Virology Practice Questions

Q: A 19-year-old woman presents to the emergency department complaining of lesions on her vulva. They have been present for several months but are now beginning to interfere with intercourse. Which viral subtypes are responsible for most cases of this disease? (Recent Neet Pattern 2016-17)

Types 6 and 11. ***Types 6 and 11*** - Human Papillomavirus (HPV) **types 6 and 11** are responsible for approximately 90% of all cases of **genital warts (condyloma acuminata)**. - These types are considered low-risk HPV as they rarely lead to cancer but can cause significant discomfort and interfere with sexual activity due to their physical presence. *Types 6 and 18* - While **HPV type 6** is a common cause of genital warts, **HPV type 18** is a high-risk type primarily associated with **cervical cancer**, not typically with vulvar warts. - Combining a low-risk and a high-risk type in this manner does not accurately represent the primary cause of condyloma acuminata. *Types 11 and 16* - **HPV type 11** causes genital warts, but **HPV type 16** is a **high-risk HPV** type strongly associated with cervical and other anogenital cancers. - While both can cause lesions, type 16 is not a primary cause of benign genital warts; it's a major cause of malignancies. *Types 11 and 31* - **HPV type 11** is linked to genital warts, but **HPV type 31** is another **high-risk HPV** type associated with cervical cancer, not typically with benign vulvar warts. - Similar to the previous option, this combination incorrectly mixes a benign wart-causing type with a high-risk oncogenic type when addressing the cause of vulvar lesions.

Q: Patients who have undergone S.O.T (Solid organ transplant) are highly susceptible to development of Kaposi sarcoma. The image shows features consistent with Kaposi Sarcoma etiologically linked with which of the following?

KSHV. **KSHV** - **Kaposi's Sarcoma-associated Herpesvirus (KSHV)**, also known as **Human Herpesvirus 8 (HHV-8)**, is the definitive etiological agent for Kaposi's sarcoma. - Immunosuppression, such as that experienced by solid organ transplant recipients, reactivates latent KSHV infection, leading to the proliferation of spindle cells and the characteristic vascular lesions of Kaposi's sarcoma. *CMV* - **Cytomegalovirus (CMV)** is a common opportunistic infection in transplant recipients, causing a variety of clinical syndromes, but it is **not directly linked** to the causation of Kaposi's sarcoma. - While CMV can contribute to general immunosuppression in transplant patients, it does not specifically induce Kaposi's sarcoma lesions. *EBV* - **Epstein-Barr Virus (EBV)** is strongly associated with **post-transplant lymphoproliferative disorder (PTLD)** in solid organ transplant recipients, not Kaposi's sarcoma. - EBV infection can lead to lymphoid malignancies due to immunosuppression, a different pathology from the angioproliferative nature of Kaposi's sarcoma. *HHV6* - **Human Herpesvirus 6 (HHV-6)** is known to cause **roseola infantum** in children and can be a significant pathogen in immunocompromised patients, potentially causing encephalitis or pneumonitis in transplant recipients. - HHV-6 is **not associated with Kaposi's sarcoma**; its oncogenic potential is less clear and not linked to this specific malignancy.

Q: Which causative organism is responsible for this disease?

Coxsackie virus. ***Coxsackie virus*** - The images show typical lesions of **Hand-Foot-and-Mouth Disease (HFMD)**, characterized by **oral ulcers** (herpangina) and a vesiculopapular rash on the **palms, soles**, and sometimes buttocks. - HFMD is most commonly caused by **Coxsackie virus A16** and other enteroviruses. *Human herpes virus 7* - This virus is primarily associated with **roseola infantum (exanthem subitum)**, characterized by rapid onset of high fever followed by a rash after the fever breaks. - The rash is typically maculopapular and found on the trunk, not primarily on the palms, soles, and mouth as seen in the image. *Pox virus* - Poxviruses cause diseases like **smallpox** and **molluscum contagiosum**, which present with different types of lesions. - **Smallpox** lesions are deep-seated, painful pustules that evolve synchronously, and **molluscum contagiosum** manifests as pearly, umbilicated papules, neither matching the depicted oral and acral rash. *Molluscum contagiosum virus* - Molluscum contagiosum virus (MCV) is a type of **poxvirus** that causes the skin infection **molluscum contagiosum**. - Its characteristic lesions are **dome-shaped, pearly papules with central umbilication**, which are not consistent with the vesicular lesions and oral ulcers shown in the image.

