Virology Practice Questions

Q: Which of the following statements about Prions is true:

They are infectious proteins. ***They are infectious proteins*** - Prions are uniquely characterized as **infectious proteinaceous particles** that lack nucleic acids. - Their mechanism of pathogenicity involves inducing conformational changes in normal host proteins, leading to disease. *They can be cultured in cell free media* - Prions cannot be cultured in cell-free media because they are **not living organisms** and require host cells to propagate by converting normal proteins. - Their replication depends on the presence of the **normal prion protein (PrPC)** in the host. *They have rich nuclear material* - Prions are fundamentally **devoid of nucleic acids** (DNA or RNA), which is a defining characteristic distinguishing them from viruses, bacteria, and other microorganisms. - Their infectious nature is solely based on their **aberrant protein structure**. *They are made up of bacteria and virus* - Prions are distinct biological entities that are **neither bacteria nor viruses**; they are misfolded proteins. - They are much simpler in structure than even the smallest viruses, lacking the complex genetic material and cellular machinery found in bacteria and viruses.

Q: LMP 1 gene plays a role in oncogenesis induced by

Epstein Barr virus. ***Epstein Barr virus*** - The **LMP1 (Latent Membrane Protein 1)** gene is a key **oncogene** encoded by the **Epstein-Barr virus (EBV)**. - LMP1 acts as a **constitutively active receptor**, mimicking CD40 and leading to the activation of several cellular signaling pathways (**NF-κB, JNK/p38, PI3K/Akt**) crucial for cell proliferation, survival, and differentiation. *Hepatitis B virus* - **Hepatitis B virus (HBV)** is associated with **hepatocellular carcinoma (HCC)**, but its oncogenic mechanisms primarily involve the **HBx protein**, which deregulates cell cycles and impacts host gene expression. - HBV does not encode an LMP1 equivalent; its oncogenesis is linked to chronic inflammation, hepatocyte regeneration, and integration of viral DNA. *Human T cell leukemia virus type 1* - **Human T-cell leukemia virus type 1 (HTLV-1)** is linked to **Adult T-cell Leukemia/Lymphoma (ATL)**, with its primary oncogene being **Tax**. - **Tax protein** activates NF-κB and other pro-proliferative pathways, but HTLV-1 does not have an LMP1 gene. *Human papilloma virus* - **Human papillomavirus (HPV)** is responsible for cervical and other anogenital cancers, with major oncogenes being **E6 and E7**. - **E6 targets p53** for degradation, and **E7 inactivates Rb**, leading to uncontrolled cell division; HPV does not encode an LMP1 gene.

Q: Which of the following is the prototype arboviral disease?

Yellow fever. ***Yellow fever*** - Yellow fever is historically and medically significant as the **first human disease** identified as arboviral. - It is transmitted by **Aedes aegypti mosquitoes** and is caused by an RNA virus of the genus **Flavivirus**. *Trench fever* - Trench fever is caused by the bacterium **Bartonella quintana**, not a virus. - It is transmitted by the **human body louse** (Pediculus humanus corporis), making it a rickettsial disease, not arboviral. *Epidemic typhus* - Epidemic typhus is caused by the bacterium **Rickettsia prowazekii** and is primarily transmitted by the **human body louse**. - It is a **rickettsial disease**, not an arboviral disease, which involves arthropod vectors like mosquitoes or ticks. *Japanese encephalitis* - While Japanese encephalitis is an important arboviral disease transmitted by **Culex mosquitoes**, it was identified much later than yellow fever. - It is a severe viral infection of the brain, but **yellow fever holds the distinction** of being the prototype.

