Virology Practice Questions

Q: A nurse has been found to be seropositive for both HbsAg and HBeAg. She is suffering from which of the following conditions?

Acute Hepatitis B infection. ### Explanation The presence of **HBsAg** (Hepatitis B surface Antigen) indicates that the patient is currently infected with the Hepatitis B virus [1]. The presence of **HBeAg** (Hepatitis B envelope Antigen) is a marker of active viral replication and high infectivity. **Why Acute Hepatitis B is the correct answer:** In the clinical context of a healthcare worker (like a nurse) presenting with these markers, it typically represents an **Acute Hepatitis B infection**. During the early phase of acute infection, HBsAg appears first, followed closely by HBeAg [1]. While HBeAg can also be present in the "Immune Tolerant" or "Reactive" phases of chronic infection, in standard NEET-PG questions, the combination of HBsAg and HBeAg without further qualifiers (like duration >6 months) is the classic laboratory profile for a highly infectious acute case. **Analysis of Incorrect Options:** * **Option A:** HBeAg stands for "envelope" antigen of HBV, not Hepatitis E. Hepatitis E is a separate RNA virus diagnosed via Anti-HEV IgM. * **Option C:** Chronic infection is defined by the persistence of HBsAg for **more than 6 months** [1]. Without a longitudinal history, acute infection is the primary clinical assumption. * **Option D:** In a past/resolved infection, HBsAg is cleared and **Anti-HBs antibodies** are present [1]. HBeAg would also be absent. --- ### High-Yield Clinical Pearls for NEET-PG * **HBsAg:** First marker to appear; indicates current infection (acute or chronic) [1]. * **HBeAg:** Indicates **high viral load**, active replication, and maximum infectivity. * **Anti-HBc IgM:** The **best marker for Acute HBV** (especially during the "Window Period" when HBsAg and Anti-HBs are both negative) [1]. * **Anti-HBc IgG:** Indicates "Remote" infection; it persists for life. * **Anti-HBs:** Indicates **immunity** (either from recovery or vaccination) [1]. If it is the *only* positive marker, it indicates vaccination.

Q: Which of the following is the characteristic site for the detection of Varicella-zoster virus (VZV) in active infection?

Skin. Explanation: **Varicella-zoster virus (VZV)**, a member of the *Alphaherpesvirinae* subfamily, is the causative agent of chickenpox (primary infection) and herpes zoster (reactivation) [1], [3]. The virus is highly **epitheliotropic**, meaning it has a specific predilection for infecting and replicating within skin cells [1]. 1. **Why Skin is Correct:** During active infection, VZV travels from the dorsal root ganglia to the skin via sensory nerves. It replicates in the epidermis, leading to the characteristic "dewdrop on a rose petal" vesicular rash [1], [4]. The fluid within these vesicles contains a high viral load, making the **skin (vesicle fluid or scrapings)** the primary and most reliable site for detection via PCR, Tzanck smear, or viral culture [2]. 2. **Why Other Options are Incorrect:** * **Cervical tissue:** This is the characteristic site for Human Papillomavirus (HPV) or Herpes Simplex Virus-2 (HSV-2), not VZV. * **Synovial fluid:** While some viruses like Parvovirus B19 or Rubella can cause arthritis, VZV is rarely isolated from joint fluid. * **Blood:** Although a transient viremia occurs during the incubation period, the viral titer in the blood is low and fleeting compared to the high concentration found in skin lesions [1]. **NEET-PG High-Yield Pearls:** * **Tzanck Smear:** A classic bedside test showing **multinucleated giant cells** with **Cowdry Type A** intranuclear inclusion bodies (seen in VZV, HSV-1, and HSV-2) [2]. * **Latency:** VZV remains latent in the **dorsal root ganglia** or cranial nerve ganglia [1]. * **Dermatomal Distribution:** Reactivation (Shingles) typically follows a single unilateral dermatome [4]. * **Gold Standard:** While Tzanck is fast, **PCR** of skin lesion swabs is now the gold standard for definitive diagnosis [2].

Q: Coxsackie B virus causes all except?

