Virology Practice Questions

Q: Which of the following is NOT a complication of chickenpox?

Pancreatitis. **Explanation:** Chickenpox, caused by the **Varicella-Zoster Virus (VZV)**, is typically a self-limiting childhood illness but can lead to several systemic complications, especially in adults and immunocompromised individuals. **Why Pancreatitis is the Correct Answer:** Pancreatitis is **not** a recognized or classic complication of primary Varicella infection. While VZV can affect multiple organ systems, the pancreas is rarely, if ever, a target during the acute phase of chickenpox. In contrast, pancreatitis is a well-known complication of other viral infections like **Mumps** and **Coxsackievirus B**. **Analysis of Incorrect Options:** * **Pneumonia:** This is the **most serious complication** of chickenpox in adults. It typically presents 3–5 days into the illness with cough and dyspnea. * **Encephalitis:** Neurological complications are well-documented. In children, **Acute Cerebellar Ataxia** (presenting with nystagmus and ataxia) is more common, while diffuse **Encephalitis** is more frequent in adults. * **Thrombocytopenia:** Hematological issues, including transient thrombocytopenia and purpura fulminans, can occur due to viral interference with platelet production or immune-mediated destruction. **High-Yield Clinical Pearls for NEET-PG:** * **Most common complication in children:** Secondary bacterial infection of skin lesions (usually *Staph. aureus* or *Strep. pyogenes*). * **Reye’s Syndrome:** A serious complication involving encephalopathy and liver failure, linked to **Aspirin** use during chickenpox. * **Congenital Varicella Syndrome:** Occurs if the mother is infected in the first 20 weeks of pregnancy; characterized by cicatricial skin scarring, limb hypoplasia, and chorioretinitis. * **Tzanck Smear:** Shows **Multinucleated Giant Cells** with Cowdry Type A intranuclear inclusion bodies.

Q: Coxsackie virus can be isolated by inoculating into which of the following?

Suckling mice. **Explanation:** The **Coxsackie virus**, a member of the *Picornaviridae* family (Genus: *Enterovirus*), is uniquely characterized by its pathogenicity in **suckling mice** (mice less than 48 hours old). This is the gold standard classical method for isolation and differentiation of the virus into two groups: * **Group A:** Causes widespread **flaccid paralysis** due to generalized myositis of skeletal muscles. * **Group B:** Causes **spastic paralysis** due to focal myositis and necrotizing steatitis (inflammation of brown fat), often involving the pancreas and CNS. **Analysis of Incorrect Options:** * **A & B (Rabbit and Guinea Pig):** These animals are commonly used for producing antisera or for specific tests like the Paul-Bunnell test (Sheep RBCs) or Koch’s phenomenon (Tubercle bacilli), but they are not the primary isolation media for Coxsackie viruses. * **D (Foot pad of mice):** This is the specific site used for the cultivation of ***Mycobacterium leprae*** (the Shepard’s model), as the bacteria prefer the cooler temperature of the extremities. **High-Yield Clinical Pearls for NEET-PG:** * **Hand-Foot-Mouth Disease (HFMD):** Most commonly caused by Coxsackie **A16** and Enterovirus 71. * **Herpangina:** Characterized by vesicular lesions on the soft palate/fauces, caused by Group A. * **Bornholm Disease (Pleurodynia):** Also known as "Devil’s Grip," caused by Group B. * **Myocarditis & Dilated Cardiomyopathy:** Most frequently associated with **Coxsackie B** infections. * **Aseptic Meningitis:** Can be caused by both groups, but Group B is a more common culprit.

Q: What is the causative agent of Infectious mononucleosis?

