Full Test Bank Chapter.25 Blood And Lymphatic Infections

Nester’s Microbiology, 9e (Anderson)

Chapter 25 Blood and Lymphatic Infections

1) The scientist responsible for the development of the first anti-plague vaccine in 1866 was

A) Alexandre Yersin.

B) Robert Koch.

C) Louis Pasteur.

D) Josef Marburg.

E) Barbara McClintock.

2) The plague bacillus is known as

A) Plasmodium vivax.

B) Pneumocystis carinii.

C) Streptococcus pyogenes.

D) Yersinia pestis.

E) Bacillus anthracis.

3) The circulation of an agent in the bloodstream is given a name ending in

A) -ase.

B) -ing.

C) -emia.

D) -ation.

E) -cyte.

4) The sac which surrounds the heart is called the

A) endocardium.

B) pericardium.

C) atrium.

D) myocardium.

E) endothelium.

5) The heart chamber that passes blood to the lungs is the

A) left ventricle.

B) right ventricle.

C) right atrium.

D) left atrium.

E) right ventricle AND left atrium.

6) Which organism may be implicated in atherosclerosis?

A) Escherichia coli

B) Pseudomonas aeruginosa

C) Staphylococcus aureus

D) Chlamydophila pneumoniae

E) Mycoplasma pneumoniae

7) The fluid which bathes and nourishes the tissue cells is the

A) cytoplasm.

B) interstitial fluid.

C) lymph.

D) blood.

E) hyperstitial fluid.

8) The small bean-shaped bodies into which the lymphatic vessels drain are the

A) lymph nodes.

B) adrenals.

C) subclavian veins.

D) valves.

E) lymph beans.

9) A visible red streak in an infected hand or foot is referred to as

A) septicemia.

B) bacteremia.

C) lymphangitis.

D) edema.

E) plasmitis.

10) Blood and lymph may carry

A) antibodies.

B) complement.

C) lysozyme.

D) interferon.

E) All of the choices are correct.

11) The spleen, in part, functions to cleanse the

A) blood.

B) lymph.

C) interstitial fluid.

D) cytoplasm.

E) fluid.

12) The condition that develops on a previously damaged heart valve is called

A) an aneurysm.

B) acute bacterial endocarditis.

C) infective endocarditis.

D) myocarditis.

E) effective endocarditis.

13) The most common agent(s) causing infective endocarditis is/are

A) Streptococcus pyogenes.

B) Pseudomonas aeruginosa.

C) normal skin or mouth microbiota.

D) Escherichia coli.

E) normal gut microbiota.

14) High levels of antibodies in patients with infectious endocarditis cause inflammation because

A) they may form immune complexes that get trapped in skin and eyes.

B) the surface antigens change rapidly and become unrecognizable.

C) the antibodies initiate type I, type II, or type III hypersensitivities.

D) the antibodies degrade quickly and debris gets trapped in these organs.

E) they may form clots that lead to life-threatening emboli.

15) The inflammatory effect of immune complexes lodged in the kidney is called

A) renal phritis.

B) glomerulonephritis.

C) rendema.

D) urethritis.

E) endophritis.

16) Which of the following is NOT a route by which bacteria that cause infective endocarditis may gain access to the bloodstream?

A) Trauma

B) Dental procedures

C) Brushing teeth

D) Ingestion

E) Kidney infection

17) Acute bacterial endocarditis differs from infective endocarditis in the

A) suddenness and severity of onset.

B) population affected.

C) resultant damage.

D) development of exotoxin shock.

E) causative organisms.

18) Which of the following is more likely to cause fatal septicemias?

A) Gram-positive bacteria

B) Gram-negative bacteria

C) Negatively stained bacteria

D) Acid-fast bacteria

E) Mycoplasmas

19) The material released from bacteria that may lead to shock and death in sepsis is

A) exotoxin.

B) protein A.

C) endotoxin.

D) interferon.

E) M protein.

20) Although sepsis affects many organs, the organ(s) most seriously and irreversibly affected is/are the

A) heart.

B) lungs.

C) kidneys.

D) spleen.