Herpangina. **Explanation:** The correct answer is **Herpangina** because it is primarily caused by **Coxsackie A virus**, not Coxsackie B. **1. Why Herpangina is the correct answer:** Herpangina is a febrile illness characterized by vesicular and ulcerative lesions on the posterior pharynx (soft palate, tonsils, and uvula). It is classically associated with **Coxsackie A viruses** (specifically types 1–10, 16, and 22). While both Group A and B are Enteroviruses, Group A typically targets the skin and mucous membranes, whereas Group B tends to target internal organs like the heart, pleura, and pancreas. **2. Analysis of Incorrect Options:** * **Aseptic Meningitis:** Both Coxsackie A and B are leading causes of viral (aseptic) meningitis. It is a common manifestation of Group B infections. * **Myocarditis:** Coxsackie B is the **most common viral cause** of acute myocarditis and pericarditis. It can lead to dilated cardiomyopathy. * **Bornholm Disease:** Also known as "Epidemic Pleurodynia" or the "Devil’s Grip," this condition is characterized by sudden, lancinating chest and abdominal pain due to inflammation of the intercostal muscles. It is almost exclusively caused by **Coxsackie B**. **High-Yield Clinical Pearls for NEET-PG:** * **Coxsackie A:** Think "Sores" (Herpangina, Hand-Foot-Mouth Disease). * **Coxsackie B:** Think "Body" (Myocarditis, Bornholm disease/Pleurodynia, Hepatitis, and even Type 1 Diabetes linkage via pancreatic damage). * **Hand-Foot-Mouth Disease (HFMD):** Most commonly caused by Coxsackie **A16** and Enterovirus 71. * **Rule of Thumb:** If the disease involves the heart or pleura, the answer is almost always Coxsackie B.

Q: Which type of poliovirus is responsible for most epidemics of poliomyelitis?

Type I virus. **Explanation:** Poliovirus is a member of the *Picornaviridae* family (genus *Enterovirus*) and exists in three distinct serotypes: Type 1 (Brunhilde), Type 2 (Lansing), and Type 3 (Leon). **Why Type I is Correct:** **Type I virus** is the most common cause of paralytic poliomyelitis and is responsible for the vast majority of epidemics. It is the most virulent and stable of the three types. Historically, Type I has been the hardest to eradicate from endemic regions due to its high transmissibility and propensity to cause large-scale outbreaks. **Analysis of Incorrect Options:** * **Type II virus:** This was the first serotype to be officially declared eradicated globally (in 2015). While it was highly immunogenic, it was less frequently associated with major epidemics compared to Type I. Most current Type 2 cases are "vaccine-derived" (cVDPV2) rather than wild-type. * **Type III virus:** This type is the least common cause of epidemics. It is, however, the most common cause of **Vaccine-Associated Paralytic Poliomyelitis (VAPP)** in some regions. Wild Poliovirus Type 3 was declared eradicated in 2019. * **Combination of Type II and III:** Epidemics are typically driven by a single dominant strain (historically Type I). A combination of II and III does not reflect the epidemiological reality of wild poliovirus transmission. **High-Yield NEET-PG Pearls:** * **Most common serotype in epidemics:** Type I. * **Most common cause of VAPP:** Type III (followed by Type II). * **Eradication Status:** Wild Poliovirus (WPV) Type 2 and Type 3 are eradicated; only WPV Type 1 remains endemic (primarily in Afghanistan and Pakistan). * **Specimen of choice:** Stool (highest viral shed). * **Culture:** Primary monkey kidney cell lines (shows characteristic "crenation" or rounding of cells).

Q: Which of the following is a primary cell culture?

Chick fibroblast. **Explanation:** Cell cultures are classified into three types based on their origin, chromosomal characteristics, and the number of times they can be subcultured. **1. Why Chick Fibroblast is Correct:** **Chick embryo fibroblast** is a **Primary Cell Culture**. These are derived directly from normal animal or human tissues (e.g., rhesus monkey kidney, human amnion, or chick embryo) by mechanical or enzymatic dissociation. * **Key Feature:** They consist of normal cells with a diploid number of chromosomes. * **Limitation:** They can be subcultured only once or twice before they die out. They are highly useful for the primary isolation of viruses and vaccine production. **2. Analysis of Incorrect Options:** * **B (HeLa) & C (HEp-2):** These are **Continuous Cell Lines** (also known as Immortal Cell Lines). They are derived from cancerous tissues and can be subcultured indefinitely. * **HeLa** is derived from a human cervical carcinoma. * **HEp-2** is derived from a human epithelioma of the larynx. * **D (HL-8):** This is a distractor; however, similar designations like **HL-60** refer to continuous leukemia cell lines. Continuous lines are heteroploid (abnormal chromosome number). **3. Clinical Pearls for NEET-PG:** * **Diplod Cell Strains:** (e.g., **WI-38, MRC-5**) are derived from human fetal lung tissues. They maintain a diploid karyotype and can be subcultured about 50 times. They are the preferred substrate for producing human viral vaccines (e.g., Rubella, Rabies). * **Vero cells:** Derived from African green monkey kidney; these are a common continuous cell line used in microbiology. * **Cytopathic Effect (CPE):** The structural changes in host cells caused by viral invasion, used to identify viruses in these cultures.

Q: Hepatitis B virus (HBV) is associated with all of the following except?

