(Courtesy of CDC/Sol Silverman Jr, DDS, University of California, San Francisco 1987; ID #6066.)

a. Abacavir alone

b. Efavirenz plus tenofovir plus emtricitabine

c. Darunavir boosted with ritonavir

d. Maraviroc plus enfuvirtide plus raltegravir

e. Nevirapine alone

68. An HIV-positive patient, after treatment with tenofovir/emtricitabine plus ritonavir-boosted atazanavir, has a CD4 T-cell count of 325/µL and a viral load of less than 50 copies of HIV RNA/mL. Previously her CD4+ T-cell count was 280/µL and viral load was 100,000 copies/mL. Which of the following best describes this patient?

a. This patient is no longer in danger of opportunistic infection

b. The 5-year prognosis is excellent

c. The patient’s HIV screening test is most likely negative

d. The patient is not infectious

e. The antiretroviral therapy has been effective

69. An HIV-positive patient with a viral load of 100,000 copies/mL of HIV RNA and a drop in his CD4 T-cell count from 240 to 50/µL has been diagnosed with Pneumocystis jiroveci pneumonia. Which of the following is the best description of the stage of this patient’s HIV disease?

a. HIV infection, stage 1

b. HIV infection, stage 2

c. HIV infection, stage 3 (AIDS)

d. HIV infection, stage unknown

70. A 19-year-old college student presents to the student health clinic complaining of sore throat, fever, swollen neck lymph nodes, and malaise of several days. His complete blood count shows WBC count 22,000/µL with 10% neutrophils, 28% lymphocytes, 47% reactive lymphocytes, and 15% monocytes. His monospot test is positive. Which of the following is causing this student’s infection?

a. Adenovirus

b. Cytomegalovirus

c. Echovirus

d. Epstein–Barr virus

e. Human metapneumovirus

71. During a medical checkup for a new insurance policy, a 60-year-old grandmother is found to be positive by a conventional EIA screening test for antibodies against HIV-1. She has no known risk factors for exposure to the virus. Which of the following is the most appropriate next step?

a. Immediately begin antiretroviral therapy

b. Perform the EIA screening test a second time

c. Request that a viral blood culture be done by the laboratory

d. Tell the patient that she is likely to develop AIDS

e. Test the patient for Pneumocystis jiroveci infection

72. A 74-year-old man who lived in Illinois developed malaise, fever, cough, and sore throat in August. Two days later, he visited his doctor because of severe headache, nausea and vomiting, and continued fever. He told his doctor that the mosquitoes had been fierce in the last 2 weeks and that he had been bitten numerous times. The doctor noted tremors in the man’s hands as well as fever of 104°F, and admitted him to the hospital for tests. Examination of CSF revealed normal glucose and protein with 150 lymphocytes/µL; PCR assays for HSV and West Nile virus (WNV) on the CSF were negative. Despite supportive care, the man slipped into a coma and died. Which of the following viruses was most likely responsible for this man’s illness?

a. Coltivirus

b. Dengue virus

c. Erythrovirus (parvovirus B19)

d. La Crosse virus

e. St. Louis encephalitis virus

73. A 64-year-old man complained of poor memory and difficulty with vision that was progressing rapidly and myoclonic jerks. Cerebrospinal fluid examination at a reference laboratory revealed the presence of 14-3-3 protein. Over the next 6 months his cognitive deterioration became severe and he died 2 months later. At autopsy, spongiform encephalopathy was noted. Which of the following is the most appropriate diagnosis for this man?

a. Sporadic Creutzfeldt–Jakob disease (CJD)

b. Familial CJD

c. Iatrogenic CJD

d. Variant CJD

74. In 2003, the zoonotic severe acute respiratory syndrome (SARS) coronavirus caused a pandemic in which over 8000 people were infected and the mortality rate was 10%. In 2012, a novel coronavirus was isolated from 12 persons in Saudi Arabia, Qatar, and Britain with severe respiratory illness; so far, 50% have died. Which of the following syndromes is more commonly caused by other known types of human coronaviruses?

a. Common cold

b. Herpangina

c. Meningitis

d. Pneumonia

e. Vesicular lesions

75. A 35-year-old intravenous (IV) drug abuser with known chronic hepatitis B virus (HBV) status suddenly presents with an acute hepatitis episode. He develops massive hepatic necrosis and dies. Which of the following is most likely responsible for the change in his condition?

a. A hepatitis B mutant has developed

b. He has contracted hepatitis D virus (HDV)

c. He has developed cirrhosis

d. His food contained hepatitis A virus (HAV)

e. His food contained hepatitis E virus (HEV)

76. Which of the following antiviral compounds inhibits activity of the pyrophosphate-binding site of viral DNA polymerases and is used to treat serious infections with cytomegalovirus?

a. Amantadine

b. Foscarnet

c. Ganciclovir

d. Ribavirin

e. Zidovudine

77. A clinic associated with a medical school and located in a lower income city district documents a series of cases involving echoviruses in school-age children. Most cases experienced common cold symptoms plus mild fever and maculopapular rash; some were hospitalized with acute onset of fever, headache, nuchal rigidity, and petechial rash. All experienced complete recovery within 1 week without specific antiviral therapy. Which of the following body systems is the main target of echoviruses?

a. Bloodstream

b. Central nervous system (CNS)

c. Intestinal tract

d. Lymphoid tissues

e. Upper respiratory tract

78. A newborn infant presents with vesicular skin lesions. He also had generalized symptoms suggestive of CNS and liver involvement. His mother had developed painful vesicular lesions on her genitalia several days prior to the birth of her son. She had not sought medical help until she was in heavy labor. At admission to labor and delivery, internal lesions were seen on her cervix and vaginal walls, but the birth was eminent, precluding C-section. Which of the following is the most rapid test for definitive identification of the most likely etiologic agent?

Vesicular lesions of congenital herpes. (Courtesy of CDC.)

a. Detection of specific HSV IgG antibodies

b. Direct immunofluorescence for HSV on cells from lesions

c. HSV PCR on cerebrospinal fluid

d. Tzanck smear

e. Viral culture of fluid from lesions

79. Several children in a day care center for preschoolers developed fever, irritability, lack of appetite, and a vesicular rash found on their hands, feet, and mouths. With which virus were these children most likely infected?