E) pancreas.

21) Enlargement of lymph nodes or spleen is often associated with

A) tularemia AND plague.

B) brucellosis AND tularemia.

C) plague.

D) gastritis AND plague.

E) tularemia, brucellosis, AND plague.

22) In order to culture the organism responsible for tularemia, the growth medium must contain

A) cysteine.

B) glucose.

C) charcoal.

D) NAD.

E) ATP.

23) The common name for tularemia is

A) Bang's disease.

B) rabbit fever.

C) Hansen's disease.

D) Chagas' disease.

E) dog tick fever.

24) The development of lymph node enlargement in the region of a skin ulcer after a tick or insect bite or handling of a wild animal suggests

A) brucellosis.

B) endocarditis.

C) sepsis.

D) tularemia.

E) Lyme disease.

25) Which of the following is/are able to survive phagocytosis?

A) Brucella species AND Staphylococcus aureus.

B) Staphylococcus aureus AND Francisella tularensis

C) Brucella species AND Francisella tularensis 

D) Francisella tularensis AND Staphylococcus epidermidis

E) All of these.

26) Brucellosis may also be known as

A) Bang's disease OR rabbit fever.

B) Bang's disease OR undulant fever.

C) undulant fever OR Hansen's disease.

D) Hansen's disease OR rabbit fever.

E) rabbit fever OR undulant fever.

27) Traditionally, the animal(s) associated with hosting Brucella is/are

A) cattle.

B) dogs.

C) goats.

D) pigs.

E) All of the choices are correct.

28) The "Black Death" may also be known as

A) tularemia.

B) plague.

C) brucellosis.

D) endocarditis.

E) necrosis.

29) The disease responsible for the death of approximately 25% the population of Europe from 1346 to 1350 was

A) typhus.

B) pneumonia.

C) influenza.

D) plague.

E) endocarditis.

30) Symptoms of plague appear in

A) one to two years.

B) two to three months.

C) one to six days.

D) three to six hours.

E) three to six months.

31) The causative agent of plague is

A) Yersinia pestis.

B) Vibrio cholerae.

C) Staphylococcus aureus.

D) Brucella abortus.

E) Infected fleas.

32) Yersinia pestis typically contains

A) one plasmid.

B) two plasmids.

C) three plasmids.

D) four plasmids.

E) no plasmids.

33) The major virulence factors of Yersinia pestis (capsule and Yops) are carried on

A) the chromosome.

B) a plasmid.

C) three separate plasmids.

D) the nuclear membrane.

E) the chromosome AND plasmids.

34) The virulence factor of Yersinia pestis that is a protease that destroys C3b and C5a is

A) Yops.

B) pla.

C) F1.

D) protein A.

E) V antigen.

35) Yops, proteins produced by Yersinia pestis,

A) interfere with phagocytosis.

B) activate plasminogen activator.

C) destroy C3b and C5a.

D) promote apoptosis.

E) control a type III secretion system.

36) The plague is typically transmitted via the bite of

A) ticks.

B) fleas.

C) lice.

D) mites.

E) mosquitoes.

37) Enlargement of lymph nodes or spleen is often associated with all of the following EXCEPT

A) tularemia.

B) brucellosis.

C) plague.

D) infectious mononucleosis.

E) vibriosis.

38) The cause of infectious mononucleosis is

A) varicella virus.

B) Staphylococcus aureus.

C) Epstein-Barr virus.

D) Francisella tularensis.

E) Yersinia pestis.

39) Epstein-Barr virus may become latent in

A) red blood cells.

B) B cells.

C) T cells.

D) nerve cells.

E) macrophages.

40) The production of heterophile antibody is associated with

A) tularemia.

B) brucellosis.

C) plague.

D) infectious mononucleosis.

E) sepsis.

41) Which of the following may be transmitted by saliva?

A) Infectious mononucleosis

B) Dengue fever

C) Plague

D) Yellow fever

E) Chikungunya

42) Yellow fever is transmitted by

A) ticks.

B) fleas.

C) Aedes mosquitoes.

D) Anopheles mosquitoes.

