Virology Practice Questions

Q: Intracytoplasmic inclusion bodies are diagnostic of which viral infection?

Rabies. **Explanation:** The presence of **intracytoplasmic inclusion bodies** is a hallmark of several viral infections, but it is classically diagnostic for **Rabies**. These specific inclusions are known as **Negri bodies**. They are eosinophilic, sharply outlined, round or oval inclusions found most commonly in the Purkinje cells of the cerebellum and the pyramidal cells of the hippocampus. Their presence is pathognomonic for Rabies, as they represent sites of viral replication (nucleocapsid accumulation). **Analysis of Options:** * **B. Measles:** This virus is unique because it produces **both** intracytoplasmic and intranuclear inclusion bodies (Warthin-Finkeldey cells). Since the question asks specifically for intracytoplasmic diagnostic inclusions, Rabies is the more specific answer. * **C. Adenovirus:** This DNA virus replicates in the nucleus, producing **intranuclear** inclusion bodies (e.g., "smudge cells"). * **D. Mumps:** While it is a cytoplasmic virus, it does not typically produce distinct, diagnostic inclusion bodies used for routine histopathological diagnosis. **High-Yield Clinical Pearls for NEET-PG:** * **Intranuclear Inclusions:** * *Cowdry Type A:* Herpes Simplex Virus (HSV), Varicella-Zoster Virus (VZV), and Yellow Fever (Torres bodies). * *Cowdry Type B:* Poliovirus. * *Owl’s Eye appearance:* Cytomegalovirus (CMV). * **Intracytoplasmic Inclusions:** * *Negri bodies:* Rabies. * *Guarnieri bodies:* Variola (Smallpox) and Vaccinia. * *Bollinger bodies:* Fowlpox. * *Molluscum bodies (Henderson-Patterson):* Molluscum contagiosum. * **Both (Intranuclear + Intracytoplasmic):** Measles and CMV (though CMV is primarily known for its large intranuclear "owl's eye").

Q: What are the most common viruses isolated from herpangina?

Coxsackievirus A. **Explanation:** **Herpangina** is a common pediatric infection characterized by sudden onset fever, sore throat, and distinctive vesicular-ulcerative lesions on the posterior oropharynx (tonsillar pillars, soft palate, and uvula). **Why Coxsackievirus A is correct:** The primary causative agents of herpangina are **Group A Coxsackieviruses** (specifically serotypes A1–10, A16, and A22). These belong to the *Enterovirus* genus of the *Picornaviridae* family. Coxsackievirus A is also the most common cause of Hand-Foot-and-Mouth Disease (HFMD), particularly serotype A16. **Analysis of Incorrect Options:** * **Coxsackievirus B:** These are more commonly associated with pleurodynia (Bornholm disease), myocarditis, pericarditis, and pancreatitis. * **Echoviruses:** While they can cause non-specific febrile illnesses and aseptic meningitis, they are infrequent causes of herpangina. * **Enterovirus 71:** Although EV-71 can cause herpangina and HFMD, it is less common than Coxsackie A and is clinically significant primarily because it is associated with severe neurological complications like brainstem encephalitis. **High-Yield Clinical Pearls for NEET-PG:** * **Site of Lesions:** Herpangina affects the **posterior** pharynx, whereas Herpetic Gingivostomatitis (HSV-1) typically affects the **anterior** mouth and gums. * **Seasonality:** Peak incidence occurs during **summer and autumn** months. * **Transmission:** Fecal-oral route is the primary mode of spread. * **Management:** Treatment is purely supportive (hydration and analgesics) as the condition is self-limiting.

