Micro

Question 1

1) Your patient is a 30-year-old man who has frequent episodes of herpes labialis. He asks you to tell him something about herpes simplex virus type 1 (HSV-1). Which one of the following would be the most accurate statement to make?
A) Acyclovir can eradicate the latent state of HSV-1 but not HSV-2
B) The main site of latency by HSV-1 is the neurons in the sensory ganglia of the face. C) HSV-1 is an enveloped virus that has a DNA genome and a DNA polymerase in the virion
D) The lesions of primary HSV-1 infections are less extensive and less severe than the lesions of recurrent HSV-1 infections
E) The laboratory diagnosis of HSV-1 infections typically involves the detection of a greater than fourfold rise in antibody titer against the virus

Answer 1

B) The main site of latency by HSV-1 is the neurons in the sensory ganglia of the face.

Question 2

2) Regarding varicella-zoster virus (VZV), which one of the following is most accurate? A) High-dose acyclovir can eliminate the latent state caused by VZV
B) The principal site of latency of VZV is in the nucleus of motor neurons
C) Domestic animals, such as pigs and chickens, are the main reservoir for VZV
D) The vaccine against varicella contains all three serotypes of formalin-killed VZV as the immunogen
E) When zoster occurs in an immunocompromised patient, acyclovir should be given to prevent disseminated infection.

Answer 2

E) When zoster occurs in an immunocompromised patient, acyclovir should be given to prevent disseminated infection.

Question 3

3) Regarding cytomegalovirus (CMV), which one of the following is most accurate?
A) CMV is usually acquired by the fecal-oral route in adults
B) Neonates born from infected mothers should be given the subunit vaccine
C) Reactivation of CMV in sensory ganglion cells leads to painful vesicles along nerves D) Lamivudine should be used to treat CMV infections in immunocompromised patients E) CMV infection of a fetus during the first trimester results in more congenital abnormalities than infection in the third trimester.

Answer 3

E) CMV infection of a fetus during the first trimester results in more congenital abnormalities than infection in the third trimester.

Question 4

4) Regarding Epstein-Barr virus (EBV) and infectious mononucleosis, which one of the following is most accurate?
A) EBV enters the latent state primarily in CD4-positive helper T cells
B) Approximately 10% of people have been exposed to EBV
C) People with infectious mononucleosis produce antibodies that agglutinate sheep red cells.
D) The atypical lymphs in the blood of people with infectious mononucleosis are EBV-infected T helper cells
E) Patients with deficient cell-mediated immunity should receive passive-active immunization against EBV

Answer 4

C) People with infectious mononucleosis produce antibodies that agglutinate sheep red cells.

Question 5

5) A 26-year-old man develops myopericarditis with mild congestive heart failure that increases over several weeks. Coxsackievirus B5 infection is diagnosed. Which of the following clinical syndromes is not associated with coxsackievirus infections?
A) Herpangina
B) Myocarditis or pericarditis
C) Aseptic meningitis
D) Acute hemorrhagic conjunctivitis
E) Progressive postpolio muscle atrophy.

Answer 5

E) Progressive postpolio muscle atrophy.

Question 6

6) A 3-month-old child develops fever, restlessness, and unusual crying. These are followed by apparent lethargy. Physical examination shows a normal-appearing infant who is minimally responsive to stimuli. A lumbar puncture yields cerebrospinal fluid with 200 white blood cells per microliter, predominantly lymphocytes. Acute aseptic meningitis is diagnosed, probably caused by an enterovirus. Enteroviruses are characterized by?
A) Latency in sensory ganglia and reactivation primarily in immunocompromised patients B) Transmission primarily by the fecal-oral route.
C) The presence of a DNA polymerase enzyme
D) The entry of cells following binding to the intercellular adhesion molecule-1 (ICAM-1) receptor
E) Undergoing antigenic shift and drift

Answer 6

B) Transmission primarily by the fecal-oral route.

Question 7

7) Which virus is not a zoonotic virus? A) Epstein-Barr virus.
B) Hantavirus
C) Ebolavirus
D) SARS-Coronavirus
E) Influenza-A (H1N1) virus

Answer 7

A) Epstein-Barr virus.