E) lice.

43) The disease caused by an enveloped single-stranded RNA arbovirus of the flavivirus family is

A) brucellosis.

B) yellow fever.

C) malaria.

D) herpes.

E) chikungunya.

44) Which of the following is caused by a protozoan?

A) Malaria

B) Yellow fever

C) Tularemia

D) Infectious mononucleosis

E) Dengue fever

45) Which of the following are transmitted by mosquitoes?

A) plague AND yellow fever.

B) yellow fever AND tularemia.

C) yellow fever AND malaria.

D) malaria AND tularemia.

E) tularemia AND plague.

46) Which species of Plasmodium causes the most serious form of malaria?

A) falciparum

B) ovale

C) malariae

D) vivax

E) knowlesi

47) The spleen enlarges in 

A) infectious mononucleosis AND Lyme disease.

B) malaria AND Lyme disease.

C) brucellosis AND sepsis.

D) infectious mononucleosis AND malaria.

E) plague AND sepsis.

48) Muscles aid the flow of venous blood.

49) Sepsis is only caused by Gram-negative bacteria.

50) Both Francisella tularensis and Brucella melitensis are able to survive phagocytosis.

51) Gram-positive organisms are more likely than other infectious agents to cause fatal sepsis.

52) The media used to successfully grow Francisella tularensis must contain cysteine.

53) The genes for the capsule and Yops of Yersinia pestis are carried on a plasmid.

54) Yellow fever is caused by a protozoan infection.

55) Both malaria and yellow fever are transmitted by mosquitoes.

56) Plasmodium falciparum causes the most serious form of malaria.

57) In a malarial infection, only sporozoites can infect the human liver.

58) What is the difference between "bacteremia" and "sepsis"?

A) Bacteremia is an infection with bacteria. Sepsis is an infection with Septic protozoans.

B) Bacteremia is the presence of living, multiplying bacteria in the bloodstream. Sepsis is the presence of endotoxins, but not necessarily of living microbial agents.

C) Sepsis is the presence of living, multiplying bacteria in the bloodstream. Bacteremia is the presence of endotoxins, but not necessarily of living microbial agents.

D) Bacteremia is a serious infection that is almost always fatal. Sepsis is less serious and can usually be treated with broad spectrum antibiotics.

E) There is no difference; both terms indicate the presence of living bacterial cells in the bloodstream.

59) How would crowded conditions in cities favor spread of bubonic plague?

A) Plague is transmitted by rats; more people means more waste, and more waste means more rats. This would favor the spread of plague.

B) Plague is transmitted by infected fleas; these fleas may be found on rodents (such as rats). More people in an area means a greater chance of interactions with animals carrying infected fleas, increasing the spread of plague.

C) Plague is transmitted by mosquitoes; more people close together gives an infected mosquito more chances to bite humans and transmit the causative agent, spreading plague.

D) Plague is transmitted by direct contact (e.g. skin to skin). More people in an area provides more chances for infected individuals to directly contact and infect other individuals, spreading plague.

E) Bubonic plague is transmitted by aerosol droplets. People in cities are always dependent on public transport, which is typically overcrowded, so are at risk of acquiring plague bacteria.

60) Why does it take more than a week before a mosquito that has just become infected with yellow fever virus can transmit the disease?

A) The virus must replicate in the gut of the mosquito before it can reach high enough numbers for transmission to a new human.

B) Mosquitoes only feed once a week, which limits their ability to transmit the disease rapidly.

C) Mosquitoes that acquire yellow fever virus become ill for a week thereafter. They have to recover before they can feed again and transmit the virus to the next host.

D) The virus multiplies in the gut of the mosquito, but then needs to migrate to the mouth of the insect in order to infect a new human being after a new bite. This migration takes time.

E) The mosquito actually transmits the virus almost immediately. It takes a week for the virus to multiply in the gut of the host before it causes any ill effects in that host.

61) The unique characteristic of Lyme disease is

A) erythema migrans.

B) induration.

C) carbuncle.

D) furuncle.

E) rash on palms.

