Virology Practice Questions

Q: Which of the following hepatitis viruses is likely to get transmitted via fecal-oral route?

Hepatitis A. ***Hepatitis A***- Hepatitis A virus (HAV) is primarily spread through the **fecal-oral route**, typically via consumption of food or water contaminated with feces.- It causes an **acute**, self-limiting infection that rarely results in chronic liver disease.*Hepatitis B*- Hepatitis B virus (HBV) is transmitted mainly through **parenteral** (exposure to infected blood), sexual contact, or perinatal (mother-to-child) routes.- Unlike HAV, HBV is a major cause of **chronic hepatitis**, cirrhosis, and hepatocellular carcinoma.*Hepatitis C*- Hepatitis C virus (HCV) transmission is predominantly **parenteral**, most commonly associated with intravenous drug use, blood transfusions (historically), and shared needles.- HCV is the leading cause of chronic viral hepatitis globally and frequently establishes persistent infection.*Hepatitis D*- Hepatitis D virus (HDV) is a defective RNA virus that requires **Hepatitis B surface antigen (HBsAg)** for its replication and assembly.- HDV is transmitted parenterally (same routes as HBV) and not via the fecal-oral route.

Q: The image shown here is used for the diagnosis of

Herpes simplex virus. ***Herpes simplex virus*** - The image is a transmission electron micrograph showing multiple enveloped virions with a characteristic dense central core and an icosahedral nucleocapsid, giving a "target" or "bull's-eye" appearance. - This morphology is a classic feature of the **Herpesviridae** family, which includes Herpes Simplex Virus (HSV), Varicella-Zoster Virus (VZV), and Cytomegalovirus (CMV). *Human immunodeficiency virus* - HIV is a **retrovirus**, and its mature virion has a distinct **cone-shaped** or **bar-shaped** core, which is morphologically different from the spherical, target-like core shown in the image. - The primary diagnostic methods for HIV are serological assays (e.g., **ELISA**) and nucleic acid tests (**PCR**), not electron microscopy. *Hepatitis B virus* - The complete infectious virion of HBV, known as the **Dane particle**, is a double-shelled spherical particle, which does not have the same internal structure as the virions in the image. - Serum from infected individuals also contains non-infectious spherical and filamentous particles of **HBsAg** which lack a nucleocapsid. *Human papillomavirus* - HPV is a **non-enveloped** DNA virus, whereas the virus in the micrograph is clearly surrounded by a lipid envelope. - It has a simple, small **icosahedral capsid** structure, lacking the complex, multi-layered appearance of a herpesvirus.

Q: Acute hemorrhagic conjunctivitis is caused by which of the following combinations?

Coxsackie A and Enterovirus 70. ### **Explanation: Acute Hemorrhagic Conjunctivitis (AHC)** **Acute Hemorrhagic Conjunctivitis (AHC)** is a highly contagious, self-limiting viral infection characterized by rapid onset, lid edema, and pathognomonic **subconjunctival hemorrhages**. #### **1. Why Option A is Correct** The primary etiological agents for AHC are **Enterovirus 70 (EV-70)** and **Coxsackievirus A24 (CA24)** variant. These are small RNA viruses belonging to the *Picornaviridae* family. * **Enterovirus 70** was the first identified cause during the 1969 pandemic. * **Coxsackie A24** is responsible for several subsequent large-scale outbreaks worldwide. #### **2. Why Other Options are Incorrect** * **Options B, C, and D:** These include **Coxsackie B**. While Coxsackievirus B is a common cause of myocarditis, pleurodynia (Bornholm disease), and meningitis, it is **not** a recognized cause of acute hemorrhagic conjunctivitis. The ocular tropism is specific to the **A24 variant** of Coxsackie A. --- ### **High-Yield Clinical Pearls for NEET-PG / INI-CET** * **Incubation Period:** Extremely short, typically **12 to 48 hours**. * **Clinical Hallmark:** Multiple **petechial hemorrhages** on the bulbar conjunctiva that may coalesce to form a large subconjunctival hemorrhage. * **Neurological Association:** A rare but serious complication of **Enterovirus 70** is a **polio-like paralysis** (radiculomyelitis), which can occur several weeks after the conjunctivitis resolves. * **Differential Diagnosis:** * **Epidemic Keratoconjunctivitis (EKC):** Caused by **Adenovirus (Serotypes 8, 19, 37)**. It presents with prominent pseudomembranes and corneal involvement (subepithelial infiltrates) but less frequent hemorrhage compared to AHC. * **Management:** Supportive treatment only (cold compresses, lubricants); antibiotics are used only to prevent secondary bacterial infection.

