Virology Practice Questions

Q: Which virus is associated with cervical cancer?

Human Papillomavirus (HPV). **Explanation:** **Human Papillomavirus (HPV)** is the primary etiological agent for cervical cancer, identified in over 99% of cases. The oncogenic potential lies in the high-risk strains (primarily **HPV 16 and 18**), which integrate their DNA into the host genome. This leads to the overexpression of oncoproteins **E6 and E7**. E6 binds to and degrades the **p53** tumor suppressor protein, while E7 inactivates the **Retinoblastoma (Rb)** protein, resulting in uncontrolled cell cycle progression and malignant transformation. **Analysis of Incorrect Options:** * **HIV (Option B):** While HIV is a significant risk factor because it causes immunosuppression (allowing HPV to persist), it does not directly transform cervical cells. Cervical cancer is an AIDS-defining illness. * **EBV (Option C):** Associated with Burkitt lymphoma, Nasopharyngeal carcinoma, and Hodgkin lymphoma, but not cervical cancer. * **HTLV (Option D):** Specifically HTLV-1 is associated with Adult T-cell leukemia/lymphoma (ATLL) and tropical spastic paraparesis. **High-Yield Clinical Pearls for NEET-PG:** * **Most common strains:** HPV 16 (most common overall, associated with Squamous Cell Carcinoma) and HPV 18 (strongly associated with Adenocarcinoma). * **Low-risk strains:** HPV 6 and 11 cause genital warts (Condyloma acuminata) but have low oncogenic potential. * **Screening:** The transformation zone is the most common site for carcinogenesis; PAP smear screens for cytological changes. * **Vaccination:** The ideal age for the HPV vaccine is 9–14 years (before sexual debut). The quadrivalent vaccine (Gardasil) targets types 6, 11, 16, and 18.

Q: Which of the following is NOT true about Rotavirus?

Rota B can be grown in cell culture. **Explanation:** Rotavirus is the most common cause of severe diarrhea in infants and young children worldwide. Understanding its classification and cultivation is crucial for NEET-PG. **Why Option B is the Correct Answer (The False Statement):** Rotaviruses are notoriously difficult to grow in standard cell cultures. While **Group A Rotavirus** can be grown in specialized cell lines (like MA104) with the addition of proteolytic enzymes (trypsin) to enhance infectivity, **Group B and Group C Rotaviruses cannot be grown in cell culture.** Therefore, the statement that "Rota B can be grown in cell culture" is incorrect. **Analysis of Other Options:** * **Option A:** Rotaviruses are the leading cause of viral gastroenteritis in both humans and children, typically presenting with vomiting followed by watery diarrhea. * **Option C:** Rotavirus is classified into groups A through G. While Group A is the most common, **Group C** is a recognized cause of sporadic cases and outbreaks of diarrhea in children. * **Option D:** In routine clinical practice, culture is not performed because it is difficult, slow, and lacks sensitivity. Diagnosis is instead made via **ELISA** or **Latex Agglutination** for antigen detection in stool. **High-Yield Clinical Pearls for NEET-PG:** * **Morphology:** Wheel-like appearance (*Rota* = wheel) under electron microscopy due to its double-shelled capsid. * **Genome:** Segmented, double-stranded RNA (11 segments). * **Pathogenesis:** Produces an enterotoxin called **NSP4**, which induces secretory diarrhea. * **Vaccines:** Live attenuated oral vaccines (Rotarix, RotaTeq, and Rotavac) are part of the Universal Immunization Programme (UIP).

Q: Nipah virus is associated with epidemics of which condition?

