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Mahon: Textbook of Diagnostic Microbiology, 4th Edition
Chapter 02: Host-Parasite Interaction
Test Bank
MULTIPLE CHOICE
1. Organisms that participate in a biologic relationship where both benefit from one another
are called:
a. Parasites
b. Symbionts
c. Hosts
d. Florae
ANS: B
Symbiosis is a relationship where two organisms live together and their association
benefits both organisms. Organisms that live in symbiosis are said to be symbionts.
Parasites are organisms that live off a host and harm the host. The host is the organism
that provides the nutrients to the other organisms. Florae are described as microorganisms
that inhabit the body sites of healthy individuals.
REF: page 24 OBJ: Level 1 – Recall
2. Parasitism is:
a. A biologic relationship between two or more organisms in which both benefit from
one another
b. A biologic relationship between only two organisms in which there are no
beneficial or harmful effects to the host
c. A biologic relationship in which one species gains benefits at the expense of the
host
d. A synonym for mutualism
ANS: C
When both organisms live together and both benefit, this is symbiosis. When both
organisms live together and neither benefits, this is commensalism. When both organisms
live together and one organism benefits at the expense of the host, this is parasitism.
Mutualism and symbiosis are synonyms.
REF: page 24 OBJ: Level 1 – Recall
3. This bacterial state occurs when a host harbors a disease-causing organism, but does not
show signs of disease.
a. Carrier
b. Transient
c. Resident
d. Indigenous
ANS: A
Transient, resident, and indigenous refer to particular types of flora associated with the
human body, whereas carrier refers to the state in which pathogenic organisms establish
themselves in a host without causing disease, but the host can still transmit the infection.
REF: page 24 OBJ: Level 1 – Recall
4. Healthy people are colonized by many different bacteria in many different sites. These
bacteria are referred to as:
a. Transient florae
b. Carrier florae
c. Maintenance florae
d. Indigenous florae
ANS: D
Indigenous florae are usual or normal florae, whereas transient florae are microbial florae
that are present at a site temporarily. Carrier and maintenance florae are not types of
microbial florae found on the human body.
REF: page 24 OBJ: Level 1 – Recall
5. Diabetics may sometimes be infected with their own resident florae. This type of
infection is called:
a. An opportunistic infection
b. A carrier state
c. Symbiosis
d. A parasitic infection
ANS: A
Opportunistic infections occur when the host has changes in body chemistry associated
with age, disease states, and drug or antibiotic effects. Carrier states are those in which a
host does not show symptoms of a disease, but it can infect other hosts with pathogenic
organisms. Symbiosis is a biologic relationship that benefits the host and the organism. A
parasitic infection is one in which the parasite receives benefits, but at the expense of the
host.
REF: page 25 OBJ: Level 1 – Recall
6. Mechanisms used by the skin to prevent infection and protect the underlying tissue from
invasion by potential pathogens include all the following EXCEPT:
a. Desquamation of the epithelium
b. Excretion of lysozyme by sweat glands
c. Antibiotics that inhibit many microorganisms
d. Mechanical separation of microorganisms from the tissues
ANS: C
The skin produces fatty acids that inhibit microorganisms, not antibiotics. The remaining
three mechanisms are described in the text on page 8.
REF: page 25 OBJ: Level 1 – Recall
7. A laboratory professional is testing a new antimicrobial soap. The tech washes her
forearm, then does a culture of the skin. Which organisms should she expect to find
growing in the culture?
a. Diphtheroids and Bacillus spp.
b. S. epidermidis and Propionibacterium
c. S. aureus and Propionibacterium
d. Diphtheroids and Propionibacterium
e. None of these organisms should be found.
ANS: B
Diphtheroids are found in moist areas such as the axillae and toes. S. aureus is a pathogen
that is not found on healthy skin. Propionibacterium colonizes the deep sebaceous
glands. Superficial antisepsis of the skin does not kill the Propionibacterium and S.
epidermidis that live in the hair follicles and sebaceous glands. Handwashing does not
remove all bacteria from the skin.
REF: page 25 OBJ: Level 2 – Interpretation
8. What mechanism allows strict anaerobes to grow in the cervices and areas between the
teeth when plaque is present?
a. A low oxidation-reduction potential occurs at the tooth surface under the plaque.
b. The bacteria secrete sugar to nourish the strict anaerobes.
c. The normal florae secrete antibiotics to kill all the other bacteria and allow the
strict anaerobes to thrive.
d. The plaque-causing bacteria secrete an alkaline fluid and change the pH around the
tooth.
