Virology Practice Questions

Q: Ramsay Hunt syndrome is caused by:

Herpes zoster. ***Correct Answer: Herpes zoster*** - **Ramsay Hunt syndrome (Herpes Zoster Oticus)** is caused by the reactivation of the **varicella-zoster virus (VZV)**, the same virus that causes chickenpox and shingles. - The reactivation specifically affects the **geniculate ganglion** of the facial nerve, leading to the classic triad: facial paralysis, ear pain, and a vesicular rash in the ear canal. - Key clinical features include **auricular vesicles**, **facial nerve palsy**, and **severe otalgia**. *Incorrect: Herpes simplex* - **Herpes simplex virus (HSV)** causes oral and genital herpes, and in some cases can lead to encephalitis or Bell's palsy, but not Ramsay Hunt syndrome. - While HSV can cause facial paralysis (Bell's palsy), it typically does not present with the characteristic vesicular rash in the ear canal or severe otalgia seen in Ramsay Hunt syndrome. *Incorrect: Influenza* - **Influenza virus** primarily causes respiratory infections with symptoms like fever, cough, and body aches. - It does not cause facial nerve paralysis or vesicular rashes characteristic of Ramsay Hunt syndrome. *Incorrect: Adenovirus* - **Adenoviruses** are a common cause of respiratory illnesses, conjunctivitis, and gastroenteritis. - They are not associated with cranial nerve palsies or the dermatological manifestations seen in Ramsay Hunt syndrome.

Q: Which of the following markers in the blood is the most reliable indicator of recent hepatitis B infection?

IgM anti - HBc. ***IgM anti - HBc*** - **IgM anti-HBc** (antibody to hepatitis B core antigen) is the most reliable marker for **recent or acute hepatitis B infection**. - It appears early in the infection and can be detected during the **window period** when HBsAg may have disappeared but anti-HBs has not yet appeared. *anti-HBe* - **Anti-HBe** (antibody to hepatitis B e-antigen) indicates **lower infectivity** and often suggests resolution of viral replication. - It usually appears after HBeAg disappears and is not a primary marker of recent infection. *HBsAg* - **HBsAg** (hepatitis B surface antigen) indicates active **hepatitis B infection** (acute or chronic), but does not differentiate recent from long-standing infection on its own. - While present in recent infection, IgM anti-HBc is more specific for **acute or recent onset**. *IgG anti - HBs* - **IgG anti-HBs** (antibody to hepatitis B surface antigen) indicates either **recovery from past infection** or **immunity due to vaccination**. - It does not signify recent infection; rather, it suggests long-term immunity.

Q: Post transplant lymphoma most commonly associated with:

Epstein-Barr virus. ***Epstein-Barr virus*** - **EBV** is strongly implicated in the pathogenesis of **post-transplant lymphoproliferative disorder (PTLD)**, especially in patients receiving immunosuppressive therapy [1]. - The immune suppression post-transplant allows for uncontrolled B-cell proliferation driven by latent EBV infection, leading to lymphoma [2]. *HHV-6* - While HHV-6 can cause reactivation and complications in transplant recipients, it is **not commonly associated** with lymphoma development. - Its clinical manifestations usually include **fever, rash, encephalitis**, and bone marrow suppression. *Herpes simplex* - **HSV** infections are common in transplant patients due to immunosuppression, presenting as mucocutaneous lesions [3]. - However, HSV is **not a known oncogenic virus** that directly contributes to the development of post-transplant lymphoma. *Cytomegalo virus* - **CMV** is a significant pathogen in transplant recipients, causing various syndromes like pneumonitis, colitis, and retinitis [3]. - Although CMV can cause **indirect immunomodulatory effects**, it is not a primary cause of post-transplant lymphoma, unlike EBV.

Q: A blood donor is not considered for safe transfusion if he has:

HBsAg +ve and IgM anti-HBc +ve. ***HBsAg +ve and IgM anti-HBc +ve*** - Positive **HBsAg** indicates active hepatitis B infection with high viral load and infectivity, making transfusion extremely unsafe. - **IgM anti-HBc** confirms acute or recent infection with peak viral replication, posing maximum transmission risk to recipients. *Anti-HBsAg and anti-HBc (+)ve* - This profile indicates **resolved past infection** with developed immunity - the donor is **HBsAg negative** and protected by antibodies. - Such donors are considered **safe for transfusion** as they lack active virus and cannot transmit hepatitis B infection. *Anti-HBsAg +ve* - Positive **anti-HBsAg (HBsAb)** alone indicates immunity from vaccination or resolved infection without active virus. - These donors are **safe for transfusion** and may even provide protective antibodies to recipients. *Anti-HBc +ve* - Isolated **anti-HBc** positivity can indicate past exposure but requires further testing to determine HBsAg and anti-HBs status. - Many blood banks defer such donors due to potential **occult hepatitis B** infection, though not all represent active infection.