Encephalitis. **Explanation:** Nipah virus (NiV) is a highly pathogenic zoonotic virus belonging to the genus **Henipavirus** (Family: Paramyxoviridae). The primary clinical manifestation of Nipah virus infection in humans is **acute encephalitis**, characterized by fever, headache, and altered consciousness, often progressing rapidly to coma and death. **Why Encephalitis is the correct answer:** The virus exhibits strong neurotropism. It enters the central nervous system via the olfactory nerve and through hematogenous spread, causing widespread vasculitis, endothelial damage, and parenchymal inflammation. This leads to severe cerebral edema and neurological deterioration, with a high case fatality rate (40% to 75%). **Analysis of other options:** * **Hepatitis:** While systemic involvement can occur, Nipah virus is not a primary hepatotropic virus. Hepatitis is not a defining clinical feature of the epidemics. * **Pneumonia:** Although Nipah virus can cause severe respiratory illness (Acute Respiratory Distress Syndrome), especially noted in the Malaysian and Singaporean outbreaks, **Encephalitis** remains the hallmark and most common cause of mortality in major epidemics (such as those in India and Bangladesh). * **All of the above:** While respiratory symptoms exist, the primary association and the "classic" board-exam presentation for Nipah is Encephalitis. **High-Yield Clinical Pearls for NEET-PG:** * **Natural Reservoir:** Fruit bats (Pteropus species). * **Transmission:** Consumption of raw date palm sap contaminated by bat saliva/urine, or direct contact with infected pigs (intermediate hosts). * **Diagnosis:** RT-PCR (gold standard) or ELISA for IgM/IgG antibodies. * **Histopathology:** Characteristic **syncytia formation** (multinucleated giant cells) in vascular endothelium. * **Recent Context:** Frequent outbreaks in Kerala, India, make this a high-priority topic.

Q: Which of the following is a member of the family Herpesviridae, characterized as an enveloped virus with an icosahedral nucleocapsid containing a double-stranded linear DNA genome?

Cytomegalovirus (CMV). **Explanation:** The question describes the classic structural characteristics of the **Herpesviridae** family. Members of this family are characterized by a **large, enveloped** virion, an **icosahedral nucleocapsid**, and a **linear double-stranded DNA (dsDNA)** genome. Between the capsid and the envelope lies a proteinaceous layer called the **tegument**. **1. Why Cytomegalovirus (CMV) is correct:** CMV (Human Herpesvirus 5) belongs to the Betaherpesvirinae subfamily. It perfectly fits the description: it is enveloped, possesses an icosahedral capsid, and contains linear dsDNA. It is a major cause of congenital infections and opportunistic infections in immunocompromised patients (e.g., transplant recipients, HIV). **2. Why the other options are incorrect:** * **Poliovirus:** A member of the *Picornaviridae* family. It is **non-enveloped** (naked) and contains a **ssRNA** genome. * **Human Papillomavirus (HPV):** A member of the *Papillomaviridae* family. While it has an icosahedral capsid and dsDNA, it is **non-enveloped** and its DNA is **circular**, not linear. * **Influenza virus:** A member of the *Orthomyxoviridae* family. It is enveloped but has a **helical** nucleocapsid and a **segmented ssRNA** genome. **Clinical Pearls for NEET-PG:** * **CMV Histology:** Look for "Owl’s eye" intranuclear inclusion bodies. * **Latency:** All Herpesviruses establish lifelong latency (CMV remains latent in mononuclear cells/lymphocytes). * **Site of Replication:** Unlike most RNA viruses, all DNA viruses (except Poxvirus) replicate in the **nucleus**. * **Envelope Origin:** Herpesviruses acquire their envelope by budding through the **inner nuclear membrane**.

Q: Which of the following conditions is NOT caused by Enterovirus (formerly Echovirus)?

Hemorrhagic conjunctivitis. **Explanation:** The question asks which condition is **NOT** caused by **Echoviruses** (a sub-genus of Enteroviruses). **1. Why "Hemorrhagic Conjunctivitis" is the correct answer:** While Echoviruses cause a wide spectrum of diseases, **Acute Hemorrhagic Conjunctivitis (AHC)** is specifically and classically caused by **Enterovirus 70** and **Coxsackievirus A24**. While these belong to the same *Enterovirus* genus, they are distinct from the Echovirus group. AHC is characterized by sudden onset of subconjunctival hemorrhage, pain, and lid edema. **2. Analysis of Incorrect Options (Conditions caused by Echoviruses):** * **Herpangina:** Primarily caused by Coxsackievirus A, but **Echoviruses** are also known causative agents. It presents with painful vesicles and ulcers on the posterior pharynx and soft palate. * **Pleurodynia (Bornholm disease):** Classically associated with Coxsackievirus B, but **Echoviruses** can also cause this paroxysmal, sharp chest pain due to intercostal muscle involvement. * **Myocarditis:** Along with Coxsackievirus B (the most common cause), **Echoviruses** are significant viral triggers for inflammatory cardiomyopathy and pericarditis. **3. NEET-PG High-Yield Pearls:** * **Echovirus** stands for *Enteric Cytopathic Human Orphan* virus. * **Aseptic Meningitis:** Echoviruses (especially types 6, 9, 11, and 30) are the **most common cause** of viral meningitis. * **Hand-Foot-Mouth Disease (HFMD):** Primarily caused by Coxsackievirus A16 and Enterovirus 71. * **Rule of Thumb:** If a question asks for the most common cause of non-polio enteroviral disease, Echoviruses are often the answer. However, for specific "hemorrhagic" eye infections, think **EV-70**.