(A: Courtesy of James Heilman, MD, Creative Attribution-Share Alike 3.0 Unported license; B: Courtesy of Ngufra, 2102-07-06, GNU Free Documentation License; C: Courtesy of DJ Midgley, May 2008, Creative Commons Attribution-Share Alike 3.0 Unported license.)

a. Coronavirus

b. Coxsackievirus A

c. Orthoreovirus

d. Respiratory syncytial virus

e. Rhinovirus

80. A 15-year-old boy is taken to his pediatrician after experiencing fever, malaise, and anorexia followed by tender swelling of his parotid glands. Which of the following is the most likely complication to occur in this patient?

a. Guillain–Barré syndrome

b. Hemorrhage

c. Myocarditis

d. Oophoritis

e. Orchitis

81. An otherwise healthy 65-year-old male was in a car accident and broke several ribs on the left side. Approximately 12 days later, he developed a painful, well-circumscribed vesicular rash over the left rib cage that persists for several weeks. The rash is most likely due to which of the following?

(Courtesy of CDC, 1995, ID#6886.)

a. Primary infection with HSV type 1

b. Reactivation of latent HSV type 1

c. Primary infection with Epstein–Barr virus

d. Reactivation of latent Epstein–Barr virus

e. Primary infection with VZV

f. Reactivation of latent VZV

82. A 3-year-old child who had not been immunized presents at the physician’s office with symptoms of coryza, cough, conjunctivitis, and photophobia. He has a low-grade fever, and small, bluish-white ulcerations are seen on the buccal mucosa opposite the lower molars. What is the causative agent of this child’s symptoms?

a. Adenovirus

b. HSV

c. Influenzavirus

d. Measles virus

e. Rubella virus

83. A sexually active woman was seen for a routine gynecologic exam that included a Pap smear. The report indicated cervical intraepithelial neoplasia. In situ hybridization showed the presence of human papillomavirus (HPV) type 16 genomes within the neoplastic cells. Which of the following processes is required for HPV to lead to the development of cancer?

a. Integration of the viral genome

b. Loss of HPV E6 and E7 genes

c. Mutation of the virus

d. Viral replication

84. Two siblings, ages 2 and 4, experience fever, rhinitis, and pharyngitis that result in laryngotracheobronchitis. Both have a harsh, bark-like cough and hoarseness. Which of the following viruses is the leading cause of their syndrome?

a. Adenovirus

b. Coxsackievirus B

c. Parainfluenza virus

d. Rhinovirus

e. Rotavirus

85. An outbreak of hepatitis occurred in an area of India with poor sanitation. Most of the patients reported fever, nausea with vomiting, and weight loss occurring over several days followed by jaundice and pruritus. Testing quickly ruled out HAV. A number of women in the area are pregnant. For which of the following are these women at risk?

a. Chronic hepatitis

b. Fetal hydrops

c. Fulminant hepatic failure

d. Guillain–Barré syndrome

e. Reye syndrome

86. An 18-year-old man was taken to an emergency medicine department because of fever and headache for 36 hours and now complaint of a stiff neck. No bacterial agents appeared to be involved and an initial diagnosis of aseptic meningitis was made. Which of the following laboratory findings in the examination of his cerebrospinal fluid led to this diagnosis?

a. Decreased protein content

b. Elevated glucose concentration

c. Eosinophilic pleocytosis

d. Lymphocytic pleocytosis

e. Neutrophilic pleocytosis

87. A street person well known to the local public health clinic appears to have acute symptoms of hepatitis and tests positive for HDV antigen. Knowing that HDV requires HBV, which of the following sets of test results shows this patient had chronic HBV infection and was superinfected with HDV?

a. HBsAg +, HBeAg +, Anti-HBcAg IgM +, Anti-HBcAg IgG -, Anti-HBsAg –

b. HBsAg +, HBeAg +, Anti-HBcAg IgM -, Anti-HBcAg IgG +, Anti-HBsAg –

c. HBsAg -, HBeAg -, Anti-HBcAg IgM -, Anti-HBcAg IgG +, Anti-HBsAg +

d. HBsAg -, HBeAg -, Anti-HBcAg IgM -, Anti-HBcAg IgG -, Anti-HBsAg +

88. A nurse develops clinical symptoms consistent with hepatitis. She recalls sticking herself with a needle approximately 5 months before, after drawing blood from a patient. Serologic tests for HBsAg, and antibodies to HBsAg and HAV are all negative; however, she is positive for HBcAg IgM antibody. Which of the following characterizes the current health state of the nurse?

a. Does not have hepatitis B

b. Has resolved hepatitis B

c. Has chronic hepatitis B

d. Is in window period of acute hepatitis B

e. Was immunized with HBsAg

89. A 65-year-old Florida fisherman forgot his insect repellent on a recent sporting trip. A week later, he developed fever, chills, headache, and flulike symptoms. He was brought to the Emergency Department by his wife with photophobia, extreme lethargy, and severe headache. CNS examination revealed cranial nerve deficits and hemiparesis. The patient was admitted to intensive care with a grave prognosis. Which of the following is the vector that transmitted the infection from which this man is suffering?

a. Bird

b. Flea

c. Mosquito

d. Sand fly

e. Tick

90. A local school district finds a large number of student absences, with the children presenting with rhinorrhea, nasal obstruction, headache, and malaise, but no fever. A strain of rhinovirus is the most likely etiologic agent of these infections. By which method is this virus most frequently spread?

a. Fecal–oral route

b. Hand-to-hand contact

c. Respiratory droplets

d. Sexual contact

e. Vertical transmission

91. A 10-month-old infant who was born 4 weeks premature was brought to the Emergency Department with high fever, rhinorrhea, cough, and difficulty breathing. On examination, the baby had dyspnea and tachypnea; rales and wheezing were heard over both lungs. The baby was admitted to Pediatric Intensive Care where she suffered respiratory failure and was placed on mechanical ventilation. Two different types of tests for respiratory syncytial virus (RSV or Pneumovirus) were negative, as were tests for parainfluenza virus, influenza A and B viruses, and adenovirus. Which of the following viruses is the most likely etiologic agent?

a. Cytomegalovirus

b. HSV type 1

c. Human metapneumovirus

d. Parvovirus B19

e. Rhinovirus

92. A 32-year-old woman was bitten on the fingers by a feral kitten that she was trying to feed. She cleaned the wounds, and after a week, the sites healed without bacterial infection. Sixty days later, she noticed pain, itching, and numbness at the sites of the bite wounds. Alarmed, she made an appointment to see her doctor the next day. By the time of the appointment, her arm was paralyzed, and she was febrile, had a headache, and was very anxious. Her doctor sent her to the hospital for a nuchal skin biopsy, which was sent to a reference laboratory for workup. The H&E stain showed viral inclusion bodies (A, arrows) and DFA (direct fluorescent antibody test) with virus-specific antiserum was positive (B). With which virus was this woman infected?