62) The stage of Lyme disease that is characterized by arthritis is the

A) primary.

B) third.

C) second.

D) fourth.

E) intermediate.

63) The most important vector of Lyme disease in the eastern United States is

A) Dermacentor virabilis.

B) Dermacentor andersoni.

C) Staphylococcus aureus.

D) Ixodes scapularis.

E) Borrelia bergdorferi.

64) Which of the following pertains to Borrelia burgdorferi?

A) Coccus

B) Bacillus

C) Spirochete

D) Filament

E) Capsid

65) The preferred host of Ixodes scapularis is the

A) wood rat.

B) white-footed mouse.

C) moose.

D) human.

E) ground squirrel.

66) The growth stage of the vector that is mainly responsible for transmitting Lyme disease is the

A) nymph stage.

B) egg.

C) moulter.

D) adult.

E) mouse.

67) When Lyme disease was first being investigated, the observation that frequently only one person in a household was infected was a clue leading to the discovery that the disease was transmitted by arthropod bites. Why was this so?

A) If the infection is spread by the bite of an arthropod, it wouldn't spread easily by respiratory secretions, direct contact, or sexual contact between individuals within the family.

B) Mosquitoes (an example of arthropods) are never inside a house. They are strictly outdoor insects, so they couldn't spread the infection inside the household.

C) Mosquitoes (an example of arthropods) only bite once in their lifetime. As such, they can only transmit the illness once before they die. Even if an infected mosquito was inside a house, it could only infect one human.

D) Arthropods lose their mechanical ability to bite a human after a single bite, much like certain bees lose their stinger after a single sting. This prevents them from transmitting the infection to more than one individual in a household.

E) These are all valid reasons that support the theory that Lyme disease must be transmitted by arthropod bites.

68) Borrelia burgdorferi is a microaerophilic spirochete.

69) Which statement about the cardiovascular and lymphatic systems is NOT true?

A) The cardiovascular and lymphatic systems are typically sterile.

B) Veins carry blood away from the heart while arteries carry blood towards the heart.

C) Inflammation of lymphatic vessels is called lymphangitis, which presents as a red streak from an infection site toward the nearest lymph node.

D) Blood is exposed to immune cells as it passes through the spleen.

E) Phagocytes in spleen red pulp remove aging or damaged RBCs, bacteria, and other antigens from the blood.

70) In infective endocarditis, septic emboli may break off. What is/are the possible outcome(s) of emboli in the circulation?

A) They may block blood vessels, leading to death of the tissue supplied by the vessel.

B) They can cause a vessel to weaken and balloon out, forming an aneurysm.

C) They lead to the formation of immune complexes that lodge in the skin, the eyes, and other body structures.

D) They can cause a vessel to weaken and balloon out, forming an aneurysm AND they may block blood vessels, leading to death of the tissue supplied by the vessel.

E) They lead to the formation of immune complexes that lodge in the skin, the eyes, and other body structures AND they can cause a vessel to weaken and balloon out, forming an aneurysm.

71) What leads to organ failure in sepsis?

A) Uncontrolled inflammation that leads to neutrohpils releasing damaging toxins and lysosomal enzymes.

B) Helper T cells and dendritic cells undergo apoptosis, causing immunosuppression that results in organ rejection.

C) Formation of small clots in capillaries, impairing blood flow to organs and causing hypoxia and cell death.

D) Accumulation of endotoxins released from Gram-negative bacteria in the organs, causing tissue damage and cell death.

E) Organisms from an infected site generate biofilms that break apart, leading to emboli and organ destruction.

72) Which of the following contribute(s) to lung damage in people with sepsis?

A) Increased capillary leakage of plasma AND damaging lysosomal enzymes released from leukocytes.

B) Damaging lysosomal enzymes released from leukocytes AND organ damage from clots in capillaries.

C) Depletion of clotting proteins AND decreased muscle tone of heart and arteries.

D) Depletion of clotting proteins AND damaging lysosomal enzymes released from leukocytes.

E) Decreased muscle tone of heart and arteries AND increased capillary leakage of plasma.

73) Select one FALSE statement about sepsis.