Q: A young adult presents with facial pain and painful vesicular lesions in the mouth. Tzanck smear reveals multinucleated giant cells with intranuclear inclusions. What is the most likely causative organism?

Herpes simplex virus. ***Herpes simplex virus*** - The presentation of **painful vesicular lesions** in the mouth and **facial pain** strongly suggests primary (e.g., gingivostomatitis) or reactivated herpes infection. - The **Tzanck smear** showing **multinucleated giant cells** with **intranuclear inclusions** is characteristic of the Herpesviridae family, confirming the clinical suspicion of HSV. *Adenovirus* - Adenovirus typically causes **pharyngoconjunctival fever**, acute respiratory disease, or viral conjunctivitis, not localized vesicular lesions in the mouth. - It does not produce the hallmark cytopathic effect of **multinucleated giant cells** on Tzanck smear. *Cytomegalovirus* - CMV usually presents as a mild **mononucleosis-like syndrome** in healthy adults or causes severe systemic disease in the immunocompromised. - CMV histology is defined by large intranuclear **"owl's eye" inclusions**, a finding different from the multinucleated giant cells seen on Tzanck smear. *Epstein-Barr virus* - EBV causes **Infectious Mononucleosis**, characterized by fever, lymphadenopathy, and pharyngitis, not primarily painful vesicular eruptions. - Although part of the herpes family, EBV typically causes unique lymphoid pathology and **Hairy Leukoplakia**, not the cytopathic changes seen on Tzanck smear.

Q: The following disease presentation is caused by:

Human parvovirus B19. ***Human parvovirus B19*** - The image shows a classic "slapped cheek" rash, which is a hallmark clinical presentation of **fifth disease**, caused by **Human parvovirus B19**. - This rash typically spares the circumoral area and develops after a prodromal phase of mild fever and malaise. *Scarlet fever* - Scarlet fever is characterized by a "sandpaper" rash, which feels rough, and often presents with **circumoral pallor**, but does not typically present as a "slapped cheek" appearance. - Patients often exhibit a **strawberry tongue** and high fever, not typically associated with the image provided. *Arthus phenomenon* - The Arthus phenomenon is a localized **type III hypersensitivity reaction** characterized by pain, swelling, and redness at the site of antigen injection, not a diffuse facial rash like the one seen. - This reaction is an immune complex-mediated process and is not an infectious disease causing a generalized rash. *Epstein-Barr virus* - Epstein-Barr virus (EBV) primarily causes **infectious mononucleosis**, which can produce a maculopapular rash, especially if the patient is treated with amoxicillin. - However, EBV rash does not typically manifest as the distinctive "slapped cheek" appearance seen in the image.

