Virology Practice Questions

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.

Q: A 2-year-old unimmunized child from a village presents with fever, decreased feeding and ear ache. All are true about the virus responsible for the condition shown except: (Recent NEET Pattern 2016-17)

Belongs to genus morbillivirus. The image shows a child with characteristic swelling of the parotid gland, indicative of Mumps. The clinical presentation (unimmunized child, fever, decreased feeding, ear ache, and parotid swelling) strongly points to Mumps. ***Correct Answer: Belongs to genus morbillivirus*** - This statement is **FALSE** and therefore the correct answer to this "EXCEPT" question. - The virus responsible for Mumps is the **Mumps virus**, which belongs to the **genus Rubulavirus** within the family Paramyxoviridae, NOT Morbillivirus. - Morbillivirus is the genus to which the **Measles virus** belongs. *Incorrect: Nonsuppurative parotitis* - **TRUE statement** - Mumps is classically characterized by **nonsuppurative parotitis**, meaning inflammation of the salivary glands (primarily parotid) without pus formation. - This is a key diagnostic feature of Mumps. *Incorrect: Can lead to aseptic meningitis* - **TRUE statement** - Aseptic meningitis is one of the most common and significant complications of Mumps, occurring in 10-15% of cases. - This complication typically presents with headache, stiff neck, and photophobia, without bacterial infection. *Incorrect: Causative virus possesses both H and N proteins* - **TRUE statement** - The Mumps virus, a member of the Paramyxoviridae family, possesses a combined **HN (hemagglutinin-neuraminidase) protein** on its surface. - The HN protein has both hemagglutinin and neuraminidase activities, responsible for binding to host cells and facilitating release of new virions from infected cells.

Q: Identify the virus shown below.

Herpes virus. ***Herpes virus*** - The image displays a virus with an **icosahedral capsid** (the blue beaded structure) surrounded by a viral envelope with various glycoproteins, all characteristic features of the Herpesvirus family. - The inner structure shows **double-stranded DNA** in a circular arrangement, consistent with the genomic structure of herpesviruses. *Rabies virus* - The rabies virus has a distinct **bullet-shaped morphology** and contains **single-stranded RNA**, which is clearly different from the depicted virus. - Its virions are typically 75 nm in diameter and 180 nm in length. *HIV* - HIV is a **retrovirus** with a conical-shaped capsid and contains **two copies of single-stranded RNA**, along with reverse transcriptase. - Its morphology and genetic material are distinct from the virus shown, which has a double-stranded DNA genome and an icosahedral capsid. *Influenza virus* - Influenza viruses have a roughly **spherical or filamentous shape** with a segmented **single-stranded RNA genome**. - Their surface is covered with hemagglutinin and neuraminidase spikes, distinct from the glycoproteins shown in the image.

Q: Which of the following diseases is caused by the virus shown below?

Swimming pool conjunctivitis. ***Swimming pool conjunctivitis*** - The image displays an **adenovirus**, characterized by its **icosahedral shape** and distinct **fiber proteins** projecting from the vertices. - Adenoviruses are a common cause of **pharyngoconjunctival fever**, often referred to as "swimming pool conjunctivitis" due to its spread in **inadequately chlorinated swimming pools**. - This is the **most characteristic disease** associated with adenovirus infection, particularly serotypes **3, 4, and 7**. *Neurodegenerative disorder* - Adenoviruses are **not associated** with neurodegenerative disorders. - Neurodegenerative conditions are typically linked to **prions, misfolded proteins**, or other viral agents like **JC virus** (progressive multifocal leukoencephalopathy). - Adenoviruses cause **acute infections**, not chronic neurodegeneration. *Solid organ graft infection* - While adenoviruses can cause severe infections in **immunocompromised patients**, including transplant recipients, this is not their most characteristic presentation. - In transplant patients, adenovirus may cause **colitis, hepatitis, or nephritis**, but these are **opportunistic infections** rather than the typical disease association. - The characteristic disease remains **conjunctivitis and respiratory infections** in immunocompetent hosts. *Solid organ graft rejection* - **Graft rejection** is an **immunological process** where the recipient's immune system attacks the transplanted organ, not a viral infection. - Adenovirus does not directly cause the mechanism of graft rejection. - While viral infections may complicate graft outcomes, rejection itself is **immune-mediated**, not infectious.

Q: Which of the following diseases is caused by the virus shown below?

Aplastic crisis. ***Aplastic crisis*** - The image depicts a **bun-shaped, non-enveloped virus** with a **single-stranded DNA genome**, characteristic of **Parvovirus B19**. - **Parvovirus B19** has a strong tropism for **erythroid progenitor cells** in the bone marrow, leading to their lysis and subsequent inhibition of erythropoiesis, which can cause **aplastic crisis**, especially in individuals with underlying hemolytic disorders like sickle cell anemia. *Burkitt lymphoma* - This lymphoma is caused by **Epstein-Barr virus (EBV)**, a **double-stranded DNA herpesvirus**, which has a different morphology than the virus depicted. - EBV is associated with B-cell proliferation, not direct destruction of erythroid precursors which leads to aplastic crises. *Primary effusion lymphoma* - This is a rare B-cell lymphoma associated with **Human Herpesvirus 8 (HHV-8)**, also known as Kaposi's sarcoma-associated herpesvirus. - HHV-8 is a **double-stranded DNA virus** with a different structure and tropism than the parvovirus shown in the image. *Vesicular vaccination lesion* - Vesicular vaccination lesions are typically caused by the **Vaccinia virus**, a **large, complex DNA virus** belonging to the Poxviridae family. - The Vaccinia virus has a distinct brick-shaped morphology and replicates in the cytoplasm, unlike the small, non-enveloped parvovirus shown.

