Virology Practice Questions

Q: All of the following are prion diseases except?

Burkitt lymphoma. ### Explanation The correct answer is **Burkitt lymphoma** because it is a malignancy of B-lymphocytes caused by the **Epstein-Barr Virus (EBV)**, not a prion. Prions are unique infectious agents composed entirely of protein (PrPSc), lacking any nucleic acid (DNA or RNA). **Analysis of Options:** * **Burkitt lymphoma (Option D):** This is a high-grade B-cell neoplasm associated with the c-myc translocation [t(8;14)]. It is etiologically linked to EBV, a DNA virus, making it the "except" in this list. * **Kuru (Option A):** A classic human prion disease historically found in the Fore people of Papua New Guinea, transmitted through ritualistic cannibalism. * **Subacute Spongiform Encephalopathies (Option B):** This is the umbrella term for all prion diseases (including Creutzfeldt-Jakob Disease). They are characterized by long incubation periods, neuronal loss, and a "spongiform" (vacuolated) appearance of the brain parenchyma without inflammatory response. * **Mink Encephalopathy (Option C):** This is a veterinary prion disease (Transmissible Mink Encephalopathy) similar to Scrapie in sheep or Bovine Spongiform Encephalopathy (Mad Cow Disease) in cattle. **NEET-PG High-Yield Pearls:** 1. **Prion Characteristics:** Resistant to standard sterilization (autoclaving at 121°C). They require **134°C for 1-2 hours** or immersion in **1N NaOH**. 2. **Diagnosis:** Confirmed by brain biopsy showing amyloid plaques. The **14-3-3 protein** in CSF is a specific marker for CJD. 3. **Human Prion Diseases:** Kuru, CJD, Variant CJD (linked to Mad Cow), Gerstmann-Sträussler-Scheinker (GSS) syndrome, and Fatal Familial Insomnia (FFI).

Q: An infant develops a cough and fever. The X-ray examination is suggestive of bronchopneumonia. Which of the following viruses is NOT a common causative agent of bronchopneumonia in infants?

Mumps virus. **Explanation:** The correct answer is **D. Mumps virus**. **Why Mumps virus is the correct answer:** Mumps virus is a member of the *Rubulavirus* genus within the Paramyxoviridae family. Its primary clinical manifestation is **nonsuppurative parotitis** (painful swelling of the salivary glands). While it is a respiratory virus transmitted via droplets, it characteristically disseminates hematogenously to glandular tissues (testes, ovaries, pancreas) and the central nervous system (meningitis). It is **not** a primary respiratory pathogen and does not cause bronchopneumonia in infants. **Why the other options are incorrect:** * **Respiratory Syncytial Virus (RSV):** This is the **most common** cause of bronchiolitis and pneumonia in infants and children under 1 year of age. It typically presents with wheezing and respiratory distress. * **Parainfluenza viruses:** Specifically Types 1, 2, and 3 are major causes of lower respiratory tract infections in infants. While Type 1 is the leading cause of Croup (Laryngotracheobronchitis), Type 3 is a frequent cause of pneumonia and bronchiolitis. * **Influenza virus A:** This virus can cause severe primary viral pneumonia or predispose patients to secondary bacterial bronchopneumonia. It is a significant cause of respiratory morbidity in the pediatric population. **Clinical Pearls for NEET-PG:** * **Most common cause of Bronchiolitis:** RSV. * **Most common cause of Croup (Laryngotracheobronchitis):** Parainfluenza Type 1 (look for "steeple sign" on X-ray). * **Mumps Complications:** Orchitis (most common in post-pubertal males, can lead to atrophy but rarely sterility) and Oophoritis. * **Mumps Diagnosis:** Elevated serum amylase (due to parotid involvement) is a high-yield laboratory finding.

