Virology Practice Questions

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.

Q: Which of the following viruses is from the Herpes virus family?

EBV. ***EBV*** - **Epstein-Barr Virus (EBV)** is a member of the **Herpesviridae** family, specifically **Human Herpesvirus 4 (HHV-4)**. - It is a **DNA virus** (double-stranded DNA), which is characteristic of all herpesviruses. - It is known to cause **infectious mononucleosis** and is associated with various malignancies. *Rubella* - **Rubella virus** belongs to the family **Togaviridae** and is the causative agent of **German measles**. - It is an **RNA virus** and is not classified within the Herpesviridae family. *Rabies* - **Rabies virus** is a member of the **Rhabdoviridae** family, specifically the genus **Lyssavirus**. - It is a neurotropic **RNA virus** causing a rapidly progressive, fatal encephalitis. *Measles* - **Measles virus**, also known as **Rubeola**, belongs to the family **Paramyxoviridae**. - It is an **RNA virus** responsible for a highly contagious airborne disease.

Q: Infantile myocarditis and pericarditis is due to

Coxsackie B. **Coxsackie B** - **Coxsackie B virus** is a well-established cause of **viral myocarditis and pericarditis**, particularly in infants and young children. - The virus can directly infect myocardial cells, leading to inflammation and damage. - Coxsackie B is the **most common viral cause** of infantile myocarditis. *Pox virus* - **Poxviruses** primarily cause **skin lesions** (e.g., smallpox, molluscum contagiosum) and are not a common cause of myocarditis or pericarditis. - While systemic infections can occur, cardiac involvement is **rare and not a typical presentation**. *Mumps* - **Mumps virus** is known for causing **parotitis** (inflammation of the salivary glands), and can also cause complications such as orchitis, meningitis, and pancreatitis. - While **mumps myocarditis** can occur, it is a **less common** presentation compared to Coxsackie B virus. *Coxsackie A* - **Coxsackie A viruses** are more commonly associated with conditions like **herpangina** (oral lesions) and **hand-foot-and-mouth disease**. - While they can occasionally cause myocarditis, **Coxsackie B viruses** are far more frequently implicated in cases of viral myocarditis and pericarditis.

Question 1

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 2

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 3

SARS is caused by novel variant of?

Accepted Answer

Coronavirus

Answer

Toga virus

Answer

Lyssa virus

Answer

Pox virus

Question 4

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

Accepted Answer

HEV

Answer

HCV

Answer

HBV

Answer

HDV

Question 5

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 6

EBV is most strongly associated with which of the following?

Accepted Answer

Nasopharyngeal carcinoma

Answer

Gastric cancer

Answer

Esophageal cancer

Answer

Hepatocellular carcinoma

Question 7

Molluscum contagiosum is caused by a:

Accepted Answer

Pox virus

Answer

Flavi virus

Answer

Adenovirus

Answer

Rubivirus

Question 8

Which of the following viruses is from the Herpes virus family?

Accepted Answer

EBV

Answer

Rubella

Answer

Rabies

Answer

Measles

Question 9

Infantile myocarditis and pericarditis is due to

Accepted Answer

Coxsackie B

Answer

Pox virus

Answer

Mumps

Answer

Coxsackie A

Question 10

Prophage is defined as:

Accepted Answer

Integrated temperate bacteriophage genome into bacterial chromosome

Answer

First cycle of division of bacterial nucleic acid

Answer

Last cycle of division of bacterial nucleic acid

Answer

Insertion of viral nucleic acid into bacteria by bacteriophage

Virology — MCQs

Virology — MCQs

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