ANS: A
The growth of the plaque-causing bacteria on the tooth’s surface contain as many as 1011
streptococci per gram, and this amount of bacteria lowers the oxidation-reduction
potential at the tooth surface. Strict anaerobes cannot grow in the presence of oxygen, and
lowering the oxidation-reduction potential lowers the amount of oxygen at the tooth
surface. Normal oral florae do not secrete sugar, antibiotics, or alkaline fluid.
REF: page 25 OBJ: Level 2 – Interpretation
9. All the following are considered pathogenic organisms found in the nasopharynx of
healthy individuals EXCEPT:
a. Haemophilus influenzae
b. Streptococcus pneumoniae
c. Moraxella catarrhalis
d. Neisseria meningitidis
ANS: C
M. catarrhalis is resident flora of the oropharynx and is an opportunistic pathogen. H.
influenzae, S. pneumoniae, and N. meningitides are all potential pathogenic organisms
and are not considered opportunistic pathogens.
REF: page 26 OBJ: Level 1 – Recall
10. The stomach can be considered the first line of defense against microbial infections
because:
a. Most microorganisms are susceptible to the antibiotics and alkaline pH present in
the stomach.
b. Most microorganisms are killed by the liver enzymes that are emptied into the
stomach during a meal.
c. The stomach produces lipase, which attacks the lipopolysaccharide cell wall of the
organisms.
d. Most microorganisms are susceptible to the acid pH of the stomach.
ANS: D
The stomach cells secrete enough acid to create an environment with a pH of
approximately 1. Bacteria that are enmeshed in food, spore-forming bacterial species in
their spore phase, and the cysts of parasites can survive the extreme pH present in the
stomach. The stomach does not produce antibiotics or lipase, and liver enzymes do not
empty into the stomach during digestion.
REF: page 26 OBJ: Level 1 – Recall
11. This type of bacteria is able to live in the colon with little to no oxygen and is the
predominant organism.
a. Anaerobes
b. Facultative anaerobes
c. Facultative gram-negative rods
d. Gram-positive cocci
ANS: A
Anaerobes make up over 90% of the microbial flora of the large intestine. The facultative
anaerobes, facultative gram-negative rods, and gram-positive cocci are present in the
colon in much smaller numbers than the anaerobes.
REF: page 26 OBJ: Level 1 – Recall
12. During the childbearing years, the normal florae of the vagina maintain a low pH, thus
encouraging colonization with all the following types of organisms EXCEPT:
a. Lactobacilli
b. Gram-negative rods
c. Anaerobic gram-negative bacilli
d. Gram-positive cocci
ANS: B
Gram-negative rods usually inhabit the vagina before puberty and in postmenopausal
women. The low pH encourages colonization of the vagina with lactobacilli, anaerobic
gram-negative bacilli, and gram-positive cocci.
REF: page 27 OBJ: Level 1 – Recall
13. After perforation of the colon, surgeons must guard against infection in the _____
because of leakage of the contents of the colon.
a. Peritoneal cavity
b. Urinary bladder
c. Vaginal flora
d. Renal vein
ANS: A
The peritoneal cavity is the space between the internal organs and the abdominal wall—a
normally sterile space. The colon contains lots of bacteria that can cause an infection in
this normally sterile space because there are no normal florae or immune system cells
here to fight off an infection. The organisms would have no natural defenses to overcome
before causing an infection.
REF: page 26 OBJ: Level 1 – Recall
14. The human body is constantly challenged by pathogens in the environment. It is not
infected by every pathogen it encounters because the microbial florae:
a. Engulf the pathogenic bacteria
b. Produce conditions at the microenvironmental level that block colonization
c. Prime our immune system
d. Activate and support the action of antigen-presenting cells, cytokines, and cell-
mediated immunity
ANS: B
Several mechanisms are used by microbial florae to ensure that colonization of
pathogenic organisms is blocked, such as lowering the reduction-oxidation potential,
lowering the pH, producing antimicrobials, and depleting the nutrients present in a
particular environment.
REF: page 27 OBJ: Level 2 – Interpretation
15. The ability of an organism to produce disease in a susceptible individual is called:
a. Pathogenicity
b. Iatrogenic infection
c. Parasitic infection
d. Opportunistic infection
ANS: A
An iatrogenic infection occurs as the result of medical treatment or procedure. A parasitic
infection occurs when an organism invades a host and only the organism benefits from
the biologic relationship. An opportunistic infection occurs when the condition of the
host changes and resident florae cause an infection.