(A: Courtesy of CDC/Dr Daniel P. Perl, 1971, ID#1958; B: Courtesy of CDC/Dr. Tierkel, ID#6455.)

a. Cytomegalovirus

b. Eastern equine encephalitis virus (EEEV)

c. Echovirus

d. HSV type 1

e. Rabies virus

93. Kuru was a fatal disease of certain New Guinea natives and was characterized by tremors and ataxia; Creutzfeldt–Jakob disease (CJD) is characterized by both ataxia and dementia. CJD has been accidentally transferred to others by contaminated growth hormone from human pituitary glands, corneal transplants, and contaminated surgical instruments. These diseases are thought to be caused by which of the following?

a. Cell wall-deficient bacteria

b. Environmental toxins

c. Flagellates

d. Prions

e. Slow viruses

94. Recently, a recombinant vaccine bait to prevent rabies in raccoons had been used in wooded suburban communities. This bait uses a large double-stranded DNA virus that replicates in the cytoplasm as the carrier of the rabies glycoprotein gene. A woman who was immunocompromised found a bait that had broken open and picked it up to dispose of it. She subsequently developed lesions on her hands 11 days after she handled the bait. What caused these lesions?

(Courtesy of CDC; MMWR 2009;58:1204-1207.)

a. Adenovirus type 5

b. Echovirus 11

c. Rabies virus

d. Vaccinia virus

e. Variola (smallpox) virus

95. A 35-year-old man developed headache, nausea, vomiting, and sore throat 8 weeks after returning from a trip abroad. He eventually refused to drink water and had episodes of profuse salivation, difficulty in breathing, and hallucinations. Two days after the patient died of cardiac arrest, it was learned that he had been bitten by a dog while on his trip. Which of the following treatments, if given immediately after the dog bite, could have helped prevent this disease?

a. Broad-spectrum antibiotics

b. High-dose acyclovir

c. IV ribavirin

d. Rabies immune globulin plus rabies vaccine

e. Tetanus immune globulin and tetanus toxoid vaccine

96. A patient who works in an industrial setting presents to his ophthalmologist with prominent subconjunctival hemorrhage, periorbital swelling, and corneal changes consistent with keratitis. The patient reported severe photophobia and the sensation that something was in his eye. Nine other workers developed similar symptoms 7 days later. The differential diagnosis should include infection with which of the following viruses?

a. Adenovirus

b. Epstein–Barr virus

c. Parvovirus

d. Respiratory syncytial virus

e. VZV

97. A hospital worker is found to be positive for hepatitis B surface antigen. Subsequent tests reveal the presence of HBeAg as well. Which of the following best describes the worker?

a. Has a biologic false-positive test for hepatitis

b. Is highly contagious

c. Is less contagious

d. Is not contagious

e. Has resolved hepatitis B

98. An extended family met for a family reunion in a rural area of Texas. All reported numerous mosquito bites. One week later several family members had headache, nausea, fever, and malaise. Two developed stiff neck and severe headache that resolved over the next 5 days, and an 8-month-old was hospitalized with diffuse encephalitis. All family members recovered completely except the infant who was left with a seizure disorder. An arbovirus was confirmed as the etiologic agent by serologic testing of the effected persons. Which of the following is the most likely etiologic agent?

a. Dengue virus

b. Lymphocytic choriomeningitis virus

c. Rubella virus

d. Western equine encephalitis virus

e. WNV

99. A 2-month-old infant was admitted to the medical center in February for treatment of bronchiolitis. An immunofluorescent assay was positive for a respiratory virus. As the infant was struggling to breathe, ribavirin treatment was started immediately. With which virus was this infant infected?

a. Coxsackievirus A

b. HBV

c. HSV

d. Parvovirus

e. Respiratory syncytial virus

100. In January, a 74-year-old woman from Iowa is brought to the emergency department by her husband. He states that she had recent onset of high fever and headache. During the last 2 days, she has been confused and cannot perform daily chores. Shortly after arrival she suffers a seizure. Her physical examination indicates some weaknesses in her left side and neck stiffness. Magnetic resonance imaging images show encephalitis localized to the right temporal lobe. What is the most likely causative agent?

a. Adenovirus

b. Coxsackievirus B

c. HSV type 1

d. Listeria monocytogenes

e. WNV

101. An 8-month-old girl suddenly developed a high fever (103°F). Her pediatrician examined her and found no signs of upper respiratory tract infection, meningitis, or encephalitis. Two days later, the girl’s fever reached 105°F and she suffered a febrile seizure. By the time the child was brought to the pediatrician’s office, her temperature had dropped. The doctor noted a generalized papular rash. What was the doctor’s most likely diagnosis for this child?

a. Erythema infectiosum caused by parvovirus B19

b. Hand-foot-and-mouth disease caused by Coxsackievirus A

c. Measles caused by Morbillivirus

d. Roseola infantum caused by human herpes virus 6

e. Rubella caused by rubella virus

102. A 5-month-old infant, seen in the emergency room in winter, presents with fever and persistent cough with wheezing. Her mother states that the baby’s older brother, age 3, had recently had a runny nose, sore throat, and fever. Physical examination of the infant revealed tachypnea and tachycardia; expiratory wheezes were heard over both lungs. The baby was cyanotic and retractions were observed and a chest x-ray showed hyperinflated lung fields. Which of the following is most likely the cause of this infection?

a. Adenovirus

b. Coxsackievirus

c. Parainfluenza virus

d. Respiratory syncytial virus

e. Rhinovirus

103. Which one of the following groups of people is most likely to be at increased risk for HIV infection?

a. Sexual partners of IV drug abusers who share needles

b. Receptionists at a hospital

c. Persons who received blood transfusions in 2013

d. Members of a household in which there is a person who is HIV-positive

e. Factory workers whose coworkers are HIV-positive

104. An obstetrician sees a pregnant patient who was exposed to rubella virus in the 18th week of pregnancy. She does not remember getting a rubella vaccination. Which of the following is the best immediate course of action?

a. Administer rubella immune globulin

b. Administer rubella vaccine

c. Order a rubella antibody titer to determine immune status

d. Reassure the patient because rubella is not a problem until after the 30th week

e. Terminate the pregnancy

105. Two viral vaccines are expected to reduce the incidence of cancers. Which vaccines are these?

a. Adenovirus and mumps virus vaccines

b. HAV and poliovirus vaccines

c. HPV 16/18 and hepatitis B vaccines

d. Measles virus and rubella virus vaccines

e. Rotavirus and VZV vaccines

106. A group of healthcare workers from the United States staffing a clinic in India were working with children admitted with acute flaccid paralysis. The illness began with fever, nausea, vomiting, and severe headache followed by neck stiffness, muscle pain and weakness, and constipation. None of the workers became ill because they had been vaccinated against this disease. Which viral vaccine protected these workers?