Q: A 25-year-old abattoir worker presents with myoclonus and amnesia for recent and remote events for last 1 year. MRI head was performed. All statements are correct about the organisms leading to this disease except:

Sensitive to ethylene dioxide. ***Sensitive to ethylene dioxide*** - Prions, the causative agents of Creutzfeldt-Jakob Disease (CJD), are **resistant to conventional sterilization methods**, including ethylene oxide, radiation, and disinfectants like formaldehyde. This statement is incorrect. - They are primarily inactivated by methods that denature proteins, such as **autoclaving at high temperatures and pressures** or strong sodium hydroxide solutions. *Absence of nucleic acid* - **Prions are infectious proteinaceous particles** that lack nucleic acid (DNA or RNA), which distinguishes them from viruses, bacteria, and other conventional pathogens. - They propagate by inducing conformational changes in normal host proteins. *CSF examination of patient shows presence of protein 14.3.3* - The presence of **14-3-3 protein** in cerebrospinal fluid (CSF) is a significant and widely used diagnostic marker for **Creutzfeldt-Jakob Disease (CJD)**. - Elevated levels of this protein indicate neuronal damage and are often found in patients with rapidly progressive dementia caused by prions. *MRI shows cortical ribboning* - **Cortical ribboning**, characterized by hyperintense signal changes in the cerebral cortex on diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) sequences, is a **highly characteristic finding in MRI scans of patients with CJD**. - This MRI finding, along with involvement of the basal ganglia and thalamus, supports the diagnosis of CJD.

Q: The following electron microscope image shows presence of:

Ebola virus. ***Ebola virus*** - The electron micrograph clearly shows characteristic **filamentous, long, and pleomorphic viral particles**, some displaying coiled or branched structures, which are hallmarks of the **Filoviridae family**, to which Ebola belongs. - The presence of distinct, elongated forms, often appearing as "shepherd's crook" shapes or U-shaped structures (as indicated by the arrows), is highly indicative of the **Ebola virus morphology**. *Swine flu virus* - Swine flu, caused by influenza viruses, typically presents as **spherical or pleomorphic virions**, but not in the distinct elongated filamentous forms seen in the image. - Influenza viruses have a segmented RNA genome enclosed within a spherical capsid and an outer envelope, giving them a more rounded appearance. *Rabies virus* - Rabies virus has a classical **bullet-shaped morphology**, which is distinctly different from the long, filamentous structures observed in the image. - Its unique shape is a key identifying feature in electron microscopy. *Polio virus* - Poliovirus is a non-enveloped RNA virus with an **icosahedral (spherical) capsid structure**, much smaller and more geometrically regular than the filamentous particles shown. - It does not exhibit the elongated, flexible morphology characteristic of filoviruses.

Q: Name the antigen marked X in the figure:

Gp120. ***Gp120*** - The image depicts the structure of the **Human Immunodeficiency Virus (HIV)**. The antigen marked 'X' is the **outer glycoprotein** that aids in viral attachment. - **Gp120** is an exposed surface glycoprotein on HIV that binds to the **CD4 receptor** on host T-cells and other immune cells. *P24 antigen* - **P24** is a **capsid protein** found within the core of the HIV virus, not on its outer surface. - It is a crucial viral protein that encases the viral RNA and enzymes. *Gp41* - **Gp41** is a **transmembrane glycoprotein** embedded in the viral envelope, acting as an anchor for Gp120. - While associated with the viral envelope, Gp41 is mostly hidden until Gp120 binds to the host cell, facilitating **membrane fusion**. *Hemagglutinin* - **Hemagglutinin** is a **surface glycoprotein** found on the influenza virus, responsible for binding to sialic acid receptors on host cells. - It is not a component of the HIV virus.

Q: Comment on the marking X in HIV virus.

Gp120. ***Gp120*** - The marking "X" points to the **outermost glycoprotein knob** on the HIV envelope, which is the **Gp120** subunit. - **Gp120** is crucial for attachment to host cells by binding to the **CD4 receptor** and co-receptors. *Gp41* - **Gp41** is a **transmembrane glycoprotein** that anchors Gp120 to the viral envelope and mediates membrane fusion. - It is located *underneath* Gp120, not the outermost knob. *p24 antigen* - The **p24 antigen** is a **capsid protein** that forms the conical core of the HIV virus, protecting the genetic material. - It is located *inside* the viral envelope, not on the surface. *p17 antigen* - The **p17 antigen** (also referred to as **matrix protein** or **MA**) forms a layer *just beneath* the viral envelope. - It helps maintain the viral structure and is not the outermost knob.

