Virology Practice Questions

Q: A patient complains about painful blisters around the angle of mouth, identify the pathogen

Herpes Simplex Virus type 1 (HSV-1). ***Herpes Simplex Virus type 1 (HSV-1)*** - HSV-1 is the primary cause of **oral herpes**, commonly presenting as **cold sores** or **fever blisters** around the mouth [1]. - The characteristic painful blisters at the angle of the mouth are typical of **recurrent HSV-1 infection** [1]. *Coxsackievirus* - Coxsackievirus primarily causes **hand-foot-and-mouth disease** or **herpangina**, characterized by lesions on the hands, feet, and inside the mouth/throat, not typically painful blisters around the external angle of the mouth [2]. - It often presents with a **rash** and **fever** in children [2]. *Epstein-Barr Virus* - Epstein-Barr Virus (EBV) is the causative agent of **infectious mononucleosis**, which presents with **fatigue**, **fever**, **sore throat**, and **lymphadenopathy**. - It does not typically cause painful blisters around the mouth. *Varicella-Zoster Virus* - Varicella-Zoster Virus (VZV) causes **chickenpox** (primary infection) and **shingles** (reactivation) [3]. - While shingles can cause painful blisters, it typically follows a **dermatomal distribution** and is not localized to the angle of the mouth in this manner [3].

Q: Which viral infection is known to cause a condition resembling erythroblastosis?

Parvovirus B19. ***Parvovirus B19*** - **Parvovirus B19** has a specific tropism for **erythroid progenitor cells** in the bone marrow. - In the fetus, congenital infection causes **severe anemia** due to destruction of red blood cell precursors, leading to **hydrops fetalis** with massive compensatory erythropoiesis. - This results in circulating **nucleated red blood cells (erythroblasts)**, hepatosplenomegaly from extramedullary hematopoiesis, and severe anemia - a picture closely **resembling erythroblastosis fetalis**. - Unlike the immune-mediated hemolysis in Rh isoimmunization, parvovirus causes direct viral destruction of erythroid precursors with similar clinical manifestations. *CMV* - **Cytomegalovirus (CMV)** is the most common congenital infection and can cause hepatosplenomegaly, jaundice, and thrombocytopenia. - However, CMV typically causes **direct hyperbilirubinemia** from hepatocellular damage rather than the hemolytic anemia pattern seen in erythroblastosis. - While CMV can affect hematopoiesis, it does not characteristically produce the massive erythroblast response and hydrops pattern typical of erythroblastosis fetalis. *EBV* - **Epstein-Barr virus (EBV)** primarily causes **infectious mononucleosis** in older children and adults, with atypical lymphocytosis. - EBV is rare in neonates and does not cause fetal hydrops or an erythroblastosis-like syndrome. - Associated with lymphoproliferative disorders and post-transplant complications rather than fetal anemia. *HSV* - **Herpes simplex virus (HSV)** causes disseminated neonatal infection with encephalitis, hepatitis, and mucocutaneous lesions. - HSV does not have tropism for erythroid precursors and does not cause the anemia, hydrops, or erythroblastosis-like picture. - Typically acquired perinatally rather than causing congenital infection with hematologic manifestations.

Q: Coxsackievirus A16 is associated with which of the following conditions?

Hand-foot-mouth disease. ***Hand-foot-mouth disease*** - **Coxsackievirus A16** is one of the most common causative agents of **hand-foot-mouth disease**, characterized by fever, oral ulcers, and a rash on the hands and feet. - This viral infection is highly contagious and frequently seen in young children. *Herpangina* - While also caused by **Coxsackieviruses** (primarily **Coxsackievirus A** types like A10 or A2), **herpangina** typically presents with lesions restricted to the posterior oropharynx, without the characteristic hand and foot rash seen in HFMD. - It involves sudden onset of fever, sore throat, and small vesicles or ulcers on the **soft palate, tonsillar pillars, and uvula**. *Yellow fever* - **Yellow fever** is caused by the **yellow fever virus**, a flavivirus, and is transmitted by mosquitoes. - It presents with fever, jaundice, and hemorrhagic symptoms, completely distinct from enteroviral infections. *Myocarditis* - **Myocarditis** can be caused by various viruses, including other **enteroviruses** like **Coxsackievirus B** types (e.g., B1-B5), along with adenoviruses and parvovirus B19. - However, **Coxsackievirus A16** is not a primary cause of myocarditis; its association is predominantly with hand-foot-mouth disease.

Q: Rubella virus belongs to which family?

