Virology Practice Questions

Q: How does HSV establish latency in the host?

Through retrograde axonal transport to dorsal root ganglia. ***Through retrograde axonal transport to dorsal root ganglia*** - HSV establishes latency by traveling via **retrograde axonal transport** from the site of infection to the sensory **dorsal root ganglia (DRG)**. - In the DRG, the virus remains dormant within the neuronal cells, expressing only latency-associated transcripts (LATs) rather than replicating. *By forming spores in epithelial cells* - HSV is a **DNA virus** and does not form spores, which are typically found in bacteria and fungi as survival structures. - While HSV infects epithelial cells initially, its latency phase is established in neurons, not by forming spores in epithelial tissues. *Through persistent viremia* - **Persistent viremia** refers to the continuous presence of viruses in the bloodstream, which is characteristic of some chronic viral infections but not how HSV establishes latency. - HSV latency involves viral DNA remaining dormant within specific neuronal cells, not actively circulating in the blood. *By integrating into host DNA* - While some viruses (like retroviruses) integrate their genetic material into the host genome, **HSV does not integrate its DNA** during latency. - HSV DNA typically remains as an **episome** (a circular, independent piece of DNA) within the nucleus of the infected neuron during latency.

Q: Which type of HSV is most commonly associated with recurrent genital herpes?

HSV-2. ***HSV-2*** - **HSV-2** is the primary cause of **genital herpes** and is significantly more likely to cause recurrent outbreaks than HSV-1 in the genital region. - The virus establishes **latency in sacral ganglia**, leading to frequent reactivation and subsequent genital lesions. *HSV-1* - While **HSV-1** can cause **genital herpes** (often through oral-genital contact), it is more commonly associated with **oral herpes (cold sores)**. - Genital infections caused by HSV-1 tend to recur less frequently and are generally less severe than those caused by HSV-2. *VZV (Varicella-Zoster Virus)* - **VZV** causes **chickenpox** (initial infection) and **shingles** (reactivation), not genital herpes. - It establishes latency in **dorsal root ganglia** and reactivation presents as a dermatomal rash (shingles). *CMV (Cytomegalovirus)* - **CMV** is a common virus that usually causes **asymptomatic infection** in healthy individuals, but can cause severe disease in immunocompromised patients or neonates. - It is not associated with genital lesions or recurrent genital herpes.

Q: Which cytopathic effect would confirm molluscum contagiosum virus infection?

Henderson-Paterson bodies. ***Henderson-Paterson bodies*** - These are characteristic **large, eosinophilic intracytoplasmic inclusion bodies** seen in keratinocytes infected with the **molluscum contagiosum virus**. - Their presence confirms a diagnosis of molluscum contagiosum upon histological examination. *Cowdry type B inclusions* - These are **intracytoplasmic inclusion bodies** associated with **adenovirus** and **poliovirus** infections. - They are not characteristic of molluscum contagiosum virus, which forms distinct Henderson-Paterson bodies. *Owl's eye inclusions* - These are large, **intranuclear inclusion bodies with a clear halo** surrounding a dense central core, classically seen in cells infected with **cytomegalovirus (CMV)**. - They are distinct from the cytoplasmic inclusions of molluscum contagiosum. *Negri bodies* - These are **eosinophilic cytoplasmic inclusions** found in the cytoplasm of hippocampal pyramidal cells and Purkinje cells of the cerebellum, pathognomonic for **rabies virus infection**. - They are associated with a different viral family and are distinct from molluscum contagiosum inclusions.

Q: A viral culture shows 'ground glass' nuclear appearance. Which inclusion body would confirm cytomegalovirus infection?

Owl's eye inclusions. ***Owl's eye inclusions*** - **Owl's eye inclusions** are characteristic large, eosinophilic intranuclear inclusions with a clear halo, pathognomonic for **cytomegalovirus (CMV)** infection. - The "ground glass" appearance observed in a viral culture is often an early indicator, and these inclusions confirm the presence of **CMV**. *Negri bodies* - **Negri bodies** are eosinophilic **intracytoplasmic** inclusions found in the pyramidal cells of the hippocampus and Purkinje cells of the cerebellum in individuals with **rabies virus** infection. - They are unrelated to CMV and would not be present in a CMV infection. *Cowdry type A* - **Cowdry type A inclusions** are acidophilic intranuclear inclusions associated with **herpes simplex virus (HSV)** and **varicella-zoster virus (VZV)** infections. - While they are intranuclear, they are distinctly different from the 'owl's eye' appearance of CMV. *Henderson-Paterson bodies* - **Henderson-Paterson bodies** are eosinophilic intracytoplasmic inclusions found in cells infected with the **Molluscum contagiosum virus**. - These inclusions are specific to molluscum contagiosum and are not associated with CMV.

