Virology Practice Questions

Q: Which microorganism does not cause hemorrhagic conjunctivitis?

Papilloma virus. **Explanation:** Acute Hemorrhagic Conjunctivitis (AHC) is a highly contagious ocular infection characterized by sudden onset of painful, red eyes, subconjunctival hemorrhages, and eyelid edema. **Why Papilloma Virus is the correct answer:** Human Papillomavirus (HPV) is primarily associated with cutaneous and mucosal warts (verrucae) and malignancies (e.g., cervical cancer). In the eye, HPV types 6 and 11 are known to cause **conjunctival papillomas** (benign epithelial tumors), but they do not cause acute inflammatory or hemorrhagic conjunctivitis. **Analysis of incorrect options:** * **Enterovirus-70 (EV-70):** This is the most common cause of large-scale epidemics of AHC. It is a member of the Picornaviridae family and is highly neurotropic, occasionally causing polio-like paralysis (Radiculomyelitis). * **Coxsackievirus A24 (CA24):** A variant of this virus is the second major cause of epidemic AHC. It presents clinically identical to EV-70 but is less frequently associated with neurological complications. * **Adenovirus:** Specifically, **Serotypes 8, 11, 19, and 37** are notorious for causing Epidemic Keratoconjunctivitis (EKC), which frequently presents with significant subconjunctival hemorrhage and pseudomembrane formation. **High-Yield Clinical Pearls for NEET-PG:** * **AHC "Big Three":** Enterovirus 70, Coxsackie A24, and Adenovirus (8, 11, 19). * **Incubation Period:** AHC has a very short incubation period (18–48 hours) and typically resolves within 7–10 days. * **Neurological Link:** Always associate **Enterovirus-70** with rare cases of **cranial nerve palsies** or spinal paralysis following the conjunctivitis. * **Adenovirus 3 & 7:** Cause Pharyngoconjunctival Fever (PCF), characterized by the triad of fever, pharyngitis, and non-hemorrhagic follicular conjunctivitis.

Q: Diseases caused by arboviruses include all except?

Trench fever. **Explanation:** The term **Arbovirus** (Arthropod-borne virus) refers to a group of viruses that are transmitted to humans via the bite of infected arthropods, primarily mosquitoes and ticks. The virus must undergo biological multiplication within the vector (extrinsic incubation period) before transmission. **Why Trench Fever is the correct answer:** Trench fever is caused by ***Bartonella quintana***, which is a **gram-negative bacterium**, not a virus. While it is transmitted by an arthropod (the human body louse), it does not fit the definition of an arbovirus because the causative agent is bacterial. **Analysis of Incorrect Options:** * **Yellow Fever:** Caused by a Flavivirus and transmitted primarily by the *Aedes aegypti* mosquito. It is a classic example of an arboviral disease. * **Japanese Encephalitis (JE):** Caused by a Flavivirus and transmitted by *Culex* mosquitoes (mainly *Culex tritaeniorhynchus*). It is the leading cause of viral encephalitis in Asia. * **Dengue:** Caused by the Dengue virus (Flavivirus, serotypes 1-4) and transmitted by *Aedes aegypti*. It is the most common arboviral disease globally. **High-Yield Clinical Pearls for NEET-PG:** * **Key Arbovirus Families:** Flaviviridae (Dengue, JE, Yellow Fever, West Nile, Zika), Togaviridae (Chikungunya), and Bunyaviridae (KFD). * **KFD (Kyasanur Forest Disease):** A high-yield Indian arbovirus transmitted by **ticks** (*Haemaphysalis spinigera*). * **Louse-borne diseases (Non-arboviral):** Epidemic typhus (*Rickettsia prowazekii*), Relapsing fever (*Borrelia recurrentis*), and Trench fever (*Bartonella quintana*). * **Yellow Fever Vaccine:** 17D strain (Live attenuated); provides immunity for life (as per WHO IHR).

Q: Which virus is a single-stranded RNA orthomyxovirus, and is responsible for annual epidemics necessitating vaccination due to antigenic drift and shift?

Influenza virus. **Explanation:** The **Influenza virus** is the correct answer as it perfectly matches the description provided. It belongs to the **Orthomyxoviridae** family and possesses a **segmented, single-stranded, negative-sense RNA genome**. The segmented nature of its genome is the key driver behind its genetic variability: * **Antigenic Drift:** Minor mutations in the Hemagglutinin (HA) and Neuraminidase (NA) genes leading to annual epidemics. * **Antigenic Shift:** Major genetic reassortment (only in Influenza A) between different strains, leading to pandemics. These changes necessitate the formulation of a new vaccine every year. **Why the other options are incorrect:** * **Measles virus (Option A):** Belongs to the *Paramyxoviridae* family. While it is an ssRNA virus, it is antigenically stable (only one serotype exists), meaning the vaccine provides lifelong immunity. * **Respiratory Syncytial Virus (RSV) (Option B):** Also a member of *Paramyxoviridae*. It lacks a segmented genome and does not undergo antigenic shift. * **Parainfluenza virus (Option D):** Another *Paramyxoviridae* member. It causes croup (laryngotracheobronchitis) but does not exhibit the significant antigenic variation seen in Influenza. **High-Yield NEET-PG Pearls:** * **Genome:** Influenza has **8 segments** (A and B) or 7 segments (C). Segmented genomes are a prerequisite for **Antigenic Shift**. * **Replication:** Unlike most RNA viruses, Influenza replicates its genome in the **nucleus** of the host cell. * **Drug of Choice:** Oseltamivir (Neuraminidase inhibitor) is used for both prophylaxis and treatment. * **Vaccine:** The most common is the **Inactivated (killed)** vaccine; the Live Attenuated Influenza Vaccine (LAIV) is administered intranasally.

