Formative 1

Question 1

You have just gotten back from a trip from New Jersey where you dined on fresh seafood for the last month. This included eating raw oysters and clams on the half shell. Approximately two weeks later you develop abdominal pain, dark urine, nausea and vomiting and jaundice. Which of the following viruses is most likely the cause of your symptoms?

Answer 1

Answer: Enterovirus 72

Enterovirus 72 is hepatitis A virus (HAV), which is transmitted by the fecal oral route. In this case, it most likely was transmitted through contaminated shellfish. The incubation period for HAV averages approximately 30 days and symptoms above are typical of an early HAV infection. Answers A, B, D, and E are incorrect as these enteroviruses don’t target the liver.

Question 2

You are an otherwise healthy anesthesiologist who over a 24-hour period develops a sore throat and what appears to be three 1-cm erythematous ulcers on the right anterior tonsillar pillar. Since systemic signs of infection were absent, you continue to perform your normal duties in the operating room and in the obstetrical suite. The next day you consult an ear, nose, and throat specialist because you are developing malaise and increased discomfort with swallowing. Physical examination reveals only the intraoral lesion, cervical adenopathy, but no cutaneous lesions. Later you find that your 2-year-old child also had a similar healing lesion in his oropharynx. Which of the following viruses is most likely the cause of your oral lesion?

Answer 2

Answer: Coxsackie A virus

You have most likely been infected with a Coxsackie A virus and have herpangina. The small lesions on your palate and the finding that your child has the healing lesions also point to herpangina. B is incorrect as the Coxsackie B viruses don’t cause herpangina. C is incorrect. While infection with EBV can cause a sore throat during the primary infection, it is not known to cause these types of lesions on the palate. D is incorrect; HHV-8 is associated with Kaposi’s sarcoma, not oral lesions. E is incorrect as mumps virus causes a benign inflammation of the parotid gland.

Question 3

You are a resident at an infectious disease clinic where you have recently treated several patients with influenza A virus infections. Approximately one week later you develop a headache, fever, fatigue, sore throat, body aches and muscle pain. Which of the following options could you pursue to shorten the disease course?

Answer 3

Answer: Begin treatment with a neuraminidase inhibitor.

You most likely have been infected with influenza virus and you are beginning to come down with the symptoms of disease. At this point a neuraminidase inhibitor may shorten the duration of the disease. Acyclovir is incorrect as this drug is used to treat herpesvirus infections. Ribavirin is incorrect as this drug is ineffective against influenza virus. D is incorrect as rimantadine is only beneficial if taken prophylactically. Immediately getting the trivalent influenza virus vaccine is incorrect as the vaccination would only prevent infection and would take several weeks before immunity is sufficient.

Question 4

Which of the following families contain negative-strand RNA viruses?

Answer 4

Answer: Filoviridae

Answers Coronaviridae, Flaviviridae, and Picornaviridae are incorrect as these families are positive strand RNA viruses. Ans B is correct. The Filoviridae are negative strand RNA viruses and are the “filamentous” viruses, which contain notable members as Ebola virus and Marburg virus. Answer D is incorrect as the parvoviridae are single stranded DNA viruses.

Question 5

Which of the following conditions places a patient at GREATEST RISK for severe viral infections?

Answer 5

Answer: Deficiency of IL-2Rγ (γc deficiency)

Deficiencies in the common gamma chain of the IL-2 receptor are the most common causes of acquired immune deficiency syndrome (AIDS). These patients are at high risk for severe infections of all types and present early in life with complicated and disseminated viral and fungal infections.
A is Incorrect. Although the local environment of the pregnant uterus is immunosuppressed in terms of supporting fetal allograft rejection, pregnancy does not place a woman at significant risk for severe viral infections. B is Incorrect. Although the elderly are at risk for certain complications of infection and may have diminished risk of acquiring infections of certain types (including viral), the risk does not approach that seen with selective immune deficiency diseases. C is Incorrect. Leukocyte Adhesion Deficiency places patients at risk for certain opportunistic bacterial and fungal infections, not viral infections. C2 is Incorrect. Deficiencies in the early components of the complement system place patients at risk for pyogenic bacterial infections with opportunistic organisms.

Question 6

Which of the following classes of antiviral drugs is most effective if given within the first two days of an influenza type A and B virus infection?