Q: Amongst the four choices, select the virus whose life cycle is shown. (AIIMS Nov 2017)

Hepatitis B. ***Hepatitis B*** - The image clearly depicts the formation of **cccDNA (covalently closed circular DNA)** in the host cell nucleus, a unique and defining characteristic of the Hepatitis B virus life cycle. - The process of **reverse transcription** (synthesis of DNA from an RNA template) occurring within the core particle in the cytoplasm, followed by its movement to the nucleus to form cccDNA, is specific to Hepatitis B. *Herpes simplex* - Herpes simplex viruses are **DNA viruses** that replicate entirely within the nucleus, and their replication does not involve an RNA intermediate or the formation of cccDNA. - They also undergo **budding from the inner nuclear membrane** into the perinuclear space, which differs from the ER budding shown. *HIV* - HIV is a **retrovirus** that utilizes reverse transcriptase to convert its RNA genome into DNA, which then integrates into the host genome. However, it does not form cccDNA. - While it does involve reverse transcription, the overall replication strategy, particularly the integration step and the budding from the cell membrane, differs significantly from the depicted process. *Influenza* - Influenza is an **RNA virus** that replicates in the nucleus (unlike most RNA viruses) but does not involve a DNA intermediate or cccDNA formation. - Its replication cycle involves transcription of viral RNA into mRNA and replication of viral RNA genomes, which is distinct from the complex DNA to RNA to DNA cycle shown.

Q: Which of the following is responsible for the abnormality shown below?

Zika virus. ***Zika virus*** - The image depicts a newborn with **microcephaly**, characterized by a significantly smaller head circumference than expected, which is a hallmark congenital abnormality associated with **Zika virus infection** during pregnancy. - Zika virus is a **teratogen** that primarily targets neural progenitor cells, leading to severe brain malformations and microcephaly in developing fetuses. *Human parvovirus B19* - This virus is known to cause **erythema infectiosum** (fifth disease) in children and can lead to **hydrops fetalis**, severe anemia, and cardiac failure in fetuses if transmitted during pregnancy. - It does not typically cause microcephaly as its primary congenital manifestation. *HHV6* - Human Herpesvirus 6 (HHV6) is the causative agent of **roseola infantum** (exanthem subitum) in young children. - While it can cause febrile seizures and encephalitis, it is not primarily associated with congenital microcephaly or other severe birth defects when acquired prenatally. *EBV* - Epstein-Barr virus (EBV) is responsible for **infectious mononucleosis** and is linked to various malignancies. - Congenital EBV infection is rare and has been associated with a range of non-specific outcomes, but it is not a recognized cause of microcephaly.

Question 1

Name the antigen marked X in the figure:

Accepted Answer

Gp120

Answer

P24 antigen

Answer

Gp41

Answer

Hemagglutinin

Question 2

Comment on the marking X in HIV virus.

Accepted Answer

Gp120

Answer

Gp41

Answer

p24 antigen

Answer

p17 antigen

Question 3

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

Question 4

A 2-year-old unimmunized child from a village presents with fever, decreased feeding and ear ache. All are true about the virus responsible for the condition shown except: (Recent NEET Pattern 2016-17)

Accepted Answer

Belongs to genus morbillivirus

Answer

Nonsuppurative parotitis

Answer

Can lead to aseptic meningitis

Answer

Causative virus possesses both H and N proteins

Question 5

A 3-year-old child presents with fever for 3 days with excessive salivation. On examination following lesions were seen. Mother says same lesions appeared 6 months back. All are true about the condition shown except:

Accepted Answer

Infectivity of type 1 virus is more temperature dependent than type 2 virus

Answer

Tzanck smear shows multinucleated giant cells

Answer

Primary target cell is mucoepithelial cells

Answer

Site of latency is trigeminal ganglia

Question 6

Identify the virus shown below.

Accepted Answer

Herpes virus

Answer

Rabies virus

Answer

HIV

Answer

Influenza virus

Question 7

Which of the following diseases is caused by the virus shown below?

Accepted Answer

Swimming pool conjunctivitis

Answer

Neurodegenerative disorder

Answer

Solid organ graft infection

Answer

Solid organ graft rejection

Question 8

Which of the following diseases is caused by the virus shown below?

Accepted Answer

Aplastic crisis

Answer

Burkitt lymphoma

Answer

Primary effusion lymphoma

Answer

Vesicular vaccination lesion

Question 9

Amongst the four choices, select the virus whose life cycle is shown. (AIIMS Nov 2017)

Accepted Answer

Hepatitis B

Answer

Herpes simplex

Answer

HIV

Answer

Influenza

Question 10

Which of the following is responsible for the abnormality shown below?

Accepted Answer

Zika virus

Answer

Human parvovirus B19

Answer

HHV6

Answer

EBV

Virology — MCQs

Virology — MCQs

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