A) Lung damage is an important cause of death in people with sepsis.

B) Sepsis can be caused by Gram-positive or Gram-negative bacteria.

C) Common causes of fatal sepsis include members of the normal microbiota of the large intestine.

D) Sepsis is sometimes a healthcare-associated illness but is more commonly a community-acquired infection.

E) Use of medical equipment where biofilms readily develop increases the risk of sepsis.

74) Select the statement about plague that is TRUE.

A) When Yersinia pestis infects the lungs, septicemic plague always develops.

B) Bubonic plague is transmitted by the bite of infected mosquitoes that have also bitten rats.

C) The causative agent of plague is a facultatively anaerobic, Gram-positive rod.

D) DIC causes the dusky color of skin and mucous membranes characteristic of bubonic plague.

E) Bubonic plague is almost always fatal.

75) Which of the following virulence factors of Yersinia pestis aid(s) in attachment to host cells?

A) Yersinia outer proteins (Yops)

B) Endotoxin

C) PsaA

D) Pla

E) V antigen

Please read the scenario and answer the questions.

You go hiking in the woods with some of your classmates. A few days after the hike, your friend Alice calls to tell you she is not feeling well and that she is going to skip soccer practice that evening. She says she has a weird rash on her leg and wonders if she was bitten by a spider while your were hiking. She sends you a photo of the rash. You are in your final semester of nursing school and have recently studied disease of the cardiovascular system. You think that the rash that Alice has is a sign of Lyme disease, and offer to take her to the urgent care to get medical help. While you are waiting to see a clinician, you review answer Alice's questions about Lyme disease.

76) What is unusual about Borrelia bergdorferi, the causative agent of Lyme disease?

A) Borrelia bergdorferi is a pathogenic spirochete.

B) The bacterium is a Gram-negative, microaerophilic pathogen.

C) The organism contains plasmids that have genes normally found on the chromosome.

D) B. bergdorferi causes flu-like signs and symptoms when it first infects a host.

E) The cells have a thin peptidoglycan cell wall with an outer membrane containing LPS.

77) What causes the characteristic erythema migrans of Lyme disease?

A) After a person acquires the causative bacteria by eating contaminated meat, the bacteria migrate to the skin in a corkscrew-like motion, killing host cells as they move and causing the bull's-eye rash.

B) After being introduced into the skin by the bite of an infected tick, the Gram-negative bacteria migrate outward in a circular manner; the LPS in their outer layer causes an inflammatory reaction.

C) After being introduced into the skin by the bite of an infected mosquito, the Gram-positive bacteria migrate outward in a corkscrew-like manner; the NAGs and NAMs in their cell wall causes an inflammatory reaction.

D) Borrelia bergdorferi cells propel themselves from host cell to host cell using actin tails, in a manner similar to Shigella cells. As they move, the bacteria destroy the host cells, causing the characteristic rash.

E) Borrelia bergdorferi is an encapsulated organism. The capsule of these cells is composed of hyaluronic acid that causes a widespread inflammatory response in the skin of the host that manifests as a rash.

78) Lyme disease is a zoonosis with humans being an accidental host. What does this mean?

A) Borrelia bergdorferi is transmitted to animals from humans AND the bacterium cannot complete its life cycle in humans.

B) Borrelia bergdorferi is found predominantly in zoo animals AND the bacterium cannot complete its life cycle in humans.

C) Borrelia bergdorferi is transmitted to humans from animals AND humans are not the normal host for the tick vector.

D) Borrelia bergdorferi is found predominantly in zoo animals AND the tick vector cannot complete its life cycle in humans.

E) Borrelia bergdorferi is found predominantly in zoo animals AND humans are not the normal host for the tick vector.

79) Why is it more difficult to treat a late persistent Lyme infection than an early disseminated Lyme infection?

A) The bacteria have developed resistance to multiple antibiotics by the late stage of the disease, so it is difficult to effectively treat a person.

B) A person with Lyme disease develops resistance to multiple antibiotics throughout the course of the disease, so treating them in the late stage of the disease becomes challenging.