Q: A 40-year-old AIDS positive patient complains of seeing floaters followed by progressive reduction in visual acuity over next weeks. Fundus examination was performed. All are true about the causative agent except: (Recent NEET Pattern 2016-17)

Eosinophilic intranuclear inclusions. ***Eosinophilic intranuclear inclusions*** - The causative agent of **CMV retinitis** (Cytomegalovirus) typically forms **basophilic intranuclear inclusions** (owl's eye inclusions), not eosinophilic ones. - This statement is therefore incorrect regarding CMV. *Shed in semen* - **CMV** is commonly shed in various bodily fluids, including **semen**, urine, and saliva, contributing to its transmission. - This is a true characteristic of CMV. *Largest virus in human herpes virus* - **CMV** (Human herpesvirus 5) is indeed the **largest virus in the human herpesvirus family**, both in terms of genome size and virion size. - This is a true characteristic of CMV. *Leads to pizza pie retinopathy* - The classic description of **CMV retinitis** on fundus examination is often referred to as "**pizza pie retinopathy**" or "cottage cheese and ketchup" appearance, due to its characteristic retinal hemorrhages and white, necrotic areas. - This is a true clinical manifestation of CMV retinitis.

Question 1

Which of the following hepatitis viruses is likely to get transmitted via fecal-oral route?

Accepted Answer

Hepatitis A

Answer

Hepatitis B

Answer

Hepatitis C

Answer

Hepatitis D

Question 2

The image shown here is used for the diagnosis of

Accepted Answer

Herpes simplex virus

Answer

Human immunodeficiency virus

Answer

Hepatitis B virus

Answer

Human papillomavirus

Question 3

Acute hemorrhagic conjunctivitis is caused by which of the following combinations?

Accepted Answer

Coxsackie A and Enterovirus 70

Answer

Coxsackie B and Enterovirus 70

Answer

Coxsackie A, Coxsackie B and Enterovirus 70

Answer

Coxsackie A and Coxsackie B

Question 4

A young adult presents with facial pain and painful vesicular lesions in the mouth. Tzanck smear reveals multinucleated giant cells with intranuclear inclusions. What is the most likely causative organism?

Accepted Answer

Herpes simplex virus

Answer

Adenovirus

Answer

Cytomegalovirus

Answer

Epstein-Barr virus

Question 5

The following disease presentation is caused by:

Accepted Answer

Human parvovirus B19

Answer

Scarlet fever

Answer

Arthus phenomenon

Answer

Epstein-Barr virus

Question 6

A 25-year-old abattoir worker presents with myoclonus and amnesia for recent and remote events for last 1 year. MRI head was performed. All statements are correct about the organisms leading to this disease except:

Accepted Answer

Sensitive to ethylene dioxide

Answer

Absence of nucleic acid

Answer

CSF examination of patient shows presence of protein 14.3.3

Answer

MRI shows cortical ribboning

Question 7

The following electron microscope image shows presence of:

Accepted Answer

Ebola virus

Answer

Swine flu virus

Answer

Rabies virus

Answer

Polio virus

Question 8

Name the antigen marked X in the figure:

Accepted Answer

Gp120

Answer

P24 antigen

Answer

Gp41

Answer

Hemagglutinin

Question 9

Comment on the marking X in HIV virus.

Accepted Answer

Gp120

Answer

Gp41

Answer

p24 antigen

Answer

p17 antigen

Question 10

A 40-year-old AIDS positive patient complains of seeing floaters followed by progressive reduction in visual acuity over next weeks. Fundus examination was performed. All are true about the causative agent except: (Recent NEET Pattern 2016-17)

Accepted Answer

Eosinophilic intranuclear inclusions

Answer

Shed in semen

Answer

Largest virus in human herpes virus

Answer

Leads to pizza pie retinopathy

Virology — MCQs

Virology — MCQs

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