Virology — MCQs

Virology Indian Medical PG Practice Questions and MCQs

Question 61: Which of the following diseases is NOT caused by HHV-8?

A. Kaposi sarcoma
B. Castleman's disease
C. Primary effusion lymphoma
D. Duncan syndrome (Correct Answer)

Explanation: **Explanation:** The correct answer is **Duncan syndrome** because it is caused by the **Epstein-Barr Virus (EBV)**, not Human Herpesvirus 8 (HHV-8). **1. Why Duncan Syndrome is the correct answer:** Duncan syndrome, also known as **X-linked Lymphoproliferative Syndrome (XLP)**, is a rare genetic immunodeficiency. It is characterized by an inappropriate and fatal immune response to EBV infection, leading to fulminant infectious mononucleosis, hypogammaglobulinemia, and malignant lymphomas. It is caused by mutations in the *SH2D1A* gene. **2. Why the other options are incorrect (HHV-8 Associations):** HHV-8, also known as **Kaposi Sarcoma-associated Herpesvirus (KSHV)**, is oncogenic and primarily infects B cells and endothelial cells. * **Kaposi Sarcoma (Option A):** A vascular tumor common in AIDS patients. HHV-8 encodes a viral G-protein coupled receptor that triggers angiogenesis. * **Castleman’s Disease (Option B):** Specifically the **multicentric** variant. It is a lymphoproliferative disorder driven by an HHV-8 encoded viral analogue of Interleukin-6 (vIL-6). * **Primary Effusion Lymphoma (Option C):** A rare B-cell non-Hodgkin lymphoma that presents as malignant effusions in body cavities (pleural, pericardial) without a discrete tumor mass. **Clinical Pearls for NEET-PG:** * **HHV-8 Transmission:** Primarily through saliva (most common) and sexual contact. * **Target Cells:** HHV-8 has a predilection for **endothelial cells** (leading to KS) and **B-cells** (leading to PEL and Castleman’s). * **EBV vs. HHV-8:** Both are Gamma-herpesviruses. Remember: EBV = Burkitt’s, Nasopharyngeal Ca, Duncan syndrome; HHV-8 = Kaposi, PEL, Multicentric Castleman’s.

Question 62: The HIV virus can be transmitted by the following routes, except?

A. Homosexual contact
B. Intact skin (Correct Answer)
C. Maternofoetal
D. Needle prick

Explanation: **Explanation:** HIV (Human Immunodeficiency Virus) is an enveloped RNA virus that requires direct access to the bloodstream or lymphatic system to initiate infection. It cannot penetrate **intact skin** because the stratum corneum acts as an effective physical barrier. Infection through the skin only occurs if there is a breach in integrity, such as an abrasion, wound, or needle stick. **Analysis of Options:** * **Homosexual/Heterosexual contact (Option A):** Sexual transmission is the most common route globally. The virus crosses the thin mucosal surfaces of the rectum, vagina, or urethra, often aided by micro-trauma during intercourse. * **Maternofoetal (Option C):** Also known as Vertical Transmission, this can occur *in utero* (transplacental), during delivery (birth canal), or postpartum via breastfeeding. * **Needle prick (Option D):** This is a form of parenteral transmission. It provides the virus direct entry into the bloodstream. The average risk of HIV transmission after a percutaneous needle-stick injury is approximately **0.3%**. **High-Yield Clinical Pearls for NEET-PG:** * **Most common route worldwide:** Heterosexual contact. * **Most efficient route of transmission:** Blood transfusion (risk >90%). * **Window Period:** The time between infection and the appearance of detectable antibodies (usually 2–8 weeks). * **Post-Exposure Prophylaxis (PEP):** Must be started within **72 hours** of exposure (ideally within 2 hours) and continued for 28 days. * **Non-transmissible fluids:** Tears, sweat, urine, and saliva (unless contaminated with visible blood) are not considered infectious for HIV.

Question 63: A patient develops hepatosplenomegaly and lymphadenopathy three weeks after sexual contact. What is the most appropriate test to rule out HIV infection in this scenario?