REF: page 30 OBJ: Level 1 – Recall
16. A patient with an indwelling catheter develops a fever and lethargy. In addition, the urine
in the catheter bag has turned a brownish color and is foul-smelling, which indicates an
infection. What type of infection does this describe?
a. Opportunistic
b. Iatrogenic
c. Pathogenic
d. Parasitic
ANS: B
An opportunistic infection occurs when a host’s condition changes and resident florae are
able to cause disease. Pathogenic describes the types of organisms that cause disease, but
not a type of infection. A parasitic infection occurs when an organism invades a host and
only the organism benefits from the biologic relationship. An iatrogenic infection occurs
as the result of medical treatment or procedures. In this case, the use of an indwelling
catheter to treat a medical condition has resulted in an infection.
REF: page 30 OBJ: Level 3 – Synthesis
17. The smaller the number of microorganisms necessary to cause infection in a competent
host, the more _____ the microorganism.
a. Opportunistic
b. Parasitic
c. Invasive
d. Virulent
ANS: D
Opportunistic refers to a type of resident flora that causes infection when the conditions
in a host change. A parasitic infection occurs when an organism invades a host and only
the organism benefits from the biologic relationship. Invasive refers to entering tissue,
not the degree of ease with which an organism can cause disease. Virulence refers to the
relative ability of a microorganism to cause disease—more virulent organisms need fewer
organisms to cause disease in a host.
REF: page 30 OBJ: Level 1 – Recall
18. Factors that determine the pathogenicity and increase the virulence of organisms include
all the following EXCEPT:
a. An organism’s ability to avoid phagocytosis
b. An organism’s ability to produce exotoxins and extracellular enzymes
c. An organism’s ability to produce infection when host conditions change
d. An organism’s ability to survive intracellularly when phagocytized
ANS: C
An organism’s ability to produce infection when host conditions change is referred to as
an opportunistic pathogen. The other three statements refer to ways that a microorganism
can survive the attack of a host’s immune system and produce disease.
REF: page 31 OBJ: Level 1 – Recall
19. The most common bacterial characteristic that allows for evasion of phagocytosis by the
host is:
a. Exotoxin production
b. Extracellular enzyme production
c. Pili
d. Polysaccharide capsule
ANS: D
Exotoxin and extracellular enzyme production and pili are factors that can increase an
organism’s virulence. The exotoxins and extracellular enzymes may be used to survive
phagocytosis, but these do not help an organism evade phagocytosis. Organisms
possessing a polysaccharide capsule are considered highly virulent because they can
evade phagocytosis. Pili are used to transfer plasmids that may contain the genes for
antimicrobial resistance and, therefore, help an organism survive in the host.
REF: page 31 OBJ: Level 1 – Recall
20. This is a leukocidin that is lethal to leukocytes and produced by staphylococci.
a. Panton-Valentine
b. Lancefield
c. Hemolysin
d. Adhesins
ANS: A
Lancefield deals with classifying -hemolytic streptococci on the basis of antigens found
on their outer covering. Hemolysins are produced by streptococci, and these lyse red
blood cells. Adhesins are cell-surface structures that mediate attachment to other cells.
The Panton-Valentine leukocidin is lethal to leukocytes and contributes to the
invasiveness of staphylococci.
REF: page 32 OBJ: Level 1 – Recall
21. Changes in these host structures can result in lower virulence of a microorganism.
a. Pili
b. Adhesin receptors
c. Surface polysaccharides
d. Phagocytes
ANS: B
Pili and surface polysaccharides are the main bacterial structures of attachments called
adhesins. Phagocytes are white blood cells that engulf invading microorganisms. Adhesin
receptors are structures found on the host cell that are necessary for attachment of
bacterial adhesins and the beginnings of an infection.
REF: page 32 OBJ: Level 1 – Recall
22. After attachment to host cells, a pathogen uses all the following mechanisms to establish
itself and cause disease EXCEPT:
a. Uses lactoferrin for iron
b. Produces an IgA protease that degrades the IgA at mucosal surfaces
c. Produces lysozyme to kill the host cell
d. Circumvents host antibodies by shifting key cell-surface antigens
ANS: C
After engulfing bacteria, the host cell releases lysosomal contents that kill the organism.
The bacteria do not produce lysozyme.
