Virology Practice Questions

Q: All of the following are true statements for Arbovirus EXCEPT:

Kyasanur Forest Disease is transmitted by mites. ***Kyasanur Forest Disease is transmitted by mites*** - This statement is **false**. Kyasanur Forest Disease (KFD) is transmitted by **ticks**, specifically the *Haemaphysalis spinigera* tick, not mites. - KFD is a **tick-borne viral hemorrhagic fever** endemic to certain regions of India, caused by a flavivirus. *West nile fever is transmitted by Culex mosquito* - This statement is **true**. **West Nile virus** is primarily transmitted to humans through the bite of infected mosquitos, mainly species of **Culex**. - The virus circulates naturally between mosquitos and **birds**, with humans being incidental hosts. *Chikungunya fever is transmitted by Aedes mosquito* - This statement is **true**. **Chikungunya virus** is transmitted to humans through the bites of infected female mosquitos, primarily **Aedes aegypti** and **Aedes albopictus**. - These mosquitos are also vectors for other diseases such as dengue and Zika. *Japanese encephalitis is caused by group B Arbovirus (Flavivirus)* - This statement is **true**. Japanese encephalitis is caused by the **Japanese encephalitis virus (JEV)**, which belongs to the **Flaviviridae family**, often referred to as group B Arboviruses. - Most human infections are asymptomatic, but severe cases can lead to **encephalitis** with high mortality.

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: Multinucleated giant cells are seen in smear from the lesions of:

Herpes simplex virus. ***Herpes simplex virus*** - **Multinucleated giant cells** with intranuclear inclusions are characteristic findings in Tzanck smears from **herpes simplex virus (HSV)** lesions [1]. - This cellular morphology results from the fusion of infected cells, a cytopathic effect of the virus [1]. *HIV* - HIV primarily infects **CD4+ T-cells** and macrophages, leading to immunosuppression, but does not typically cause multinucleated giant cells in skin lesion smears. - While HIV can be associated with various opportunistic skin lesions, the hallmark cytological finding from the primary infection itself is not multinucleated giant cells. *Poliovirus* - Poliovirus is an **enterovirus** that primarily affects the central nervous system, causing paralytic disease. - It does not cause skin lesions characterized by multinucleated giant cells. *Rabiesvirus* - Rabiesvirus is a **neurotropic virus** that causes acute encephalitis in mammals. - The characteristic pathological finding in rabies is the presence of **Negri bodies** (intracytoplasmic inclusions) in neurons, not multinucleated giant cells in skin smears. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 365-366.

Q: A young pregnant woman presents with fulminant hepatic failure. The most likely aetiological agent is -

Hepatitis E virus. ***Hepatitis E virus*** - **Hepatitis E virus (HEV)** infection is known to cause **fulminant hepatic failure** in pregnant women, leading to high maternal and fetal mortality rates. - The severity of HEV infection is significantly increased during pregnancy, particularly in the third trimester. *Hepatitis A virus* - **Hepatitis A virus (HAV)** typically causes an acute, self-limiting hepatitis and rarely leads to fulminant hepatic failure, even in pregnant women. - While HAV can impact pregnancy outcomes, the incidence of fulminant failure is much lower compared to HEV. *Hepatitis B virus* - **Hepatitis B virus (HBV)** infection can cause chronic hepatitis and cirrhosis, but acute HBV infection rarely results in fulminant hepatic failure during pregnancy. - The primary concern with HBV in pregnancy is vertical transmission to the neonate. *Hepatitis C virus* - **Hepatitis C virus (HCV)** infection often leads to chronic hepatitis and can progress to cirrhosis and hepatocellular carcinoma over decades. - Acute HCV infection rarely causes fulminant hepatic failure, and its impact on pregnancy is usually less severe in terms of acute liver failure compared to HEV.