A. ELISA
B. Western blot
C. p24 Antigen assay (Correct Answer)
D. Lymph node biopsy

Explanation: **Explanation:** The patient is presenting with symptoms suggestive of **Acute Retroviral Syndrome (ARS)**, which typically occurs 2–4 weeks after exposure. During this early phase, the patient is in the **"Window Period,"** where the virus is replicating rapidly, but the body has not yet produced detectable levels of anti-HIV antibodies. **Why p24 Antigen Assay is correct:** The p24 antigen is a structural protein of the HIV capsid. It becomes detectable in the serum as early as **1–3 weeks** after infection, well before antibody seroconversion. Therefore, it is the most appropriate test to rule out or diagnose HIV during the window period when antibody-based tests would yield a false negative. **Analysis of Incorrect Options:** * **ELISA (Option A):** Standard 3rd generation ELISA detects anti-HIV antibodies. Since antibodies take 3–12 weeks to develop (seroconversion), ELISA is often negative during the acute phase. * **Western Blot (Option B):** This is a supplemental/confirmatory test that detects specific antibodies against HIV proteins (gp120, gp41, p24). Like ELISA, it depends on the host's immune response and is unreliable during the early window period. * **Lymph Node Biopsy (Option C):** While it might show follicular hyperplasia, it is non-specific and not a diagnostic tool for HIV infection. **NEET-PG High-Yield Pearls:** * **Window Period:** The time between infection and the appearance of detectable antibodies. * **Sequence of markers:** RNA (7–10 days) → p24 Antigen (14–21 days) → Antibodies (4–12 weeks). * **Best Initial Screening:** 4th Generation ELISA (p24 antigen + IgM/IgG antibodies) is now the gold standard as it shortens the window period. * **Diagnosis in Infants:** For babies born to HIV-positive mothers, **PCR (DNA/RNA)** is the test of choice because maternal IgG antibodies can persist for up to 18 months, making ELISA unreliable.

Question 64: Lipschutz bodies are seen in which of the following conditions?

A. Hepatitis
B. Vaccinia
C. Variola
D. Herpes simplex (Correct Answer)

Explanation: **Explanation:** **Lipschütz bodies** are characteristic **eosinophilic intranuclear (Type A) inclusion bodies** found in cells infected with the **Herpes Simplex Virus (HSV)**. In virology, inclusion bodies are distinct structures formed during viral replication. For HSV, these inclusions represent the site of viral assembly within the nucleus, often surrounded by a clear halo (the "owl's eye" appearance, though more classically associated with CMV, can be a descriptor for Type A inclusions generally). **Analysis of Options:** * **Herpes Simplex (Correct):** HSV-1, HSV-2, and Varicella-Zoster Virus (VZV) all produce Cowdry Type A (Lipschütz) intranuclear inclusions. * **Hepatitis (Incorrect):** Hepatitis B is associated with "ground-glass" hepatocytes (cytoplasmic accumulation of HBsAg), not Lipschütz bodies. * **Vaccinia & Variola (Incorrect):** These belong to the Poxvirus family. Unlike Herpes, Poxviruses replicate in the cytoplasm. They produce **Guarnieri bodies**, which are eosinophilic **intracytoplasmic** inclusion bodies. **High-Yield Clinical Pearls for NEET-PG:** * **Cowdry Type A (Intranuclear):** Seen in HSV, VZV (Lipschütz bodies), and CMV (Owl’s eye). * **Cowdry Type B (Intranuclear):** Seen in Poliovirus and Adenovirus. * **Intracytoplasmic Inclusions:** * **Negri bodies:** Rabies (found in Hippocampus/Purkinje cells). * **Guarnieri bodies:** Variola (Smallpox) and Vaccinia. * **Bollinger bodies:** Fowlpox. * **Molluscum bodies (Henderson-Patterson):** Molluscum contagiosum. * **Tzanck Smear:** A rapid bedside test for HSV/VZV that identifies **multinucleated giant cells**, though it cannot differentiate between the two.

Question 65: Which of the following Ebola virus strains is considered non-pathogenic to humans?