a. HAV

b. Measles virus

c. Poliovirus

d. Rubella virus

e. Yellow fever virus

107. A 70-year-old nursing home patient refused the influenza vaccine and subsequently developed influenza, which rapidly progressed to viral pneumonia, for which she was hospitalized. Two days later, she became profoundly worse, was hypoxemic on oxygen, and had a WBC count of 22,000/µL with 80% neutrophils. She died of acute pneumonia 1 week after contracting the flu. Which of the following microorganisms was most likely responsible for her fatal illness?

a. Escherichia coli

b. Klebsiella pneumoniae

c. Legionella pneumophila

d. Listeria monocytogenes

e. Staphylococcus aureus

108. Along with several children at his elementary school who had similar symptoms, a 6-year-old boy was sent home from school because his eyes were red with a watery, nonpurulent discharge. He had a fever of 102°F and complained of sore throat. A rapid test for Group A Streptococcus was negative and his doctor told the boy’s mother that her child would recover within a week. Which of the following organisms was the most likely cause of his infection?

a. Adenovirus

b. Chlamydia trachomatis

c. Haemophilus aegyptius

d. HSV type 1

e. Staphylococcus aureus

109. A husband and wife performed the yearly spring cleaning of their mountain cabin, located in the southwestern part of the United States. The woman presented to her physician 2 weeks later with fever, myalgia, headache, and nausea, followed by progressive pulmonary edema and respiratory failure. How did she acquire this viral infection?

a. Contact with her husband

b. Drinking water in the cabin

c. Inhaling aerosolized rodent excreta

d. Mosquito bite

e. Tick bite

110. A 35-year-old professional businesswoman notices the appearance of several hyperkeratotic, well-demarcated growths on the palm side of her index finger and on her toe. They do not change in size and cause her only minimal discomfort. Biopsy of one of the lesions is shown at 40x. Which of the following viruses is the most likely etiologic agent?

(A: File in public domain; obtained from Wikimedia Commons; B: H&E stain (40×) of skin biopsy. By Nephron; permission through GNU Free Documentation License.)

a. Adenovirus

b. HPV

c. Molluscipoxvirus

d. Echovirus

e. VZV

111. A 32-year-old gay male went to his community STD clinic, where it was found that he had perianal condyloma accuminatum. Physical removal was recommended due to the size of the sessions along with immunomodulatory therapy. Which of the following drugs was most likely selected?

a. Acyclovir

b. 5-Fluorouracil

c. Imiquimod

d. Podophyllin

e. Trichloroacetic acid

112. A 7-year-old girl with sickle cell anemia was brought to her physician by her parents who reported that she seemed to be extremely fatigued and pale-looking. They stated that several of her classmates had recently had rashes and bright red cheeks. On examination, the doctor did not see a rash, but observed that her conjunctiva, gums, and nail beds were pale and that she had tachycardia. A CBC revealed that her hemoglobin level had fallen by 2 g/dL from her last result 3 months ago; her reticulocyte count was 0.05%. From which of the following is this child suffering?

a. Aplastic crisis from parvovirus B19 infection

b. Pericarditis caused by Coxsackievirus B

c. Gastroenteritis with bleeding caused by Norovirus

d. Exacerbated anemia from Coltivirus infection

e. Hemorrhagic cystitis caused by BK polyomavirus

113. An infant who appeared healthy at birth developed sensorineural hearing loss within the first year of life. Viral culture on urine from this child is positive for a relatively slow-growing virus (3 weeks). With which virus was this infant most likely infected at birth?

a. Cytomegalovirus

b. HSV type 2

c. Rubella virus

d. Measles virus

e. VZV

114. A 6-month-old infant has had watery diarrhea for 5 days; he vomited a couple of times. The stools have no blood or pus. He is dehydrated. He has not been outside of Cincinnati, but two other toddlers who visited for a day are also sick. What is the most likely cause of this child’s diarrhea?

a. Enterovirus

b. Norovirus

c. Rotavirus

d. Salmonella enterica

e. Staphylococcus aureus enterotoxin

115. Subacute sclerosing panencephalitis (SSPE) begins with mild changes in personality, behavior and memory, and seizures. The process is progressive and ends with dementia and death. Infection with which virus precedes SSPE?

a. Epstein–Barr virus

b. HIV

c. JC polyomavirus

d. Measles virus

e. Mumps virus

116. A couple who had been hiking in Utah in May developed fever, myalgias, headache, and pain behind their eyes. The fever was present for 3 days, subsided, and then recurred, lasting 3 days. Their doctor recommended antipyretic therapy and told them they should not donate blood for 6 months. With which virus was this couple most likely infected?

a. Coltivirus

b. Coxsackievirus B

c. Dengue virus

d. Sin Nombre hantavirus

e. Western equine encephalitis virus

117. An outbreak of disease caused by a virus occurred in Uganda, Africa. Clinical manifestations included hemoptysis and bleeding from the eyes, skin, and gastrointestinal (GI) tract. The mortality rate exceeded 70%. The virus appeared to be transmitted in the village by contact with the blood and bodily secretions of effected individuals; thus, infections rates were higher among those caring for the sick. Which viral disease occurred in this outbreak?

a. Dengue hemorrhagic fever

b. Ebola hemorrhagic fever

c. Hantavirus pulmonary syndrome

d. West Nile encephalitis

e. Yellow fever

118. A transplant patient who had serologic evidence of previous Epstein–Barr virus infection was taking high levels of immunosuppressive medications. He presents with generalized lymphadenopathy, fever, night sweats, weight loss, abdominal pain, and tonsillitis. The dosage of immunosuppressive drugs given to the patient is decreased, and the lymphadenopathy regresses. Which of the following is the best diagnosis for this patient?

a. Burkitt lymphoma

b. Hodgkin lymphoma

c. Infectious mononucleosis

d. Lymphoproliferative disorder

e. Nasopharyngeal carcinoma (NPC)

119. An infant is born to an HIV-positive mother who did not receive anti-retroviral therapy during her pregnancy. The mother’s HIV viral load, tested just before delivery, was 15,000 copies/mL. Both mother and baby tested positive for HIV antibodies by rapid testing. Since this infant is at risk of vertical transmission of HIV from her mother, the pediatrician decided to treat her prophylactically with a reverse transcriptase inhibitor. Which of the following is the most appropriate choice for prophylaxis?