Q: SARS is caused by novel variant of?

Coronavirus. ***Coronavirus*** - **Severe Acute Respiratory Syndrome (SARS)** is caused by a novel strain of **coronavirus**, specifically SARS-CoV. - Coronaviruses are a large family of viruses known to cause respiratory illnesses ranging from the common cold to more severe diseases. *Togavirus* - Togaviruses are a family of **RNA viruses** that include **Rubella virus** and **Alphaviruses** (e.g., Eastern equine encephalitis virus). - They are typically transmitted by **arthropod vectors** and do not cause SARS. *Lyssavirus* - Lyssaviruses belong to the family Rhabdoviridae and are the causative agents of **rabies**, a severe neurological disease. - They are transmitted through the bite of an infected animal and are not associated with SARS. *Poxvirus* - Poxviruses are a family of **DNA viruses** that include **Variola virus** (smallpox) and **Monkeypox virus**. - They are known for causing characteristic skin lesions and are not responsible for SARS.

Q: Chronic viral hepatitis is seen with all of the following viruses, except?

HEV. ***HEV*** - While HEV can cause acute hepatitis, it **rarely progresses to chronic infection** in immunocompetent individuals. - Chronic HEV infection is primarily seen in **immunocompromised patients**, such as organ transplant recipients. *HCV* - **Hepatitis C virus** is well-known for its high propensity to establish chronic infection, with about 75-85% of acutely infected individuals developing **chronic hepatitis** [1]. - Chronic HCV infection can lead to **cirrhosis**, liver failure, and hepatocellular carcinoma [1]. *HBV* - **Hepatitis B virus** is a major cause of chronic hepatitis worldwide, especially when acquired perinatally or in early childhood [1]. - Approximately 5-10% of immunocompetent adults who acquire acute HBV infection progress to **chronic hepatitis** [1]. *HDV* - **Hepatitis D virus** is a defective virus that requires co-infection with HBV to replicate; therefore, chronic HDV infection only occurs in individuals with chronic HBV. - Co-infection or superinfection with HDV often **accelerates the progression of liver disease** to cirrhosis and liver failure.

Q: The following serological status is noted in a patient: HbsAg positive and HbeAg positive. Diagnosis is?

Active hepatitis B with high infectivity. ***Active hepatitis B with high infectivity*** - The presence of **HBsAg** indicates ongoing **hepatitis B infection** (either acute or chronic) [1]. - The presence of **HBeAg** signifies active **viral replication** and **high infectivity**, meaning the patient can easily transmit the virus [1]. *Chronic viral hepatitis* - While the patient does have hepatitis B, simply stating "chronic viral hepatitis" is less specific and doesn't fully capture the **infectivity status**. - **Chronic hepatitis B** is defined by **HBsAg persistence** for more than six months, but a high infectivity state is specifically implied by HBeAg positivity [1]. *Remote infection* - **Remote infection** would typically be indicated by the presence of **anti-HBs** and **anti-HBc IgG** antibodies, with no detectable HBsAg [1]. - The patient's **HBsAg positive** status rules out a remote infection where the virus has been cleared [1]. *Resolved hepatitis B infection* - A resolved hepatitis B infection is characterized by **loss of HBsAg** and the development of **anti-HBs antibodies**, indicating immunity [1]. - The patient's **HBsAg positive** status definitively indicates that the infection is not resolved and is still active [1].

Q: EBV is most strongly associated with which of the following?