Q: Which of the following is NOT true of chickenpox rash?

Scabs are infectious. The correct answer is **D. Scabs are infectious**. ### Explanation In Chickenpox (caused by the Varicella-Zoster Virus), the infectivity period extends from **1–2 days before the appearance of the rash** until **all lesions have crusted (scabbed) over**. Unlike the fluid in vesicles and pustules, which contains live virus, the **scabs (crusts) are not infectious**. Once the rash has completely scabbed, the patient is no longer considered a source of transmission. ### Analysis of Incorrect Options * **A. Centripetal in distribution:** This is a hallmark of chickenpox. The rash begins on the trunk (where it is most dense) and spreads peripherally to the face and limbs. This is the opposite of Smallpox, which is centrifugal. * **B. Palms and soles are mostly spared:** Chickenpox typically avoids the palms and soles. If a vesicular rash involves these areas, clinicians should consider Hand-Foot-Mouth Disease (Coxsackievirus) or Syphilis. * **C. Pleomorphic rash:** This refers to the presence of multiple stages of lesions (macules, papules, vesicles, and crusts) simultaneously in the same anatomical area. This occurs because the rash appears in successive "crops." ### NEET-PG High-Yield Pearls * **Dew-drop on a rose petal:** Classic description of the varicella vesicle on an erythematous base. * **Tzanck Smear:** Shows **Multinucleated Giant Cells** with Cowdry Type A intranuclear inclusions (also seen in HSV). * **Starry Sky Appearance:** Refers to the pleomorphic nature of the rash. * **Incubation Period:** Typically 14–16 days (Range 10–21 days). * **Congenital Varicella Syndrome:** Characterized by cicatricial skin scarring, limb hypoplasia, and chorioretinitis.

Q: Basophilic inclusion bodies are seen in which virus?

Adenovirus. **Explanation:** In virology, inclusion bodies are distinct structures formed during viral replication, serving as "viral factories." Their staining characteristics (acidophilic vs. basophilic) and location (intranuclear vs. intracytoplasmic) are high-yield diagnostic markers for the NEET-PG exam. **1. Why Adenovirus is correct:** Adenoviruses are non-enveloped DNA viruses that replicate entirely within the host cell nucleus. They produce characteristic **intranuclear basophilic (blue-staining) inclusion bodies**. These are often described as "smudge cells" (large, dark, dense inclusions that obscure the nuclear detail), particularly seen in *Adenovirus* pneumonia or urinary tract infections. **2. Analysis of Incorrect Options:** * **Poliovirus:** As an Enterovirus (RNA virus), it replicates in the cytoplasm. It typically does not produce prominent diagnostic inclusion bodies used in routine histopathology. * **Measles virus:** Characterized by **Warthin-Finkeldey giant cells** (multinucleated). It is unique because it produces **both intranuclear and intracytoplasmic acidophilic** (eosinophilic) inclusion bodies (Cowdry type A). * **Herpes virus:** Produces **acidophilic (eosinophilic) intranuclear** inclusion bodies, famously known as **Cowdry Type A** (or "owl’s eye" appearance in CMV, though CMV is also a herpesvirus). **High-Yield Clinical Pearls for NEET-PG:** * **Basophilic Intranuclear:** Adenovirus, Molluscum contagiosum (Henderson-Patterson bodies - though these are technically intracytoplasmic, they are a common basophilic trap). * **Acidophilic Intranuclear (Cowdry A):** HSV, VZV, Yellow Fever (Councilman bodies). * **Acidophilic Intracytoplasmic:** Rabies (Negri bodies), Variola (Guarnieri bodies), Molluscum contagiosum (Henderson-Patterson). * **Both (Intranuclear + Intracytoplasmic):** Measles, CMV.

Q: Dengue hemorrhagic fever is caused by which virus family?