Epstein-Barr virus (EBV). **Explanation:** **1. Why Epstein-Barr Virus (EBV) is correct:** Infectious Mononucleosis (IM), also known as "Glandular Fever" or the "Kissing Disease," is primarily caused by the **Epstein-Barr Virus (EBV)**, a member of the *Gammaherpesvirinae* subfamily (HHV-4). The virus infects B-lymphocytes by binding to the **CD21 receptor** (CR2). The characteristic clinical triad includes fever, pharyngitis, and lymphadenopathy. A hallmark of the disease is the presence of **atypical lymphocytes (Downey cells)** in the peripheral blood smear, which are actually activated T-cells responding to the infected B-cells. **2. Why the other options are incorrect:** * **HIV (Option A):** While Acute Retroviral Syndrome can mimic IM symptoms (fever, sore throat), HIV is a retrovirus that primarily targets CD4+ T-cells and leads to progressive immunodeficiency. * **HBV (Option B):** Hepatitis B is a hepadnavirus that primarily targets hepatocytes, leading to jaundice and liver inflammation, rather than a lymphoproliferative syndrome. * **HSV (Option C):** Herpes Simplex Virus typically causes vesicular lesions (cold sores or genital herpes) and encephalitis, not the systemic lymphadenopathy seen in IM. **3. NEET-PG High-Yield Pearls:** * **Diagnosis:** The **Paul-Bunnell Test** (detecting heterophile antibodies) is the classic screening test. * **Complication:** Patients treated with **Ampicillin or Amoxicillin** for a misdiagnosed sore throat often develop a characteristic maculopapular rash. * **Malignancy Link:** EBV is strongly associated with Burkitt Lymphoma (t(8;14)), Nasopharyngeal Carcinoma, and Hodgkin Lymphoma. * **Splenic Rupture:** Patients are advised to avoid contact sports due to the risk of spontaneous or traumatic splenic rupture.

Q: Which virus is associated with the Edmonston strain?

Measles. **Explanation:** The **Edmonston strain** is the parent strain of the **Measles virus** (Rubeola) used in the development of live-attenuated vaccines. It was originally isolated in 1954 by John Enders and Thomas Peebles from the blood of a young patient named David Edmonston. 1. **Measles (Correct):** The original Edmonston strain was further attenuated through multiple passages in human and chick embryo cells to create the **Edmonston-B** strain. Most modern measles vaccines used worldwide (such as the **Schwartz** and **Moraten** strains) are further derivatives of this original Edmonston isolate. 2. **Incorrect Options:** * **Hepatitis-B:** The vaccine is a recombinant subunit vaccine containing HBsAg produced in yeast (*Saccharomyces cerevisiae*). * **Mumps:** The most common vaccine strain is the **Jeryl Lynn** strain (named after the daughter of Maurice Hilleman). * **Rubella:** The standard vaccine strain used globally is **RA 27/3** (where RA stands for Rubella Abortus), isolated from the kidney cells of an aborted fetus. **High-Yield Clinical Pearls for NEET-PG:** * **Measles Vaccine:** It is a live-attenuated vaccine, typically administered at 9 months (as per the National Immunization Schedule in India) and 15-18 months (as MMR). * **Vitamin A:** Supplementation is mandatory during measles management to reduce morbidity and mortality (prevents blindness and pneumonia). * **Koplik Spots:** Pathognomonic bluish-white spots on an erythematous base found on the buccal mucosa opposite the lower second molars. * **SSPE (Subacute Sclerosing Panencephalitis):** A rare, late neurological complication caused by a persistent mutant measles virus.

Q: Herpes simplex virus causes all except?

Infectious mononucleosis. **Explanation:** The correct answer is **Infectious Mononucleosis**. While this condition is caused by a member of the Herpesviridae family, it is specifically caused by **Epstein-Barr Virus (EBV/HHV-4)** and occasionally Cytomegalovirus (CMV), but **not** by Herpes Simplex Virus (HSV-1 or HSV-2). **Why the other options are incorrect:** * **Encephalitis:** HSV-1 is the most common cause of sporadic fatal viral encephalitis worldwide, typically involving the temporal lobes. * **Pharyngitis:** Primary HSV-1 infection in adults frequently presents as acute pharyngotonsillitis, while in children, it often manifests as gingivostomatitis. * **Whitlow (Herpetic Whitlow):** This is a painful infection of the finger caused by HSV-1 (often in healthcare workers or children) or HSV-2 (via autoinoculation from genital lesions). **High-Yield Clinical Pearls for NEET-PG:** * **HSV Encephalitis:** Look for "Temporal lobe involvement" and "Hemorrhagic necrosis" on MRI. CSF analysis shows lymphocytic pleocytosis and increased RBCs. * **Diagnosis:** The gold standard for HSV diagnosis is **PCR**. However, for exams, remember the **Tzanck Smear**, which shows **Multinucleated Giant Cells** with Cowdry Type A intranuclear inclusions. * **Infectious Mononucleosis Triad:** Fever, Pharyngitis, and Lymphadenopathy. Key lab findings include **Atypical lymphocytes (Downey cells)** and a positive Heterophile antibody (Monospot) test. * **Treatment:** Acyclovir is the drug of choice for HSV infections, acting as a nucleoside analog that inhibits viral DNA polymerase.