Q: All of the following are true about cytomegalovirus except:

Causes lymphocyte enlargement. **Explanation:** The correct answer is **C (Causes lymphocyte enlargement)**. While Cytomegalovirus (CMV) is a member of the Herpesviridae family, the hallmark of its pathology is **cytomegaly (enlargement of the cell)**, characterized by large cells with prominent intranuclear inclusions ("Owl's eye" appearance). It does not specifically cause the enlargement of lymphocytes; rather, it typically induces a **lymphocytosis** with **atypical lymphocytes** (Downey cells), which are activated T-cells responding to the infection. **Evaluation of other options:** * **Option A & D:** CMV is the most common cause of **congenital viral infections**. It can be transmitted transplacentally (vertical transmission) from mother to fetus, leading to "Cytomegalic Inclusion Disease." Clinical features include microcephaly, periventricular calcifications, hepatosplenomegaly, and sensorineural hearing loss. * **Option B:** CMV is officially classified as **Human Herpesvirus 5 (HHV-5)**, belonging to the Beta-herpesvirinae subfamily. **High-Yield Clinical Pearls for NEET-PG:** * **Morphology:** Large cells with "Owl’s eye" intranuclear inclusions. * **Transmission:** Saliva, urine, blood, semen, breast milk, and organ transplants. * **Clinical Presentation:** In immunocompetent hosts, it causes a Mononucleosis-like syndrome (Heterophile antibody/Monospot test **negative**). In HIV patients (CD4 <50), it causes retinitis, esophagitis, and colitis. * **Treatment:** Ganciclovir is the drug of choice; Foscarnet is used for resistant cases.

Q: KFD (Kyasanur Forest Disease) is caused by which type of virus?

Flavivirus. **Explanation:** **Kyasanur Forest Disease (KFD)**, popularly known as "Monkey Fever," is caused by the Kyasanur Forest Disease Virus (KFDV). 1. **Why Flavivirus is Correct:** KFDV belongs to the family **Flaviviridae** and the genus *Flavivirus*. It is a tick-borne viral hemorrhagic fever endemic to the Western Ghats of India (specifically Karnataka). It is transmitted to humans via the bite of infected ticks (*Haemaphysalis spinigera*) or through contact with infected monkeys (Langurs and Bonnet macaques), which act as amplifiers. 2. **Why Other Options are Incorrect:** * **Myxovirus:** This group includes Orthomyxoviruses (e.g., Influenza) and Paramyxoviruses (e.g., Measles, Mumps). These are primarily respiratory viruses, not tick-borne hemorrhagic agents. * **Alphavirus:** Part of the *Togaviridae* family, these include viruses like Chikungunya and Sindbis. While they are arboviruses, they typically cause fever and arthralgia rather than the specific hemorrhagic manifestations of KFD. * **Phlebovirus:** A genus within the *Phenuiviridae* family (formerly Bunyaviridae), which includes Rift Valley Fever and Sandfly fever. While some are tick-borne, KFD specifically belongs to the Flavivirus genus. **High-Yield Clinical Pearls for NEET-PG:** * **Vector:** *Haemaphysalis spinigera* (Hard tick). * **Reservoir/Amplifier:** Monkeys (Sudden deaths in local monkey populations are a sentinel sign of an outbreak). * **Clinical Presentation:** Biphastic illness—initial high fever, headache, and severe myalgia, followed by a second phase of neurological symptoms or hemorrhagic manifestations in some patients. * **Diagnosis:** PCR (early phase) or IgM ELISA. * **Prevention:** A formalin-inactivated KFDV vaccine is used in endemic areas of India.

Q: Which of the following viruses does NOT cause pneumonia?