REF: pages 32-33 OBJ: Level 1 – Recall
23. Dissemination of a pathogen is:
a. When a pathogen penetrates and grows in tissues
b. When a pathogen multiplies intracellularly
c. When a pathogen circumvents host antibodies by shifting key cell-surface
antigens.
d. When infection with a pathogen spreads from the initial infection site to distant
sites such as organs and tissues
ANS: D
Invasion of a pathogen allows the microbe to take advantage of the host’s transport
system (the blood) and seek out other areas that can be infected. This occurs only if the
pathogen can elude the host’s immune system during this journey. Invasion is when a
pathogen penetrates and grows in tissues. Intracellular multiplication of a pathogen
occurs when an organism can survive phagocytosis. When a pathogen shifts key cell-
surface antigens it is evading a host’s immune system.
REF: page 33 OBJ: Level 1 – Recall
24. A physician notices that several patients are infected with Clostridium difficile, but only a
few of the patients are symptomatic for disease. The reason for this discrepancy is:
a. Only those strains of the organism carrying the extrachromosomal DNA coding for
the toxin gene will produce toxin and cause the individuals to be symptomatic.
b. Only those strains of the organism carrying DNA coding for the toxin within its
main DNA molecule will produce toxin and cause the individuals to be
symptomatic.
c. The exotoxin produced contains only the nontoxic portion.
d. The exotoxin must be produced in conjunction with extracellular enzymes to cause
problems.
ANS: A
The exotoxin gene is commonly encoded for by phages, plasmids, or transposons and
does not normally reside within an organism’s main DNA molecule. Exotoxins are highly
characterized molecules that are composed of a nontoxic subunit that binds the toxin to
the host cells, allowing attachment of the toxin. Exotoxins exhibit their effects without
the aid of extracellular enzymes. Extracellular enzymes are another factor that contributes
to the virulence and invasiveness of organisms.
REF: page 33 OBJ: Level 2 – Interpretation
25. The effects of endotoxins consist of dramatic changes in all the following EXCEPT:
a. Blood pressure
b. Fluid imbalance
c. Clotting
d. Body temperature
ANS: B
Unlike shock caused by fluid loss, such as that seen in severe bleeding, septic shock is
unaffected by fluid administration. An increase in body temperature occurs within an
hour after exposure. Severe hypotension occurs within 30 minutes after exposure. The
endotoxin also initiates coagulation, which can result in intravascular coagulation.
REF: page 33 OBJ: Level 2 – Interpretation
26. A patient is brought to the emergency room with the following symptoms: body
temperature of 102° F, blood pressure 90/60, a WBC of 2.0 cells/liter, and disseminated
intravascular coagulation. This person has gram-negative rods growing in his blood.
What is responsible for this condition?
a. Exotoxin
b. Extracellular enzymes
c. Endotoxin
d. Exfoliating toxin
ANS: C
Effects of the lipid A portion of the lipopolysaccharide present in the cell walls of gram-
negative bacteria include increased body temperature, hypotension, intravascular clotting,
neutropenia, metabolic changes, changes in humoral and cellular immunity, and changes
resistance to infection.
REF: page 33 OBJ: Level 3 – Synthesis
27. Healthy skin secretes these substances to help prevent colonization by transient and
possibly pathogenic organisms.
a. Long-chain fatty acids
b. Sebaceous glands
c. Bacteriostatic substances
d. Antibodies
ANS: A
Long-chain fatty acids produced by the sebaceous glands allow the skin environment to
be acidic, leading to a low pH environment. Many pathogens prefer the near-neutral
environment in the body to produce disease. Bacteriocidal substances are produced by the
florae that colonize the skin, and antibodies are produced by lymphocytes.
REF: page 34 OBJ: Level 1 – Recall
28. Lysozyme is:
a. An antibody produced by the skin
b. A low-molecular-weight enzyme that hydrolyzes the peptidoglycan layer of
bacterial cell walls
c. An exotoxin that digests the lipopolysaccharide layer of the bacterial cell wall
d. A radical similar to hydrogen peroxide
ANS: B
Antibodies are produced only the lymphocytes. Exotoxins are produced by bacteria and
are toxic to the host. Lysozyme is a low-molecular-weight enzyme that hydrolyzes the
peptidoglycan layer of bacterial cell walls.