Question 8

8) One month after school has been let out for the summer, a 16-year-old girl develops fever, myalgia, and headache. An outbreak of an illness with similar symptoms caused by an echovirus is known to be occurring in the community.
The primary anatomic site of echovirus multiplication in the human host is?
A) The muscular system
B) The central nervous system
C) The alimentary tract.
D) The blood and lymph system E) The respiratory system

Answer 8

C) The alimentary tract.

Question 9

9) Which of the following statements about enteroviral meningitis is true? A) Vaccines are generally available to protect against the disease
B) The main symptom is muscle paralysis
C) Transmission is usually by the fecal-oral route.
D) The causative agents do not survive well in the environment E) Recovery is rarely complete

Answer 9

C) Transmission is usually by the fecal-oral route.

D) The causative agents do not survive well in the en

Question 10

10) Which of the following properties of enteroviruses is not shared by rhinoviruses? A) Single-stranded RNA genome
B) Production by cleavage of viral proteins from a polyprotein precursor
C) Resistance to lipid solvents
D) Stability at acid pH (pH 3.0). E) Icosahedral symmetry

Answer 10

D) Stability at acid pH (pH 3.0).

Question 11

11) Outbreaks of hand-foot-and-mouth disease, characterized by oral ulcerations and vesicular rashes, occur and may result in infant deaths. The disease is caused by? A) Foot-and-mouth disease virus.
B) Chickenpox virus
C) Nonpolio enteroviruses D) Rhinoviruses
E) Rubella virus

Answer 11

A) Foot-and-mouth disease virus.

Question 12

12) Live, attenuated oral polio vaccine (OPV) and inactivated polio vaccine (IPV) are both available. In which one of the following situations is the use of OPV preferred?
A) Routine infant vaccination
B) Mass immunization programs in areas of high poliomyelitis endemicity.
C) Adult immunization
D) Patients who are receiving immunosuppressive therapy E) Family contacts of immunocompromised patients

Answer 12

B) Mass immunization programs in areas of high poliomyelitis endemicity.

Question 13

13) Each of the following clinical syndromes is associated with infection by picornaviruses except?
A) Myocarditis or pericarditis
B) Hepatitis
C) Mononucleosis. D) Meningitis

Answer 13

C) Mononucleosis.

Question 14

14) Which of the following statements is most characteristic of poliovirus? A) The genome is double-stranded DNA
B) Intestinal replication is extensive.
C) Congenital infections are frequent
D) A skin test can identify previous exposure E) Amantadine chemoprophylaxis is effective

Answer 14

B) Intestinal replication is extensive.

Question 15

15) Coxsackieviruses appear worldwide particularly in young persons. Their epidemiology and pathogenesis most closely resembles?
A) Adenoviruses
B) Influenza A
C) Polioviruses. D) Hepatitis A E) Mumps

Answer 15

C) Polioviruses.

Question 16

16) Which of the following is the site of latent infection of Varicella zoster virus following primary infection?
A) Lymphoid tissues
B) Kidney
C) Neurons.
D) Skin
E) Salivary glands

Answer 16

C) Neurons.

Question 17

17) A 20-year-old university student was brought to the emergency department by his dorm mate with a petechial rash, headache, nuchal rigidity, and vomiting. Which of the following describes the most likely causal agent?
A) Gram-negative coccus, capsule, ferments maltose.
B) Gram-negative coccus, ferments glucose only
C) Gram-negative coccobacillus, capsular serotype b
D) Gram-positive coccus, alpha hemolytic, optochin sensitive E) Gram-positive rods, growth at 4°C

Answer 17

A) Gram-negative coccus, capsule, ferments maltose.

Question 18

18) Which one of the following agents lacks nucleic acid? A) Bacteria
B) Viruses
C) Viroids
D) Prions
E) Protozoa

Answer 18

D) Prions

Question 19

19) One major advantage of the conjugate meningococcal vaccines compared with the polysaccharide vaccine is?
A) Stimulation of mucosal secretory IgA
B) Fewer side effects
C) A T cell-dependent response to vaccine is induced. D) Inclusion of serogroup B

Answer 19

C) A T cell-dependent response to vaccine is induced.