Q: Which of the following cell types is NOT a target for the initiation and maintenance of HIV infection?

Neutrophil. ### Explanation The primary mechanism of HIV entry into host cells depends on the interaction between the viral envelope glycoprotein **gp120** and the host cell **CD4 receptor**, along with co-receptors (**CCR5** or **CXCR4**). **Why Neutrophils are the Correct Answer:** Neutrophils (Option D) do not express the CD4 receptor on their surface. Therefore, they cannot be directly infected by HIV. While HIV infection can lead to secondary "neutropenia" or functional defects in neutrophils due to a compromised cytokine environment, these cells are not targets for viral entry, replication, or maintenance. **Analysis of Incorrect Options:** * **CD4 T cells (Option A):** These are the primary targets for HIV. The virus binds to CD4 and the CXCR4 co-receptor (T-tropic strains), leading to progressive depletion of these cells, which is the hallmark of AIDS. * **Macrophages (Option B):** Macrophages express CD4 and the **CCR5** co-receptor (M-tropic strains). They are resistant to the cytopathic effects of the virus, allowing them to serve as long-term **reservoirs** for HIV and transport the virus to the brain. * **Dendritic Cells (Option C):** These cells (including follicular dendritic cells and Langerhans cells) play a crucial role in the **initiation** of infection. They capture HIV in mucosal surfaces using the **DC-SIGN** receptor and transport the virus to regional lymph nodes, effectively "presenting" it to CD4 T cells. **High-Yield Clinical Pearls for NEET-PG:** * **Primary Receptor:** CD4. * **Co-receptors:** CCR5 (early infection/macrophages) and CXCR4 (late infection/T cells). * **Homozygous mutation in CCR5 (Δ32):** Confers resistance to HIV infection. * **Viral Entry Protein:** gp120 (attachment); gp41 (fusion). * **Reservoirs:** Macrophages and Memory CD4 T cells are the major anatomical and cellular reservoirs that prevent total viral clearance.

Q: BK virus affects which organ transplantation?

Kidney. **Explanation:** The **BK virus** is a member of the *Polyomaviridae* family. It is a ubiquitous virus that most individuals acquire during childhood, after which it remains **latent in the renal tubular epithelium** and uroepithelium. **Why Kidney is correct:** In the setting of profound immunosuppression, particularly following **renal transplantation**, the virus reactivates. This leads to **BK Virus-Associated Nephropathy (BKVAN)**, characterized by tubulointerstitial inflammation and graft dysfunction. It is a major cause of allograft failure, affecting up to 10% of kidney transplant recipients. It also causes **hemorrhagic cystitis** in bone marrow transplant patients. **Why other options are incorrect:** * **Liver:** While viruses like CMV or Hepatitis B/C are concerns in liver transplants, BK virus does not typically target hepatic tissue. * **Lung:** Lung transplant complications are more commonly associated with CMV or fungal infections (Aspergillus). * **Marrow:** While BK virus causes hemorrhagic cystitis in bone marrow recipients, the primary organ "affected" by the pathology of the virus itself (nephropathy) is the kidney. In the context of "organ transplantation" (solid organ), the kidney is the classic association. **High-Yield Clinical Pearls for NEET-PG:** 1. **Diagnosis:** Look for **"Decoy cells"** (cells with large intranuclear inclusions) in urine cytology. 2. **Mnemonic:** **B**K virus affects the **B**e**K**ay (BK) → **B**idney (Kidney). 3. **JC Virus:** A related Polyomavirus that causes **Progressive Multifocal Leukoencephalopathy (PML)** in immunocompromised patients. 4. **Treatment:** Primarily involves the reduction of immunosuppressive therapy and occasionally Cidofovir.

