Viruses Practice Questions

Question 1

An HIV-positive 48-year-old man comes to the emergency department because of a 3-month history of recurrent, painful mouth ulcers. This time, the pain is so severe that the patient cannot eat. He has a history of a seizure disorder but currently does not take any medications. He appears very ill. His temperature is 39.0°C (102.2°F). Physical examination shows numerous vesicular ulcerations on the lips and sloughing of the gums, buccal mucosa, and hard palate. Genetic analysis of the pathogen isolated from the lesions shows a mutation in a gene encoding viral phosphotransferases. Which of the following drugs is the most appropriate treatment?

Accepted Answer

Foscarnet

Answer

Acyclovir

Answer

Famciclovir

Answer

Cidofovir

Answer

Ganciclovir

Question 2

A scientist in Boston is studying a new blood test to detect Ab to the parainfluenza virus with increased sensitivity and specificity. So far, her best attempt at creating such an exam reached 82% sensitivity and 88% specificity. She is hoping to increase these numbers by at least 2 percent for each value. After several years of work, she believes that she has actually managed to reach a sensitivity and specificity even greater than what she had originally hoped for. She travels to South America to begin testing her newest blood test. She finds 2,000 patients who are willing to participate in her study. Of the 2,000 patients, 1,200 of them are known to be infected with the parainfluenza virus. The scientist tests these 1,200 patients’ blood and finds that only 120 of them tested negative with her new test. Of the following options, which describes the sensitivity of the test?

Accepted Answer

90%

Answer

82%

Answer

86%

Answer

98%

Answer

84%

Question 3

A 27-year-old woman who recently emigrated from Brazil comes to the physician because of fever, fatigue, decreased appetite, and mild abdominal discomfort. She has not seen a physician in several years and her immunization status is unknown. She drinks 2 alcoholic beverages on the weekends and does not use illicit drugs. She is sexually active with several male partners and uses condoms inconsistently. Her temperature is 38°C (99.8°F). Physical examination shows right upper quadrant tenderness and scleral icterus. Serology confirms acute infection with a virus that has partially double-stranded, circular DNA. Which of the following is most likely involved in the replication cycle of this virus?

Accepted Answer

Reverse transcription of viral RNA to DNA

Answer

Adhesion of virus to host ICAM-1 receptor

Answer

Cleavage of gp160 to form envelope glycoprotein

Answer

Bacterial translation of viral DNA

Answer

Transcription of viral DNA to RNA in the cytoplasm

Question 4

A 40-year-old man presents with problems with his vision. He says he has been experiencing blurred vision and floaters in his left eye for the past few days. He denies any ocular pain, fever, or headaches. Past medical history is significant for HIV infection a few years ago, for which he is noncompliant with his antiretroviral medications and his most recent CD4 count was 100 cells/mm3. His temperature is 36.5°C (97.7°F), the blood pressure is 110/89 mm Hg, the pulse rate is 70/min, and the respiratory rate is 14/min. Ocular exam reveals a decreased vision in the left eye, and a funduscopic examination is shown in the image. The patient is admitted and immediately started on intravenous ganciclovir. A few days after admission he is still complaining of blurry vision and floaters, so he is switched to a different medication. Inhibition of which of the following processes best describes the mechanism of action of the newly added medication?