Question 20

20) A previously healthy 12-month-old girl presents to the emergency department with a 1- day history of fever, vomiting, and lethargy. The child has had a few upper respiratory infections and ear infections, but her history is otherwise unremarkable. The family stated that they did not vaccinate their child due to religious objections. The child’s temperature is 38.8°C. On the physical examination, Brudzinski’s and Kernig’s signs are positive. An organism from the cerebrospinal fluid (CSF) does not grow on blood or MacConkey agars but does grow on media supplemented with hemin and nicotinamide adenine dinucleotide (NAD). Which of the following would most likely be observed on Gram stain from the girl’s CSF?
A) Gram-positive rod
B) Gram-negative coccobacilli. C) Gram-negative diplococci
D) Gram-positive diplococci
E) Gram-positive cocci in clusters

Answer 20

B) Gram-negative coccobacilli.

Question 21

21) A 40-year-old woman presents with a 1-day history of fever, headache, vomiting, and abdominal cramps. She was diagnosed with lung cancer three months ago and is currently undergoing chemotherapy. A lumbar puncture is performed, and the CSF shows pleocytosis with a neutrophil predominance, gram-positive rods, elevated protein, and decreased glucose. The most likely virulence mechanism mediating this infection is:
A) A polysaccharide capsule
B) Intracellular survival and spread. C) Lipopolysaccharide (LPS)
D) Pili
E) Superantigen production

Answer 21

B) Intracellular survival and spread.

Question 22

22) Which of the following is a characteristic of abnormal prions (PIPSc)? A) Effectively disinfected by heating to at least 100°C
B) Genome has RNA but not DNA
C) Levels remain constant throughout disease
D) Normally found in the tissues of animals and humans E) Occur due to the misfolding of normal prions protein.

Answer 22

E) Occur due to the misfolding of normal prions protein.

Question 23

.23) Which of the following organisms is most likely the cause of this patient’s death? A) Clostridium tetani
B) Herpes simplex virus
C) Rabies virus.
D) Toxoplasma gondii E) West Nile virus

Answer 23

C) Rabies virus.

Question 24

24) Which of the following scenarios is most probable for transmission of this organism? A) Animal bite.
B) Cat litter box
C) Mosquito bite
D) Sexual
E) Unwashed wound

Answer 24

A) Animal bite.

Question 25

25) Which of the following pathologies is indicative of this infection in a postmortem evaluation of tissue?
A) Bielschowsky bodies
B) Cowdry type A bodies
C) Cowdry type B bodies D) Negri bodies.
E) Paschen bodies

Answer 25

D) Negri bodies.

Question 26

26) Which of the following is most useful in the antemortem diagnosis of this infection? A) Clinical signs
B) Culture
C) Western blot
D) Polymerase chain reaction (PCR) E) Skin biopsy.

Answer 26

E) Skin biopsy.

Question 27

.27) If the patient had seen a doctor at the initial time of infection, he could have been treated and almost certainly survived. Which of the following describes the appropriate treatment at the time of infection?
A) Antibiotic therapy with a carbapenem and an aminoglycoside
B) Antiviral treatment with cidofovir
C) Immune modulatory therapy with interferon
D) Immune suppression with high-dose steroids and cyclosporine, followed by rituximab E) Passive immunization with immunoglobulin and active immunization with vaccine.

Answer 27

E) Passive immunization with immunoglobulin and active immunization with vaccine.

Question 28

28) 47-year-old man with poorly controlled diabetes mellitus developed a bloody nasal discharge, facial edema, and necrosis of his nasal septum. Culture of his cloudy nasal secretions yielded Rhizopus species. What is the most important implication of this finding?
A) No diagnostic value because this mold is an airborne contaminant B) Consider treatment for rhinocerebral mucormycosis (zygomycosis). C) Strongly suggestive of ketoacidosis
D) Strongly suggestive of HIV infection
E) The patient has been exposed to indoor mold contamination

Answer 28

B) Consider treatment for rhinocerebral mucormycosis (zygomycosis).

Question 29

29) A 75-year-old man presents with headache and confusion. He has a low grade fever and 10 lymphocytes in his CSF. Cultures of sputum, urine, blood, and SF yielded no pathogens. For which of the following fungal agents would detection of circulating antigen be a useful diagnostic test?
A) Candida albicans
B) Aspergillus fumigatus
C) Histoplasma capsulatum D) Coccidioides immitis
E) Cryptococcus neoformans.

Answer 29

E) Cryptococcus neoformans.

Question 30

30) A diabetic patient has developed fever and swelling around the eye. Material taken from the adjacent nasal sinus shows large nonseptate hyphae. Which of the following agents is the most probable cause?
A) Candida
B) Aspergillus C) Trichophyton D) Rhizopus.
E) Sporothrix

Answer 30

D) Rhizopus.