Flavivirus. **Explanation:** **Dengue virus** is a member of the **Flaviviridae** family (genus *Flavivirus*). It is a single-stranded, positive-sense RNA virus transmitted primarily by the *Aedes aegypti* mosquito. Dengue Hemorrhagic Fever (DHF) typically occurs due to "Antibody-Dependent Enhancement" (ADE), where a secondary infection with a different serotype (out of the four: DEN 1-4) leads to an exaggerated immune response, increased vascular permeability, and thrombocytopenia. **Analysis of Options:** * **Flavivirus (Correct):** This family includes major human pathogens like Dengue, Yellow Fever, West Nile, Zika, and Japanese Encephalitis viruses. They are characterized by being enveloped, icosahedral viruses. * **Alphavirus:** Part of the *Togaviridae* family; includes viruses like **Chikungunya**, which presents with similar joint pain but rarely causes the plasma leakage seen in DHF. * **Bunyavirus:** This family includes the Crimean-Congo hemorrhagic fever (CCHF) and Hantavirus. While they cause hemorrhagic fevers, they are distinct from the Flavivirus genus. * **Orbivirus:** A genus within the *Reoviridae* family (e.g., Bluetongue virus), primarily affecting ruminants and not associated with Dengue. **High-Yield Clinical Pearls for NEET-PG:** * **Vector:** *Aedes aegypti* (Day biter; breeds in artificial collections of clean water). * **Diagnosis:** **NS1 Antigen** is the marker of choice for early diagnosis (Days 1–5). IgM/IgG ELISA is used after Day 5. * **Tourniquet Test:** A positive test (≥10 petechiae per square inch) is a clinical indicator of capillary fragility in DHF. * **Saddle-back fever:** Refers to the biphasic fever pattern often seen in Dengue. * **Most common complication:** Plasma leakage leading to Dengue Shock Syndrome (DSS).

Q: Epidemic pleurodynia is caused by which virus?

Coxsackie B virus. **Explanation:** **Epidemic Pleurodynia** (also known as Bornholm disease or "Devil’s Grip") is a clinical syndrome characterized by the sudden onset of severe, paroxysmal, lancinating chest and upper abdominal pain, often accompanied by fever and malaise. 1. **Why Coxsackie B is correct:** The primary causative agents of epidemic pleurodynia are the **Group B Coxsackieviruses** (specifically types B1–B6). These viruses infect the intercostal muscles, leading to acute inflammation (myositis). The pain is typically pleuritic in nature, worsening with deep inspiration or movement, which explains the clinical nomenclature. 2. **Why other options are incorrect:** * **Coxsackie A virus:** These are primarily associated with **Herpangina** and **Hand-Foot-and-Mouth Disease (HFMD)**. While there is some overlap, they do not typically cause pleurodynia. * **Polio virus:** This virus selectively targets the anterior horn cells of the spinal cord, leading to asymmetrical flaccid paralysis; it does not cause primary muscle inflammation like pleurodynia. * **Enterovirus:** While Coxsackieviruses belong to the *Enterovirus* genus, "Enterovirus" as an option is too broad. In NEET-PG, when a specific subtype (Coxsackie B) is provided, it is the preferred answer over the general genus. **High-Yield Clinical Pearls for NEET-PG:** * **Coxsackie B** is also the most common viral cause of **Myocarditis** and **Pericarditis**. * **Coxsackie A16** is the most common cause of Hand-Foot-and-Mouth Disease. * **Bornholm Disease** is named after the Danish island where an outbreak was famously described. * **Diagnosis:** Usually clinical, but can be confirmed via RT-PCR from throat or stool samples. Treatment is purely supportive (NSAIDs for pain).

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.

Question 1

Which microorganism does not cause hemorrhagic conjunctivitis?

Accepted Answer

Papilloma virus

Answer

Adenovirus

Answer

Coxsackie-24

Answer

Enterovirus-70

Question 2

Diseases caused by arboviruses include all except?

Accepted Answer

Trench fever

Answer

Yellow fever

Answer

Japanese encephalitis

Answer

Dengue

Question 3

Which virus is a single-stranded RNA orthomyxovirus, and is responsible for annual epidemics necessitating vaccination due to antigenic drift and shift?

Accepted Answer

Influenza virus

Answer

Measles virus

Answer

Respiratory syncytial virus

Answer

Parainfluenza virus

Question 4

Which of the following is NOT true of chickenpox rash?

Accepted Answer

Scabs are infectious

Answer

Centripetal in distribution

Answer

Palms and soles are mostly spared

Answer

Pleomorphic rash

Question 5

Basophilic inclusion bodies are seen in which virus?

Accepted Answer

Adenovirus

Answer

Poliovirus

Answer

Measles virus

Answer

Herpes virus

Question 6

Dengue hemorrhagic fever is caused by which virus family?

Accepted Answer

Flavivirus

Answer

Alphavirus

Answer

Bunyavirus

Answer

Orbivirus

Question 7

Epidemic pleurodynia is caused by which virus?

Accepted Answer

Coxsackie B virus

Answer

Coxsackie A virus

Answer

Polio virus

Answer

Enterovirus

Question 8

All of the following are prion diseases except?

Accepted Answer

Burkitt lymphoma

Answer

Kuru (KJD)

Answer

Subacute spongiform encephalopathies

Answer

Mink encephalopathy

Question 9

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 10

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

Virology — MCQs

Virology — MCQs

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