A. Zaire
B. Reston (Correct Answer)
C. Cote d'Ivoire
D. Bundibugyo

Explanation: **Explanation:** The **Ebola virus** belongs to the family *Filoviridae*. There are six identified species within the genus *Ebolavirus*, but their pathogenicity in humans varies significantly. **Why Reston is the correct answer:** The **Reston virus (RESTV)** is unique because, while it can cause severe and fatal Hemorrhagic Fever in non-human primates (monkeys) and can infect pigs, it is **non-pathogenic to humans**. Although humans can seroconvert (develop antibodies) after exposure, there have been no documented cases of clinical illness or death in humans to date. It was first discovered in 1989 in laboratory monkeys imported from the Philippines to Reston, Virginia. **Analysis of incorrect options:** * **A. Zaire ebolavirus:** The most virulent and well-known strain. It is responsible for the largest outbreaks, including the 2014–2016 West Africa epidemic, with mortality rates as high as 90%. * **C. Cote d'Ivoire (Taï Forest virus):** Known to cause human disease. The first case was a scientist who performed an autopsy on a wild chimpanzee; it causes severe respiratory and hemorrhagic symptoms. * **D. Bundibugyo ebolavirus:** Identified in 2007 in Uganda. It is pathogenic to humans, though it typically has a lower case-fatality rate (approx. 25-40%) compared to the Zaire strain. **High-Yield NEET-PG Pearls:** * **Transmission:** Primarily through direct contact with infected blood, secretions, or organs (zoonotic source: Fruit bats are the natural reservoir). * **Structure:** Negative-sense, single-stranded, enveloped RNA virus with a characteristic **filamentous/shepherd’s crook** appearance. * **Diagnosis:** Gold standard is **RT-PCR**; ELISA for antigen detection is also used. * **Vaccine:** The **rVSV-ZEBOV** vaccine is highly effective against the Zaire strain.

Question 66: Coxsackie A virus does not cause which of the following conditions?

A. Herpangina
B. Hand, foot and mouth disease (HFM)
C. Laryngotracheobronchitis (Correct Answer)
D. Aseptic meningitis

Explanation: **Explanation:** The correct answer is **Laryngotracheobronchitis (C)**. Laryngotracheobronchitis, commonly known as **Croup**, is most frequently caused by the **Parainfluenza virus (Type 1 and 2)**. It is characterized by subglottic edema leading to a "barking" cough and inspiratory stridor. Coxsackie viruses are not typical causative agents for this respiratory syndrome. **Analysis of other options:** * **Herpangina (A):** This is a classic manifestation of **Coxsackie A** (specifically types 1–10, 16, and 22). It presents with high fever, sore throat, and vesiculopapular lesions on the posterior pharynx (soft palate and tonsillar pillars). * **Hand, Foot, and Mouth Disease (B):** Primarily caused by **Coxsackie A16** (and Enterovirus 71). It presents with vesicular eruptions on the palms, soles, and oral mucosa. * **Aseptic Meningitis (D):** Both Coxsackie A and B are leading causes of viral (aseptic) meningitis. While Coxsackie B is more common, several serotypes of Coxsackie A are frequently implicated. **High-Yield Clinical Pearls for NEET-PG:** * **Coxsackie A vs. B:** Remember the mnemonic **"A for Appendages/Apertures"** (Skin/HFM, Mouth/Herpangina) and **"B for Body"** (Heart/Myocarditis, Pleura/Bornholm disease, Pancreas/Diabetes). * **Bornholm Disease:** Also known as "Devil’s Grip" (Pleurodynia), it is caused by **Coxsackie B**. * **Myocarditis/Pericarditis:** Coxsackie B is the most common viral cause of acute myocarditis. * **Seasonality:** Enteroviruses (including Coxsackie) typically peak during the **summer and fall** months.

Question 67: Cytomegalovirus (CMV) belongs to which family of DNA viruses?