Hepatic adenoma. **Explanation:** The correct answer is **C. Hepatic adenoma**. **1. Why Hepatic Adenoma is the correct answer:** Hepatic adenoma is a **benign** liver tumor primarily associated with **oral contraceptive pill (OCP) use**, anabolic steroid use, or glycogen storage diseases. It is not caused by viral infections. Hepatitis B Virus (HBV) is a known oncogenic virus that integrates into the host genome, leading to malignant transformation rather than benign adenomatous growth. **2. Analysis of Incorrect Options:** * **Hepatic Cancer (Hepatocellular Carcinoma - HCC):** HBV is a major risk factor for HCC. The HBx protein acts as a transcriptional transactivator that disrupts cell cycle control and inhibits p53 (a tumor suppressor gene), directly promoting malignancy. * **Chronic Hepatitis:** Approximately 5–10% of adults and up to 90% of infected neonates fail to clear the surface antigen (HBsAg) within 6 months, leading to chronic hepatitis. * **Cirrhosis:** Chronic inflammation and immune-mediated destruction of hepatocytes lead to extensive fibrosis and regenerative nodules, culminating in cirrhosis. HBV is one of the leading causes of cirrhosis worldwide. **3. NEET-PG High-Yield Pearls:** * **HBV Genome:** It is a partially double-stranded circular DNA virus (Hepadnaviridae). * **Oncogenesis:** HBV can cause HCC **without** preceding cirrhosis (unlike HCV, where cirrhosis is usually a prerequisite). * **Extrahepatic Manifestations:** HBV is strongly associated with **Polyarteritis Nodosa (PAN)** and Membranous Glomerulonephritis. * **Ground Glass Hepatocytes:** A classic histological finding in chronic HBV infection due to the accumulation of HBsAg in the endoplasmic reticulum.

Q: Which of the following statements about rabies virus is incorrect?

It is a DNA virus.. **Explanation:** **1. Why Option A is the Correct Answer (The Incorrect Statement):** Rabies virus belongs to the family **Rhabdoviridae** and the genus *Lyssavirus*. It is a **single-stranded, negative-sense RNA virus**, not a DNA virus. It is characterized by its distinct bullet-shaped morphology and an envelope covered with glycoprotein spikes. **2. Analysis of Other Options:** * **Option B:** In rabies research, "Street virus" (found in nature) has a highly variable incubation period. However, the **"Fixed virus"** (used for vaccine production, derived by repeated serial passage in brains of rabbits) has a shortened and **fixed incubation period** (usually 4–6 days). * **Option C:** **Negri bodies** are pathognomonic intracytoplasmic eosinophilic inclusion bodies. They are most commonly and characteristically found in the **Pyramidal cells of the Hippocampus (Ammon’s horn)** and Purkinje cells of the cerebellum. * **Option D:** According to WHO and National guidelines, **Category III** (High risk) exposures include single or multiple transdermal bites or scratches, licks on broken skin, or contamination of mucous membranes with saliva. Any bite on the **fingers/hands** (highly innervated areas) or lacerated wounds are automatically classified as Class III, requiring both vaccine and Rabies Immunoglobulin (RIG). **Clinical Pearls for NEET-PG:** * **Shape:** Bullet-shaped virus. * **Genome:** ssRNA, linear, non-segmented, negative sense. * **Centripetal spread:** Moves via retrograde axonal transport to the CNS. * **Hydrophobia:** Occurs due to forceful spasms of the diaphragm and accessory respiratory muscles when attempting to swallow. * **Diagnosis:** Direct Fluorescent Antibody (DFA) test on skin biopsy (from the nape of the neck) or corneal impression is a gold standard intra-vitam test.

Q: Papillomavirus has been found in all of the following lesions except?

Condyloma latum. **Explanation:** The correct answer is **Condyloma latum** because it is a clinical manifestation of **Secondary Syphilis**, caused by the spirochete *Treponema pallidum*, not Human Papillomavirus (HPV). **1. Why Condyloma latum is the correct answer:** Condyloma lata are flat, moist, wart-like papules typically found in intertriginous areas (like the anogenital region) during the secondary stage of syphilis. They are highly infectious and contain a high load of spirochetes. In contrast, HPV-related lesions are usually more "verrucous" or cauliflower-like in appearance. **2. Why the other options are incorrect:** * **Oral papillomas:** These are benign epithelial tumors caused by HPV types 6 and 11. * **Verruca vulgaris:** Also known as common warts, these are caused by HPV (primarily types 2 and 4) and can occur on the oral mucosa. * **Condyloma acuminatum:** These are genital warts caused by low-risk HPV types 6 and 11. They are characterized by a "cauliflower-like" appearance and koilocytic changes on histology. **High-Yield Clinical Pearls for NEET-PG:** * **The "L" Rule:** Condyloma **L**atum = **L**ues (Syphilis); Condyloma **A**cuminatum = **A**PV (HPV). * **Koilocytes:** The hallmark histological finding for HPV infection (cells with perinuclear halos and wrinkled "raisinoid" nuclei). * **HPV Oncogenesis:** Types 16 and 18 are high-risk for cervical and oropharyngeal carcinoma due to E6 (inhibits p53) and E7 (inhibits Rb) proteins. * **Syphilis Diagnosis:** Condyloma latum is best diagnosed via Dark-field microscopy or serology (RPR/VDRL).