Togavirus. ***Togavirus*** - The **Rubella virus** is categorized under the family **Togaviridae**, specifically within the genus *Rubivirus*. - This classification is based on its genetic structure, being an **enveloped, positive-sense, single-stranded RNA virus**. *Rheovirus* - **Reoviruses** are characterized by a **double-stranded segmented RNA genome** and are typically non-enveloped. - This contrasts with Rubella's single-stranded, non-segmented RNA and enveloped structure. *Picornavirus* - **Picornaviruses** are a family of **non-enveloped, positive-sense, single-stranded RNA viruses** that are structurally different from Rubella. - Examples include species like **poliovirus** and **rhinovirus**, which do not share the distinct biological properties of Rubella. *Orthomyxovirus* - **Orthomyxoviruses** are a family of **enveloped, negative-sense, segmented RNA viruses**, which includes influenza viruses. - Their genomic organization and replication strategy are fundamentally different from those of the Rubella virus.

Q: Genital warts are caused by which virus?

Human Papillomavirus (HPV). ***Human Papillomavirus (HPV)*** - **HPV** is the causative agent of **genital warts**, which are benign epithelial growths. - Specific low-risk HPV types, primarily **HPV types 6 and 11**, are responsible for the vast majority of genital wart cases. *Herpes simplex virus (HSV)* - **HSV** causes **genital herpes**, characterized by painful blisters and ulcers, not warts. - There are two main types: **HSV-1** (often oral herpes) and **HSV-2** (primarily genital herpes). *Cytomegalovirus (CMV)* - **CMV** is a common virus that usually causes **asymptomatic infection** in healthy individuals but can lead to severe disease in immunocompromised patients or neonates. - It is not associated with the formation of genital warts. *Varicella zoster virus (VZV)* - **VZV** is responsible for **chickenpox** (varicella) in primary infection and **shingles** (herpes zoster) during reactivation. - It does not cause genital warts.

Q: What is the Australian antigen for hepatitis B?

HBsAg. ***HBsAg*** - **HBsAg** stands for **Hepatitis B surface antigen**, which was originally discovered by Baruch Blumberg in 1965 and was initially called the **Australia antigen** due to its discovery in the serum of an Australian aboriginal. - Its presence indicates an **active hepatitis B infection**, either acute or chronic. *HBeAg* - **HBeAg** (Hepatitis B e-antigen) is a marker of **viral replication** and **infectivity**. - It is distinct from HBsAg and indicates a high level of **transmissibility** of the virus. *HBDAg* - **HBDAg** is not a standard or recognized antigen for hepatitis B. - The correct antigen for hepatitis D is **HDAg** (Hepatitis D antigen), which is only found in individuals co-infected with hepatitis D virus and hepatitis B virus. *HBV DNA* - **HBV DNA** refers to the viral genetic material of the hepatitis B virus. - While its presence indicates active viral replication and is used to monitor **viral load**, it is not an antigen but rather the **viral genome** itself.

Q: Acute Hemorrhagic Conjunctivitis is primarily caused by which type of Enterovirus?

Enterovirus type 70. ***Enterovirus type 70*** - **Enterovirus type 70** is the most common cause of **Acute Hemorrhagic Conjunctivitis (AHC)**, particularly in epidemic outbreaks. - AHC presents with rapid onset of **ocular pain**, **redness**, **swelling**, and **subconjunctival hemorrhages**. *Enterovirus type 68* - **Enterovirus D68 (EV-D68)** is primarily known for causing **respiratory illnesses**, ranging from mild to severe, and is associated with acute flaccid myelitis. - While it can cause respiratory symptoms, it is not a primary cause of **Acute Hemorrhagic Conjunctivitis**. *Enterovirus type 69* - **Enterovirus type 69** is a rare serotype and is not typically associated with specific human diseases or large-scale outbreaks. - Unlike EV70, it is not recognized as a significant cause of **conjunctivitis**. *Enterovirus type 71* - **Enterovirus A71 (EV-A71)** is a common cause of **hand, foot, and mouth disease (HFMD)**, especially in children, and can also lead to severe neurological complications. - While it causes various infections, it is not the primary cause of **hemorrhagic conjunctivitis**.

Q: Von Magnus phenomenon:

Virus yields have high hemagglutination but low infectivity. ***Virus yields have high hemagglutination but low infectivity*** - The **von Magnus phenomenon** describes the serial passaging of influenza virus at high multiplicity of infection, leading to the production of **defective interfering particles (DIPs)**. - These DIPs retain their ability to **hemagglutinate** (due to intact hemagglutinin proteins) but have lost significant portions of their genome, resulting in **low infectivity**. *Is a normal replicative cycle* - The von Magnus phenomenon is characterized by an **abnormal replicative cycle** and the accumulation of defective viral particles. - A normal replicative cycle involves the production of **fully infectious** viral progeny. *Virus yield has low hemagglutination* - The abnormal particles produced during the von Magnus phenomenon, known as **defective interfering particles (DIPs)**, typically retain their **hemagglutinin protein**. - This allows them to still induce **hemagglutination**, despite their reduced infectivity. *Virus has high infectivity* - A hallmark of the von Magnus phenomenon is the production of virus particles with **significantly reduced infectivity**. - This is due to the deletion or mutation of essential genetic material necessary for a productive infection.