Q: Exanthema subitum is caused by -

HHV. ***HHV*** - **Exanthema subitum**, also known as **roseola infantum**, is most commonly caused by **Human Herpesvirus 6 (HHV-6)** and sometimes **Human Herpesvirus 7 (HHV-7)**. - It is characterized by high fever followed by a **maculopapular rash** once the fever subsides. *HIV* - **Human Immunodeficiency Virus (HIV)** causes **Acquired Immunodeficiency Syndrome (AIDS)**, leading to a weakened immune system. - While HIV can cause various skin manifestations, **exanthema subitum** is not one of its primary or characteristic presentations. *HCV* - **Hepatitis C Virus (HCV)** primarily causes **hepatitis**, infecting the liver and potentially leading to chronic liver disease. - HCV is not known to cause **exanthema subitum** or similar childhood exanthems. *HPV* - **Human Papillomavirus (HPV)** is responsible for **warts** and certain **cancers**, particularly cervical cancer. - HPV does not cause **exanthema subitum**; its manifestations are typically localized to skin and mucous membranes as proliferative lesions.

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: True about prions are all except -

Cannot be inherited. ***Cannot be inherited*** - This statement is **false** because prion diseases, such as **familial Creutzfeldt-Jakob disease (fCJD)** and **Gerstmann-Sträussler-Scheinker syndrome (GSS)**, can indeed be inherited due to mutations in the **PRNP gene**. - These genetic mutations lead to the production of an abnormal prion protein, PrPSc, which can then misfold and cause disease. *Can be transmitted by corneal transplant* - **Prion diseases** can be transmitted through corneal transplants, as the **cornea** can harbor infectious prions. - This route of transmission is an example of **iatrogenic CJD**, highlighting the importance of cautious donor screening. *Can occur sporadically* - The most common form of human prion disease, **sporadic Creutzfeldt-Jakob disease (sCJD)**, occurs without any known genetic mutation or environmental exposure. - This accounts for about 85-90% of all CJD cases, where the initial misfolding of the prion protein is spontaneous. *Can be transmitted by human growth hormone preparation* - **Iatrogenic Creutzfeldt-Jakob disease (iCJD)** has been linked to the use of human growth hormone preparations derived from cadaveric pituitary glands. - Before the advent of recombinant human growth hormone, these preparations could transmit prions from infected donors.

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.

Question 1

All of the following are true statements for Arbovirus EXCEPT:

Accepted Answer

Kyasanur Forest Disease is transmitted by mites

Answer

West nile fever is transmitted by Culex mosquito

Answer

Chikungunya fever is transmitted by Aedes mosquito

Answer

Japanese encephalitis is caused by group B Arbovirus (Flavivirus)

Question 2

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 3

Multinucleated giant cells are seen in smear from the lesions of:

Accepted Answer

Herpes simplex virus

Answer

HIV

Answer

Poliovirus

Answer

Rabiesvirus

Question 4

A young pregnant woman presents with fulminant hepatic failure. The most likely aetiological agent is -

Accepted Answer

Hepatitis E virus

Answer

Hepatitis A virus

Answer

Hepatitis B virus

Answer

Hepatitis C virus

Question 5

Exanthema subitum is caused by -

Accepted Answer

HHV

Answer

HIV

Answer

HCV

Answer

HPV

Question 6

Which of the following is the prototype arboviral disease?

Accepted Answer

Yellow fever

Answer

Trench fever

Answer

Epidemic typhus

Answer

Japanese encephalitis

Question 7

True about prions are all except -

Accepted Answer

Cannot be inherited

Answer

Can be transmitted by corneal transplant

Answer

Can occur sporadically

Answer

Can be transmitted by human growth hormone preparation

Question 8

Ramsay Hunt syndrome is caused by:

Accepted Answer

Herpes zoster

Answer

Herpes simplex

Answer

Influenza

Answer

Adenovirus

Question 9

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 10

Post transplant lymphoma most commonly associated with:

Accepted Answer

Epstein-Barr virus

Answer

HHV-6

Answer

Herpes simplex

Answer

Cytomegalo virus

Virology — MCQs

Virology — MCQs

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