Virology Practice Questions

Q: Which pox virus does Variola belong to?

Orthopoxvirus. ***Orthopoxvirus*** - **Variola virus**, the causative agent of **smallpox**, is a member of the **Orthopoxvirus genus**. - Other notable members of this genus include **vaccinia virus** (used in smallpox vaccine) and **monkeypox virus**. *Parapoxvirus* - This genus includes viruses such as **Orf virus**, which causes contagious pustular dermatitis in sheep and goats, occasionally transmitted to humans. - Parapoxviruses typically cause localized skin lesions and are not associated with **smallpox**. *Yatapox virus* - The **Yatapox virus genus** includes the **Tanapox virus** and **Yabapox virus**, which primarily affect monkeys but can cause mild, self-limiting skin lesions in humans. - They are distinct from the **Variola virus** and do not cause smallpox. *Molluscipox virus* - This genus contains **Molluscum contagiosum virus**, which causes **molluscum contagiosum**, a common skin infection characterized by small, flesh-colored, dome-shaped papules. - It is genetically and clinically distinct from **Variola virus**.

Q: Which virus is implicated in Burkitt's lymphoma?

Epstein-Barr virus. ***Epstein-Barr virus*** - The **Epstein-Barr virus (EBV)** is strongly associated with Burkitt's lymphoma, particularly the endemic form found in equatorial Africa. - EBV infection leads to **B-cell proliferation** and can promote oncogenesis in the presence of other co-factors, such as a c-MYC translocation. *Arbovirus* - **Arboviruses** are transmitted by arthropod vectors (e.g., mosquitoes, ticks) and cause diseases like dengue fever and Zika virus, not Burkitt's lymphoma. - They primarily cause **viremia** and symptoms related to central nervous system involvement or hemorrhagic fever. *Picornavirus* - **Picornaviruses** are a family of small, non-enveloped RNA viruses that include enteroviruses (e.g., poliovirus, coxsackievirus) and rhinoviruses. - They typically cause diseases like **poliomyelitis**, **common cold**, and **gastroenteritis**, not lymphoid malignancies. *Coxsackievirus* - **Coxsackieviruses** are a genus of enteroviruses within the Picornaviridae family and are known to cause diseases such as hand-foot-and-mouth disease, myocarditis, and aseptic meningitis. - There is **no established link** between Coxsackievirus infection and Burkitt's lymphoma.

Q: All of the following are true about the papovavirus except:

They are RNA viruses.. ***They are RNA viruses*** - Papovaviruses, including **polyomaviruses** and **papillomaviruses**, are **double-stranded DNA viruses**, not RNA viruses. - Their genome is composed of **DNA**, which is a key characteristic distinguishing them from RNA viruses. *Papovaviruses can produce papillomas in humans* - **Human Papillomaviruses (HPVs)**, a subgroup of papovaviruses, are well-known for causing **papillomas** (warts) in humans. - Certain high-risk HPVs are also associated with **cervical cancer** and other anogenital cancers. *SV - 40 is oncogenic* - **Simian Virus 40 (SV40)**, a type of polyomavirus (which falls under the broader papovavirus group), is indeed **oncogenic** in certain animal models. - It has been studied extensively for its ability to induce tumors and transform cells in vitro through its **tumor antigens**. *They are non-enveloped icosahedral viruses* - Both **polyomaviruses** and **papillomaviruses** share the structural characteristic of being **non-enveloped**. - They also possess an **icosahedral capsid** symmetry, which encases their DNA genome.

Q: The EBV receptor located on the surface of B cells is?

CD21. ***CD21*** - CD21 acts as a receptor for **Epstein-Barr Virus (EBV)** on the surface of B cells, facilitating viral entry [1][2]. - It also plays a role in B cell activation and **signal transduction** upon antigen binding [1]. *CD22* - CD22 is a **negative regulatory** molecule that contributes to B cell function but does not serve as a receptor for EBV. - It primarily modulates the response to **B cell receptor (BCR)** signaling. *CD24* - CD24 is a **glycoprotein** involved in cell adhesion and does not act as a receptor for EBV on B cells. - It is not prominently associated with the functions related to viral entry or B cell activation. *CD23* - CD23 is a low-affinity IgE receptor involved in regulating **B cell activation**, but it is not the receptor for EBV. - Its main roles relate to **allergic responses** and not viral interactions. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 199-200. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 368-369.

Q: Which virus characteristically reactivates in a dermatomal distribution?