Q: Monkeypox, a viral zoonotic disease, is caused by

a double-stranded DNA virus. ***a double-stranded DNA virus*** - Monkeypox is caused by the **monkeypox virus (MPXV)**, which belongs to the **Poxviridae family**. - Viruses in the Poxviridae family are known for having a **double-stranded DNA genome**. *a single-stranded RNA virus* - Many common viruses, such as **SARS-CoV-2 (COVID-19)**, **influenza virus**, and **HIV**, are single-stranded RNA viruses. - This genomic structure is fundamentally different from that of the monkeypox virus. *a single-stranded DNA virus* - Viruses like **Parvovirus B19** are single-stranded DNA viruses. - This type of genome is less common in human pathogens compared to double-stranded DNA or RNA viruses. *a double-stranded RNA virus* - Viruses such as **rotaviruses**, which cause gastroenteritis, are double-stranded RNA viruses. - While also double-stranded, its RNA nature distinguishes it from the DNA genome of monkeypox virus.

Q: Consider the following statements regarding dengue virus : 1. It has four distinct serotypes. 2. Infection with any one serotype confers lifelong immunity for that virus serotype. 3. Secondary infection with dengue serotype 2 leads to severe form of dengue. Which of the statements given above are correct?

1 and 2 only. ***1 and 2 only*** - Dengue virus indeed has **four distinct serotypes (DENV-1, DENV-2, DENV-3, DENV-4)**, explaining different epidemiological patterns and reinfections. - Infection with one serotype provides **lifelong homologous immunity** against that specific serotype, meaning a person will not get sick again from the same serotype. *2 and 3 only* - While statement 2 is correct, statement 3 is not universally true, as severe dengue can occur with secondary infection of any serotype, although **DENV-2** and **DENV-3** are more frequently implicated. - This option incorrectly excludes the fact that dengue has four distinct serotypes, which is a fundamental aspect of its biology and epidemiology. *1 and 3 only* - While statement 1 is correct, statement 3 is a simplification; severe dengue in secondary infections is due to **antibody-dependent enhancement (ADE)**, which can happen with various heterologous serotypes, not exclusively DENV-2. - This option incorrectly implies that infection with one serotype does not confer lifelong immunity to that specific serotype, which is a key characteristic of dengue immunity. *1, 2 and 3* - This option is incorrect because statement 3, while partially true, is too absolute. Severe dengue can be linked to **DENV-2** or **DENV-3** in secondary infections but isn't exclusive to DENV-2. - The risk of severe dengue is due to a **secondary infection** with a **heterologous serotype**, not specifically serotype 2, though DENV-2 often causes more severe illness in secondary infections.

Q: Which one of the following is a characteristic of Human Immunodeficiency Virus (HIV)?

It is easily killed by heat. ***It is easily killed by heat*** - HIV is an **enveloped RNA virus** that is highly susceptible to inactivation by heat, typically at **56-60°C for 30 minutes**. - This characteristic is important for **sterilization of medical equipment** and understanding the environmental stability of the virus. - Heat lability is a key feature of enveloped viruses due to disruption of the lipid envelope. *It is easily killed by T4 lymphocytes* - **CD4+ T lymphocytes (T4 cells)** are the primary **target cells** for HIV, meaning the virus infects and ultimately destroys them. - HIV evades the immune system and **replicates within** these cells, leading to progressive immunodeficiency. - The virus is NOT killed by T4 cells; rather, it uses them for replication and destroys them in the process. *It cannot cross blood brain barrier* - HIV is known to **cross the blood-brain barrier (BBB)** early in infection, leading to neurological complications. - Presence of HIV in the central nervous system contributes to conditions like **HIV-associated neurocognitive disorder (HAND)** and HIV encephalopathy. - Infected macrophages and monocytes serve as "Trojan horses" carrying the virus across the BBB. *It is resistant to acetone* - HIV is an **enveloped virus**, and its lipid envelope is **susceptible to dissolution by lipid solvents** such as acetone, alcohol, and detergents. - This property makes HIV vulnerable to inactivation by common disinfectants and explains its poor environmental stability. - The envelope is essential for viral entry, so its disruption renders the virus non-infectious.