C) Borrelia bergdorferi produces extremely resistant endospores in the late stage of the disease. Once these have been formed, it is very difficult to treat the disease.

D) The bacteria are no longer dividing in the late stage of Lyme disease, and as antibiotics only work against actively dividing bacteria, they are less effective at this stage.

E) Borrelia bergdorferi forms dense biofilms under the skin of infected people in the late stage of the disease. Bacteria within biofilms are protected from the effects of antibiotics and are difficult to kill.

80) Which statement is NOT true of Lyme disease?

A) Untreated Lyme disease can lead to serious complications, including arthritis and cardiovascular and neurological problems.

B) The main reservoirs for Borrelia bergdorferi are infected white-footed mice, deer, deer ticks, and deer mosquitoes.

C) Several different antibiotics can be used to treat patients in the early stages of Lyme disease, including doxycycline, amoxicillin, and cefuroxime.

D) Chronic Lyme disease signs and symptoms such as arthritis occur due to persisting bacteria and the host's immune response to them.

E) Signs and symptoms of Lyme disease occur in three phases, although individual patients may be asymptomatic in one or more of these stages. 

Please read the following scenario and answer the questions.

Two people are brought to the Emergency Department where you work. The first patient reports fever, abdominal pain, vomiting, and diarrhea. The second patient appears extremely ill. Her family tells you that she also had gastrointestinal signs and symptoms a few days ago. She has now developed severe skin blistering, has a very high fever and is only semi-conscious. When you question the first patient and the family of the second patient, you discover that they know each other and that they have all recently returned from a beach vacation in a major city on the U.S. Gulf Coast. The group tells you that the enjoyed a raw oyster dinner on the last day of their summer vacation. They think that both patients are probably just allergic to seafood, but given the severity of the signs and symptoms of your patients, you suspect that they may have Vibrio vulnificus infection. Lab tests confirm your suspicion. You give the families information on this disease.

81) Which of the statements regarding Vibrio vulnificus infection and its causative agent is FALSE?

A) Vibrio vulnificus is a Gram-negative, motile, curved, rod-shaped bacterium that is related to V. cholerae but lacks a capsule.

B) V. vulnificus releases degradative enzymes as well as toxins in a coordinated manner, controlled by a quorum-sensing mechanism.

C) V. vulnificus produces endotoxin, which causes an uncontrolled inflammatory response that leads to endotoxic shock.

D) In most people, V. vulnificus causes fever, vomiting, diarrhea, and abdominal pain, but immunocompromised people are at risk of developing sepsis.

E) V. vulnificus produces a cytotoxin called RTX that kills epithelial cells by forming pores in their membranes.

82) Patients with V. vulnificus infection are given a combination of synergistic antibiotics. This means that

A) each antibiotic works independently, but does not inhibit the action of the other antibiotic(s) in the combination.

B) the action of one antibiotic diminishes the effect of the other(s) in the combination.

C) the antibiotics work together to produce a stronger effect than each antibiotic on its own.

D) one antibiotic in the combination is always broad spectrum while the other(s) is/are always narrow spectrum.

E) the antibiotics given in combination are always broad spectrum medications.

83) You find out that the seriously ill patient has an underlying condition. Which of the following likely predisposed her to the more severe infection?

A) Cirrhosis

B) Asthma

C) Glomerulonephritis

D) Osteoporosis

E) Cystitis

84) People with chronic liver disease frequently have elevated levels of iron in their blood. Iron is needed by V. vulnificus for growth. How does it acquire iron from the host?

A) V. vulnificus produces siderophores that allow it to scavenge iron.

B) V. vulnificus produces a hemolysin that lyses blood cells to release iron-containing hemoglobin.

C) V. vulnificus produces a hemolysin that lyses blood cells to release iron-containing hemoglobin AND it produces siderophores that allow it to scavenge iron.

D) V. vulnificus produces a hemolysin that lyses white blood cells to release iron-containing hemoglobin AND it produces transferrins that allow it to scavenge iron.

E) V. vulnificus produces a hemolysin that lyses white blood cells to release iron-containing hemoglobin AND it produces lactoferrins that allow it to scavenge iron.