A. Poxviridae
B. Herpesviridae (Correct Answer)
C. Papovaviridae
D. Parvoviridae

Explanation: **Explanation:** **Correct Answer: B. Herpesviridae** Cytomegalovirus (CMV) is a member of the **Herpesviridae** family. Like all herpesviruses, it is a large, enveloped virus with a linear double-stranded DNA (dsDNA) genome and an icosahedral capsid. A hallmark of this family is the ability to establish **latent infections**; CMV specifically remains latent in mononuclear cells (monocytes, lymphocytes, and myeloid progenitors). Within the family, CMV is classified under the **Beta-herpesvirinae** subfamily (along with HHV-6 and HHV-7). **Analysis of Incorrect Options:** * **A. Poxviridae:** These are the largest DNA viruses (e.g., Variola, Molluscum contagiosum). Unlike most DNA viruses, they replicate in the **cytoplasm** because they carry their own DNA-dependent RNA polymerase. * **C. Papovaviridae:** This older taxonomic group (now split into Papillomaviridae and Polyomaviridae) includes HPV and BK/JC viruses. These are small, non-enveloped viruses with circular dsDNA. * **D. Parvoviridae:** Notable for being the **smallest** DNA viruses (e.g., B19 virus). They are unique because they possess a **single-stranded DNA (ssDNA)** genome, unlike the other options. **High-Yield Clinical Pearls for NEET-PG:** * **Histology:** CMV infection is characterized by enlarged cells containing large, granular, basophilic intranuclear inclusions surrounded by a clear halo, known as **"Owl’s Eye" appearance**. * **Congenital Infection:** CMV is the most common viral cause of congenital anomalies (SNHL, periventricular calcifications, and microcephaly). * **Infectious Mononucleosis:** CMV causes a heterophile-antibody **negative** (Monospot negative) mononucleosis-like syndrome. * **Treatment:** **Ganciclovir** is the drug of choice; Valganciclovir is used for prophylaxis in transplant patients.

Question 68: Hand, foot and mouth disease is caused by which of the following viruses?

A. Cytomegalovirus
B. HIV infection
C. Coxsackie A virus (Correct Answer)
D. Herpes simplex virus

Explanation: **Explanation:** **Hand, Foot, and Mouth Disease (HFMD)** is a common viral illness primarily affecting infants and children. It is most frequently caused by **Coxsackie A virus (specifically A16)**, which belongs to the *Picornaviridae* family (Genus: Enterovirus). Another significant cause is **Enterovirus 71**, which is often associated with more severe neurological complications. **Why the correct answer is right:** * **Coxsackie A virus:** This virus typically causes a characteristic clinical triad: a vesicular rash on the **palms and soles** (hand and foot) and painful ulcerative lesions in the oral cavity (**herpangina**). The transmission is via the feco-oral or respiratory route. **Why the incorrect options are wrong:** * **Cytomegalovirus (CMV):** Primarily causes infectious mononucleosis-like syndrome or congenital infections (cytomegalic inclusion disease). It does not present with the specific hand-foot-mouth distribution. * **HIV Infection:** While HIV can cause various mucocutaneous manifestations during acute retroviral syndrome or late-stage AIDS, it is not the causative agent of the specific HFMD syndrome. * **Herpes Simplex Virus (HSV):** HSV-1 typically causes gingivostomatitis or herpes labialis (cold sores). While it causes oral ulcers, it does not typically involve a vesicular rash on the palms and soles. **High-Yield Clinical Pearls for NEET-PG:** * **Herpangina:** Also caused by Coxsackie A; involves fever and sore throat with vesicles on the posterior pharynx (tonsillar pillars/soft palate), unlike HFMD which involves the anterior mouth. * **Seasonality:** HFMD outbreaks typically peak in summer and autumn. * **Complications:** Enterovirus 71 is high-yield for its association with **aseptic meningitis**, encephalitis, and acute flaccid paralysis. * **Differential Diagnosis:** Must be distinguished from Foot-and-Mouth Disease (FMD), which is a disease of livestock (Aphthovirus) and does not affect humans.

Question 69: Epstein-Barr virus is associated with all the following conditions EXCEPT:

