Virology

Topics in this chapter

• Viral Structure, Symmetry and Classification
• Viral Replication and Genome Strategies
• Viral Diagnostics and Inclusion Bodies
• DNA Viruses and Associated Diseases
• RNA Viruses and Viral Syndromes
• Vector-Borne and Neurotropic Viruses
• Viral Prevention, Vaccination and Prophylaxis

Practice questions

1. Question 1Q-9EB3B7

   A 32-year-old HIV-positive male presents with rapidly progressive dementia and visual disturbances. Magnetic resonance imaging of the brain shows asymmetric white matter lesions without mass effect or contrast enhancement. Polymerase chain reaction of the cerebrospinal fluid is positive for JC virus. This condition is caused by the reactivation of which type of viral genome?

   1. A.Double-stranded DNA, circular
   2. B.Single-stranded DNA, linear
   3. C.Double-stranded RNA, segmented
   4. D.Single-stranded positive-sense RNA, linear
   See the answer and solution
2. Question 2Q-E18C84

   A 4-year-old child presents with high-grade fever, cough, coryza, and conjunctivitis for 3 days, followed by the appearance of erythematous maculopapular rash starting from the face and spreading downwards, along with bluish-white spots on the buccal mucosa. Which of the following laboratory findings is classically associated with this infection?

   1. A.Warthin-Finkeldey cells in lymphoid tissue
   2. B.Negri bodies in Purkinje cells
   3. C.Cowdry A bodies in conjunctival scrapings
   4. D.Owl-eye inclusion bodies in endothelial cells
   See the answer and solution
3. Question 3Q-9FB26A

   A virology laboratory receives a specimen for viral culture from a patient with suspected viral hemorrhagic fever. The virus is known to be an enveloped, negative-sense, single-stranded RNA virus with a segmented genome belonging to the Bunyaviridae family (specifically Hantavirus). Which of the following statements is true regarding viral replication of this group?

   1. A.Replication occurs entirely in the nucleus of the host cell
   2. B.Replication occurs in the cytoplasm, and viral assembly involves budding into the Golgi apparatus
   3. C.The genome acts directly as mRNA upon entry into the host cell cytoplasm
   4. D.Replication requires a reverse transcriptase enzyme encoded by the virion
   See the answer and solution
4. Question 4Q-393866

   During an outbreak of acute gastroenteritis in a pediatric ward, several children and staff members are affected. Electron microscopy of stool samples reveals small, non-enveloped, round viruses with a cup-shaped depression on their surface (often described as having a 'Star of David' appearance). What is the causative agent?

   1. A.Rotavirus
   2. B.Norovirus
   3. C.Adenovirus
   4. D.Astrovirus
   See the answer and solution
5. Question 5Q-8E68A2

   A 25-year-old medical student sustains a needle-stick injury while drawing blood from a patient known to be HBsAg-positive and HBeAg-positive. The student's baseline anti-HBs titer is < 10 IU/L. According to CDC guidelines, what is the most appropriate post-exposure prophylaxis?

   1. A.Hepatitis B immune globulin (HBIG) only
   2. B.Hepatitis B vaccine series only
   3. C.Both HBIG and initiation of the Hepatitis B vaccine series
   4. D.Observation and repeat serology in 6 months
   See the answer and solution