Question 31

31) A 48-year-old alcoholic man is admitted to a hospital because of stupor. He is unkempt and homeless and lives in an encampment with other homeless people, who called the authorities when he could not be easily aroused. His temperature is 38.5°C, and his blood pressure 125/80 mm Hg. He moans when attempts are made to arouse him. He has positive Kernig and Brudzinski signs, suggesting meningeal irritation. Physical examination and chest radiography show evidence of left lower lobe lung consolidation. An endotracheal aspirate yields rust-colored sputum. Examination of a Gram-stained sputum smear shows numerous polymorphonuclear cells and numerous Gram-positive lancet shaped diplococci. On lumbar puncture, the cerebrospinal fluid is cloudy and has a white blood cell count of 570/ML with 95% polymorphonuclear cells; Gram-stain shows numerous Gram positive diplococci. Based on this information, the likely diagnosis is?
A) Pneumonia and meningitis caused by S.aureus
B) Pneumonia and meningitis caused by S.pyogenes
C) Pneumonia and meningitis caused by S.pneumoniae.
D) Pneumonia and meningitis caused by E.faecalis
E) Pneumonia and meningitis caused by Neisseria meningitidis

Answer 31

C) Pneumonia and meningitis caused by S.pneumoniae.

Question 32

32) A 6-year-old boy develops a fever and headache. He is taken to the emergency department, where he is noted to have a stiff neck, suggesting meningeal irritation. A lumbar puncture is done, and culture of the cerebrospinal fluid grows N. meningitidis serogroup B. Which of the following should be considered for his family (household) members?
A) No prophylaxis or other steps are necessary
B) They should be given N. meningitidis pilin vaccine
C) They should be given N. meningitidis serogroup B polysaccharide capsule vaccine D) They should be given rifampin prophylaxis.
E) They should be given sulfonamide prophylaxis

Answer 32

D) They should be given rifampin prophylaxis.

Question 33

33) A 19-year-old female college student has a fever, sore throat, and lymphadenopathy accompanied by lymphocytosis with atypical cells and an increase in sheep cell agglutinins. The diagnosis is most likely?
A) Infectious hepatitis
B) Infectious mononucleosis. C) Chickenpox
D) Herpes simplex infection E) Viral meningitis

Answer 33

B) Infectious mononucleosis.

Question 34

34) Vaccines have been demonstrated to be efficacious in preventing herpesvirus disease in which one of the following situations?
A) Herpes simplex virus type 1 primary infection
B) Herpes simplex virus type 2 reactivation
C) Varicella-zoster reactivation.
D) Cytomegalovirus primary infection E) Epstein-Barr virus reactivation

Answer 34

C) Varicella-zoster reactivation.

Question 35

35) Which of the following statements about rabies vaccines for human use is true? A) Contain live, attenuated rabies virus
B) Contain multiple antigenic types of rabies virus
C) Can treat clinical cases of rabies
D) Can be used for post exposure prophylaxis.
E) They are associated with Guillain-Barre syndrome

Answer 35

D) Can be used for post exposure prophylaxis.

Question 36

36) If the preliminary CSF Gram stain resulted in gram ( +) bacilli, coverage against what pathogen should be included?
A) Streptococcus pneumoniae
B) Listeria monocytogenes.
C) Haemophilus influenzae D) Neisseria meningitidis

Answer 36

B) Listeria monocytogenes.

Question 37

37) A young man developed excessive salivation, aversion to drinking water, and hallucinations after eight weeks of a fox bite, and died in cardiac arrest. Which of the following measures might have prevented this death if implemented upon bite?
A) Interleukin 2 infusions
B) Acyclovir prophylaxis
C) Specific vaccine and immunoglobulin administration. D) Ribavirin treatment
E) Intensive care treatment

Answer 37

C) Specific vaccine and immunoglobulin administration.

Question 38

38) Each of the following statements concerning Cryptococcus neoformans is correct EXCEPT:?
A) Its natural habitat is the soil, especially associated with pigeon feces
B) Pathogenesis is related primarily to the production of exotoxin A.
C) Budding yeasts are found in the lesions
D) The initial site of infection is usually the lung

Answer 38

B) Pathogenesis is related primarily to the production of exotoxin A.