REF: page 35 OBJ: Level 1 – Recall
29. Interferon is a substance produced by the body that inhibits viral replication. Interferon
accomplishes this task by:
a. Digesting the virus that is attempting to attach to the host cell
b. Destroying the host cell before the virus can attach and replicate
c. Binding to surface receptors that stimulate the cell to synthesize enzymes that
inhibit viral replication over several days
d. Stimulating platelets to produce -lysins
ANS: C
Interferon is produced by eukaryotic cells in response to a viral infection, and it
stimulates the cell to synthesize enzymes that inhibit viral replication over several days.
Interferons are not enzymes and cannot digest viruses. Destroying the host cell before the
virus can attach would be counterproductive, as the purpose is to keep the host cells
viable and free of infection. The -lysin’s cationic proteins are produced by platelets
during coagulation and are active against gram-positive bacteria, not viruses.
REF: page 36 OBJ: Level 2 – Interpretation
30. All the following activities must occur for phagocytosis to take place and be effective in
host defense EXCEPT:
a. Attachment of the particle to the phagocyte
b. Ingestion
c. Killing
d. Migration of lymphocytes to the area of infection (chemotaxis)
ANS: D
Phagocytes are neutrophils or macrophages. Lymphocytes are not phagocytic and cannot
engulf bacteria.
REF: page 36 OBJ: Level 1 – Recall
31. This process results in enhanced phagocytosis by neutrophils.
a. Opsonization
b. Chemotaxis
c. Digestion
d. Glycolysis
ANS: A
Chemotaxis is the process of phagocytes migrating toward the site of the infection.
Digestion is when the contents of the lysozyme is mixed with the phagocytized bacteria.
Glycolysis is a metabolic process where glucose is broken down and energy is generated.
REF: page 36 OBJ: Level 1 – Recall
32. One of the most effective defenses bacteria have against phagocytosis is:
a. Enzymes
b. The capsule
c. Plasmids
d. Lipopolysaccharide layer
ANS: B
Enzymes facilitate host cell destruction but do not have any effect on phagocytosis.
Plasmids carry small pieces of DNA that can code for toxins, enzymes, and antibiotic
resistance. The lipopolysaccharide layer acts as an endotoxin that causes septic shock.
REF: page 37 OBJ: Level 1 – Recall
33. Innate immunity consists of all the following components EXCEPT:
a. Physical and chemical barriers such as the skin and mucous membranes
b. Blood proteins that act as mediators of infection
c. Secretion of bacteriocidal substances onto the skin and mucous membranes
d. A cellular mechanism capable of phagocytosis
e. All of the above are part of the innate immune system
ANS: C
Many substances are produced by the skin and mucous membranes that inhibit the
growth of pathogens by forming an inhospitable environment but do not kill the
pathogen. All the other answers are correct.
REF: page 38 OBJ: Level 2 – Interpretation
34. The major constituents of the adaptive or specific immune response are:
a. Neutrophils
b. Macrophages
c. Monocytes
d. Lymphocytes
ANS: D
Neutrophils, macrophages, and monocytes are all phagocytic cells that function in innate
immunity, not the specific immune response. Lymphocytes produce antibodies in
response to specific antigens present in the blood.
REF: page 40 OBJ: Level 1 – Recall
35. This class of antibodies is a pentamer.
a. IgM
b. IgG
c. IgA
d. IgE
ANS: A
IgM is made up of five basic immunoglobulin subunits and is considered a pentamer. IgG
is a monomer. IgA is a dimer, and IgE is a monomer.
REF: page 41 OBJ: Level 1 – Recall
36. A subsequent exposure to the same antigen elicits a(n) _____, characterized by a rapid
increase in IgG antibody associated with higher levels, a prolonged elevation, and a more
gradual decline in antibody levels.
a. Primary immune response
b. Anamnestic immune response
c. Opsonin immune response
d. Innate immune response
ANS: B
The primary immune response consists of production of IgM antibodies. The innate
immune response does not consist of antibody production but rather physical and
chemical barriers to infection and phagocytosis.
REF: page 42 OBJ: Level 1 – Recall
37. These are low-molecular-weight proteins secreted by T cells.
a. Antibodies
b. Opsonins
c. Lymphokines
d. Lysozyme
ANS: C
Antibodies are produced by B cells. Opsonins are antibodies or pieces of complement
that help make a pathogen ready to be phagocytized. Lysozyme is the enzyme present in
host cell vacuoles that assist in killing a phagocytized microorganism. Lymphokines are
produced by T cells as a result of antigen binding, activation, cell division, and
differentiation.