A. Bell's palsy
B. Hepatitis
C. Guillain-Barré syndrome
D. Laennec's cirrhosis (Correct Answer)

Explanation: **Explanation:** **Epstein-Barr Virus (EBV)**, a member of the *Herpesviridae* family (HHV-4), is a ubiquitous virus primarily known for causing Infectious Mononucleosis. It is associated with a wide spectrum of clinical conditions, ranging from benign lymphoproliferative disorders to malignancies and neurological complications. **Why Laennec’s Cirrhosis is the correct answer:** Laennec’s cirrhosis is a historical term for **Alcoholic Cirrhosis**, characterized by micronodular scarring of the liver due to chronic alcohol abuse. It is a metabolic and toxic consequence of ethanol consumption, not an infectious process. EBV does not cause chronic cirrhosis or permanent fibrotic liver remodeling. **Analysis of Incorrect Options:** * **Hepatitis:** EBV is a "non-hepatotropic" virus that frequently causes mild, self-limiting hepatitis as part of the Infectious Mononucleosis syndrome. It typically presents with transiently elevated transaminases and hepatomegaly. * **Bell’s Palsy:** EBV is a recognized viral trigger for facial nerve (CN VII) paralysis. It is often cited alongside HSV-1 and VZV as a cause of lower motor neuron facial palsy. * **Guillain-Barré Syndrome (GBS):** EBV is one of the classic viral triggers for GBS (an acute inflammatory demyelinating polyneuropathy), following the molecular mimicry mechanism. **High-Yield Clinical Pearls for NEET-PG:** * **Malignancies:** EBV is strongly linked to Burkitt’s Lymphoma (t 8;14), Nasopharyngeal Carcinoma, Hodgkin’s Lymphoma (Mixed cellularity), and Oral Hairy Leukoplakia (in HIV). * **Diagnosis:** Look for **Atypical Lymphocytes (Downey cells)** on peripheral smear and a positive **Paul-Bunnell Test** (Heterophile antibodies). * **Receptor:** EBV binds to the **CD21** receptor (CR2) on B-cells.

Question 70: Herpes viruses acquire their envelope from which cellular membrane?

A. Nuclear membrane (Correct Answer)
B. Nucleolar membrane
C. Cytoplasmic membrane
D. None of the above

Explanation: **Explanation:** The **Herpesviridae** family is unique among DNA viruses because of its specific replication and assembly process. Unlike most enveloped viruses that acquire their lipid bilayer from the plasma membrane, Herpes viruses undergo **primary budding through the inner nuclear membrane.** 1. **Why Option A is Correct:** After the viral DNA replicates and nucleocapsids are assembled inside the host cell nucleus, they must exit to the cytoplasm. The nucleocapsid buds through the inner nuclear membrane into the perinuclear space, acquiring its initial envelope. While this envelope undergoes a complex "de-envelopment and re-envelopment" process at the Golgi apparatus for final maturation, the **primary source** of the herpesvirus envelope is the **nuclear membrane**. 2. **Why Other Options are Incorrect:** * **Option B (Nucleolar membrane):** The nucleolus is a non-membrane-bound structure within the nucleus responsible for ribosome synthesis; it does not provide envelopes for viruses. * **Option C (Cytoplasmic/Plasma membrane):** Most other enveloped viruses (like Orthomyxoviruses or Retroviruses) acquire their envelope from the plasma membrane as they exit the cell. Herpes viruses are the classic exception to this rule. **NEET-PG High-Yield Pearls:** * **Tzanck Smear:** Look for multinucleated giant cells and **Cowdry Type A** intranuclear inclusion bodies (Lipschütz bodies) in HSV and VZV infections. * **Site of Latency:** HSV-1 (Trigeminal ganglion), HSV-2 (Sacral ganglion), VZV (Dorsal root ganglion), EBV (B-cells). * **Rule of Thumb:** All DNA viruses replicate in the nucleus **except Poxvirus** (replicates in the cytoplasm). All RNA viruses replicate in the cytoplasm **except Influenza and HIV/Retrovirus** (replicate in the nucleus).

Practice by Chapter

Virus Structure and Classification

Practice Questions

Viral Replication

Practice Questions

Pathogenesis of Viral Infections

Practice Questions

DNA Viruses: Herpesviruses

Practice Questions

DNA Viruses: Poxviruses and Adenoviruses

Practice Questions

Hepatitis Viruses

Practice Questions

RNA Viruses: Orthomyxoviruses

Practice Questions

RNA Viruses: Paramyxoviruses

Practice Questions

Enteroviruses and Rhinoviruses

Practice Questions

Arboviruses

Practice Questions

HIV and Retroviruses

Practice Questions

Oncogenic Viruses

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free

Virology — MCQs

Virology — MCQs

On this page

Practice by Chapter

Want unlimited practice?