the patient
C) can be observed by examination of the patient
D) only occurs during invasive infections

Question 33

Hyaluronidase

A) dissolves blood clots
B) allows the pathogens to spread to other tissues
C) or spreading factor is important for streptococci colonization
D) or adhesion is important for staphylococci to adhere to tissue

Question 34

An infection that is confined to a specific area of the body:

A) local infection
B) focal infection
C) systemic infection
D) latent infection

Question 35

Which of the following is not a stage of an infectious disease?

A) invasive
B) incubation
C) syndrome
D) prodromal

Question 36

Sudden or severe onset of signs and symptoms during acme is referred to as

A) incubation
B) fulminating
C) prodrome
D) decline

Question 37

Infection that does not produce a full set of signs and symptoms is called:

A) mixed infection
B) secondary infection
C) superinfection
D) inapparent infection

Question 38

Noncommunicable infectious diseases

A) are especially common among young children
B) include Klebsiella pneumonia which is only slightly contagious
C) are not spread form one host to another
D) two of the above

Question 39

Which of the following do not affect the incubation period of an infectious disease?

A) nature of the microorganism
B) virulence factors
C) the number of invading microorganisms
D) time between when symptoms arise and microbe is transmitted

Question 40

Alpha-hemolysins

A) are neurotoxins
B) are exotoxins
C) are enzymes that synthesize hemoglobin
D) two of the above

Question 41

In the United States,infectious diseases are currently

A) responsible for more deaths than cardiovascular diseases
B) the number one cause of mortality
C) ranked after cancer, accidents, diabetes and cardiovascular disease in mortality
D) two of the above

Question 42

The 1918 Influenza Epidemic was the worst one on record. People infected early in the epidemic had a mild flu,while those later infected had a much more severe form of the disease. What is the explanation for this observation and what laboratory studies mimic these results? Why do you think this doesn't occur for all infectious diseases?

Question 43

An acute disease becomes ______ when the body can not get rid of it; while a local disease becomes _______ when it disseminates into deeper organs and tissues.

A) contagious; systemic
B) contagious; secondary
C) chronic; systemic
D) chronic; secondary

Question 44

Exotoxins

A) are soluble substances secreted into host tissues
B) build up after antibiotic treatment
C) require the bacteria to die or divide
D) consist of lipopolysaccharide (LPS)

Question 45

Botulinum Toxin

A) when used for cosmetic purposes is called Botox
B) relieves muscle spasms in dystonia
C) is produced by Clostridium botulinum
D) all of the above

Question 46

Leukocidin

A) is an altered toxin that retains its antigenicity
B) is an endotoxin
C) is insoluble in host tissues
D) destroys or damages neutrophils

Question 47

Toxoid

A) is an altered toxin that retains its antigenicity
B) is an endotoxin
C) is insoluble in host tissues
D) destroys or damages neutrophils

Question 48

A disease in which the agent is acquired directly from the environment and is not transmittable is a

A) local disease
B) secondary disease
C) noncommunicable disease
D) acute disease

Question 49

A productive infection

A) has continued and prolonged production of viruses in a host
B) is controlled by the host immune system and later causes disease
C) occurs when the virus enters the cell and produces offspring
D) often leads to a viral syndrome

Question 50

Endotoxins

A) are more powerful than exotoxins
B) are unstable
C) have nonspecific effects such as fever
D) are actively excreted into medium

Question 51

Transposal of virulence is all of the following except

A) a laboratory technique in which a pathogen is passed from its normal host to a new host
B) involves animal passaging experiments to adapt a pathogen to its normal host
C) was used by Pasteur to prepare rabies virus
D) increases the virulence for the new host but may reduce the virulence in the normal host

Question 52

A secondary infection that occurs after the use of broad-spectrum antibiotics and the subsequent destruction of the normal microbiota would be considered a

A) sapremia
B) prodrome
C) superinfection
D) mixed infection

Question 53

What are the difficulties in demonstrating Koch's postulates for human infections? Why was it difficult to demonstrate that Leprosy or HIV satisfied Koch's Postulate?

Question 54

While infectious diseases are diseases caused by infectious agents,many diseases are classified as non-infectious even when infectious agents interact with other factors in causing the disease. Give three examples of an infectious disease interacting with a non-infectious disease and describe the relationship as to whether the infectious disease is a causative agent or a complicating factor.

Question 55

Microbial competition

A) explains diseases from microbes that occur after antibiotic treatment
B) encompasses both direct and indirect harm to the host
C) explains why some bacteria are harmless in one site but turn pathogenic in another
D) is beneficial when commensal bacteria prevent pathogens from colonizing