a. Abacavir

b. Lopinavir

c. Nevirapine

d. Raltegravir

e. Zidovudine

120. A 25-year-old woman from East Texas donated blood in late July. The next day, she called the Blood Center reporting sudden onset of fever, malaise, myalgia, and backache. The staff at the Blood Center notified the woman 3 days later that her blood had tested positive for an arthropod-borne virus. With which virus was this young woman infected?

a. WNV

b. St. Louis encephalitis virus

c. Dengue virus

d. HSV

e. Coltivirus

121. A 25-year-old graduate student presents to the local clinic with fever, malaise, lymphadenopathy, and pharyngitis. His spleen is not enlarged and although there is a predominance of lymphocytes reported in his peripheral smear, the heterophile antibody test is negative. What is the most likely etiology of this student’s infection?

a. Adenovirus

b. Cytomegalovirus

c. Epstein–Barr virus

d. Parvovirus B19

e. Hepatitis C virus (HCV)

122. A middle-aged man with a long history of multiple operations and blood transfusions was diagnosed with chronic hepatitis C. He was then treated with pegylated interferon-α (IFN-α) and weight-dosed ribavirin. How does IFN-α affect HCV?

a. Blocks viral envelope fusion with host cell membrane

b. Directly inhibits the viral RNA polymerase

c. Induces the antiviral state in host cells to prevent HCV replication

d. Inhibits the viral protease

e. Interferes with guanosine-dependent processes within the cell

123. A 35-year-old man presents with symptoms of jaundice, right upper quadrant pain, and vomiting. His ALT is elevated. He is diagnosed with HAV infection after eating at a restaurant where others were also infected. Which of the following should be done to protect his 68-year-old father and his 6-month-old son?

a. Administer IFN-α to both

b. Give each one dose of γ-globulin

c. Immunize both with one dose of hepatitis A vaccine

d. Quarantine household contacts and observe

e. No treatment is necessary

124. A 42-year-old male AIDS patient presented to the dermatology clinic for evaluation of skin lesions. He had numerous plaque-like lesions over his arms, chest, and neck. Oral examination revealed the lesion shown in the image on his palate. What is the most likely etiologic agent of these lesions?

(Courtesy of CDC/Sol Silverman Jr, DDS, University of California, San Francisco 1987; ID#6070.)

a. Bartonella henselae

b. Human herpesvirus 8

c. HPV

d. Human T-cell leukemia virus

e. Staphylococcus aureus

125. Latent infection of neurons occurs with which of the following viruses?

a. Adenovirus

b. Epstein–Barr virus

c. HSV

d. Measles virus

e. Rabies virus

126. On November 6, a patient had the onset of an illness characterized by fever, chills, headache, cough, and chest pain. The illness lasted 1 week. On December 5, she had another illness very similar to the first, which lasted 6 days. She had no influenza immunization during this period. Her hemagglutination inhibition antibody titers to nH1N1 influenza virus were as follows:

November 6: 10     November 30: 10     December 20: 160

There was no laboratory error. Which of the following is the best conclusion from these data?

a. The patient was ill with influenza on November 6

b. The patient was ill with influenza on December 5

c. The patient was ill with influenza on December 20

d. It is impossible to relate either illness with the nH1N1 influenza virus

127. Recently, a new dsDNA nonenveloped virus has been associated with a human cancer. The viral genome was found to be integrated into the host chromosome of cells in an aggressive skin cancer, Merkel cell carcinoma. To which genus does this new virus belong?

a. Alphavirus

b. Erythrovirus

c. Orthohepadnavirus

d. Polyomavirus

e. Rotavirus

128. A tourist who recently returned from a Caribbean cruise suddenly develops fever, headache, pain behind her eyes, severe joint, bone, and muscle pain, and a maculopapular rash. The ship had made numerous stops at various islands to allow exploratory trips. The tourist reported significant encounter with mosquitoes at one of the stops. Which of the following is the most likely diagnosis?

a. Dengue

b. Hemorrhagic fever with renal syndrome

c. Hepatitis C

d. Rubella

e. Yellow fever

129. A 30-year-old female who had a history of serious illness requiring surgery and infusion of multiple blood products developed fever, nausea, and jaundice. Her condition has continued for 2 years as a clinically mild disease with fluctuating levels of bilirubin and liver enzymes. Recent blood chemistry testing showed her serum aspartate aminotransferase (AST) to be 352 U/L, ALT 512 U/L, and total bilirubin 4.5 mg/dL. Which of the following best characterizes the virus most likely causing her illness?

a. DNA virus belonging to the Hepadnaviridae

b. ss(+)RNA virus belonging to the Hepeviridae

c. ss(+)RNA virus belonging to the Picornaviridae

d. ss(+)RNA virus belonging to the Flaviviridae

e. ss(-)RNA virus known as Deltavirus

130. An IV-drug user discovered that a friend with whom he shared needles for injections was diagnosed with viral hepatitis. He had his blood drawn at the local public health clinic and tested for HBV. Which of the following markers is usually the first viral marker detected after infection with HBV?

a. HBcAg

b. HBeAg

c. HBsAg

d. HBeAg IgG

e. HBcAg IGM

131. A 55-year-old woman who had immigrated 30 years ago to the United States from Dominica in the Caribbean presented with cutaneous lesions and hepatosplenomegaly. She was hypercalcemic, had lymphocytosis, and bone lesions were demonstrated on x-ray. Peripheral smear showed cloverleaf lymphocytes, consistent with acute T-cell leukemia (CD4+ lymphocytes), in which a provirus was found. Which virus is most likely responsible for her disease?

a. HIV-1

b. HIV-2

c. HTLV-1

d. HTLV-2

132. A 19-year-old male presented to his family physician complaining of severe pain in his eye and intolerance to light. His eye was red and tearing. Ophthalmic visualization revealed coalescing dendritic ulcers in his right eye that were easily seen with fluorescein staining of the cornea. The patient stated that he does not wear contact lenses, and that he had never had fever blisters; his mother to corroborated this. What is the most likely etiologic agent of his ulcer?