Q: Consider the following hepatitis viruses : 1. Hepatitis A 2. Hepatitis B 3. Hepatitis C 4. Hepatitis E Which of the above can be commonly transmitted through the faeco-oral route?

1 and 4. ***Correct Answer: 1 and 4*** * Hepatitis A virus (**HAV**) and Hepatitis E virus (**HEV**) are primarily transmitted via the **faecal-oral route**, typically through contaminated food or water. * These infections are often acute and self-limiting, causing symptoms like jaundice, fatigue, and nausea. * HAV is more common in areas with poor sanitation, while HEV often causes waterborne outbreaks, particularly in developing countries. *Incorrect: 1 and 3 only* * While **Hepatitis A** is transmitted faecal-orally, **Hepatitis C** is primarily transmitted through blood-to-blood contact, such as sharing needles or contaminated blood transfusions. * Hepatitis C rarely, if ever, spreads via the faecal-oral route. *Incorrect: 2, 3 and 4* * **Hepatitis B** and **Hepatitis C** are transmitted through parenteral routes (e.g., blood, sexual contact, perinatal transmission), not via the faecal-oral route. * Although Hepatitis E is faecal-orally transmitted, including B and C makes this option incorrect. *Incorrect: 1, 2 and 3* * **Hepatitis A** is transmitted faecal-orally, but **Hepatitis B** and **Hepatitis C** are primarily transmitted through blood and body fluids (parenteral route). * This option incorrectly includes Hepatitis B and C in the faecal-oral transmission category.

Q: Which is the most specific causative agent of Rabies?

Rabies lyssavirus (RABV). ***Rabies lyssavirus (RABV)*** - **Rabies lyssavirus (RABV)**, also known as the **classical rabies virus** or **genotype 1**, is the primary and most specific causative agent of rabies in humans and animals worldwide. - While other lyssaviruses (Lagos bat, Mokola, Duvenhage, Australian bat lyssavirus, etc.) can cause rabies-like illnesses, **RABV is overwhelmingly responsible** for the vast majority of documented rabies cases globally. - It is transmitted primarily through dog bites in endemic regions and causes acute, progressive, fatal encephalomyelitis. *Lagos bat lyssavirus (LBV)* - **Lagos bat lyssavirus (genotype 2)** is a distinct species within the *Lyssavirus* genus that can cause rabies-like disease, primarily in bats in Africa. - It is **rarely associated with human rabies** and is not the most common or specific cause globally. *Mokola lyssavirus (MOKV)* - **Mokola lyssavirus (genotype 3)** is another lyssavirus found in Africa, isolated from shrews, rodents, and rarely humans. - Although it can cause a fatal encephalomyelitis similar to rabies, human cases are **extremely rare**, and it is not considered the typical rabies virus. *Duvenhage lyssavirus (DUVV)* - **Duvenhage lyssavirus (genotype 4)** is a bat-associated lyssavirus found in Africa, first isolated in 1970. - Human cases are **exceptionally rare** (only a few documented cases), and it is not the primary causative agent of classic rabies.

Q: A patient presents with genital grouped vesicles, as shown in the image. What is the most likely causative organism?

Herpes simplex virus. ***Herpes*** - The image shows **grouped vesicles** on an erythematous base, which is the classic presentation of **genital herpes** caused by the **Herpes simplex virus (HSV)**. - These lesions are typically painful and can recur, indicating a viral etiology. *Haemophilus* - *Haemophilus ducreyi* causes **chancroid**, which presents as **painful genital ulcers** with ragged borders and often associated with inguinal lymphadenopathy. - It does not present as grouped vesicles. *Klebsiella* - *Klebsiella granulomatis* causes **donovanosis (granuloma inguinale)**, characterized by progressive, **painless ulcerative lesions** that are highly vascular and bleed easily. - This organism does not cause vesicular lesions. *Treponema* - *Treponema pallidum* causes **syphilis**, which in its primary stage presents as a **painless chancre** (a solitary ulcer) or in secondary stage as a diffuse rash. - It does not cause grouped vesicles.

Q: How does the presence of STIs increase the risk of HIV transmission?