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: 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: 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: Herpangina is caused by the virus -

Group A Coxsackie. ***Group A Coxsackie*** - Herpangina is a common viral illness characterized by small, painful ulcers on the **soft palate** and tonsillar pillars, predominantly caused by various serotypes of **Coxsackievirus group A**, particularly A1-A10, A16, and A22. - This **enterovirus** infection is highly contagious and often seen in infants and young children, especially during summer and fall. *Group B Coxsackie* - **Group B Coxsackieviruses** are primarily associated with diseases like **pleurodynia** (**Bornholm disease**), myocarditis, and pericarditis, rather than herpangina. - While both Group A and B Coxsackieviruses are enteroviruses, their typical clinical manifestations differ significantly. *Adenovirus* - **Adenoviruses** are known to cause a range of illnesses, including respiratory infections (**pharyngitis**, pneumonia), conjunctivitis, and gastroenteritis. - They are not typically implicated in the etiology of herpangina, which is characterized by specific oral lesions. *Measles* - **Measles virus** (a paramyxovirus) causes measles, a highly contagious systemic illness characterized by a generalized maculopapular rash, cough, coryza, and conjunctivitis, along with **Koplik spots** in the mouth. - Measles does not cause the vesicular and ulcerative lesions seen in herpangina; Koplik spots are distinct enanthem findings.

Q: Hand-foot-mouth disease is caused by:

Coxsackie-A virus. ***Coxsackie-A virus*** - Hand-foot-mouth disease (HFMD) is most commonly caused by **Coxsackievirus A16** within the species **Human enterovirus A**. - Other **Coxsackievirus A serotypes** can also cause HFMD, particularly **A6, A10**, and **Enterovirus A71**. *Coxsackie-B virus* - **Coxsackievirus B** is known to cause a range of illnesses, including **myocarditis**, **pleurodynia (Bornholm disease)**, and **pericarditis**. - While it belongs to the same genus (Enterovirus), it is not the typical causative agent of HFMD. *EBV* - **Epstein-Barr Virus (EBV)** is a herpesvirus that causes **infectious mononucleosis**, **Burkitt's lymphoma**, and **nasopharyngeal carcinoma**. - It is transmitted through saliva and is **not associated with HFMD**. *CMV* - **Cytomegalovirus (CMV)** is a common virus that can cause a wide spectrum of diseases, especially in immunocompromised individuals and congenitally. - It is known for causing mononucleosis-like syndrome, congenital infections, and retinitis, but it is **not associated with HFMD**.

Question 1

Which of the following statements about Prions is true:

Accepted Answer

They are infectious proteins

Answer

They can be cultured in cell free media

Answer

They have rich nuclear material

Answer

They are made up of bacteria and virus

Question 2

LMP 1 gene plays a role in oncogenesis induced by

Accepted Answer

Epstein Barr virus

Answer

Hepatitis B virus

Answer

Human T cell leukemia virus type 1

Answer

Human papilloma virus

Question 3

Which of the following is the prototype arboviral disease?

Accepted Answer

Yellow fever

Answer

Trench fever

Answer

Epidemic typhus

Answer

Japanese encephalitis

Question 4

Ramsay Hunt syndrome is caused by:

Accepted Answer

Herpes zoster

Answer

Herpes simplex

Answer

Influenza

Answer

Adenovirus

Question 5

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 6

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

Accepted Answer

H1N1

Answer

H5N1

Answer

H3N1

Answer

H7N1

Question 7

False about antigenic drift-

Accepted Answer

Causes pandemic

Answer

Affected by previous antibodies

Answer

Occurs due to mutation

Answer

Occurs more frequently

Question 8

Infective diarrhea is caused by all except -

Accepted Answer

Flavivirus

Answer

Enterovirus

Answer

Calicivirus

Answer

Rotavirus

Question 9

Herpangina is caused by the virus -

Accepted Answer

Group A Coxsackie

Answer

Group B Coxsackie

Answer

Adenovirus

Answer

Measles

Question 10

Hand-foot-mouth disease is caused by:

Accepted Answer

Coxsackie-A virus

Answer

Coxsackie-B virus

Answer

EBV

Answer

CMV

Virology — MCQs

Virology — MCQs

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