(Courtesy of HK Yang et al, Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea, 30 August 2012. Permission licensed under the Creative Commons Attribution 2.5 Generic license.)

a. Acanthamoeba

b. Foreign body

c. Fusarium

d. HSV type 1

e. Severe allergy

133. Reactivation of VZV is known to occur in persons receiving immunosuppressive therapy. Which of the following is the best antiviral for treating this infection?

a. Amantadine

b. Boceprevir

c. Ribavirin

d. Valacyclovir

e. Zidovudine

134. An infant with microcephaly, jaundice, and hepatosplenomegaly was also small for gestation, and had thrombocytopenia. Radiology of the neonate’s head revealed intracranial calcifications. Which one of the following viruses most likely caused these congenital malformations?

a. Rubella virus

b. Respiratory syncytial virus

c. HIV

d. Mumps virus

e. Cytomegalovirus

135. A 32-year-old woman who had not received the usual pediatric vaccinations developed fever, headache, malaise, and ear pain accompanied by swelling of the parotid glands. One week later, her fever subsided but she developed pelvic pain and tenderness. With which virus was she infected?

a. Cytomegalovirus

b. Mumps virus

c. Rabies virus

d. Respiratory syncytial virus

e. Rubella virus

136. Worldwide 3 to 5 million cases of severe influenza illnesses and 250,000 to 500,000 deaths occur annually. Great effort is made annually to prepare influenza vaccines against circulating strains of Influenzavirus A and B. Yet, in some years, the vaccine is less effective in neutralizing the virus even though the circulating strains are the same type as that from the previous year; that is, both are H1N1 or both are H2N3. Which of the following mechanisms is responsible for this problem?

a. Antigenic drift

b. Antigenic shift

c. Complementation

d. Intramolecular recombination

e. Phenotypic mixing

137. A visitor from rural Mexico visited the United States and was admitted to a hospital after being diagnosed with probable rabies. Which of the following is the best representation of his prognosis?

a. He should survive without complications

b. He should survive but have seizures for life

c. He has a 50% chance of survival if aggressive therapy is instituted

d. Rabies is almost invariably fatal

138. Although vaccination with live, attenuated, or killed viral vaccines has been the most effective way of controlling viral disease in the population, common colds remain widespread because of the multiple serotypes identified. Which of the following viruses represents this problem?

a. Cytomegalovirus

b. Mumps virus

c. Rabies virus

d. Respiratory syncytial virus

e. Rhinovirus

139. A 3-year-old girl who was in day care presented with sudden onset of fever, nausea, vomiting, and anorexia. Her sclera were yellow and her abdomen was tender to palpation. Blood chemistries showed an AST of 640 U/L and ALT was 520 U/L. Previously, two other children had had similar symptoms. Which of the following tests would be most likely to reveal the etiology of her hepatitis?

a. Viral culture of stool

b. Test for hepatitis B surface antigen

c. Electron microscopy on stool specimen

d. Detection of rotavirus antigen

e. Anti-HAV IgM

140. In January, two school districts saw a sudden increase in absences. At the same time, sales of over-the-counter medications for fever, cough, and cold symptoms increased dramatically. To determine the etiology of this outbreak of respiratory illness, the public health department conducted a survey of local physicians to see what types of patients they were currently seeing most. The doctors all reported increased numbers of patients complaining of abrupt onset of high fever, severe headache, and myalgia followed by sore throat, dry cough, weakness, and severe fatigue. The patients were ill for 3 to 5 days, but many reported persistent malaise. What is the most likely diagnosis for this outbreak?

a. Common cold

b. Hand-foot-and-mouth disease

c. Influenza

d. Pharyngitis

e. Pneumonia

141. A vaccine against Morbillivirus (measles virus), introduced in 1963, has decreased the incidence of measles from an expected event in the life of every child to 50 to 200 cases per year in the United States. Which of the following best characterizes the vaccine that has dramatically reduced the incidence of this disease in the United States?

a. Inactivated virus

b. Live attenuated virus

c. Recombinant viral protein

d. Virus-specific immunoglobulin

e. Wild-type live virus

142. A newlywed couple was surprised to find that both experienced genital herpes lesions in their first year of marriage. Both were given an antiviral that is activated only in infected cells. Which of the following is the viral enzyme responsible for activation of the drug of choice for this infection?

a. DNA-dependent DNA polymerase

b. Integrase

c. Protease

d. RNA-dependent RNA polymerase

e. Thymidine kinase

143. A neonate born to a woman with chronic hepatitis B infection is at great risk of contracting the virus and subsequently becoming a chronic carrier of HBV. Which of the following is the best approach to preventing the neonate becoming infected?

a. Give hepatitis B immunoglobulin (HBIg) at birth

b. Give HBIg at 6 months, when maternal antibodies have diminished

c. Immunize with recombinant HBV vaccine (rHBV) at birth

d. Immunize with rHBV at 1 year

e. Give HBIg and immunize with rHBV vaccine at birth

144. Twenty days after contact with an individual with an acute disease presentation, a 12-year-old girl has fever (low grade), malaise, and a rash composed of crops of vesicles that lasts 5 days. This common childhood disease is caused by which of the following viruses?

a. Adenovirus

b. Cytomegalovirus

c. HPV

d. Measles virus

e. VZV

145. Over 400 military recruits undergoing basic training experienced an acute respiratory disease outbreak in their second month of camp. Most had high fever and sore throats with coughing; 27 developed pneumonia, five severe enough to require intensive care, and one died. Which of the following agents is the most likely cause of this outbreak?

a. VZV

b. Rotavirus

c. Papillomavirus

d. Cytomegalovirus

e. Adenovirus

146. Which of the following genetic disorders predisposes patients to widespread HPV infection and cutaneous squamous cell carcinoma?

a. Epidermodysplasia verruciformis

b. Familial adenomatous polyposis

c. Li–Fraumeni syndrome

d. NPC

e. Xeroderma pigmentosum

147. A 9-month-old girl, who has never been vaccinated, presents with a 3-day history of fever and watery, nonbloody diarrhea. On physical examination, she appears dehydrated. Which of the following describes the genome of the most likely infecting organism?

a. Double-stranded DNA

b. Single-stranded DNA

c. Segmented single-stranded minus-sense RNA

d. Nonsegmented single-stranded plus-sense RNA

e. Segmented double-stranded RNA

148. A 20-year-old college football player presented himself to the local emergency medicine department complaining of headache, fever, and malaise for 2 weeks and now a sore throat. The physician noted enlarged lymph nodes and hepatosplenomegaly. Laboratory tests found increased number of atypical lymphocytes and a reactive heterophile antibody test. The physician advised him not to play football until his symptoms had resolved. What is the best explanation for this advice?