Mumps virus. **Explanation:** The correct answer is **Mumps virus**. While many respiratory and systemic viruses can lead to pulmonary involvement, Mumps virus is characteristically associated with glandular and neurological involvement rather than pneumonia. **Why Mumps virus is the correct answer:** Mumps is primarily a systemic viral infection caused by a Rubulavirus (Paramyxoviridae). Its hallmark clinical presentation involves **nonsuppurative parotitis** (salivary gland swelling). Common complications include orchitis (most common in post-pubertal males), oophoritis, pancreatitis, and aseptic meningitis. It does not typically involve the lower respiratory tract or cause pneumonia. **Why the other options are incorrect:** * **Cytomegalovirus (CMV):** A major cause of viral pneumonia, particularly in **immunocompromised patients** (e.g., post-transplant recipients or HIV patients). Histology typically shows "Owl’s eye" intranuclear inclusions. * **Measles virus:** A member of the Paramyxoviridae family that frequently causes respiratory complications. It can cause primary viral pneumonia (**Hecht’s giant cell pneumonia**) or lead to secondary bacterial pneumonia. * **Retrovirus (HIV):** While HIV itself doesn't cause pneumonia directly, it leads to profound immunosuppression, making patients highly susceptible to opportunistic pulmonary infections (e.g., *Pneumocystis jirovecii*, CMV, and fungal pneumonias). Additionally, HTLV-1 (another retrovirus) is associated with chronic lung diseases. **High-Yield Clinical Pearls for NEET-PG:** * **Measles:** Look for Koplik spots and Warthin-Finkeldey giant cells. * **CMV:** Most common viral cause of pneumonia in bone marrow transplant recipients. * **Mumps:** Most common cause of bilateral parotitis; most common cause of viral orchitis. * **RSV:** The most common cause of bronchiolitis and pneumonia in infants.

Q: A patient's serum shows HbsAg and IgM to Hbc. What is the diagnosis?

Acute hepatitis. To understand the diagnosis of Hepatitis B, one must interpret the "Serological Window." **1. Why Option B is Correct:** The presence of **HBsAg** (Hepatitis B surface Antigen) indicates that the virus is currently present in the body. The presence of **IgM anti-HBc** (Immunoglobulin M antibody to Hepatitis B core antigen) is the hallmark of a **recent/acute infection** (typically within the last 6 months). When both are positive, it confirms a diagnosis of **Acute Hepatitis B**. **2. Why the other options are incorrect:** * **Options A & D (Chronic Hepatitis B):** In chronic infection, HBsAg persists for more than 6 months, but the body switches from producing IgM to **IgG anti-HBc**. Therefore, the presence of IgM specifically rules out chronicity. * **Option C (Acute Hepatitis C):** This is incorrect because HBsAg and anti-HBc are specific biomarkers for the Hepatitis B virus (HBV), not Hepatitis C (HCV). HCV diagnosis would require HCV RNA or Anti-HCV antibodies. **3. NEET-PG High-Yield Pearls:** * **Window Period:** This is the interval where HBsAg has disappeared but Anti-HBs has not yet appeared. During this time, **IgM anti-HBc** is the *only* positive marker (the "Window Marker"). * **HBeAg:** Indicates high viral replication and high infectivity. * **Anti-HBs:** Its presence indicates immunity (either via recovery or vaccination). * **Vaccination Profile:** A vaccinated individual will be positive for **Anti-HBs** only (negative for HBsAg and Anti-HBc).

Q: Lymphocytosis with atypical lymphocytes is seen in infection with which of the following viruses?