Q: Which of the following is NOT true of Kyasanur forest disease?

Caused by a retrovirus. ### Explanation **Kyasanur Forest Disease (KFD)**, also known as "Monkey Fever," is a viral hemorrhagic fever endemic to South India (primarily Karnataka). **Why Option B is the correct answer:** KFD is **not** caused by a retrovirus. It is caused by the **Kyasanur Forest Disease Virus (KFDV)**, which belongs to the family **Flaviviridae** (Genus: *Flavivirus*). It is a single-stranded RNA virus. Retroviruses (like HIV) use reverse transcriptase to integrate into the host genome, a mechanism not seen in KFDV. **Analysis of other options:** * **Option A (Transmitted by soft ticks):** This statement is **False**, making it a controversial option in some older texts. However, in the context of this specific question, the viral classification (Option B) is the more definitive "incorrect" statement. KFD is primarily transmitted by **Hard Ticks** (*Haemaphysalis spinigera*). * **Option C (Incubation period is 3-8 days):** This is **True**. The typical incubation period ranges from 3 to 8 days after a tick bite. * **Option D (A killed vaccine is available):** This is **True**. A formalin-inactivated (killed) KFDV vaccine is used in endemic areas for individuals aged 7–65 years. **High-Yield Clinical Pearls for NEET-PG:** * **Reservoirs:** Rats, shrews, and monkeys (Langurs and Bonnet macaques). * **Amplifier Host:** Monkeys (Sudden death of monkeys in a forest is an early warning sign of an outbreak). * **Vector:** *Haemaphysalis spinigera* (Hard tick). * **Clinical Presentation:** Biphasic illness—initial febrile phase with severe headache and myalgia, followed by a second phase in some patients involving meningoencephalitis or hemorrhagic manifestations. * **Diagnosis:** PCR (early phase) or IgM ELISA.

Question 1

A nurse has been found to be seropositive for both HbsAg and HBeAg. She is suffering from which of the following conditions?

Accepted Answer

Acute Hepatitis B infection

Answer

Concurrent Hepatitis B and Hepatitis E infection

Answer

Chronic Hepatitis B infection

Answer

Past Hepatitis B infection

Question 2

Which of the following is the characteristic site for the detection of Varicella-zoster virus (VZV) in active infection?

Accepted Answer

Skin

Answer

Cervical tissue

Answer

Synovial fluid

Answer

Blood

Question 3

Coxsackie B virus causes all except?

Accepted Answer

Herpangina

Answer

Aseptic meningitis

Answer

Myocarditis

Answer

Bornholm disease

Question 4

Which type of poliovirus is responsible for most epidemics of poliomyelitis?

Accepted Answer

Type I virus

Answer

Type II virus

Answer

Type III virus

Answer

Combination of Type II and Type III viruses

Question 5

Which of the following is a primary cell culture?

Accepted Answer

Chick fibroblast

Answer

Hela

Answer

HEP-2

Answer

HL-8

Question 6

What is the reason why most patients suffering from recurrent herpes labialis rarely give a history of having the acute form of herpetic gingivostomatitis?

Accepted Answer

The primary infection was subclinical

Answer

Etiological agents differ

Answer

The acute form occurs only in severely immunocompromised individuals

Answer

The patient has received antibodies during intrauterine life and the antibodies have persisted

Question 7

Hepatitis B virus (HBV) is associated with all of the following except?

Accepted Answer

Hepatic adenoma

Answer

Hepatic cancer

Answer

Chronic hepatitis

Answer

Cirrhosis

Question 8

Which of the following statements about rabies virus is incorrect?

Accepted Answer

It is a DNA virus.

Answer

Vaccine virus has a fixed incubation period.

Answer

Negri bodies are found in the hippocampus.

Answer

All bites on fingers with laceration are class three injuries.

Question 9

Papillomavirus has been found in all of the following lesions except?

Accepted Answer

Condyloma latum

Answer

Oral papillomas

Answer

Verruca vulgaris of the oral mucosa

Answer

Condyloma acuminatum

Question 10

Which of the following is NOT true of Kyasanur forest disease?

Accepted Answer

Caused by a retrovirus

Answer

Transmitted by soft ticks

Answer

Incubation period is 3-8 days

Answer

A killed vaccine is available

Virology — MCQs

Virology — MCQs

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