Herpes zoster. ***Herpes zoster (Correct Answer)*** - This virus, also known as **varicella-zoster virus (VZV)**, causes **chickenpox** during primary infection and remains latent in **sensory ganglia** (dorsal root ganglia). - Upon reactivation, it travels along the **sensory nerve** to the skin, producing a characteristic **vesicular rash in a dermatomal distribution**. - This dermatomal pattern is the hallmark clinical feature that distinguishes zoster reactivation. *Herpes simplex (Incorrect)* - **Herpes simplex virus (HSV)** typically causes **localized outbreaks** like cold sores (HSV-1) or genital herpes (HSV-2). - While it establishes latency in sensory ganglia, its reactivation pattern usually involves a **smaller, localized area** rather than a full dermatome. - Reactivation occurs at the same site repeatedly, not in a dermatomal distribution. *Influenza virus (Incorrect)* - This is a **respiratory virus** that causes acute systemic symptoms like fever, cough, and myalgia. - It does **not establish latency** in ganglia or any other tissue. - It causes no skin manifestations or dermatomal rashes; it primarily affects the **respiratory tract**. *Rotavirus (Incorrect)* - Rotavirus is a common cause of **gastroenteritis**, particularly in infants and young children. - It replicates in the **gastrointestinal tract** and causes severe diarrhea and vomiting. - It does **not establish latency** and has no skin manifestations or dermatomal distribution.

Q: Which of the following is an RNA oncogenic virus?

Human T-lymphotropic Virus (HTLV). ***Human T-lymphotropic Virus (HTLV)*** - **HTLV-1** is a well-established **RNA oncogenic virus** that causes Adult T-cell Leukemia/Lymphoma (ATLL). - It utilizes **reverse transcriptase** to convert its RNA genome into DNA, which then integrates into the host cell's genome, leading to malignant transformation. *Cytomegalovirus (CMV)* - CMV is a **DNA virus** and belongs to the Herpesviridae family. - While it can cause disease, it is not primarily classified as an **oncogenic virus**, although some studies suggest associations with certain cancers. *Hepatitis B Virus (HBV)* - HBV is a **DNA virus** that primarily causes acute and chronic hepatitis. - It is a major risk factor for **hepatocellular carcinoma (HCC)**, but it itself is a DNA virus, not an RNA virus. *Human Immunodeficiency Virus (HIV)* - HIV is an **RNA retrovirus**, but it is generally considered **non-oncogenic** in the direct sense. - While HIV-infected individuals have an increased risk of certain cancers (e.g., Kaposi's sarcoma, non-Hodgkin lymphoma), these are usually due to **immunosuppression** allowing co-infecting oncogenic viruses (like HHV-8 or EBV) to proliferate, rather than direct oncogenic action of HIV itself.

Q: Which of the following statements about Norwalk virus is false?

Cultivated in cell culture. ***Cultivated in cell culture*** - **Norwalk virus** (now known as **norovirus**) is notoriously difficult to cultivate in standard laboratory cell cultures, making research and vaccine development challenging. - Its inability to grow in vitro is a defining characteristic, differentiating it from many other common viruses. *Belongs to calciviridae* - This statement is **true**; Norwalk virus is the prototype and best-known member of the genus *Norovirus* within the family **Caliciviridae**. - **Caliciviridae** are a family of non-enveloped, positive-sense, single-stranded RNA viruses. *Causes gastroenteritis* - This statement is **true**; Norovirus is the leading cause of **acute gastroenteritis** worldwide, particularly in outbreaks in crowded settings such as cruise ships, hospitals, and schools. - It causes symptoms like **nausea, vomiting, diarrhea**, and abdominal cramps. *Is a RNA virus* - This statement is **true**; Norovirus has a **single-stranded, positive-sense RNA genome**. - Its RNA genome is essential for its replication cycle as it can directly serve as mRNA.

Q: Viroids are characterized by which of the following?

Small, circular single-stranded RNA. ***Small, circular single-stranded RNA*** - **Viroids** are infectious agents consisting solely of a short strand of **circular, single-stranded RNA** that is self-replicating. - They lack a protein coat, unlike viruses, and are primarily known to cause diseases in plants. *Naked pathogenic human viruses* - While viroids are **naked** (lacking a protein coat), they are not classified as **viruses** and typically do not infect **humans**. - Viroids are distinct from human-pathogenic viruses in their structure and host range. *Fragments of viruses* - Viroids are not **fragments of viruses** but are distinct infectious entities. - They are much smaller than viruses and have a simpler genetic structure, not derived from viral components. *DNA with protein coat* - Viroids do not contain **DNA**; their genetic material is exclusively **RNA**. - They also lack a **protein coat**, which distinguishes them from conventional viruses that possess both nucleic acid and protein components.

Q: Which virus is associated with Hodgkin's lymphoma?