Q: Which of the following viruses possesses a lipid envelope?

Herpesvirus. **Explanation:** The presence or absence of a lipid envelope is a fundamental classification feature in virology. Enveloped viruses acquire their lipid bilayer from host cell membranes (plasma, nuclear, or ER membranes) during the budding process. **1. Why Herpesvirus is Correct:** Herpesviruses (e.g., HSV, VZV, CMV, EBV) are large, **enveloped**, double-stranded DNA viruses. Uniquely, they acquire their envelope by budding through the **inner nuclear membrane** of the host cell. The envelope contains viral glycoproteins essential for attachment and entry into host cells. **2. Why the other options are incorrect:** * **Reovirus (Option A):** These are non-enveloped, double-stranded RNA viruses. They possess a unique double-layered icosahedral capsid which makes them resistant to detergents and acidic environments (like the GI tract). * **Picornavirus (Option B):** This family (including Poliovirus, Rhinovirus, and Hepatitis A) consists of small, non-enveloped, positive-sense single-stranded RNA viruses. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for DNA Viruses:** "HHAPPPPy" (Herpes, Hepadna, Adeno, Papilloma, Polyoma, Pox, Parvo). * **Enveloped DNA:** Herpes, Hepadna, Pox. * **Non-enveloped DNA:** Adeno, Papilloma, Polyoma, Parvo. * **Sensitivity:** Enveloped viruses are generally more fragile; they are easily inactivated by heat, detergents, and lipid solvents (like ether or alcohol). Non-enveloped (naked) viruses are typically more stable in the environment and are often transmitted via the feco-oral route. * **Exception:** Poxvirus is the only DNA virus that replicates in the cytoplasm and carries its own DNA-dependent RNA polymerase.

Q: Inclusion bodies of vaccinia are known as?

Guarnieri bodies. **Explanation:** **Guarnieri bodies** are the characteristic intracytoplasmic inclusion bodies seen in cells infected with the **Vaccinia virus** (the virus used in the smallpox vaccine) and the Variola virus (Smallpox). Since Poxviruses are unique among DNA viruses because they replicate entirely within the **cytoplasm**, these inclusions represent "viral factories" where viral replication and assembly occur. They appear as eosinophilic (pinkish) masses on H&E staining. **Analysis of Incorrect Options:** * **Negri bodies:** These are pathognomonic intracytoplasmic eosinophilic inclusions found in pyramidal cells of the hippocampus and Purkinje cells of the cerebellum in **Rabies**. * **Asteroid bodies:** These are star-shaped eosinophilic inclusions found within giant cells in granulomatous conditions, most classically **Sarcoidosis** and Sporotrichosis. * **Schuffner dots:** These are fine stippling (morphological changes) seen in red blood cells infected with **Plasmodium vivax** and *Plasmodium ovale* malaria. **High-Yield Clinical Pearls for NEET-PG:** * **Poxvirus Rule:** Most DNA viruses replicate in the nucleus and produce intranuclear inclusions (e.g., Herpes - Cowdry Type A). Poxviruses are the **exception**; they replicate in the cytoplasm and produce **intracytoplasmic** inclusions (Guarnieri bodies). * **Molluscum Contagiosum:** Another Poxvirus that produces large, eosinophilic intracytoplasmic inclusions known as **Henderson-Patterson bodies**. * **Cowdry Type A:** Seen in HSV and VZV (Lipshutz bodies). * **Owl’s Eye Appearance:** Characteristic intranuclear inclusion of **CMV**.