a. To avert heat exhaustion

b. To avoid rupture of his spleen

c. To prevent malnutrition

d. To stave off an aplastic crisis

149. A humanitarian healthcare worker deployed in emergency to Darfur, Sudan, forgot to use insect repellant. Four days after being bitten several times by mosquitoes, he developed fever, chills, headache, back ache, and muscle aches. Two days later, he suffered a nosebleed and noticed his stools were black. The next day, he was jaundiced and vomited black material. Despite supportive care, he developed organ failure and died. What was the cause of this patient’s death?

a. Dengue hemorrhagic shock

b. Hantavirus cardiopulmonary syndrome

c. Hemorrhagic fever with renal syndrome

d. SARS

e. Yellow fever

150. A patient who had not been vaccinated against influenza has hem-agglutination inhibition titers against influenzavirus A as follows: acute = 10, convalescent = 80. Which of the following is the correct conclusion concerning this patient?

a. No infection

b. Primary infection

c. Anamnestic response

d. Past infection

151. A 10-year-old boy in a malarial area of Africa was diagnosed with a poorly differentiated B-cell tumor of the jaw that was characterized by a translocation of the c-myc oncogene, t(8:14). The boy also has an elevated antibody titer to a specific viral early antigen with a restricted pattern of fluorescence. This disease is caused by which of the following?

a. Borrelia burgdorferi

b. Chlamydia trachomatis

c. Cytomegalovirus

d. Epstein–Barr virus

e. HSV

152. A 55-year-old Chinese man in southern China sought medical help due to a serious otitis media, which was related to obstruction of his Eustachian tubes. Medical examination and laboratory testing resulted in a diagnosis of NPC. Which of the following viruses may be detected by the PCR in a variety of cells of patients with this type of carcinoma?

a. Epstein–Barr virus

b. Measles virus

c. Mumps virus

d. Parvovirus B19

e. Rubella virus

153. A patient with HIV infection that has progressed to AIDS had been treated previously for cytomegalovirus pneumonia. For which additional CMV disease would this patient also be at risk?

a. Aplastic crisis

b. Kidney failure

c. Retinitis

d. Reye syndrome

e. SSPE

154. An estimated 6.2 million new HPV infections occur annually in the United States. The peak incidence occurs in adolescents and young adults under 25 years of age. Which of the following specimens is best for screening for the presence of HPV infection of the cervix?

a. DNA molecular probe for HPV genomes

b. HPV-specific antibodies

c. Pap smear on cells from cervix for koilocytes

d. PCR for HPV DNA

e. Viral culture for HPV

155. A business man who contracted dengue in the Philippines during a business trip in 2011 took his family to the Caribbean for a vacation in 2012. The entire family was plagued with mosquito bites while walking early one morning. Four days later, the man, his wife, and their 17-old-daughter experienced sudden onset of fever of 103 to 104°F, chills and severe head, back, and muscle aches. He had pain behind his eyes. Their 12-year-old son had similar symptoms but lessened in intensity, while their 6-year-old daughter had fever that broke and returned and a rash. Their fevers lasted 3 to 4 days with onset of rash in all. Shortly after their fevers subsided, the man and the 6-year-old developed abdominal pain, petechiae, and bleeding gums. What complication did this man and child develop?

a. Acute respiratory distress syndrome

b. Dengue hemorrhagic fever

c. Encephalitis

d. Guillain–Barré syndrome

e. Secondary bacterial infection

156. A 16-year-old male developed chest pain and dyspnea, which gradually worsened. He was examined in the Emergency Department where tachycardia and signs of heart failure were noted. Electrocardiographic changes were seen and chest x-ray revealed cardiomegaly. An enterovirus was isolated from a stool specimen. Which of the following was the agent most likely isolated?

a. Coxsackievirus A

b. Coxsackievirus B

c. Echovirus 11

d. Enterovirus 70

e. Poliovirus 3

157. A 38-year-old woman has developed crops of vesicular lesions. After 3 days, she developed pneumonia and was hospitalized. Which of the following would be most likely to be present in lung cells obtained by bronchoalveolar biopsy?

a. Cowdry A inclusion bodies

b. Guarnieri bodies

c. Koilocytes

d. Negri bodies

e. Owl’s eye cells

158. A patient diagnosed with influenza reported onset of symptoms 18 hours ago. Which of the following is the most appropriate treatment for this patient?

a. Amantadine

b. Foscarnet

c. Oseltamivir

d. Ribavirin

e. Zidovudine

159. A group of 15 young college students harvested oysters from a bay near Galveston despite a warning sign that the area was contaminated with sewage. Ten ate the oysters raw. Twenty-five days later, six of them presented to their physicians with sudden onset of acute jaundice and liver function abnormalities. Which of the following is the most likely cause of their infections?

a. HAV

b. HBV

c. HCV

d. HDV

e. HEV

160. An 18-month old developed acute gastroenteritis with fever and watery diarrhea that lasted 10 days. She had been vaccinated against rota-virus at 2 and 4 months of age as recommended. Eight days later, both of her brothers, ages 3 and 6, developed acute gastroenteritis. Which of the following tests would most likely reveal the etiologic agent of their gastroenteritis?

a. Culture for Norovirus

b. DFA for enterovirus on intestinal biopsy

c. EIA for adenovirus 40/41

d. EM examination of stool for astrovirus

e. Serology for Rotavirus

161. An outbreak of diarrhea in a day care center is suspected to be of rotaviral origin. Which test is most appropriate to diagnose this outbreak?

a. Culture

b. EIA

c. Electron microscopy

d. Histologic examination of biopsy

e. Serology

162. Adults and children experienced an outbreak of diarrhea with nausea and vomiting while aboard a cruise ship in the Caribbean. The causative agent was detected by EIA testing. Which virus listed below was most likely responsible for this outbreak?

a. Adenovirus 40/41

b. Astrovirus

c. HAV

d. Norovirus

e. Rotavirus

163. An outbreak of diarrhea occurred among elderly patients in an assisted care facility, which had been repeatedly cited by the public health department for poor hygiene practices. The agent that caused the infections had a starlike morphology in electron micrographs. EIA tests for several agents of viral gastroenteritis were negative. Which virus was most likely responsible for this outbreak?

a. Adenovirus 40/41

b. Astrovirus

c. HAV

d. Norovirus

e. Rotavirus

164. A young refugee from Afghanistan developed mild fever, cervical lymphadenopathy, and a rash that began on her face and spread downward over her trunk. After 3 days, the rash disappeared. She had not been immunized against any infections except diphtheria and tetanus. What is the best diagnosis for this child?