Q: Measles is caused by a

Single stranded RNA enveloped virus. **Explanation:** Measles virus belongs to the **Genus Morbillivirus** within the **Family Paramyxoviridae**. Understanding its structural classification is fundamental for NEET-PG. 1. **Why Option A is Correct:** The Measles virus is a **pleomorphic, enveloped virus** containing a **single-stranded, negative-sense, non-segmented RNA** genome. The envelope is derived from the host cell plasma membrane and contains two critical glycoprotein spikes: the **Hemagglutinin (H)** protein (for attachment) and the **Fusion (F)** protein (for cell entry and syncytia formation). Notably, unlike other Paramyxoviruses, Measles lacks Neuraminidase activity. 2. **Why Other Options are Incorrect:** * **Option B:** Non-enveloped RNA viruses include Picornaviruses (like Polio) or Caliciviruses. Measles requires its lipid envelope for infectivity; detergents or heat easily inactivate it. * **Options C & D:** Double-stranded RNA (dsRNA) is characteristic of the **Reoviridae** family (e.g., Rotavirus). Most human pathogenic RNA viruses, including all Paramyxoviruses, are single-stranded. **High-Yield Clinical Pearls for NEET-PG:** * **Koplik’s Spots:** Pathognomonic bluish-white spots on an erythematous base found on the buccal mucosa opposite the lower second molars (precedes the rash). * **Vitamin A:** Supplementation is recommended by the WHO to reduce morbidity and mortality in children with Measles. * **Complications:** The most common complication is **Otitis Media**; the most common cause of death is **Pneumonia** (Hecht’s giant cell pneumonia). * **SSPE:** Subacute Sclerosing Panencephalitis is a rare, fatal, late complication occurring years after the initial infection due to a persistent defective virus in the CNS. * **Vaccine:** Live attenuated (Edmonston-Zagreb strain) administered at 9 months and 16-24 months.

Q: Which of the following are arboviral diseases?

Japanese encephalitis, Dengue, Yellow fever. **Explanation** **1. Understanding the Concept (Why B is correct):** Arboviruses (Arthropod-borne viruses) are a functional group of viruses transmitted to humans through the bites of infected arthropods, primarily mosquitoes and ticks. * **Japanese Encephalitis (JE):** Transmitted by the *Culex tritaeniorhynchus* mosquito. It is the leading cause of viral encephalitis in Asia. * **Dengue:** Transmitted by the *Aedes aegypti* mosquito. It is a member of the Flaviviridae family. * **Yellow Fever:** Also transmitted by the *Aedes aegypti* mosquito. It is characterized by jaundice and hemorrhagic manifestations. Since all three diseases listed in Option B are transmitted via arthropod vectors, it is the most comprehensive and correct choice. **2. Analysis of Incorrect Options:** * **Options A, C, and D:** While the diseases listed in these options are indeed arboviral, they are **incomplete**. In NEET-PG, when multiple options contain correct facts, the "most complete" answer is the correct one. Option B encompasses all the major arboviruses mentioned across the other choices. **3. High-Yield Clinical Pearls for NEET-PG:** * **Flaviviridae Family:** All three (JE, Dengue, Yellow Fever) belong to the *Flaviviridae* family and contain ssRNA. * **Vector Specificity:** Remember "C" for *Culex* and "C" for Rice fields (JE); "A" for *Aedes* and "A" for Urban areas (Dengue/Yellow Fever). * **KFD (Kyasanur Forest Disease):** A high-yield Indian arbovirus transmitted by **ticks** (*Haemaphysalis spinigera*). * **Non-Arboviruses:** Note that diseases like Malaria and Kala-azar are arthropod-borne but are **protozoal**, not viral. Similarly, Rabies is viral but **not** arboviral (transmitted via animal bites).

Q: Class II exposure in animal bites includes which of the following?

Scratches without oozing of blood. The WHO and National Guidelines for Rabies Prophylaxis categorize animal exposures into three classes to determine the necessary Post-Exposure Prophylaxis (PEP). ### **Explanation of the Correct Option** **Option A (Scratches without oozing of blood)** is the correct answer because **Category II** exposure is defined as minor transdermal scratches or abrasions without bleeding, or nibbling of uncovered skin. These require immediate local wound treatment and the administration of the Rabies vaccine (ARV), but generally do not require Rabies Immunoglobulin (RIG). ### **Analysis of Incorrect Options** * **Option B (Licks on a fresh wound):** This is **Category III**. Any lick on broken skin (fresh wound) or mucous membranes allows the virus direct access to neural tissue, necessitating both ARV and RIG. * **Option C (Scratch with oozing of blood):** Any scratch or bite that causes **bleeding** (transdermal) is automatically classified as **Category III**, requiring full PEP (Vaccine + RIG). * **Option D (Bites from wild animals):** According to Indian guidelines, all bites by wild animals are high-risk and are treated as **Category III** regardless of the severity of the wound. ### **High-Yield Clinical Pearls for NEET-PG** * **Category I:** Touching/feeding animals, licks on **intact** skin. (Action: None, if history is reliable). * **Category II:** Minor scratches, no bleeding. (Action: Vaccine only). * **Category III:** Single/multiple transdermal bites, scratches with blood, licks on broken skin, or contact with bats. (Action: Vaccine + RIG). * **Site of RIG:** RIG should be infiltrated **in and around the wound**. Any remaining volume is injected IM at a site distant from the vaccine. * **Wound Care:** Immediate flushing with soap and water for 15 minutes is the most effective first-step in reducing viral load. Avoid suturing wounds; if necessary, do so only after RIG infiltration.