Q: What is the first antibody to appear in plasma during acute hepatitis B infection?

IgM Anti-HBc. ### Explanation In the serological course of an acute Hepatitis B Virus (HBV) infection, **IgM Anti-HBc** (Immunoglobulin M antibody to Hepatitis B core antigen) is the first **antibody** to appear in the plasma. #### Why IgM Anti-HBc is Correct: While **HBsAg** is the first *marker* (antigen) to appear in the blood, **IgM Anti-HBc** is the first *antibody* produced by the immune system. It typically appears shortly after HBsAg, often before the onset of clinical symptoms. Crucially, it is the only marker present during the **"Window Period"**—the interval when HBsAg has disappeared but Anti-HBs has not yet become detectable. #### Why Other Options are Incorrect: * **Anti-HBs:** This antibody appears only after the resolution of the infection or following vaccination. Its presence indicates immunity and clinical recovery. * **Anti-HBe:** This antibody appears after the disappearance of the HBeAg (envelope antigen). It signifies a transition from high viral replication to a low-replicative state; it is not the initial antibody response. * **IgG Anti-HBc (Distinction):** While not an option here, it is important to note that IgG Anti-HBc replaces IgM over time and persists for life, indicating a past exposure rather than an acute phase. #### High-Yield Clinical Pearls for NEET-PG: * **Window Period Marker:** IgM Anti-HBc is the diagnostic marker of choice for acute HBV during the window period. * **HBsAg:** First marker to appear overall (Antigen). * **HBeAg:** Indicator of high infectivity and active viral replication. * **Vaccination Profile:** A vaccinated individual will be **Anti-HBs positive** but **Anti-HBc negative** (since the vaccine contains only the surface antigen). * **Natural Infection Profile:** A person recovered from natural infection will be positive for **both** Anti-HBs and Anti-HBc (IgG).

Q: Which virus was the first to have an oncogene identified in it?

Retrovirus. **Explanation:** The correct answer is **Retrovirus**. The discovery of oncogenes is fundamentally linked to the study of retroviruses, specifically the **Rous Sarcoma Virus (RSV)**. In the 1970s, researchers identified the ***v-src*** gene in RSV, which was the first viral oncogene ever discovered. This led to the groundbreaking realization that viral oncogenes are actually mutated versions of normal cellular genes (proto-oncogenes) captured from the host genome, a process known as transduction. **Analysis of Options:** * **Epstein-Barr Virus (EBV):** While EBV was the first virus directly linked to human cancer (Burkitt’s Lymphoma), it is a DNA virus. Its mechanism of oncogenesis involves viral proteins (like LMP-1) rather than the classical "oncogene" identified in early retroviral research. * **Echovirus:** This is an Enterovirus (Picornaviridae family). It is primarily associated with aseptic meningitis and gastrointestinal issues; it is not an oncogenic virus. * **Adenovirus:** Certain serotypes are oncogenic in rodents (e.g., Type 12), but they were not the first identified source of oncogenes. Their transformation mechanism involves E1A and E1B proteins that inactivate host tumor suppressor genes (p53 and Rb). **High-Yield Clinical Pearls for NEET-PG:** * **Bishop and Varmus:** The scientists who won the Nobel Prize for discovering that oncogenes are cellular in origin (*c-src*). * **Mechanism:** Retroviruses cause cancer via **Insertional Mutagenesis** (slow-transforming) or by carrying a **transduced oncogene** (fast-transforming). * **Human Retrovirus:** HTLV-1 is the only retrovirus directly linked to human cancer (Adult T-cell Leukemia/Lymphoma).

Q: A 64-year-old man with a travel history to Southern Minnesota presents with a 2-day history of fever, headache, and vomiting. Today, he appears confused and is disoriented to simple questions. His cerebrospinal fluid analysis shows 75% neutrophils (PMNs) and is otherwise clear. A head CT scan is normal. What is the most likely cause of his symptoms?