a. Chickenpox

b. Erythema infectiosum

c. Measles

d. Hand-foot-and-mouth disease

e. Rubella

165. A 57-year-old man diagnosed previously with chronic hepatitis C is being treated for his infection. Which of the following tests is the best to evaluate his therapy for an early virologic response?

a. HCV IgG

b. HCV IgM

c. HCV RNA level

d. Liver biopsy

e. Serum ALT levels

166. A 45-year-old man with active chronic hepatitis B infection is being treated to reduce liver inflammation and fibrosis and to prevent progression to cirrhosis. He is HBeAg-positive and had begun a 48-week course of pegylated IFN-α, but he was unable to tolerate the side effects. Which of the following would be the best antiviral to treat this patient?

a. Acyclovir

b. Foscarnet

c. Ribavirin

d. Tenofovir

e. Zidovudine

167. Two weeks after a series of mid-July thunderstorms resulted in an explosion of the mosquito population, a 10-year-old boy living on a farm in southern Minnesota was brought to the emergency room by his parents. He has a 2-day history of fever, headache, and vomiting, but today he appeared confused. His cerebrospinal fluid was clear with 100 WBC (75% lymphocytes) and a head CT was normal. Enterovirus infection was quickly ruled out by PCR testing. Which of the following is the most likely cause of his symptoms?

a. La Crosse virus

b. Poliovirus

c. Rabies virus

d. St. Louis encephalitis virus

e. Venezuelan equine encephalitis virus

168. Which of the following would be present in a neonate with congenital rubella syndrome (CRS) but not in a neonate with cytomegalic inclusion disease (congenital CMV infection)?

a. Intrauterine growth retardation

b. Hepatosplenomegaly

c. Mental retardation

d. Patent ductus arteriosus

e. Sensorineural hearing loss

169. Viruses have various ways of entering the human body and producing disease. Which of the following descriptions accurately describes the route of transmission and target disease for the virus indicated?

a. Coronavirus: fecal–oral; peptic ulcers

b. Echovirus: fecal–oral; aseptic meningitis

c. HIV: respiratory droplet; anemia

d. Influenzavirus: blood-borne; maculopapular rash

e. Rabies virus: rodent-borne; pneumonia

170. A 68-year-old man from central California who liked to sit in the park and doze developed fever, headache, muscle weakness, and nausea and vomiting. His muscle weakness progressed, and he was admitted to the hospital with acute flaccid paralysis. No focal lesions were seen on MRI. After a prolonged hospital stay, he was discharged to a rehabilitation center where he regained function. With which virus was this man most likely infected?

a. WNV

b. St. Louis encephalitis virus

c. Poliovirus

d. HSV

e. Coltivirus

171. An immunocompromised patient presented with a progressive cerebral deterioration evidenced by difficulty speaking, memory loss, and loss of coordination that led to paralysis. An MRI revealed lesions in the white matter; brain biopsy revealed foci of demyelination, astrocytosis, and nuclear inclusion bodies within oligodendrocytes. Normal CSF findings (cell count, glucose, protein) were present, but viral DNA was found in the CSF by PCR. Which of the following viruses causes is the etiologic agent of this patient’s disease?

a. HPV

b. JC polyomavirus

c. Prion variant CJD

d. Measles virus

e. WNV

172. An irritable 18-month-old toddler with fever and blister-like ulcerations on mucous membranes of the oral cavity refuses to eat (representative image, left). The symptoms worsen and then slowly resolve over a period of 2 weeks. Six months later, the child develops a single vesicular lesion that resolves in 6 days (representative image, right); she does not have fever. Which of the following scenarios is most likely?

(A: Courtesy of CDC/Robert E. Sumpter, 1987, ID#12616; B: Courtesy of CDC/Dr. Herrmann, 1964, ID#5434.)

a. The virus will remain latent in the trigeminal ganglia

b. The vesicular lesions will not recur

c. The child will develop Guillain–Barré syndrome

d. The child will develop hepatocellular carcinoma later in life

e. The child will develop SSPE

173. A sexually active 17-year-old man presents to the local free clinic to check some small papules that appeared on his penis. The papules are small, white lesions with a central depression. There is no discharge or pain on urination. What is the virus most likely causing these lesions?

a. Adenovirus

b. Coxsackievirus A

c. HPV type 6

d. Molluscipoxvirus

e. Orf virus

174. A 3-month-old infant born at prematurely at 30 weeks of gestation is in the neonatal intensive care unit in November. The first cases of respiratory syncytial virus have been diagnosed in the city. Which of the following may be given to this infant as prophylaxis to prevent respiratory syncytial virus (RSV) infection?

a. IFN-α

b. Palivizumab

c. Pooled immunoglobulin

d. Ribavirin

e. Rituximab

175. Malnourished children are at risk for complications of measles, leading to greater morbidity and mortality. Which of the following should be given to children to reduce these risks?

a. Vitamin A

b. Vitamin B

c. Vitamin C

d. Vitamin D

e. Vitamin E

176. Which of the following immune responses is required to prevent target infection by poliovirus, EEEV, and La Crosse virus?

a. Complement activation

b. Cytotoxic T cells specific for the virus

c. Natural killer cells

d. Neutralizing IgG specific for the virus

e. Neutrophils

177. A 45-year-old woman living in Washington, DC, had been complaining to her landlord about mice in her apartment. A week ago, she suffered flu-like symptoms accompanied by swollen lymph nodes and a rash, which had resolved over 5 days. Four days later, she developed a severe headache and other signs of viral encephalitis. She reported no contact with mosquitoes. With which virus was she most likely infected?

a. La Crosse virus

b. Lassa fever virus

c. Lymphocytic choriomeningitis virus

d. Sin Nombre hantavirus

e. Western equine encephalitis virus

178. An elderly man had been in several military conflicts during the early 1980s and received blood transfusions for injuries. He recently consulted his physician for what was diagnosed as cryoglobulinemia and glomerulonephritis. Additional testing revealed that he was infected by a flavivirus whose transmission was bloodborne. Which of the following viruses was involved in this infection?

a. HAV

b. HBV

c. HCV

d. HDV

e. HEV

179. An outbreak of influenza occurred in a rural community. Since influenza can be treated if therapy is begun within 48 hours of onset of symptoms, specific detection of the virus is important. Which of the following tests listed is the most rapid for detection of influenza viruses?

a. Cold agglutinin test

b. Culture of respiratory secretions on monkey kidney cells

c. Detection of influenza antigen in respiratory secretions

d. Electron microscopy of sputum

e. Paired sera for specific antibody response

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