Q: Swine Flu pandemic in 2009 was caused due to which strain:

H1N1. ***H1N1*** - The 2009 **Swine Flu pandemic** was caused by a novel strain of **influenza A virus** designated as **H1N1**. - This virus was a reassortant strain with genes from **swine, avian, and human influenza viruses**. *H5N1* - **H5N1** is known as the **Avian Influenza** or **Bird Flu** and has caused outbreaks primarily in poultry and some human cases, but was not responsible for the 2009 pandemic. - While concerning due to its high pathogenicity in birds and potential for transmission to humans, it did not achieve **sustained human-to-human transmission** like H1N1. *H3N1* - **H3N1** is an influenza A subtype that is not commonly associated with **major human pandemics**. - While influenza viruses constantly mutate, **H3N1** did not cause the 2009 Swine Flu pandemic. *H7N1* - **H7N1** is another influenza A subtype that can cause outbreaks, primarily in **birds**. - It has not been identified as the cause of widespread human pandemics like the **2009 H1N1 event**.

Q: The presence of which of the following factors in viruses makes protective vaccines a possibility?

Protein coat. ***Protein coat*** - The **protein coat** (capsid) of viruses contains **antigenic proteins** that can be recognized by the host immune system. - Vaccines work by exposing the immune system to these viral proteins, stimulating the production of **antibodies** and memory cells for future protection. *Lipids* - While some viruses have a **lipid envelope**, lipids themselves are generally **poor antigens** and do not effectively stimulate a protective immune response on their own. - The immune response against enveloped viruses is primarily directed at the **glycoproteins** embedded within the lipid envelope, not the lipids themselves. *Enzymes* - Viruses contain various enzymes (e.g., reverse transcriptase, RNA polymerase) essential for their replication, but these are typically **intracellular targets**. - **Enzymes** are not usually present on the viral surface in an exposed manner that would consistently trigger a protective antibody response. *Polysaccharide* - **Polysaccharides** are common components of bacterial capsules but are generally **not significant components** of viral structure. - Viruses are primarily composed of nucleic acids and proteins, and the immune response to viruses rarely involves polysaccharides.

Q: The etiological agent for roseola infantum is:

Human Herpesvirus 6 (HHV-6). ***Human Herpesvirus 6 (HHV-6)*** - **HHV-6** is the primary cause of **roseola infantum**, also known as exanthem subitum. - This virus is responsible for the characteristic high fever followed by a rash often seen in infants and young children. *Epstein-Barr Virus (EBV)* - **EBV** is the causative agent of **infectious mononucleosis**, not roseola infantum. - While both are herpesviruses, their clinical presentations and target cell specificities differ significantly. *Cytomegalovirus (CMV)* - **CMV** is another herpesvirus that can cause a variety of symptoms, especially in immunocompromised individuals or congenitally. - It is not typically associated with the classic presentation of **roseola infantum**. *Adenovirus* - **Adenoviruses** are a common cause of respiratory infections, conjunctivitis, and gastroenteritis. - They do not cause **roseola infantum**, which is characterized by a specific fever-rash sequence.

Q: False about antigenic drift-

Causes pandemic. ***Causes pandemic*** - **Antigenic drift** involves minor changes in surface antigens that may lead to localized outbreaks or epidemics, usually not global pandemics. - **Antigenic shift**, which involves major changes, is typically responsible for causing pandemics. *Affected by previous antibodies* - Antigenic drift results in minor changes in **surface antigens**, allowing the virus to evade existing antibodies partially. - This means individuals with prior immunity or vaccination may still be susceptible to infection, though the disease might be milder. *Occurs due to mutation* - **Antigenic drift** is caused by point mutations in the genes encoding surface antigens like **hemagglutinin (HA)** and **neuraminidase (NA)**. - These mutations accumulate over time, leading to gradual changes in the viral antigens. *Occurs more frequently* - **Antigenic drift** occurs continually and frequently, particularly in influenza viruses, leading to the need for annual vaccine updates. - This continuous process of minor antigenic changes is why influenza vaccines are reformulated each year.

