Viruses — MCQs

An investigator is developing a new vaccine. After injecting the agent, the immune response is recorded by measuring vaccine-specific antibodies at subsequent timed intervals. To induce the maximum immunogenic response, this vaccine should have which of the following properties?

A 54-year-old male presents to the emergency department with nasal congestion and sore throat. He also endorses ten days of fatigue, rhinorrhea and cough, which he reports are getting worse. For the last four days, he has also had facial pain and thicker nasal drainage. The patient’s past medical history includes obesity, type II diabetes mellitus, and mild intermittent asthma. His home medications include metformin and an albuterol inhaler as needed. The patient has a 40 pack-year smoking history and drinks 6-12 beers per week. His temperature is 102.8°F (39.3°C), blood pressure is 145/96 mmHg, pulse is 105/min, and respirations are 16/min. On physical exam, he has poor dentition. Purulent mucus is draining from his nares, and his oropharynx is erythematous. His maxillary sinuses are tender to palpation. Which one of the following is the most common risk factor for this condition?

A 16-year-old girl is brought to the physician because of a 1-month history of fever, headaches, and profound fatigue. Her temperature is 38.2°C (100.8°F). Examination shows splenomegaly. Laboratory studies show: Leukocyte count 13,000/mm3 (15% atypical lymphocytes) Serum Alanine aminotransferase (ALT) 60 U/L Aspartate aminotransferase (AST) 40 U/L Heterophile antibody assay negative EBV viral capsid antigen (VCA) antibodies negative HIV antibody negative In an immunocompromised host, the causal organism of this patient's symptoms would most likely cause which of the following conditions?

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 and her temperature is 38.0°C (100.4°F); pulse, 95/min; respirations, 20/min; and supine and upright blood pressure, 130/70 mm Hg and 100/65 mm Hg, respectively. Conjunctival suffusion is seen. Ecchymoses are observed on the lower extremities. She is bleeding from one of her intravenous lines. The peripheral blood smear is negative for organisms. The laboratory studies show the following: 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 (N = 5–50 U/L) Creatinine 2 mg/dL Which of the following is the most likely causal pathogen?

A 58-year-old man is brought to the emergency department because of confusion, weight loss, and anuria. He has chronic kidney disease, hypertension, and type 2 diabetes mellitus. He was diagnosed with acute lymphoblastic leukemia at the age of 8 years and was treated with an allogeneic stem cell transplantation. He is HIV-positive and has active hepatitis C virus infection. He drinks around 8 cans of beer every week. His current medications include tenofovir, emtricitabine, atazanavir, daclatasvir, sofosbuvir, insulin, amlodipine, and enalapril. He appears lethargic. His temperature is 36°C (96.8°F), pulse is 130/min, respirations are 26/min, and blood pressure is 145/90 mm Hg. Examination shows severe edema in his legs and generalized muscular weakness. Auscultation of the lung shows crepitant rales. Laboratory studies show positive HCV antibody and positive HCV RNA. His HIV viral load is undetectable and his CD4+ T-lymphocyte count is 589/μL. Six months ago, his CD4+ T-lymphocyte count was 618/μL. An ECG of the heart shows arrhythmia with frequent premature ventricular contractions. Arterial blood gas analysis on room air shows: pH 7.23 PCO2 31 mm Hg HCO3- 13 mEq/L Base excess -12 mEq/L The patient states he would like to donate organs or tissues in the case of his death. Which of the following is an absolute contraindication for organ donation in this patient?

A 4-month-old boy is brought to the physician because of a lesion on his right thigh. Yesterday, he was administered all scheduled childhood immunizations. His vital signs are within normal limits. Physical examination shows a 2-cm sized ulcer with surrounding induration over the right anterolateral thigh. Which of the following is the most likely cause of his symptoms?

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?

A 50-year-old woman returns from a family trip to the Caribbean with three days of fever, watery diarrhea, and vomiting. She states that she tried to avoid uncooked food and unpeeled fruits on her vacation. Of note, her grandson had caught a cold from daycare prior to the trip, and she had been in close contact with the infant throughout the trip. She denies rhinorrhea or coughing. On exam, her temperature is 99.1°F (37.3°C), blood pressure is 110/68 mmHg, pulse is 113/min, and respirations are 12/min. Her stool culture is negative for bacteria. Which of the following describes the most likely cause?

A 38-year-old woman comes to the physician because of a 2-day history of a red, itchy, burning rash on her vulva. She has had three similar episodes over the last two years that have all self-resolved. Genitourinary examination shows a small area of erythema with an overlying cluster of vesicles on the inside surface of the vulva. Latent infection of which of the following is most likely responsible for this patient's recurrent symptoms?

A previously healthy 25-year-old man comes to the physician because of a 4-day history of fever, joint and body pain, diffuse headache, and pain behind the eyes. This morning he noticed that his gums bled when he brushed his teeth. He returned from a backpacking trip to the Philippines 4 days ago. His temperature is 39.4°C (103.0°F). Physical examination shows a diffuse maculopapular rash. His leukocyte count is 3,200/mm3 and platelet count is 89,000/mm3. Further evaluation shows increased serum levels of a flavivirus. Which of the following is the most likely causal pathogen?