Answer 6

Answer: Neuraminidase inhibitors

The answer is neuraminidase inhibitors such as Tamiflu (oseltamimivir) and Relenza (Zanamivir). Ion channel blockers is incorrect. Answers entry inhibitors, nucleotide transcriptase inhibitors, and protease inhibitors are incorrect as no inhibitors exist in these classes of drugs that are effective in treating influenza virus infections.

Question 7

Which of the following characteristics is an advantage of the inactivated poliovirus vaccine over the live poliovirus vaccine?

Answer 7

Answer: The inactivated vaccine cannot revert to a virulent virus.

Question 8

Advantages of live attenuated poliovirus vaccine

Answer 8

The inactivated vaccine induces IgA responses in the gastrointestinal tract.
The inactivated vaccine induces lifelong immunity.
The inactivated vaccine is more easily administered.
The inactivated vaccine requires a single immunization.

Question 9

Which of the following anti-viral drugs is a protease inhibitor?

Answer 9

Answer: Darunavir

A is incorrect as abacavir is a nucleoside reverse transcriptase inhibitor.
C is incorrect as nevirapine is non-nucleoside reverse transcriptase inhibitor.
D is incorrect a raltegravir is an integrase inhibitor.
E is incorrect as zidovudine or AZT is a nucleoside reverse transcriptase inhibitor.

Question 10

Which of the families of viruses contain members with a lipid envelope?

Answer 10

Answer: Orthomyxoviridae

The orthomyxoviruses contain the influenza viruses, which have a lipid envelope with three viral membrane proteins, the hemaglutinin, neuraminidase, and M2 protein

Question 11

Icosahedral viruses w/o an envelope

Answer 11

Adenoviridae
Calciviridae
Papovaviridae
Reoviridae

Question 12

What is the average incubation period and the incidence of developing a chronic HBV infections?

Answer 12

60-90 days; 9-10%.

Question 13

As a member of a first responder team prepared to assist in the event of a biowarfare attack, you are asked to consider being immunized for smallpox. The vaccine consists of a heterologous attenuated live virus, vaccinia, which is given at multiple puncture sites in the skin overlaying the deltoid muscle. What type of anti-viral immunity is intended to be induced by this form of vaccine?

Answer 13

Answer: Induction of serum antibodies and cytotoxic T cells

The primary purpose immunization is to induce circulating antibodies and memory T and B cells, which can be rapidly mobilized upon a subsequent encounter with a pathogen. The smallpox virus can be cleared by circulating antibodies and cytotoxic T cells are also protective, although there is evidence that CTLs mediate much of the skin damage associated with the smallpox rash. A is Incorrect. While vaccines can induce interferons, these immune mediators are short-lived. B is Incorrect. Vaccines do not alter a host’s innate immune responses. C is Incorrect. Vaccines can induce neutralizing secretory IgA antibodies, but immunization must be by the mucosal route (eg., oral or respiratory). D is Incorrect. NK cells are a component of the innate immune system. There numbers and activity are not altered by vaccination.

Question 14

A two year-old boy is brought to the emergency room in February with coryza and a barking-like cough. Physical examination reveals a low-grade fever and an absence of wheezing and stridor. The patient is diagnosed to have the croup, given a single dose of dexamethasone to reduce the inflammation in the respiratory tract and sent home to rest. Which of the following viruses is most likely the cause of this child’s respiratory disease?

Answer 14

Answer: Parainfluenza virus

The barking cough is usually a symptom of the croup or laryngotracheitis. The croup is a common respiratory illness that is responsible for up to 15% of emergency department visits due to respiratory disease in children in the United States. The parainfluenza viruses are the major cause of the croup (50-75%) with parainfluenza virus type 1 being most common. A, B, C, and E are incorrect. The adenovirus a. , coronavirus b., bocavirus c. and rhinoviruses e. can also cause the croup but are not as common as the parainfluenza viruses.

Question 15

A patient comes to the Infectious Diseases clinic at KUMC complaining of fever, fatigue, upper abdominal discomfort, and dark colored urine. The patient was a 40-year -old man that had returned from central Mexico approximately 4 weeks ago. He was a large animal veterinarian who was visiting a local veterinary school to present lectures on infectious diseases of swine, which included face time with live animals and inspections of raw pig meat. He had no history of intravenous drug use, unprotected sex, drinking contaminated water or eating raw shellfish. His laboratory results revealed elevated serum liver enzymes with a total bilirubin level of 6 mg/dL, direct bilirubin level was 3.9 mg/dL, serum aspartate aminotransferase (AST) concentration was 1458 U/L, alanine aminotransferase (ALT) was 2232 U/L, and alkaline phosphatase (AP) was 196 U/L. The peak of liver enzymes was observed on the tenth day after the start of the clinical manifestations and returned to normal values on day 25. Which of the following viruses was most likely the cause of this patient’s disease?