Q: Infective diarrhea is caused by all except -

Flavivirus. ***Flavivirus*** - **Flaviviruses** are primarily associated with arthropod-borne diseases like **dengue fever**, **Zika virus**, and **yellow fever**, which typically manifest with fever, rash, and hemorrhagic symptoms, rather than infective diarrhea. - While some gastrointestinal symptoms can occur with flaviviruses, infective diarrhea is not their primary or defining clinical presentation. *Enterovirus* - **Enteroviruses** can cause a variety of clinical syndromes, including **gastroenteritis**, with symptoms like diarrhea, nausea, and vomiting. - Examples include **Coxsackievirus** and **Echovirus**, which are well-known causes of viral diarrhea, especially in children. *Calicivirus* - **Caliciviruses**, particularly **Norovirus** (a type of calicivirus), are a leading cause of **epidemic non-bacterial gastroenteritis** in adults and children worldwide. - They commonly cause acute onset of vomiting, watery diarrhea, and abdominal cramps. *Rotavirus* - **Rotavirus** is a major cause of **severe, watery diarrhea** and vomiting in infants and young children globally. - It replicates in the small intestine, damaging enterocytes and leading to malabsorption and increased fluid secretion.

Q: All are caused by Parvo virus infection except:

Gianotti crosti syndrome. ***Gianotti crosti syndrome*** - This syndrome is typically caused by **Epstein-Barr virus**, **Hepatitis B virus**, coxsackievirus, echovirus, or enterovirus, NOT parvovirus B19. - It presents with a **papulovesicular rash** mainly on the face, buttocks, and extremities, often linked to distinct viral etiologies. *Aplastic crisis* - **Parvovirus B19** has a tropism for **erythroid progenitor cells**, causing their destruction and leading to temporary cessation of red blood cell production [1]. - This can precipitate an **aplastic crisis**, especially in individuals with underlying hemolytic anemias like sickle cell disease [1]. *Papular- purpuric gloves and socks syndrome (PPGSS)* - PPGSS is a rare but characteristic manifestation of **Parvovirus B19** infection, presenting with a sharply demarcated papular-purpuric rash. - The rash typically affects the **hands ("gloves") and feet ("socks")**, often accompanied by fever and oral erosions. *Erythema infectiosum* - Also known as **Fifth Disease**, this is a common benign childhood rash caused by **Parvovirus B19** [1]. - It presents with a characteristic **"slapped cheek" rash** on the face, followed by a lacy, reticular rash on the trunk and extremities [1].

Question 1

Ramsay Hunt syndrome is caused by:

Accepted Answer

Herpes zoster

Answer

Herpes simplex

Answer

Influenza

Answer

Adenovirus

Question 2

Which of the following markers in the blood is the most reliable indicator of recent hepatitis B infection?

Accepted Answer

IgM anti - HBc

Answer

anti-HBe

Answer

HBsAg

Answer

IgG anti - HBs

Question 3

Post transplant lymphoma most commonly associated with:

Accepted Answer

Epstein-Barr virus

Answer

HHV-6

Answer

Herpes simplex

Answer

Cytomegalo virus

Question 4

A blood donor is not considered for safe transfusion if he has:

Accepted Answer

HBsAg +ve and IgM anti-HBc +ve

Answer

Anti-HBc +ve

Answer

Anti-HBsAg +ve

Answer

Anti-HBsAg and anti-HBc (+)ve

Question 5

Swine Flu pandemic in 2009 was caused due to which strain:

Accepted Answer

H1N1

Answer

H5N1

Answer

H3N1

Answer

H7N1

Question 6

The presence of which of the following factors in
viruses makes protective vaccines a possibility?

Accepted Answer

Protein coat

Answer

Lipids

Answer

Enzymes

Answer

Polysaccharide

Question 7

The etiological agent for roseola infantum is:

Accepted Answer

Human Herpesvirus 6 (HHV-6)

Answer

Epstein-Barr Virus (EBV)

Answer

Cytomegalovirus (CMV)

Answer

Adenovirus

Question 8

False about antigenic drift-

Accepted Answer

Causes pandemic

Answer

Affected by previous antibodies

Answer

Occurs due to mutation

Answer

Occurs more frequently

Question 9

Infective diarrhea is caused by all except -

Accepted Answer

Flavivirus

Answer

Enterovirus

Answer

Calicivirus

Answer

Rotavirus

Question 10

All are caused by Parvo virus infection except:

Accepted Answer

Gianotti crosti syndrome

Answer

Aplastic crisis

Answer

Papular- purpuric gloves and socks syndrome (PPGSS)

Answer

Erythema infectiosum

Virology — MCQs

Virology — MCQs

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