Q: Which of the following statements about paramyxoviruses is false?

Are DNA viruses. ***Are DNA viruses*** - Paramyxoviruses are characterized by their **single-stranded, negative-sense RNA genome**, not DNA. - Their replication and transcription processes occur in the cytoplasm, which is typical for RNA viruses. *Belong to the family Paramyxoviridae* - This statement is correct; paramyxoviruses are indeed classified under the **family Paramyxoviridae**. - This family includes important human pathogens like measles, mumps, and respiratory syncytial virus (RSV). *Have linear nucleic acid* - This statement is correct as paramyxoviruses possess a **linear, non-segmented RNA genome**. - The linear nature differentiates them from viruses with segmented genomes, such as influenza viruses. *Are RNA viruses* - This statement is correct; paramyxoviruses are characterized by their **RNA genome**. - Specifically, they are **negative-sense, single-stranded RNA viruses**.

Q: What is a potential outcome of the integration of a viral genome into a host cell chromosome?

All of the options. ***All of the options*** - The insertion of a viral genome, known as a **provirus**, into the host chromosome can lead to a variety of sustained and complex interactions. - This integration can cause **long-term changes** in cell behavior, including altered gene expression and cell cycle regulation, which may manifest as any of the specified outcomes. *Malignancy* - Viral integration can interrupt or activate host genes, such as **oncogenes** or **tumor suppressor genes**, leading to uncontrolled cell proliferation and potential tumor formation. - An example is **human papillomavirus (HPV)** integrating into host cells, increasing the risk of cervical cancer. *Altered growth* - Integration can change the cell's normal growth patterns, either by promoting excessive division or by causing cell cycle arrest, impacting tissue development and function. - This can be due to the insertion of viral promoters or enhancers near growth-regulating genes. *Latency* - The integrated viral genome can remain dormant within the host chromosome without producing new viral particles for extended periods, a state known as **latency**. - During latency, the virus can be reactivated later to cause a productive infection, as seen with **herpesviruses**.

Question 1

A patient complains about painful blisters around the angle of mouth, identify the pathogen

Accepted Answer

Herpes Simplex Virus type 1 (HSV-1)

Answer

Coxsackievirus

Answer

Epstein-Barr Virus

Answer

Varicella-Zoster Virus

Question 2

Which viral infection is known to cause a condition resembling erythroblastosis?

Accepted Answer

Parvovirus B19

Answer

EBV

Answer

CMV

Answer

HSV

Question 3

Coxsackievirus A16 is associated with which of the following conditions?

Accepted Answer

Hand-foot-mouth disease

Answer

Herpangina

Answer

Yellow fever

Answer

Myocarditis

Question 4

Rubella virus belongs to which family?

Accepted Answer

Togavirus

Answer

Orthomyxovirus

Answer

Rheovirus

Answer

Picornavirus

Question 5

Genital warts are caused by which virus?

Accepted Answer

Human Papillomavirus (HPV)

Answer

Cytomegalovirus (CMV)

Answer

Herpes simplex virus (HSV)

Answer

Varicella zoster virus (VZV)

Question 6

What is the Australian antigen for hepatitis B?

Accepted Answer

HBsAg

Answer

HBeAg

Answer

HBDAg

Answer

HBV DNA

Question 7

Acute Hemorrhagic Conjunctivitis is primarily caused by which type of Enterovirus?

Accepted Answer

Enterovirus type 70

Answer

Enterovirus type 68

Answer

Enterovirus type 69

Answer

Enterovirus type 71

Question 8

Von Magnus phenomenon:

Accepted Answer

Virus yields have high hemagglutination but low infectivity

Answer

Virus has high infectivity

Answer

Is a normal replicative cycle

Answer

Virus yield has low hemagglutination

Question 9

Which of the following statements about paramyxoviruses is false?

Accepted Answer

Are DNA viruses

Answer

Belong to the family Paramyxoviridae

Answer

Are RNA viruses

Answer

Have linear nucleic acid

Question 10

What is a potential outcome of the integration of a viral genome into a host cell chromosome?

Accepted Answer

All of the options

Answer

Altered growth

Answer

Malignancy

Answer

Latency

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