Accepted Answer

Nucleic acid synthesis

Answer

Protein synthesis

Answer

Progeny virus release

Answer

Viral penetration into host cells

Answer

Viral uncoating

Question 5

A 30-year-old forest landscape specialist is brought to the emergency department with hematemesis and confusion. One week ago she was diagnosed with influenza when she had fevers, severe headaches, myalgias, hip and shoulder pain, and a maculopapular rash. After a day of relative remission, she developed abdominal pain, vomiting, and diarrhea. A single episode of hematemesis occurred prior to admission. Two weeks ago she visited rainforests and caves in western Africa where she had direct contact with animals, including apes. She has no history of serious illnesses or use of medications. She is restless. Her temperature is 38.0℃ (100.4℉); the pulse is 95/min, the respiratory rate is 20/min; and supine and upright blood pressure is 130/70 mm Hg and 100/65 mm Hg, respectively. Conjunctival suffusion is noted. Ecchymoses are observed on the lower extremities. She is bleeding from one of her intravenous lines. The peripheral blood smear is negative for organisms. Filovirus genomes were detected during a reverse transcription-polymerase chain reaction. The laboratory studies show the following:
Laboratory test
Hemoglobin 10 g/dL
Leukocyte count 1,000/mm3
Segmented neutrophils 65%
Lymphocytes 20%
Platelet count 50,000/mm3
Partial thromboplastin time (activated) 60 seconds
Prothrombin time 25 seconds
Fibrin split products positive
Serum  
Alanine aminotransferase (ALT) 85 U/L
Aspartate aminotransferase (AST) 120 U/L
γ-Glutamyltransferase (GGT) 83 U/L
Creatinine 2 mg/dL
Which of the following is the most appropriate immediate step in management?

Accepted Answer

Intravenous fluids and electrolytes

Answer

Esophagogastroduodenoscopy

Answer

Postexposure vaccination of close contacts

Answer

Parenteral artesunate plus sulfadoxine/pyrimethamine

Answer

Use of N95 masks

Question 6

An investigator studying viral replication isolates the genetic material of an unidentified virus strain. After exposing a cell culture to the isolated, purified viral genetic material, the cells begin to produce viral polymerase and subsequently replicate the viral genome. Infection with the investigated strain is most likely to cause which of the following conditions?

Accepted Answer

Poliomyelitis

Answer

Rotavirus infection

Answer

Hepatitis B

Answer

Rabies

Answer

Influenza

Question 7

You are seeing a 4-year-old boy in clinic who is presenting with concern for a primary immune deficiency. He has an unremarkable birth history, but since the age of 6 months he has had recurrent otitis media, bacterial pneumonia, as well as two episodes of sinusitis, and four episodes of conjunctivitis. He has a maternal uncle who died from sepsis secondary to H. influenza pneumonia. If you drew blood work for diagnostic testing, which of the following would you expect to find?

Accepted Answer

Abnormally low number of B cells

Answer

Abnormally low number of T cells

Answer

Abnormally high number of B cells

Answer

Elevated immunoglobulin levels

Answer

Abnormally high number of T cells

Question 8

A 28-year-old male presents to his primary care physician with complaints of intermittent abdominal pain and alternating bouts of constipation and diarrhea. His medical chart is not significant for any past medical problems or prior surgeries. He is not prescribed any current medications. Which of the following questions would be the most useful next question in eliciting further history from this patient?

Accepted Answer

"Can you tell me more about the symptoms you have been experiencing?"

Answer

"Does the diarrhea typically precede the constipation, or vice-versa?"

Answer

"Is the diarrhea foul-smelling?"

Answer

"Please rate your abdominal pain on a scale of 1-10, with 10 being the worst pain of your life"

Answer

"Are the symptoms worse in the morning or at night?"

Question 9

Two viruses, X and Y, infect the same cell and begin to reproduce within the cell. As a result of the co-infection, some viruses are produced where the genome of Y is surrounded by the nucleocapsid of X and vice versa with the genome of X and nucleocapsid of Y. When the virus containing genome X surrounded by the nucleocapsid of Y infects another cell, what is the most likely outcome?

Accepted Answer

Virions containing genome X and nucleocapsid X will be produced

Answer

Virions containing genome Y and nucleocapsid Y will be produced

Answer

No virions will be produced

Answer

Virions containing genome X and nucleocapsid Y will be produced

Answer

Virions containing genome Y and nucleocapsid X will be produced

Question 10

A 30-year-old man is admitted to the hospital with a presumed pneumonia and started on antibiotics. Two days later, the patient shows no improvement. Blood cultures reveal yeast with pseudophyphae. Which of the following cell types is most likely deficient or dysfunctional in this patient?

Accepted Answer

Neutrophils

Answer

Eosinophils

Answer

Macrophages

Answer

T-cells

Answer

B-cells

Viruses

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