Epstein-Barr Virus (EBV). ### Explanation **Correct Answer: C. Epstein-Barr Virus (EBV)** **Why it is correct:** Epstein-Barr Virus (EBV) is the primary causative agent of **Infectious Mononucleosis (IM)**. The hallmark of this condition is absolute lymphocytosis where more than 10% of the lymphocytes are **atypical lymphocytes**, also known as **Downey cells**. The underlying medical concept is crucial: EBV infects B-cells via the **CD21 receptor**. However, the "atypical lymphocytes" seen on a peripheral blood smear are actually **activated CD8+ T-cells (Cytotoxic T-cells)** reacting against the EBV-infected B-cells. These cells are larger than normal lymphocytes, possess abundant cytoplasm, and have a "ballerina skirt" appearance as they indent around neighboring red blood cells. **Why the other options are incorrect:** * **A. HSV:** Typically causes localized vesicular lesions (cold sores or genital herpes). While it can cause systemic symptoms, it does not characteristically produce a peripheral smear dominated by atypical lymphocytosis. * **B. HBV:** Primarily targets hepatocytes. While it involves immune-mediated liver injury, the hematological profile does not typically feature Downey cells. * **D. RSV:** A major cause of bronchiolitis and pneumonia in infants. It is characterized by respiratory distress and syncytia formation in lung tissue, not systemic atypical lymphocytosis. **NEET-PG High-Yield Pearls:** * **Paul-Bunnell Test:** Detects heterophile antibodies; used for rapid diagnosis of EBV. * **Differential Diagnosis:** Cytomegalovirus (CMV) also causes a "mononucleosis-like syndrome" with atypical lymphocytes, but it is **Heterophile Antibody Negative**. * **Associated Malignancies:** EBV is linked to Burkitt Lymphoma (t 8;14), Nasopharyngeal Carcinoma, and Hodgkin Lymphoma. * **Clinical Triad of IM:** Fever, Pharyngitis, and Lymphadenopathy (posterior cervical). Splenomegaly is also a common finding.

Q: Which of the following viral infections is characterized by the presence of inclusion bodies in neurons?

Rabies. ### Explanation **Correct Answer: A. Rabies** Rabies is a neurotropic viral infection caused by the *Lyssavirus* (Rhabdoviridae family). The hallmark histopathological finding is the **Negri body**. These are pathognomonic, eosinophilic, intracytoplasmic inclusion bodies found within the cytoplasm of neurons, most commonly in the **Purkinje cells of the cerebellum** and the **pyramidal cells of the hippocampus (Ammon’s horn)**. They represent sites of viral replication (nucleocapsid accumulation). **Analysis of Incorrect Options:** * **B. Diphtheria:** This is a bacterial infection caused by *Corynebacterium diphtheriae*. It produces an exotoxin that inhibits protein synthesis. While it can cause neurological symptoms (polyneuropathy) due to demyelination, it does not produce viral inclusion bodies. * **C. Yellow Fever:** This is a flavivirus infection. Its characteristic inclusion bodies are **Councilman bodies**, which are eosinophilic globules found in the **hepatocytes** (liver), representing apoptotic hepatocytes, not neurons. * **D. Japanese Encephalitis (JE):** While JE is a neurotropic flavivirus that causes severe inflammation of the brain parenchyma, it does not typically present with well-defined, diagnostic inclusion bodies like Rabies. Diagnosis relies on IgM ELISA in CSF/Serum. **High-Yield Clinical Pearls for NEET-PG:** * **Negri Bodies:** Intracytoplasmic, eosinophilic, found in neurons (Hippocampus/Cerebellum). * **Guarnieri Bodies:** Intracytoplasmic; seen in Variola (Smallpox) and Vaccinia. * **Cowdry Type A:** Intranuclear; seen in Herpes Simplex Virus (HSV) and Varicella-Zoster Virus (VZV). * **Cowdry Type B:** Intranuclear; seen in Poliovirus. * **Owl’s Eye Appearance:** Intranuclear inclusions seen in Cytomegalovirus (CMV). * **Henderson-Peterson Bodies:** Intracytoplasmic; seen in Molluscum contagiosum.

Q: Which virus has a single-stranded RNA genome with segmented genes?