85) Which of the following is/are the modes of transmission for T. francisella? 

A) By inhalation

B) Through minor cuts or abrasions

C) Via ingestion of contaminated meat

D) By tick bites

E) All of these

86) How does F. tularensis avoid the immune system?

A) By having altered surface components AND by destroying lymphocytes. 

B) By escaping from the macrophage phagolysosome AND by producing streptokinases.

C) By synthesizing a large polysaccharide capsule AND by degrading complement component C3b.

D) By synthesizing a large polysaccharide capsule AND by escaping the macrophage phagolysosome.

E) By having altered surface components AND by escaping the macrophage phagolysosome.

87) Which of the following is NOT a possible sign/symptom or complication of brucellosis?

A) Depression

B) Endocarditis

C) Meningitis

D) Erythema migrans

E) Osteomyelitis

88) Which of the following is NOT a zoonosis?

A) Brucellosis

B) Infectious mononucleosis

C) Lyme disease

D) Tularemia

E) Plague

89) Which statement about infectious mononucleosis is FALSE?

A) Initial signs and symptoms of EBV infection resemble those of pharyngitis.

B) In a non-productive EBV infection, the virus establishes a latent infection and is maintained as either a plasmid or a provirus.

C) EBV-infected B cells produce a heterophile antibody that plays no role in the pathology of mononucleosis, but can be used for diagnosis.

D) Infectious mononucleosis results in lymph node and spleen enlargement, and is occasionally fatal because the spleen may rupture.

E) Antiviral medications such as acyclovir and famciclovir inhibit both productive and non-productive EBV infections.

90) What is the significance of immune complex formation in infective endocarditis?

A) They can be deposited in tissues and organs, causing damage.

B) They lead to the formation of biofilms that are difficult to eliminate.

C) They cause disseminated intravascular coagulation.

D) They result in the enzymatic destruction of neutrophils and macrophages.

E) They lead to the development of autoimmunity.

91) Which of the following possibly explains the development of dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS)?

A) Previously formed antibodies to one serotype of dengue virus bind to the second serotype and rather than neutralizing it, facilitate its entry into cells that express Fc receptors. This leads to increased numbers of infected cells and a high viral load.

B) Previously formed antibodies to one serotype of dengue virus suppress the immune response to infection with other serotypes; this allows the second infection to become much more severe than the first infection.

C) Infection with one serotype of dengue virus results in the formation of clots in small blood vessels throughout the body; viruses from a second infection enter these clots and multiply uninhibited within them, resulting in serious disease.

D) Antibodies generated in response to one serotype of dengue virus cross react with a second serotype of the virus. This leads to the formation of immune complexes that lodge in the brains of infected people, causing serous illness.

E) Dengue viruses are DNA viruses that can integrate into the chromosome of the host cell. If a cell is already infected with one serotype of the virus, infection with a second serotype will lead to the death of that cell.

92) Why might the Yersinia pestis from a patient with pneumonic plague be more dangerous than the same organism from fleas?

A) The organism mutates in a person with pneumonic plague, so is more dangerous.

B) The organism involved in pneumonic plague is resistant to multiple antibiotics.

C) The organism acquired this way is already fully virulent, so is especially dangerous.

D) Y. pestis in the lungs has a polysaccharide capsule while that in fleas does not.

E) These are all true.

93) Which is NOT a reason that it would be more difficult to eradicate Lyme disease than rubeola or rubella?

A) Lyme disease is transmitted by Ixodes tick vectors—it would be impossible to eliminate these ticks from earth. 

B) The causative agent of Lyme disease is harbored in intermediate hosts (mice and deer)—elimination of these would be impossible.

C) Rubeola and rubella only infect humans—if all humans were immune (through vaccination for example), the diseases would be eliminated. 

D) Lyme disease is cannot be treated successfully with antimicrobials, while rubella and rubeola can be successfully treated—it is thus easier to eliminate them.

E) These are all valid reasons to explain why eradicating Lyme disease would be more difficult than eliminating rubella and rubeola.