By disrupting mucosal barriers and causing inflammation. ***By disrupting mucosal barriers and causing inflammation*** - Many STIs, particularly those causing **genital ulcers** (e.g., herpes, syphilis) or inflammation (e.g., gonorrhea, chlamydia), disrupt the integrity of the **mucosal barriers** in the genital tract. This provides easier entry points for HIV, as the epithelial cells act as a physical barrier. - The inflammatory response triggered by STIs leads to the recruitment of **HIV target cells** (CD4+ T-cells and macrophages) to the site of infection, increasing their concentration in genital secretions and making them more accessible to HIV during exposure. *By direct enhancement of HIV replication* - While some inflammatory cytokines can enhance HIV replication in vitro, this is not the primary or most significant mechanism by which STIs increase transmission risk in vivo. - The main mechanism involves increased exposure to target cells and disrupted barriers rather than direct viral replication enhancement. *By increasing CD4 receptor density on target cells* - STIs do not demonstrably increase the density of **CD4 receptors** on the surface of individual target cells. - Instead, they increase the *number* of available CD4+ target cells at the site of exposure due to inflammation and immune cell infiltration. *By inhibiting cytotoxic T-cell responses* - Some STIs might have localized immunosuppressive effects, but their primary contribution to increased HIV transmission risk is not through a generalized inhibition of **cytotoxic T-lymphocyte (CTL) responses**. - The key mechanisms are related to physical barriers and increased target cell availability, not suppression of the systemic antiviral immune response.

Question 1

A 19-year-old woman presents to the emergency department complaining of lesions on her vulva. They have been present for several months but are now beginning to interfere with intercourse. Which viral subtypes are responsible for most cases of this disease? (Recent Neet Pattern 2016-17)

Accepted Answer

Types 6 and 11

Answer

Types 6 and 18

Answer

Types 11 and 16

Answer

Types 11 and 31

Question 2

Patients who have undergone S.O.T (Solid organ transplant) are highly susceptible to development of Kaposi sarcoma. The image shows features consistent with Kaposi Sarcoma etiologically linked with which of the following?

Accepted Answer

KSHV

Answer

CMV

Answer

EBV

Answer

HHV6

Question 3

Which causative organism is responsible for this disease?

Accepted Answer

Coxsackie virus

Answer

Human herpes virus 7

Answer

Pox virus

Answer

Molluscum contagiosum virus

Question 4

Monkeypox, a viral zoonotic disease, is caused by

Accepted Answer

a double-stranded DNA virus

Answer

a single-stranded RNA virus

Answer

a single-stranded DNA virus

Answer

a double-stranded RNA virus

Question 5

Consider the following statements regarding dengue virus :

1. It has four distinct serotypes.
2. Infection with any one serotype confers lifelong immunity for that virus serotype.
3. Secondary infection with dengue serotype 2 leads to severe form of dengue. Which of the statements given above are correct?

Accepted Answer

1 and 2 only

Answer

2 and 3 only

Answer

1 and 3 only

Answer

1, 2 and 3

Question 6

Which one of the following is a characteristic of Human Immunodeficiency Virus (HIV)?

Accepted Answer

It is easily killed by heat

Answer

It is easily killed by T4 lymphocytes

Answer

It cannot cross blood brain barrier

Answer

It is resistant to acetone

Question 7

Consider the following hepatitis viruses :
1. Hepatitis A
2. Hepatitis B
3. Hepatitis C
4. Hepatitis E
Which of the above can be commonly transmitted through the faeco-oral route?

Accepted Answer

1 and 4

Answer

1 and 3 only

Answer

2, 3 and 4

Answer

1, 2 and 3

Question 8

Which is the most specific causative agent of Rabies?

Accepted Answer

Rabies lyssavirus (RABV)

Answer

Lagos bat lyssavirus (LBV)

Answer

Mokola lyssavirus (MOKV)

Answer

Duvenhage lyssavirus (DUVV)

Question 9

A patient presents with genital grouped vesicles, as shown in the image. What is the most likely causative organism?

Accepted Answer

Herpes simplex virus

Answer

Haemophilus

Answer

Klebsiella

Answer

Treponema

Question 10

How does the presence of STIs increase the risk of HIV transmission?

Accepted Answer

By disrupting mucosal barriers and causing inflammation

Answer

By direct enhancement of HIV replication

Answer

By increasing CD4 receptor density on target cells

Answer

By inhibiting cytotoxic T-cell responses

Virology — MCQs

Virology — MCQs

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