Epstein-Barr virus (EBV). ***EBV*** - **Epstein-Barr Virus (EBV)** is strongly associated with the development of Hodgkin's lymphoma, particularly in patients presenting with mixed cellularity [1]. - EBV is found in the **Reed-Sternberg cells**, a characteristic feature of Hodgkin's lymphoma [1]. *HHV8* - **HHV8** is mainly associated with Kaposi's sarcoma and primary effusion lymphoma, not Hodgkin's lymphoma. - It typically affects immunocompromised individuals, especially those with HIV/AIDS, which differs from Hodgkin's lymphoma associations. *HHV6* - While **HHV6** can cause certain diseases like roseola in children, it is not linked to Hodgkin's lymphoma. - There is minimal evidence connecting it with lymphomagenesis in broader contexts. *CMV* - **Cytomegalovirus (CMV)** is primarily recognized for causing opportunistic infections, especially in immunocompromised patients. - Its association with Hodgkin's lymphoma is not substantiated, making it irrelevant in this context. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 616-618.

Q: E6 and E7 genes of which virus are implicated in oncogenesis?

HPV. ***HPV*** - The **E6** and **E7** oncoproteins of **High-Risk Human Papillomavirus (HPV)** are critical for oncogenesis, primarily in cervical cancer. - **E6** degrades the tumor suppressor protein **p53**, and **E7** inactivates the **retinoblastoma (Rb)** protein, leading to uncontrolled cell proliferation. *Cytomegalovirus (CMV)* - While CMV can be associated with certain cancers like glioblastoma, its direct role in oncogenesis does not involve specific E6/E7 genes. - CMV primarily causes opportunistic infections and congenital abnormalities, not through the mechanism of E6/E7. *Epstein-Barr Virus (EBV)* - EBV is associated with various cancers such as **nasopharyngeal carcinoma** and **Burkitt lymphoma**. - Its oncogenic mechanisms involve proteins like **LMP1** and **EBNA2**, which dysregulate cell growth, rather than E6/E7. *Human T-lymphotropic Virus type 1 (HTLV-1)* - HTLV-1 is the causative agent of **Adult T-cell Leukemia/Lymphoma (ATLL)**. - Its oncogenic potential is linked to the **Tax protein**, which alters gene expression and promotes T-cell proliferation, not through E6/E7.

Question 1

Which pox virus does Variola belong to?

Accepted Answer

Orthopoxvirus

Answer

Parapoxvirus

Answer

Yatapox virus

Answer

Molluscipox virus

Question 2

Which virus is implicated in Burkitt's lymphoma?

Accepted Answer

Epstein-Barr virus

Answer

Arbovirus

Answer

Picornavirus

Answer

Coxsackievirus

Question 3

All of the following are true about the papovavirus except:

Accepted Answer

They are RNA viruses.

Answer

Papovaviruses can produce papillomas in humans.

Answer

SV - 40 is oncogenic

Answer

They are non-enveloped icosahedral viruses

Question 4

The EBV receptor located on the surface of B cells is?

Accepted Answer

CD21

Answer

CD23

Answer

CD24

Answer

CD22

Question 5

Which virus characteristically reactivates in a dermatomal distribution?

Accepted Answer

Herpes zoster

Answer

Herpes simplex

Answer

Rotavirus

Answer

Influenza virus

Question 6

Which of the following is an RNA oncogenic virus?

Accepted Answer

Human T-lymphotropic Virus (HTLV)

Answer

Cytomegalovirus (CMV)

Answer

Hepatitis B Virus (HBV)

Answer

Human Immunodeficiency Virus (HIV)

Question 7

Which of the following statements about Norwalk virus is false?

Accepted Answer

Cultivated in cell culture

Answer

Is a RNA virus

Answer

Causes gastroenteritis

Answer

Belongs to Caliciviridae

Question 8

Viroids are characterized by which of the following?

Accepted Answer

Small, circular single-stranded RNA

Answer

Naked pathogenic human viruses

Answer

Fragments of viruses

Answer

DNA with protein coat

Question 9

Which virus is associated with Hodgkin's lymphoma?

Accepted Answer

Epstein-Barr virus (EBV)

Answer

Cytomegalovirus (CMV)

Answer

Human herpesvirus 8 (HHV8)

Answer

Human herpesvirus 6 (HHV6)

Question 10

E6 and E7 genes of which virus are implicated in oncogenesis?

Accepted Answer

HPV

Answer

Cytomegalovirus (CMV)

Answer

Epstein-Barr Virus (EBV)

Answer

Human T-lymphotropic Virus type 1 (HTLV-1)

Virology — MCQs

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