Q: All the following hepatitis viruses are transmitted by the parenteral route except?

Hepatitis E virus. ### Explanation The transmission of hepatitis viruses is a high-yield topic for NEET-PG, categorized primarily into two routes: **Enteric** (fecal-oral) and **Parenteral** (blood-borne/sexual). **1. Why Hepatitis E is the Correct Answer:** Hepatitis E virus (HEV), along with Hepatitis A virus (HAV), is transmitted via the **fecal-oral route**, typically through contaminated water or food. It is not primarily transmitted through blood or parenteral routes. A key clinical distinction for HEV is its high mortality rate (up to 20%) in **pregnant women** due to fulminant hepatic failure. **2. Analysis of Incorrect Options (Parenteral Viruses):** * **Hepatitis B (HBV):** Transmitted via blood, sexual contact, and vertically (mother to child). It is a DNA virus and the most common cause of chronic hepatitis worldwide. * **Hepatitis C (HCV):** Primarily transmitted through blood (IV drug use, transfusions). It has the highest rate of progression to **chronicity** (approx. 80%). * **Hepatitis D (HDV):** A defective RNA virus that requires the HBsAg coat of HBV to replicate. It is transmitted parenterally either as a co-infection or super-infection with HBV. **3. NEET-PG Clinical Pearls:** * **Vowels go with the Bowels:** Hepatitis **A** and **E** are transmitted via the fecal-oral route. * **Consonants are Blood-borne:** Hepatitis **B, C, and D** are transmitted parenterally. * **HEV Genotypes:** Genotypes 1 and 2 are associated with waterborne epidemics in humans; Genotypes 3 and 4 are zoonotic (pork consumption). * **Incubation Period:** HEV has an average incubation period of 2–9 weeks.

Question 1

Intracytoplasmic inclusion bodies are diagnostic of which viral infection?

Accepted Answer

Rabies

Answer

Measles

Answer

Adenovirus

Answer

Mumps

Question 2

What are the most common viruses isolated from herpangina?

Accepted Answer

Coxsackievirus A

Answer

Coxsackievirus B

Answer

Echoviruses

Answer

Enterovirus 71

Question 3

Measles is caused by a

Accepted Answer

Single stranded RNA enveloped virus

Answer

Single stranded RNA non-enveloped virus

Answer

Double stranded RNA enveloped virus

Answer

Double stranded RNA non-enveloped virus

Question 4

Which of the following statements is NOT true about viral envelopes?

Accepted Answer

The envelope is essential for viral propagation in the next generation.

Answer

The lipid bilayer is derived from host cell membranes.

Answer

The viral proteins embedded within the envelope are encoded by the virus itself.

Answer

The envelope is susceptible to dissolution by organic solvents like ether.

Question 5

Which immunoassay is performed in HIV to detect the presence of antibodies to individual viral proteins?

Accepted Answer

Western Blot

Answer

NASBA

Answer

ELISA

Answer

PCR

Question 6

Which of the following are arboviral diseases?

Accepted Answer

Japanese encephalitis, Dengue, Yellow fever

Answer

Japanese encephalitis, Dengue

Answer

Japanese encephalitis, Yellow fever

Answer

Dengue, Yellow fever

Question 7

Class II exposure in animal bites includes which of the following?

Accepted Answer

Scratches without oozing of blood

Answer

Licks on a fresh wound

Answer

Scratch with oozing of blood on palm

Answer

Bites from wild animals

Question 8

When compared to the Western blot technique, the ELISA test is:

Accepted Answer

More sensitive, less specific

Answer

Less sensitive, less specific

Answer

More sensitive, more specific

Answer

Less sensitive, more specific

Question 9

All of the following are true regarding influenza, except?

Accepted Answer

Amantadine is active against influenza B only.

Answer

Point mutations in the hemagglutinin gene cause antigenic drift.

Answer

Acquisition of a completely new hemagglutinin gene causes antigenic shift.

Answer

Amantadine shortens the illness.

Question 10

All the following hepatitis viruses are transmitted by the parenteral route except?

Accepted Answer

Hepatitis E virus

Answer

Hepatitis B virus

Answer

Hepatitis C virus

Answer

Hepatitis D virus

Virology — MCQs

Virology — MCQs

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