REF: page 42 OBJ: Level 1 – Recall
38. Immunity to intracellular bacterial pathogens, such as Mycobacterium tuberculosis, is
primarily cell mediated, through the activities of:
a. Interferons and macrophages
b. Antibodies and lymphokines
c. Lysozyme, T lymphocytes, and antibodies
d. T lymphocytes, lymphokines, and macrophages
ANS: D
Interferons are useful against viruses, not bacteria. Macrophages are effective against
intracellular pathogens because they are phagocytes. Antibodies are not useful against
intracellular pathogens because they cannot reach the pathogen that lives inside the cell.
Lysozyme is an enzyme that is used to kill bacteria once they are phagocytized. T
lymphocytes, lymphokines, and macrophages are used by the immune system to battle
intracellular pathogens most effectively.
REF: page 43 OBJ: Level 2 – Interpretation
39. What virus causes immune suppression in the host by targeting and destroying the host’s
CD4+ T cells?
a. HIV
b. Hepatitis B
c. Epstein-Barr
d. Cytomegalovirus
ANS: A
HIV is known to destroy CD4+ T cells. Hepatitis B causes disease in liver cells, not
white blood cells. The Epstein-Barr virus and cytomegalovirus show depressed T-cell or
antibody responses to other unassociated antigens.
REF: page 43 OBJ: Level 1 – Recall
40. Once infected with Borrelia recurrentis, a 2- to 15-day incubation period follows where
high numbers of organisms are found in the blood. The infected individual experiences
high fever, rigors, severe headache, muscle pains, and weakness. This febrile period lasts
for about 3 to 7 days, but ends quickly with the induction of an immune response.
However, a similar but less severe course of symptoms recurs several days to weeks later.
What causes this relapse?
a. The organism systematically changes its surface antigens during the course of a
single infection.
b. The organism produces extracellular toxins that cause the symptoms.
c. This organism survives inside infected cells and once the cell dies, the organism is
released into the blood, causing this relapse.
d. This relapse occurs as the host is trying to mount the secondary antibody response.
ANS: A
Borrelia recurrentis has the ability to change its surface antigens during the course of an
infection. This means that the specific immune response mounted by the host is no longer
effective against the new bacterial antigen. This is why the relapse occurs. B. recurrentis
does not produce extracellular toxins. This organism does not survive once phagocytized.
The secondary antibody response occurs in conjunction with the primary response, and
there is no lapse to allow for a recurrence of symptoms.
REF: page 43 OBJ: Level 3 – Synthesis
41. Pathogens can be transmitted through all the following routes EXCEPT:
a. Ingestion
b. Handwashing
c. Sexual contact
d. Air
ANS: B
Pathogens can be transmitted by ingestion, sexual contact, and air. Handwashing is major
a method to prevent spread of infections.
REF: page 43 OBJ: Level 1 – Recall
42. Because infections can be encountered via the air, _____ can cause transmission of some
pathogens.
a. Cuts
b. Eyes
c. Coughing
d. Children
ANS: C
Airborne infections are the most commonly encountered infections. They are transmitted
by droplets in the air that can be generated by coughing or sneezing. Cuts, eyes, and
children are not usual pathways for airborne transmission of a pathogen.
REF: page 43 OBJ: Level 1 – Recall
43. This is a form of food poisoning that can be life threatening.
a. S. aureus
b. B. cereus
c. C. difficile
d. C. botulinum
ANS: D
S. aureus and B. cereus produce food poisoning, but that is usually self-limiting. C.
difficile is an intestinal normal flora that can produce diarrhea through an opportunistic
mechanism. Clostridium botulinum produces one of the most toxic substances known to
humankind: botulism toxin. This substance is responsible for the food poisoning and it
can be life threatening.
REF: page 45 OBJ: Level 1 – Recall
44. The classic example of a bite-wound infection is:
a. Rabies
b. S. aureus
c. Plague
d. Ebola
ANS: A
S. aureus can produce severe skin infections, but they are usually not the result of a bite.
The plague is an arthropod-transmitted disease. Ebola is transmitted by blood and body
fluid contact. Rabies is produced as a result of a bite from a rabid animal.
REF: page 46 OBJ: Level 1 – Recall
45. The resulting disease from this route of transmission is a disease of animals that is
transmitted to humans.
a. Sexual contact
b. Zoonotic
c. Airborne
d. Ingestion
ANS: B
Sexual contact, airborne, and ingestion are all routes of transmission for diseases of
humans that are passed from person to person. Zoonotic describes diseases of animals
that infect humans.
REF: page 46 OBJ: Level 1 – Recall