Q: Which of the following groups of viruses is most likely involved in viral meningitis?

Enterovirus. **Explanation:** **Enteroviruses** (specifically Coxsackievirus A and B, and Echoviruses) are the most common cause of viral (aseptic) meningitis worldwide, accounting for more than **85–90% of all cases**. They belong to the *Picornaviridae* family. These viruses typically follow a fecal-oral route of transmission, replicate in the pharynx and GI tract, and then spread hematogenously to the central nervous system. Clinical presentation usually includes fever, headache, photophobia, and meningeal signs, often occurring in seasonal outbreaks (summer and autumn). **Why other options are incorrect:** * **Adenovirus:** While it can cause respiratory infections, conjunctivitis, and hemorrhagic cystitis, it is a rare cause of meningitis, usually seen only in immunocompromised individuals. * **Human Papilloma Virus (HPV):** This virus is strictly epitheliotropic, causing cutaneous warts and mucosal lesions (including cervical cancer). It does not have a neurotropic phase and does not cause meningitis. * **Poxvirus:** This group (including Variola and Molluscum contagiosum) primarily causes skin lesions. While complications can occur, they are not standard causes of viral meningitis. **High-Yield Clinical Pearls for NEET-PG:** * **CSF Findings in Viral Meningitis:** Normal glucose, normal to slightly elevated protein, and **lymphocytic pleocytosis** (though neutrophils may predominate in the first 24 hours). * **Mollaret Meningitis:** Recurrent lymphocytic meningitis often associated with **HSV-2**. * **Most common cause of Viral Encephalitis:** Sporadic cases are most commonly caused by **HSV-1** (targeting the temporal lobes). * **Enterovirus 71:** Notable for causing Hand-Foot-Mouth Disease (HFMD) and severe neurological complications like brainstem encephalitis.

Question 1

Antenatal maternal HIV diagnosis is of importance in:

Accepted Answer

Preventing vertical transmission

Answer

Terminating pregnancy

Answer

Discharging the patient

Answer

Isolating the patient

Question 2

Which of the following is NOT included in the diagnostic criteria for AIDS?

Accepted Answer

Presence of any of the opportunistic infections like tuberculosis, Pneumocystis carinii pneumonia, or cytomegalovirus disease

Answer

CD4 count < 200 cells/mm³

Answer

CD8 count < 500 cells/mm³

Answer

CD4:CD8 ratio = 1

Question 3

Which of the following is NOT a complication of chickenpox?

Accepted Answer

Pancreatitis

Answer

Pneumonia

Answer

Encephalitis

Answer

Thrombocytopenia

Question 4

Coxsackie virus can be isolated by inoculating into which of the following?

Accepted Answer

Suckling mice

Answer

Rabbit

Answer

Guinea pig

Answer

Foot pad of mice

Question 5

What is the causative agent of Infectious mononucleosis?

Accepted Answer

Epstein-Barr virus (EBV)

Answer

Human Immunodeficiency Virus (HIV)

Answer

Hepatitis B Virus (HBV)

Answer

Herpes Simplex Virus (HSV)

Question 6

Which virus is associated with the Edmonston strain?

Accepted Answer

Measles

Answer

Hepatitis-B

Answer

Mumps

Answer

Rubella

Question 7

Herpes simplex virus causes all except?

Accepted Answer

Infectious mononucleosis

Answer

Encephalitis

Answer

Pharyngitis

Answer

Whitlow

Question 8

Which of the following cell types is NOT a target for the initiation and maintenance of HIV infection?

Accepted Answer

Neutrophil

Answer

CD4 T cell

Answer

Macrophage

Answer

Dendritic cell

Question 9

BK virus affects which organ transplantation?

Accepted Answer

Kidney

Answer

Liver

Answer

Lung

Answer

Marrow

Question 10

Which of the following groups of viruses is most likely involved in viral meningitis?

Accepted Answer

Enterovirus

Answer

Adenovirus

Answer

Human papilloma virus

Answer

Poxvirus

Virology — MCQs

Virology — MCQs

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