Answer 15

Answer: Hepatitis E virus

HEV is a zoonotic disease that occurs in swine. Certain genotypes of HEV are prevalent in swine but can be transmitted to humans. Hep A is unlikely, as he claims to have not eating raw shellfish or drank contaminated water. Hep B, C, and D are not correct, as he had no risk factors associated with the transmission of these viruses.

Question 16

A HAART regimen includes a reverse transcriptase inhibitor that causes a potentially fatal hypersensitivity reaction in about 5% of patients. The presence of the HLA*B5701 allele is a predictor of this adverse effect. The drug is:

Answer 16

Abacavir

Skin rash (~50% of patients) and hypersensitivity (~5% of patients) is associated with abacavir. The HLA*B5701 polymorphism is present in nearly all patients that experience the hypersensitivity reaction, but only about 50% of patients with that allele will exhibit this adverse effect, so clearly other causative factors are required. B is incorrect - Efavirenz is associated with CNS effects and rash, but not hypersensitivity. C is incorrect - Nevirapine is associated with rash and hepatic and GI effects, but not hypersensitivity. D is in correct - Tenofovir is associated with GI and renal effects, but not hypersensitivity. E is incorrect - Zidovudine is associated with bone marrow suppression and GI effects, but not hypersensitivity.

Question 17

A drug used in the management of hepatitis B (HBV) and that is part of a curative therapy for hepatitis C (HCV) must be administered by either subcutaneous or intramuscular injection. It usually is given in a PEGylated form to prolong its half-life. The drug is:

Answer 17

Answer: Interferon-alpha

Interferons are not absorbed from the GI tract, and are rapidly degraded by proteases. The PEGylated forms are far more resistant to degradation, and thus only require weekly, as opposed to daily, dosing. A is incorrect - Enfuvirtide is a peptide, and given parenterally, but for HIV treatment. C is incorrect - Lamivudine is administered orally. D is incorrect - Ribavirin is administered orally. E is in correct - Telaprevir is administered orally.

Question 18

A 47-year-old male patient from Dagestan was referred to the Department of Gastroenterology at KUMC. Physical examination showed jaundice, liver/spleen enlargement and dark urine. The following serological, biological and molecular analyses were performed and results indicated:

HIV-1  negative
HBsAg positive
HbeAg positive
anti-HBs           negative
anti-HBe           negative
anti-HBc IgM   positive
anti-HDV         positive
HDV DNA       1 x 109 copies
HDV RNA       2 x106 copies
ALT     567 IU/ml

The patient was started on a 2-month course of treatment with pegylated interferon-alpha-2α. Two months later no significant decrease of HBV DNA levels was observed and HDV RNA remained detectable. Which of the following drugs could be added to the therapy to enhance the virologic response against HBV/HDV?

Answer 18

Tenofovir

Question 19

A 26 year old patient has been diagnosed with genital herpes and is prescribed an appropriate drug for initial therapy. The anti-viral prescribed is a pro-drug, requiring sequential action of a host esterase, a viral kinase, and then host kinases to convert it to its active form. The drug is:

Answer 19

Answer: Valacyclovir

Valacyclovir has higher bioavailability than does acyclovir, but is rapidly hydrolyzed by esterases to acyclovir following absorption. The initial phosphorylation of acyclovir is specifically catalyzed by viral thymidine kinase, and the subsequent conversion to the active triphosphate derivative is catalyzed by mammalian kinases. A is incorrect. Acyclovir does not require initial metabolism by esterases. B is incorrect. Foscarnet is a pyrophosphate analog. None of the metabolic steps listed apply to this drug. C is incorrect. Ganciclovir does not require esterase action, and is used for treatment of CMV, not genital herpes. D is incorrect. Trifluridine does not interact with esterases, and is phosphorylated by host kinases.