Influenza virus. **Explanation:** The correct answer is **Influenza virus**. The fundamental concept here is the classification of viral genomes based on their nucleic acid structure and segmentation. **1. Why Influenza Virus is Correct:** Influenza viruses (Orthomyxoviridae) possess a **single-stranded RNA (ssRNA)** genome that is **segmented**. Influenza A and B typically have 8 segments, while Influenza C has 7. This segmentation is clinically critical because it allows for **genetic reassortment** (Antigenic Shift) when two different strains infect the same cell, leading to pandemics. **2. Why the Other Options are Incorrect:** * **Rotavirus & Reovirus:** While these viruses have **segmented** genomes, they consist of **double-stranded RNA (dsRNA)**, not single-stranded. Rotavirus (a member of the Reoviridae family) typically has 11 segments. * **Measles Virus:** This is a member of the Paramyxoviridae family. It has a **single-stranded RNA** genome, but it is **non-segmented** (unipartite). **3. NEET-PG High-Yield Pearls:** * **Mnemonic for Segmented Viruses:** "**BOAR**" — **B**unyavirus, **O**rthomyxovirus (Influenza), **A**renavirus, and **R**eovirus. * **Antigenic Shift vs. Drift:** Segmentation allows for **Shift** (major changes/pandemics via reassortment). Point mutations cause **Drift** (minor changes/epidemics). * **Replication Exception:** Unlike most RNA viruses that replicate in the cytoplasm, **Influenza virus** replicates its genome in the **nucleus**. * **Amantadine/Rimantadine** target the M2 ion channel (only in Influenza A), while **Oseltamivir/Zanamivir** are Neuraminidase inhibitors effective against both A and B.

Question 1

All of the following are prion diseases except?

Accepted Answer

Burkitt lymphoma

Answer

Kuru (KJD)

Answer

Subacute spongiform encephalopathies

Answer

Mink encephalopathy

Question 2

An infant develops a cough and fever. The X-ray examination is suggestive of bronchopneumonia. Which of the following viruses is NOT a common causative agent of bronchopneumonia in infants?

Accepted Answer

Mumps virus

Answer

Parainfluenza viruses

Answer

Influenza virus A

Answer

Respiratory syncytial virus

Question 3

All of the following are true about cytomegalovirus except:

Accepted Answer

Causes lymphocyte enlargement

Answer

May be transmitted from pregnant mother to fetus

Answer

Is Human herpesvirus 5

Answer

Causes congenital diseases

Question 4

KFD (Kyasanur Forest Disease) is caused by which type of virus?

Accepted Answer

Flavivirus

Answer

Myxovirus

Answer

Alphavirus

Answer

Phlebovirus

Question 5

Which of the following viruses does NOT cause pneumonia?

Accepted Answer

Mumps virus

Answer

Cytomegalovirus

Answer

Measles virus

Answer

Retrovirus

Question 6

A patient's serum shows HbsAg and IgM to Hbc. What is the diagnosis?

Accepted Answer

Acute hepatitis

Answer

Chronic hepatitis

Answer

Acute infection of hepatitis C

Answer

Chronic infection of hepatitis B

Question 7

Lymphocytosis with atypical lymphocytes is seen in infection with which of the following viruses?

Accepted Answer

Epstein-Barr Virus (EBV)

Answer

Herpes Simplex Virus (HSV)

Answer

Hepatitis B Virus (HBV)

Answer

Respiratory Syncytial Virus (RSV)

Question 8

Which of the following viral infections is characterized by the presence of inclusion bodies in neurons?

Accepted Answer

Rabies

Answer

Diphtheria

Answer

Yellow fever

Answer

Japanese encephalitis

Question 9

Which of the following statements about perinatal transmission of HIV is incorrect?

Accepted Answer

Postnatal transmission is not possible.

Answer

It cannot be diagnosed by routine confirmatory tests.

Answer

The infant transmission rate is less than 50%.

Answer

The virus can be isolated from mother's milk.

Question 10

Which virus has a single-stranded RNA genome with segmented genes?

Accepted Answer

Influenza virus

Answer

Rotavirus

Answer

Reovirus

Answer

Measles virus

Virology — MCQs

Virology — MCQs

On this page

Practice by Chapter

Want unlimited practice?