West Nile virus. ### Explanation **Correct Answer: D. West Nile virus** The patient presents with **Encephalitis** (fever, headache, altered mental status/confusion). The key diagnostic clue is the **CSF pleocytosis with a predominance of neutrophils (PMNs)**. While most viral encephalitides present with lymphocytic pleocytosis, **West Nile Virus (WNV)** is a classic exception where an early neutrophilic shift is frequently observed. The travel history to the Midwestern United States (Minnesota) during summer/fall months is highly suggestive of WNV, which is the most common cause of epidemic viral encephalitis in the US. **Analysis of Incorrect Options:** * **A. California Encephalitis virus:** While also an arbovirus found in the Midwest, it primarily affects children (La Crosse strain) and is less common in the elderly compared to WNV. * **B. Enterovirus:** This is the most common cause of viral *meningitis*. While it can cause encephalitis, the CSF typically shows a rapid shift to lymphocytes, and the clinical severity in an elderly patient with profound confusion points more strongly toward WNV. * **C. Herpes Simplex Virus (HSV):** HSV is the most common cause of sporadic (non-epidemic) encephalitis. However, it typically presents with **temporal lobe involvement** on imaging (CT/MRI) and hemorrhagic CSF (RBCs), neither of which are present here. **NEET-PG High-Yield Pearls:** * **WNV Vector:** *Culex* mosquito; **Reservoir:** Birds (Crow/Blue Jay deaths are sentinels). * **CSF Paradox:** WNV is a "High-Yield" exception—think neutrophils in the CSF for early viral presentation. * **Clinical Sign:** Look for "West Nile Poliomyelitis" (acute flaccid paralysis) as a specific complication. * **Diagnosis:** IgM antibody capture ELISA (MAC-ELISA) in CSF is the gold standard.

Question 1

Which virus is associated with cervical cancer?

Accepted Answer

Human Papillomavirus (HPV)

Answer

Human Immunodeficiency Virus (HIV)

Answer

Epstein-Barr Virus (EBV)

Answer

Human T-lymphotropic Virus (HTLV)

Question 2

Which of the following is NOT true about Rotavirus?

Accepted Answer

Rota B can be grown in cell culture

Answer

Causes diarrhea in man and children

Answer

Rota C can cause diarrhea in children

Answer

Culture cannot be done

Question 3

Nipah virus is associated with epidemics of which condition?

Accepted Answer

Encephalitis

Answer

Hepatitis

Answer

Pneumonia

Answer

All of the above

Question 4

Which of the following is a member of the family Herpesviridae, characterized as an enveloped virus with an icosahedral nucleocapsid containing a double-stranded linear DNA genome?

Accepted Answer

Cytomegalovirus (CMV)

Answer

Poliovirus

Answer

Human Papillomavirus (HPV)

Answer

Influenza virus

Question 5

Which of the following conditions is NOT caused by Enterovirus (formerly Echovirus)?

Accepted Answer

Hemorrhagic conjunctivitis

Answer

Herpangina

Answer

Pleurodynia

Answer

Myocarditis

Question 6

Which of the following viruses possesses a lipid envelope?

Accepted Answer

Herpesvirus

Answer

Reovirus

Answer

Picornavirus

Answer

All of the above

Question 7

Inclusion bodies of vaccinia are known as?

Accepted Answer

Guarnieri bodies

Answer

Negri bodies

Answer

Asteroid bodies

Answer

Schuffner dots

Question 8

What is the first antibody to appear in plasma during acute hepatitis B infection?

Accepted Answer

IgM Anti-HBc

Answer

Anti-HBs

Answer

Anti-HBe

Question 9

Which virus was the first to have an oncogene identified in it?

Accepted Answer

Retrovirus

Answer

Epstein-Barr Virus

Answer

Echovirus

Answer

Adenovirus

Question 10

A 64-year-old man with a travel history to Southern Minnesota presents with a 2-day history of fever, headache, and vomiting. Today, he appears confused and is disoriented to simple questions. His cerebrospinal fluid analysis shows 75% neutrophils (PMNs) and is otherwise clear. A head CT scan is normal. What is the most likely cause of his symptoms?

Accepted Answer

West Nile virus

Answer

California Encephalitis virus

Answer

Enterovirus

Answer

Herpes Simplex Virus (HSV)

Virology — MCQs

Virology — MCQs

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