Question 20

A 4-month-old boy is brought to the KUMC emergency department with rhinorrhea (nasal discharge) and tachypnea for the past 4 days. He had become lethargic, hypoxic and developed a fever during the night, which had prompted his mother to bring him to the ER. When interviewing the mother, the child had not been drinking or eating well for the past 1 to 2 days but had no vomiting or diarrhea. He had a cough and his mother reported that when he breathes, he sounds “funny.” The history reveals the child had been recently exposed to other sick children at his daycare center. A chest X-ray revealed an infiltrate in the middle right lobe and lung biopsy revealed cells that had formed “syncytia.” Tests for RSV and bacteria were negative. The child is hospitalized, put on supportive therapy and is released 4 days later. Which of the following viruses is most likely responsible for this child’s respiratory disease?

Answer 20

Answer:
Human metapneumovirus

Many viruses can cause respiratory disease in young children. The symptoms presented are indicative of RSV but tests for RSV are negative, in which case human metapneumovirus should be suspected. The paramyxoviruses are known for their ability to induce giant cell (syncytia) formation. None of the other four viruses are known to cause syncytia.

Question 21

A 23-year-old male athlete was admitted to the KUMC emergency department in an unconscious state. Up to this point the patient had not had any health problems. However, his mother reported that 24 h previously, he had complained of mild fever and malaise. She also reported he had complained of insomnia, but denied any previous health problems or coronary artery disease. The patient was not on any medications and had no allergies. There was no history of alcohol or tobacco consumption. Shortly before admission to hospital, the patient had complained of severe chest pain. On admission the peripheral white cell count was 20,000 with 74% polymorphonuclear leukocytes and 26% lymphocytes. The electrocardiogram was abnormal with incomplete right bundle branch block and occasional premature ventricular contraction. The echocardiography revealed a severe cardiomyopathy with poor heart function and areas of very thin myocardium, suggesting myocarditis. While undergoing intensive medical intervention he had convulsive seizures and then collapsed and was declared dead 35 min after admission. At autopsy, histological examination of the left ventricle section revealed signs of active myocarditis, which consisted of large infiltrates of lymphocytes associated with severe myocardial necrosis. Which of the following viruses was most likely the cause of this patient’s myocarditis?

Answer 21

Answer: Coxsackie B virus

The Coxsackie B viruses are most often associated with viral myocarditis but the Coxsackie A and echoviruses have also been implicated in this disease in humans.
Cytomegalovirus, Herpes simplex virus type 1, Influenza A virus and Reovirus type 3 are not known to cause cardiac disease in healthy individuals.

Question 22

A 15 month-old white girl is brought to the Infectious Disease Clinic at KUMC on the day after she received her pneumococcal vaccinations. These had initially been booked when she was 13 months old but were postponed twice owing to minor illnesses. On the day after her vaccinations she developed conjunctivitis, a cough, and fever, with gradual worsening of her symptoms over the next few days. Four days after the onset of symptoms, she refused food and had an episode of vomiting. The next day, small erythematous macules appeared behind her ears. Tiny white papules were present on the buccal mucosa. The eruption became papular and spread to her face, trunk, and limbs. The rash gradually became more confluent and maculopapular. Which of the following viruses is most likely the cause of this child’s disease?

Answer 22

Measles virus

B19 virus, HHV-6, Measles virus, Rubella virus and Varicella-zoster virus
can cause a rash so it is important to distinguish between them.
However, there are symptoms listed above (conjunctivitis, cough, tiny papules on her buccal mucosa known as Koplik’s spots) that indicate this child has a measles virus infection. A is incorrect as B19 virus causes a “slapped cheek syndrome”. B19 virus infections do not present with with conjunctivitis, or Koplik’s spots. B is incorrect as as HHV-6 cause roseola infantum, which usually presents with a high fever (40C) which lasts for approximately three days. In 15% of the cases a febrile seizure occurs. This is followed by a mild, pink, morbilliform exanthem which is self-limiting. Conjunctivitis, and Koplik’s spots are not present. D is incorrect as rubella causes presents with a mild fever of 102 F (38.9 C) or lower, headache, stuffy or runny nose, inflamed red eyes, enlarged, tender lymph nodes at the base of the skull, the back of the neck and behind the ears. With rubella a fine, pink rash that begins on the face and quickly spreads to the trunk and then the arms and legs, before disappearing in the same sequence. E is incorrect as chickenpox presents with a fever of 100.4F (38C) to 103F (39.4C), feeling tired, and sluggish, little or no appetite, headache and sore throat. The rash appears 1-2 days later with an itchy rash followed by red or swollen spots that blister, often leaking fluid. This vesicular type crusts over and eventually heals. There is no conjunctivitis or Koplik’s spots.