Nasopharyngeal carcinoma. ***Nasopharyngeal carcinoma*** - **Epstein-Barr virus (EBV)** is strongly and consistently associated with the development of **nasopharyngeal carcinoma**, particularly the undifferentiated (endemic) type. - EBV DNA is found in virtually **100% of undifferentiated nasopharyngeal carcinomas**, highlighting its critical role in the pathogenesis of this cancer. - This represents one of the strongest virus-cancer associations in human medicine. *Gastric cancer* - While EBV is linked to a specific subtype of **EBV-associated gastric adenocarcinoma**, it accounts for only about **10% of gastric cancers**. - This makes it a less strong and less prevalent association compared to nasopharyngeal carcinoma. *Esophageal cancer* - **Esophageal cancer** (adenocarcinoma and squamous cell carcinoma) has various risk factors such as GERD, smoking, and alcohol consumption. - **EBV is not a significant etiologic factor** for esophageal cancer. - There is no strong, consistent evidence linking EBV as a primary cause of esophageal malignancy. *Hepatocellular carcinoma* - **Hepatocellular carcinoma** is primarily associated with **hepatitis B virus (HBV)** and **hepatitis C virus (HCV)**, not EBV. - Other risk factors include chronic liver disease, cirrhosis, aflatoxin exposure, and alcohol abuse. - EBV does not play a significant role in hepatocellular carcinoma pathogenesis.

Q: Molluscum contagiosum is caused by a:

Pox virus. ***Pox virus*** - **Molluscum contagiosum** is a common **cutaneous viral infection** caused by the **Molluscum Contagiosum Virus (MCV)**. - MCV belongs to the **Poxviridae family**, which are known for causing characteristic skin lesions. *Flavi virus* - **Flaviviruses** are a genus of RNA viruses, which cause diseases like **Dengue fever**, **Yellow fever**, and **Zika virus infection**. - They typically cause **systemic illnesses** with fever and rash, rather than localized skin lesions like molluscum contagiosum. *Adenovirus* - **Adenoviruses** are DNA viruses primarily associated with **respiratory infections** (e.g., common cold, bronchitis) and **conjunctivitis**. - They are not known to cause the characteristic **umbilicated papules** seen in molluscum contagiosum. *Rubivirus* - **Rubivirus** is a genus that includes the **Rubella virus**, which causes **German measles** (Rubella). - Rubella is characterized by a **maculopapular rash** and **lymphadenopathy**, which is distinct from the **umbilicated papules** seen in molluscum contagiosum.

Question 1

A 35-year-old woman presents with painful genital ulcers that recur every few months. Current examination reveals multiple shallow ulcers on the labia minora. PCR testing is positive for HSV-2. Which of the following best explains the mechanism of viral latency in this condition?

Accepted Answer

Establishment of dormancy in sensory ganglia as episomal DNA

Answer

Immune evasion through antigenic drift

Answer

Persistent viremia

Answer

Integration into host genome

Question 2

How does HSV establish latency in the host?

Accepted Answer

Through retrograde axonal transport to dorsal root ganglia

Answer

By forming spores in epithelial cells

Answer

Through persistent viremia

Answer

By integrating into host DNA

Question 3

Which type of HSV is most commonly associated with recurrent genital herpes?

Accepted Answer

HSV-2

Answer

HSV-1

Answer

VZV (Varicella-Zoster Virus)

Answer

CMV (Cytomegalovirus)

Question 4

Which cytopathic effect would confirm molluscum contagiosum virus infection?

Accepted Answer

Henderson-Paterson bodies

Answer

Cowdry type B inclusions

Answer

Owl's eye inclusions

Answer

Negri bodies

Question 5

A viral culture shows 'ground glass' nuclear appearance. Which inclusion body would confirm cytomegalovirus infection?

Accepted Answer

Owl's eye inclusions

Answer

Negri bodies

Answer

Cowdry type A

Answer

Henderson-Paterson bodies

Question 6

SARS is caused by novel variant of?

Accepted Answer

Coronavirus

Answer

Toga virus

Answer

Lyssa virus

Answer

Pox virus

Question 7

Chronic viral hepatitis is seen with all of the following viruses, except?

Accepted Answer

HEV

Answer

HCV

Answer

HBV

Answer

HDV

Question 8

The following serological status is noted in a patient: HbsAg positive and HbeAg positive. Diagnosis is?

Accepted Answer

Active hepatitis B with high infectivity

Answer

Chronic viral hepatitis

Answer

Remote infection

Answer

Resolved hepatitis B infection

Question 9

EBV is most strongly associated with which of the following?

Accepted Answer

Nasopharyngeal carcinoma

Answer

Gastric cancer

Answer

Esophageal cancer

Answer

Hepatocellular carcinoma

Question 10

Molluscum contagiosum is caused by a:

Accepted Answer

Pox virus

Answer

Flavi virus

Answer

Adenovirus

Answer

Rubivirus

Virology — MCQs

Virology — MCQs

On this page

Practice by Chapter

Want unlimited practice?